31 Dec 2013

Logging into a Windows PC and 10m WSPR

When I came to log in on my old (lab) Windows XP PC today it was a nightmare. Firstly it had not been used for almost 4 months and refused to bring up the log-in page. Then I'd forgotten my log-in details: even my old hint did not help. In the end after many attempts all was sorted but what a struggle with my poor addled brain currently. I've even made a small start on the tax return online. At the moment I am making lots of typos on the PC and everything takes twice as long as it did.

 I've started WSPRing on 10m for the first time since September! My old life is slowly returning, thank God. Not bad reports too.

Initial 10m WSPR reports with 2W out

Release Date

The latest news from Addenbrooke's Hospital is I should be  home for good by Jan 6th. After that, apart from continuing to get better, I hope to buy a new rig and do my on-line tax return! Expect blogging proper again within a week or so. I continue to slowly improve on all fronts but find I am making lots of errors typing on the PC still.

Currently on 2 days' home leave over New Year (1 night at home) but have to return to hospital by 5pm Wednesday.

11 Dec 2013

IC7100 from Icom

When it comes to new 100W HF rigs the new IC7100 looks to be relatively good value at just under £1300 in the UK. This includes 4m and 70 cm coverage and DSTAR. I am a little skeptical about the clarity of the LCD touchscreen display.  Other good rigs don't cover 4m or bands above 6m.I am still tempted when I get " released" from my hospital prison. My heart is still in QRP but the Elecraft KX3 is a similar price with  just 8-10W,fewer bands and arguably less well suited to base station digital use. We'll have to see when I get out of my hospital  "prison". I may just buy a second FT817 and another auto ATU. 

9 Dec 2013

Books

The last few weeks has seen me devouring a number of novels to kill the monotony of being in hospital still. Latest estimates are mid January for going home ,when I hope to be able to swallow some soft foods. Books read include:

"Oranges are not the only fruit" by Janice Winterton
"Night Fire" by Ken Follett
"Eye of the Needle "
"The Girl with the Dragon Tattoo " by Stieg Larsson

At the moment it takes about 3 days for a 560 page book. I am REALLY looking forward to going home when the ham radio blogging can resume.

Interestingly, I have read very few amateur radio books apart from  1 QST and a few RadComs and PWs. So far I have had visits  from around 45 people including a few local hams. My brother has raised over £1000 for the charity "Headway" as a result of my bleed on the brain.

1 Dec 2013

Latest Health News

All being well, I should get home from hospital for brief home visit within the next 3 weeks. Thereafter, the is a good chance of getting home for good, probably in January. I still cannot eat or drink normally but I can do the excercises to improve my swallow as well at home as in hospital. My walking is wobbly on a walking frame, but getting better, and my writing and speech are a mess still, but also heading in the right direction. Being at home will be so much better after around 4 months in hospital wards. Physically I can see and hear well, my  memory seems to be maily intact, so  I have lots to be grateful for. The facilities lacking should work eventually. A good chance of more "normal service" on the amateur radio blog  from mid-January.

In the meantime my brother John  has raised almost £1000 for the brain injury charity Headway. I cannot thank hi  enough. My continued thanks for all donations including some very large donations from my American friends. This has been a very long haul personally and a big reminder how precious normal, everyday life is. We take everything for granted whereas we need to remind ourselves just  how wonderful everything is.

27 Nov 2013

Health "progress"

Got told today that my swallow response is not progressing and it is possible I may NEVER be able to eat normally. I have been given a series of exercises aimed at helping to correctly position the larynx.Only lots of time will tell.

My return home full time is likely to be in the new year after more therapy on my walking and writing.All the hard word on speech would be at home.

13 Nov 2013

8 plus weeks and still in hospital

Sorry that my stroke is still making the hardest job near impossible. This has taken 10 minutes.

16 Sep 2013

In hospital -bleed on the brain

At the weekend I was rushed into Addenbrookes hospital with excruciating headaches and punch drunk legs. After CAT and MRI scan they have confirmed it was a bleed on the brian from a blood vessel in the cerebellum which is being dispersed with drugs and can be treated. Service and care has been excellent at NHS Cambridge. We are lucky to have a world class hospital so close to us.

13 Sep 2013

Optical forward scatter and frequency?

Perhaps some of my readers can help me - what optical frequency is likely to be best for forward scatter off air molecules and dust particles? My tests to date have been over non line-of sight paths up to about 9km at 481THz (red light), but IR should work in daylight with filtered PIN diodes on RX, but I don't know whether infra-red frequencies scatter more easily or worse than red light?  With red light, the RX can easily be de-sensitised by bright sunlight, and this should be (?) less of an issue with filtered IR detectors, I think.

As the atmosphere scatters blue light very well (giving it a blue colour) one might expect IR to scatter less well than shorter wavelengths like visible red or ultra-violet? See http://en.wikipedia.org/wiki/Atmosphere_of_Earth .

On 472kHz again this evening and future plans

In the next few days I need to buy some more wire and coax to continue my antenna experiments. The first thing I shall be trying is the larger "in the air" TX loop for the LF and MF bands - probably 136kHz , 472kHz and 1.8MHz coverage. The lower part of the loop can be several strands of PVC covered wire or coax in parallel to reduce resistive losses but the "up in the air" part will have to be 1mm diameter to avoid sag and being visible to the neighbours. I think I should be able to increase the loop area by 50% and reduce the wire losses by about 50%, so there should be a useful increase in ERP. This could be some weeks away though.

In the meantime I am continuing to TX and RX on 472kHz WSPR with the odd shape loop I currently have running along the garden fence and back along the surface of the lawn. It works, but as I said yesterday, it is some dB below what I can achieve in my small back garden whilst maintaining low visual impact to avoid neighbour issues.

After confirming the performance with the larger loop in the coming weeks, I shall try a short Marconi vertical to compare results - better omni coverage expected, but may not be as effective as the loop in the best directions?

After that, I shall probably be returning to 481THz and infra-red frequencies for more over the horizon scatter tests. I particularly want to try some IR scatter tests in daylight as I find going out on dark nights unpleasant.

World's oldest photographs

As I have come down with a bug of some sort, feeling light-headed and with a headache, I've been sleeping a lot today and not doing too much. My 472kHz WSPR has been running periodically.

Sitting here this afternoon, I chanced on this interesting YouTube video showing the world's earliest photos. Fascinating to look at - see http://www.youtube.com/watch?v=3LkaFCa29mQ .

You may also like The World's 10 Most Mysterious Photos - see http://www.youtube.com/watch?v=E7Cd5FWMusE.

12 Sep 2013

472kHz (630m) WSPR experiment results

Comparing the loop in the air against the simple earth electrode (EE) antenna across the garden these are the results. Remember the loop could be improved by making it larger, using thicker wire and mounting it more fully vertical.

G4KPX - about 6dB better on loop
G6AVK - little difference
PA3ABK/2 - 1-3dB better on loop
G8HUH - little difference
M0PPP - copied on loop, no copy on EE
G3WCB - just copied on EE, no copy on loop

Conclusions?  Well the loop, as it currently is arranged, is a bit better than the EE antenna by a few dB, in some directions, but not amazingly so. Will try a loop up in the air more in the coming weeks and we'll compare results again.

TXing tonight with a 472kHz "in the air" loop

As the next stage in my experiments from the new QTH at LF and MF, this afternoon I converted my earth-electrode antenna into a complete "in the air" loop by removing the earth connections and joining the wires with a length of wire along the grass. The DC resistance of the loop is 0.9ohms and the enclosed area somewhere around 60-100 sq m although the loop is far from vertical and the bottom wire actually runs along the grass rather than up in the air. The measured loop current is around 0.9A and tuning very sharp with around 1.7nF in series and matched with a 3C90 step down transformer. According to my calculations of radiation resistance, the ERP should be in the 20-40mW region, considerably greater than with the earth-electrode antenna.
630m WSPR spots of G3XBM so far this evening
My first report this evening was from PA3ABK/2  at -28dB S/N but I am hopeful of a few more 472kHz spots tonight. I expect that the results with the loop will be better than with the earth-electrode system, but the loop can be further improved by raising the upper wire (bigger vertical enclosed loop area) and thickening up the lower wire to reduce resistive losses further.

I am doing things one step at a time so I can assess the difference.

UPDATE 1800z:  M0PPP has spotted me several times this evening but had failed to copy me in the last 2 weeks, so this is encouraging. Also reports from G8HUH and G6AVK.

10 Sep 2013

More 10m WSPR

With the weather miserable here today - I just managed to cut the grass before the rain set in - I went on 10m WSPR mid-afternoon to see what was doing. With 2W I got a couple of reports from 4X1RF at 3519km at -3 and 0dB S/N, which is VERY strong, but nothing else so far.

This evening, I hope to be WSPRing on 472kHz again (using the original earth-electrode arrangement still) whilst we entertain my brother and his wife. They are coming to stay for a few days. I shall be checking results periodically using my iPod Touch monitoring the WSPRnet database in between drinks and eating dinner.

POSTSCRIPT: I was just about to QSY away from 10m when I noticed I had spotted K3NAL at 5930km. At the time of writing, I seem to be the only European station copying him. Maybe I shall stay on 10m a little longer this afternoon, or perhaps try 10m PSK31 for some QSOs. 10m is another "magic band". Less so at the peak of the cycle but often open to distant places when not expected and definitely under-used in the quiet solar years.  

9 Sep 2013

472kHz - 7 unique WSPR reports so far on earth-electrode antenna


Although not working as well as I had hoped, my very simple earth-electrode antenna is getting WSPR reports. As of this evening, I have been spotted by 7 unique stations so far. Results remind me of my first efforts on 500kHz with a simple wire down the garden some years back. My ERP then was in the uW range and this may well be the sort of ERP I am actually using now currently. A better antenna IS a must!

First 10m spot from the new QTH + more on 20m

Today I ran WSPR on 10m to see what propagation was like. Although European stations further south were catching N-S openings trans-equatorial openings and even VK6, it was harder going from here in the UK and I only managed 1 spot with 2W and that was from 4X1RF - thank you.

Back on 20m it was a different story where I had a huge number of reports from places including KL7L in Alaska,  with just 500mW to the Par EF-10/20/40 antenna. 20m is always a good bet, although not one of my usual favourite bands.

As the autumn progresses I hope 10m will come back to life again. Conditions should be excellent in October and November with still decent sunspot numbers and of course the big CQWW DX contests to add to the activity levels. By autumn next year things will certainly be on the slide down to the next minimum, but the slope down is gradual and conditions can remain decent for several more years yet.

I really must get the full transceiver version of my 10m WISPY WSPR rig boxed up so I can free up the FT817 to do other things.

8 Sep 2013

Earth-electrode antenna for 472kHz in the new garden - not too brilliant

After trying a number of different orientations of earth-electrode pairs in my garden, I have come to the conclusion that this antenna structure does not work very well here in the new QTH. I am a little surprised as the earth-electrode antenna worked well just 350m away at the old QTH. Whatever orientation I try I seem to be always in the -22 to -28dB S/N region with G6AVK 78km away.

Why is it not so good? Well, the most likely answer is that the effective distance between the far and near ground rod electrodes is smaller, even with a similar physical separation. This could be because of buried water pipes and utilities criss-crossing the garden, although I wasn't aware of any, or different soil/rock conditions, although the chalk layer is about as far down here as at the old QTH and the soil is a similar alkaline sort. The fact that the 8.97kHz earth-mode results were so poor last week rather hinted at a problem that was not present at the old QTH.
 
I haven't quite exhausted every layout possible in  my strange shaped back garden, so there are more things to try with earth-electrodes, but it is looking like I shall have to erect a short Marconi or a fully in the air loop antenna to get better ERP on 472kHz. On my previous tests at the old QTH, a full in the air loop with 1mm diameter wire and an enclosed area of around 80m sq was around 8dB better than the earth-electrode antenna, but far more critical to tune and match because of the hi-Q. If my earth-electrode antenna is several dB down on the performance of the same structure at the old QTH then I could be expecting >10dB improvement or even more.

Half the fun is the testing and finding out what does and does not work.  The coming week we have visitors staying, so not too much time to experiment. I shall have to stick to WSPRing on 20 and 10m.

Portuguese Lesser Chirpy 10m transceiver

CT5JZX version of the Lesser Chirpy transceiver for 10m CW
In an email from CT5JZX, Pedro tells me he has made a version of my Lesser Chirpy 10m QRP CW transceiver. He has already received some beacons with it - he only has a crystal in the beacon part of the band at present - and hopes to TX with it soon when he has some other crystals. He has made a neat job of it in the plastic casing.

It is some time since I fired mine up and currently it is in a box in the loft after my recent QTH move.

VK on 20m WSPR this morning


5 VK (Australian) spots in the very first transmission slot
Whilst waiting for the bathwater to fill, I went on 20m WSPR this morning with the Par 40/20/10 end-fed antenna to see what was about. To my amazement I got no less than 4 VK reports (Australia) in the first transmission plus a lot of other reports too. The little antenna down the garden is certainly working just fine.

7 Sep 2013

2m contest this weekend

After several PSK31 QSOs on 20m, I returned to 2m SSB to see what was doing in the contest running this weekend. First impressions are there are far fewer stations active than last Tuesday evening in the UKAC contest. I have worked a few stations using 5W and the halo but so far only JO01, JO02 and IO92 squares i.e. not that far away.

.....me thinks it is time to QSY to 472kHz WSPR and watch the TV, HI.

First PSK31 QSO from new QTH


E74DO in his shack
After a little while on WSPR I decided to try PSK31 on 20m running 2W to the Par antenna. I replied to a CQ from E74DO and got a 599 report. PSK31 is not a mode I too much like, but it does work when the band is busy and with QRP.

A little later (1646z) I had a nice PSK31 QSO with Svan TF3FIN in Reykavik on 20m.

HF antenna erected at new QTH

This afternoon, I strung out my Par 40/20/10 horizontal end-fed HF antenna for 40, 20 and 10m from the base of my V2000 vertical to a tall branch of the silver birch tree at the end of my garden. Being a bungalow, the height is nothing great at around 4m above ground average. Match is excellent on 10m and 20m but the end wants trimming a few cm to improve the match on 40m.

I have just started WSPR beaconing at 1W on 20m to see how it performs and on the first transmission was spotted by N6RFM, LA6TPA, LA9JO and 4X1RF with reasonable reports. So, initial results look OK.

This now means I have the following TX capability from the new QTH:

(1) 630m - earth-electrode antenna
(2) 40, 20 and 10m HF - Par 40/20/10 antenna
(3) 6, 2 and 70cm - VHF/UHF V2000 vertical
(4) 2m - horizontal halo antenna
(5) 481THz optical - 110mm lens TX

All these antennas are unobtrusive and neighbour friendly. Now let me see how soon I can achieve QRP DXCC from this new QTH.

Experimenting will mean these antennas will come and go.

6 Sep 2013

472kHz - next steps

Ok, so after several more hours I am still getting WSPR spots from just G4KPX and G6AVK. Clearly the ERP with the present earth-electrode set-up in the new garden is in the low uW region only.

I'm going to try to string up a full wire loop for TX and see how this performs. I have a couple of options: (1) a thickish wire loop along the fence made from coax cable about 10m x 2m, or (2) a 1mm diameter PVC coated wire loop with a larger enclosed area. The former would be totally hidden and, because of the higher Q, may perform as well as the larger loop with thinner wire. The former is worth trying as it would be a very "stealth" antenna, totally invisible to neighbours ....and the XYL.

472kHz experiments continued

In my narrower, but wider, garden, I am still trying to work out the best layout for an earth-electrode antenna for 472kHz.

Today I started by trying to find out about the ground connections at the house end, measuring the resistance between various radiators and the mains ground to see which ones had a direct copper connection to a good ground. The answer is none! All the radiators seem to be connected with plastic pipes in the roof. The only direct "copper to ground" connections found in my water system were in the airing cupboard, the kitchen taps and the utility room taps.

The other tests (ongoing) are to a different remote ground further up the side of the garden, further from the shack but not further from the house. I am trying to see if this gives, effectively, a longer earth-electrode baseline between ground points.

So far this evening, with the (perhaps) slightly longer baseline, I am getting consistent reports from G6AVK (78km) but no-one else yet. As best I can judge, reports are very similar to those with the earlier grounding arrangements.  PA3ABK is a very strong signal at -6dB S/N.

5 Sep 2013

First 8.976kHz VLF earth-mode tests from the new QTH

This evening, I did a couple of tests on 8.976kHz earth-mode from the new QTH with my 5W beacon TX. Initially I used the far earth rod about 12m from the house paired with a mains ground and set out on my travels with my loop to my usual first test site just outside the village. This is a car park for the Devil's Dyke walk. Unfortunately the car park has been invaded by gypsies, so I decided to move on to my next test site in the village of Reach (2km). Nothing at all was copied of my beacon.

Then I returned home and used the mysterious copper rod that goes into the ground just outside my shack as the local ground and still keeping the ground rod 12m away as the "far" electrode. I think this may have at one time been an oil pipe from a central heating oil tank. I have no idea where it goes. This earth-electrode pair has launched my 472kHz WSPR signal which has been copied in Belgium and Holland, but results have been disappointing, so I was not expecting much on 8.976kHz.

Rather than travel 2km, I parked outside my old QTH about 0.35km away in the village. My 8.976kHz signals were copied, but not very strongly. I suspect that this was true earth-mode without any real assistance from utilities as I do not believe either ground rod at the TX end is coupled to utilities grounds or copper pipes going into the road.
Weak signals over a 0.35km path

Path tested this evening plotted with Google Earth
Conclusions so far are that both for VLF earth-mode work and for 472 and 136kHz radiated work I need to much improve the earth-electrode arrangement in my garden to get credible results. I need to do some sort of mapping of the garden to see where would result in a good solid connection to copper water pipes going into the road (probably at the outside copper tap) and the best place to locate the "far" electrode as far away from the house (and other houses) and buried pipes as possible.

Loop preamp

After some thought I'm almost certain now to buy a Wellbrook RX loop for use on 136 and 472kHz receive. This loop will also be useful for a number of other applications such as 160m and 80m monitoring and possibly some VLF work.

The ALA1530LF looks perfect for the task being able to cover 20kHz to 30MHz with excellent IP2 and IP3 performance. One concern is that a receiver is being hit with signals from right across the spectrum: although the loop preamp itself will not fall over, the receiver after it might. So, I think a small, high dynamic range tuned preamp with a few dB of gain may be needed ahead of the receiver.  The additional gain may be needed as many HF rigs have poor LF and VLF sensitivity.

A simple preamp is easy to design for either 136 and 472kHz bands. Something along these lines (see below) should be suitable for 472kHz reception. I'm not actually sure that the ceramic filter will be needed: just the single hi-Q tuned circuit on the input may be enough to protect the subsequent RX from being blasted with everything.

Bitsbox - excellent service yet again

www.bitsbox.co.uk
A couple of days ago I realised I needed a few tools to help me: a "helping hands" clip to hold PCBs and breadboards whilst soldering, a desoldering tool, some trimming tools, more solder, switches etc. So, I placed an order with Bitsbox, a small UK supplier I've used before. The order was easy to place, a Paypal payment was accepted and the order received very quickly indeed with a low fixed price for delivery by first class post. They have a good range of parts in stock and their service has always been first class. I can highly recommend Bitsbox if you need a few bits for your amateur radio hobby.

3 Sep 2013

2m UKAC this evening with QRP and a halo


Stations worked on 2m SSB with 5W and halo tonight
After 90 minutes of 2m contesting this evening I decided to QSY to 472kHz WSPR even though there was another hour to go.  The contest was my first from the new QTH running 5W into the 2m halo on the roof. In all I managed 12 QSOs with the best DX GW4FZN/P near Bala at 272km. Best DX heard was G4PPT/M in IO70 near Penzance, Cornwall.

The RSGB UK Activity Contests are every Tuesday evening on different VHF/UHF bands each week of the month. Great fun for an hour or so and well supported.

Early morning 6m Es opening

After breakfast I checked 6m beacons this morning at around 0730z and was surprised to hear IW3FZQ/B and YU1EO/B coming through marginally. I then went on to work YL3IQ in KO17OD square at 599 each way on 5W CW at 0736z. Conditions on 6m are still good at times, and surprisingly at such an early time so late in the sporadic-E season. Currently WSPRing on 6m but only UK spots this lunchtime.

2 Sep 2013

3 countries now on 472kHz WSPR with short earth-electrode antenna

Limited success this evening on 472kHz with the earth-electrode antenna with the copper pipe grounding at the house end. Reports from G8HUH, OR7T and PA3ABK/2 this evening, but I am left feeling that results are still some 6-10dB down on at the last QTH. The system is far from optimised yet though.

Tomorrow evening I will have a go at the 2m UKAC contest with the halo but hope to try some different antenna arrangements on 472kHz later in the week. So far 6 unique station reports on 472kHz WSPR in 6 different QTH locator squares. I do feel that a better antenna is needed, somehow!

VHF tropo (non ducting) history

Whilst trying to locate an up-to-date list of VHF 2m beacons I am likely to be able to copy here on a halo, I chanced upon a site with a history of non-ducting tropo (NDT) going back to the work by Marconi in the 1920s and 1930s. See http://www.quercus.demon.co.uk/thistory.html. Interesting reading.

2m halo added to VHF/UHF antennas

This morning, whilst waiting for the Virgin Media installers to arrive, I added the 2m halo to the mast supporting my V2000 6/2/70cms vertical, allowing me horizontal 2m operation again. The picture shows the antenna on the gable end of the bungalow.
V2000 and 2m halo antenna installed
I have also been trying a different ground point for the 472kHz earth-electrode system at the house end. I shall have to wait until this evening to try this. Current into the loop is higher, so I hope performance will be a bit better.

The second picture was the sunset last night as seen from the shack window. It was beautiful.

GB3VHF on the halo

1 Sep 2013

Removing earth rods?

At my old QTH I have 3 solid copper earth rods driven in about 0.8m into the soil. Does anyone have any recommendations on how to remove these please? They are pretty solidly embedded in the soil but it would be good to be able to reuse these at the new QTH as solid copper earth rods are not cheap.

Initial results on 472kHz at the new QTH

Well, I have been WSPR beaconing over a period of about 24 hours at the new QTH on 472kHz. Actual operating time has been just a few hours this evening and last night plus a little bit this morning. Based on the (limited) reports received - just from G6AVK (78km), G3WCB (101km) and G4KPX (14km) and no-one else despite quite a bit of activity - I think the earth electrode antenna is some dB down compared with results "down the hill" at the old location.  On RX, the noise level here is lower using the earth electrode antenna but that may also suggest less efficiency - less signals and less noise being picked up. Having said that, I have spotted stations never seen before (I think) such as G3WCB and have spotted a couple of PA stations.
The QRP operating kit in the shack
The reasons for the poorer performance could be the shorter baseline or the directionality is such that my usual reporters are getting a weaker signal. It may also be due to the use of the mains earth at the shack end and not the copper central heating piping: some of my central heating piping here is plastic, so grounding to the radiator in the shack does not guarantee a good low loss ground! At the old QTH all the central heating pipes were copper and the copper extended into the road.  I need to do a test with a fairly local station to see how signals compare such as G4HJW although I am not sure Bernie is still on 472kHz currently.

So, conclusions so far? Mixed and a little disappointing, but it is early days and lots to try still.

31 Aug 2013

M0UKD's version of my 472kHz transverter

It is always pleasing to see other versions of my designs being successfully built. This evening I chanced upon M0UKD's website showing his nice version of my 472kHz transverter. He added an output for a frequency counter which is a useful addition. John gets around 12W out, which is about right.

MS Essentials

My wife's PC just flagged up that its McAfee anti-virus protection runs out in 15 days time. Rather than renew it I decided to uninstall the entire McAfee suite of programs and instead install the FREE MS Essentials protection program. I have this on my own PCs and, as far as I can tell, it seems to protect them pretty effectively.  Like others have found, MS Essentials runs in the background in an unobtrusive way without undue overhead.

50 nanowatts ERP tests on 70cms FM

This afternoon I did a quick test using my signal generator on 432.975kHz FM using my V2000 vertical. I put up a 50nW ERP FM signal with a 1kHz tone and looked for the RX signal on my little VX3 hand portable with its tiny helical antenna at my old QTH some 300m away from the new location. Although unable to copy the signal downstairs, the signal was S3 in the old shack upstairs. Based on this test with a pretty inefficient RX antenna, I think the 10nW signal would be copyable around 1-2km away with a mag-mount on the car. It goes to show how far QRM can travel.

Back on 472kHz WSPR and 8.97kHz

This afternoon, I put my earth-electrode antenna in the garden at the new QTH with the remote electrode against the far fence and the local ground connected to the mains ground in the shack. Check your mains earthing before trying this. Separation is about 15m i.e. a little less than at the old location. On 8.97kHz the current into the ground looks about right and the TX current similar to that at the old QTH. On 472kHz the match seems a little different but I have had several spots from G6AVK at 78km when using low milliwatts ERP. I need to optimise the match on 472kHz.

I am now going to try the earth-electrode antenna on 160m and 80m. All being well I'll do a remote RX test on 8.97kHz to see how my VLF beacon compares.

30 Aug 2013

Shack pic

Well today I completed the set-up of my "building desk" in the new shack. After several weeks out of action, I am now ready again to start building gear. For the first time my desk for building kit is in the same room as the operating position, so I can readily test gear "on-air" by simply connecting a coax cable or wire. This image is not very good quality I am afraid.

Late summer Es on 6m

It is getting later in the sporadic E season but there are still plenty of openings to be enjoyed. As I have yet to erect any antennas for the HF bands at the new QTH, I have been listening and working stations on 6m. This week without much operating time I have managed to find a couple of Es openings that have allowed me to work into HA, I, EA5, EA6 (Menorca) and EA7 on 2W SSB or CW to the V2000 vertical.

Using my 3G dongle to provide an internet connection (roll on Sept 2nd and my Virgin Media connection - I hope) I've also been WSPRing on 6m but so far just a few UK spots received.

29 Aug 2013

Our windmill

Just across our front garden wall we have a windmill that is almost 200 years old. It is currently undergoing a complete renovation with new cap, 4 new sails, new external rendering and lots of work inside too. Today, a 60 ton crane lifted the newly renovated (6 ton) cap onto the top of the windmill.

In the next couple of months the 4 sails go back on. The video was shot out of my lounge window today. When fully restored it will be well worth a visit as is a visit to our local museum next door.

From an amateur radio perspective the windmill will be a perfect aiming point for optical comms as it is about 20m from my shack. I suspect it will act as a good reflector for microwaves too.

See http://www.burwellmuseum.org.uk.btck.co.uk/StevensMill for more information.

28 Aug 2013

More antenna progress at the new QTH

After having our little grandchildren stay for 6 days (without their parents) the new home has now returned to normal (i.e. tidy) and all the toys have been put away, mine excepted! So, apart from sorting out and decorating the old QTH, my thoughts are increasingly turning to the autumn ham projects again.

I've just collected my Par 10/20/40 end-fed HF antenna and a 1m solid copper ground rod from the old QTH with the aim of erecting the former and pounding in the latter in the next few days. The Par antenna will allow me to get active on some of the HF bands. The earth rod will form the far end of my new earth electrode pair "antenna" which will be used for a series of tests on 8.97, 136 and 472kHz from the new garden. My 8.97kHz beacon can be fired up in QRSS quite easily so RX tests out in the fens can start as soon as the earth-electrode antenna is ready. It will be fascinating to see how this compares at the new QTH.

My big wheel for 2m has still to be procured or made and erected. When this is in place I shall try some QRP weak signal work as mentioned before.

Something else I want to do is some tests locally on 6, 2 and 70cm using a signal generator connected to my V2000 antenna. Tests with G6ALB suggest just a few uW are enough to reach the next village. So I was wondering what the coverage to a mobile would be like locally with, say, 10uW from my generator? A drive-around test in all directions might be fun.

We are still waiting for Virgin Media internet and home phone access though - due Sept 2nd - to allow proper WSPR tests to begin. I bought a 3G wi-fi dongle with 3GB of data which is being used as a stop-gap. WSPR is my mode of choice when testing new antennas or new set-ups as the internet database (near instant) feedback gives a very good idea of how things are working.

Belgium on 472kHz

Rik Strobbe ON7YD reports that some Belgian amateur classes (holders of a HAREC licence) now have access to the 472kHz band with 5W EIRP and without mode restrictions. Unfortunately Rik's PA failed on TX on the new band and is having to rely instead on a 6W transverter for now with just 20mW ERP.

22 Aug 2013

V2000 erected and first QSOs on 6, 2 and 70cms from new QTH

On Tuesday I completed the erection of my tri-band colinear at the new QTH and carried out some tests over a 3km path to G6ALB to see how results compared between my old and new QTH on 6, 2 and 70cms. I was expecting results "on the hill" to be somewhat better, but in actual fact over this short path the results were identical within the limits of experimental error. Andrew put in various levels of attenuation to see how low he could go and still copy me. On 2m for example he could put in 43dB attenuation and still just copy me. 43dB is an attenuation of 20000 times suggesting just a few uW is enough to cover this distance.

Yesterday morning I was able to work through the Welwyn Garden City 70cm repeater, although conditions were up a bit. Last night I worked several I and HA stations on 6m SSB and CW during an unexpected Es opening, getting good reports with my 5W.  Conclusion so far: the antenna works fine.

I am now considering that big-wheel for 2m on the same mast. I am looking forward to working some SSB/CW stations again on 2m.

17 Aug 2013

Assembling the new shack

Today I started to collect all the remaining kit from the old building shack and set it up in the new QTH.  The large pieces of test gear are the easy bit. It is all the boxes and bags of "these might come in handy some day" components and crystals that are the problem. Also wire: I have so many reels of "useful" wire! My plan is to continue this over the weekend and get most of the useful stuff moved and other, less useful, kit boxed and stored in a box should I ever need it.  I am really hoping that I can be a lot better organised going forwards. Once I start an electronics building project the workbench goes from orderly to chaos very quickly!

When I was an RF engineer (not a very good one BTW) we used to keep resistors and capacitors in little open topped brown envelopes in a box on the bench. This worked very well and was easier and less space intensive that racks of storage drawers. I may go back to this for the more common non ESD sensitive components.

16 Aug 2013

Moved to new QTH

Although still without internet and phone - thanks Virgin Media - we have now moved to the new QTH. I have still to erect my V2000 vertical but hope to have this up over the weekend. Amateur radio is taking a back seat whilst teething troubles with plumbing and electrics are sorted.  Until we get internet at the new QTH these blog postings are likely to be few and far between.

13 Aug 2013

Moving tomorrow - emotions mixed

So, after 37.5 years in our current home, we move tomorrow to a newly renovated bungalow in the same village.  Emotions are running high this evening: this has been the place where our children were born and raised, where our grandchildren have stayed and played, where I have enjoyed all sorts of fun on the radio. The new home should be lovely and better in many ways, yet this evening my wife and I are feeling rather sad at having to say goodbye to our "old" home.

Actually we are not quite saying a final farewell as we still own the old property and intend to keep it for some years to come. At the moment we are deciding whether to rent it out on long lets or to furnish it for weekly holiday lets. The house is in a quiet road on the edge of the village overlooking pleasant countryside and the local church. If we decide on holiday lets we could even come back to stay for a few days or at least use it for the family for a few weeks each year.  These are decisions for the weeks ahead.  More immediately we have to get ready for the removals men arriving at 8.45am in the morning.

This morning I went up to the chimney of the new home with the builder who was fixing a cowling. The view from up there is spectacularly good confirming it should make an excellent VHF/UHF/microwave location. This is something I shall look forward to!

12 Aug 2013

Virgin Media cock-up

This evening I am VERY annoyed! 

A day before we are due to move we have been informed by our phone/TV and broadband provider (Virgin Media) that they cannot now do the installation at the new property until (at least) Sept 2nd and not on Aug 15th as promised a few weeks ago. This means we have no home phone, no internet and no TV (other than Freeview) for at least 2-3 weeks. What annoys me is that had I known this 2 weeks ago I might have decided to go elsewhere. They apparently need to dig a hole in the road to get the cable through and need local authority approval to do the digging. Let's hope we don't get a "job's worth" who takes a month to process the approval to dig.

I asked several people at Virgin Media if I could have my phone redirected to my mobile ("no, we can't do that") and if I could be loaned a 3G dongle so I could get internet connectivity ("no, we can't do that"). Why ever NOT?? What a total shower they are!

So, if you need to contact me please do so via my mobile number which I have emailed to some of you.

Also, do not expect to see blog updates for some weeks until I manage to get internet services at the new home and replies to emails are likely to take some time.

To add to my woes today, this morning I managed to knock a tin of paint all over our bedroom carpet when painting a piece of furniture.

All in all, today has been quite stressful what with packing for the move on Wednesday and trying to sort out everything.

11 Aug 2013

The Chinese HF SSB/CW transceivers are REALLY coming.....

Steve G1KQH has alerted me to a new QRP HF multi-mode transceiver from China that is available on eBay. The English translation leaves a lot to be desired, but this again signals that the Chinese are starting to get very close to marketing credible HF transceivers that we can expect to see sold by the likes of Martin Lynch and Waters and Stanton. In my view we are 12 months away from this point, but when some really decent HF rigs become available be prepared for some VERY tough times for Yaesu, Icom and Kenwood.

See: http://www.aliexpress.com/store/product/Whole-ham-kn920-kn-920-utrashort-wave-ham-radio-station-equipment-shiortwave-SW-free-shipping/926979_1075987935.html


On the same theme, Hamshop in the Czech Republic has announced it is the EU dealer for the single band KN-Q7A SSB transceivers from CRKITs in China. These are neat little single band 40 and 20m transceivers available as kits or ready built. They are getting rave reviews on eHam.net.

Rotatable mast bonus

Regular readers may remember that I was asking about rotators some months back. Well, I have just realised that the place where I intend to fix my 2 inch diameter mast at the new QTH is such that I can rotate it by hand by opening a window about 10 feet from my new operating position. This means, if I so choose, I can erect a small beam for 2m and 70cm, or a combined 2/70cm beam and turn it 360 degrees very quickly using the trusty "Armstrong" method. So, initially I'll erect the V2000 vertical but may well add some small (not too sharp) beams for VHF/UHF contest and tropo work. Turning a beam by hand is quicker than a rotator and allows signals to be peaked by ear.

Anyone have any recommendations for a combined 2m/70cm horizontally polarised beam with around 3-6 elements, ideally fed with a single 50 ohm coax? I have seen combined 2m/70cm HB9CV antennas but think there are other options too.

8 Aug 2013

First building projects for the new shack

It will take a few weeks to settle into the new home and get things straight, but already my mind is turning to projects for the autumn. Several of these are hang-overs from the current QTH i.e. "gunner" projects (I'm gunner do this or that!) or projects already started but needing to be completed. This is the list so far. You can be 100% certain this list will grow and change.
  1. Check the LF/MF/HF noise environment at the new QTH. I have no real idea how this will be. I am more in the middle of the village at the new QTH, so suspect switchmode PSU and other noise sources may be more of an issue?
  2. Finish the 10m WISPY transceiver. Both the direct conversion RX and DSB TX have been built and successfully used on air, but I have still to put the 2 bits together as one transceiver in a box.
  3. Finish the optics for my G4HJW designed Finningley optical transceiver. I finished the electronics build some weeks ago but the move got in the way of the mechanical parts. I need a new stable tripod for this too.
  4. Carry out some VLF earth-mode tests at 8.97kHz from the new QTH to compare results after the QTH move. My baseline earth-electrode "antenna" will be very slightly shorter and the direction more NW-SE (it was E-W before).
  5. Carry out some 472 and 136kHz WSPR tests using the earth-electrode antenna. Again, the aim is to see how results compare at the new QTH. The earth-electrode's new loop direction will affect who can copy me.
Whether I concentrate on HF/MF/LF or move more to VHF/UHF will depend on the noise environment. Although there are plenty of things to try to reduce QRM if this proves to be a problem, it may be the perfect excuse to try something new, such as weak signal QRP work at VHF and UHF. We'll soon know.

Starting to equip new shack

Although our move is a few days away still, I am starting to move my equipment across to the new shack. I may erect my V2000 vertical this weekend too, so that I can have a first QSO from the new shack on the East Cambs 2m FM net on 144.575MHz next Monday at 8pm.

I am debating where to put the triband antenna: either on a gable end over the garage or on a longer pole attached to the rear wall of the garage. The latter would make antenna changes slightly easier as the pole would be attached at ground level, so no ladder climbing needed.

My understanding is that outside of a conservation area I do not need planning permission for a second antenna on the house such as a V2000 vertical as long as the linear horizontal dimension is not greater than 1m, which it would not be. A 2m big wheel on the same pole would probably be OK too. I should be able to string a 10m or 15m dipole from this support to a tree at the other end of the garden that would feed conveniently into the shack just below.

4 Aug 2013

All my antennas now dismantled ready for the move

Today was an historic day: for the first time in around 20 years or more, I have NO antennas up outside at this QTH. The Par 10/20/40 end-fed HF antenna and the trusty V2000 VHF/UHF tri-band colinear were taken down this evening. The V2000 has been up continuously now for the best part of 10-12 years and is in remarkable condition still. Apart from a bit of dirt on the fibre glass covers and a little oxidisation on the metalwork, it is like new and electrically still works perfectly. There are several "copies"  of this antenna around, some of which are nothing like the original version.

It will be some days before I get the antennas sorted and erected at the new QTH, but at least the brackets and antenna hardware are now down and available for a suitable moment.

68-76kHz LF band allocated in the USA

Just in from WG2XRS/4.....
"You might have heard a group of us have received a license covering 68 to 76 kHz with 10 W ERP for most all modes including SSB!  Authorization came yesterday and already have W4DEX on QRSS and into W1VD and others with very solid sigs on 72.4 kHz.  Am gearing up for that operation as we speak.Bob, WG2XRS/4."
This is fascinating news. Although getting anything like 10W ERP is a major challenge at 73kHz, much weaker amateur signals have spanned the Atlantic in the early 2000s when the 73kHz band was available by NoV here in the UK. See  http://homepage.ntlworld.com/mike.dennison/index/lf/transcontinental/2001-2/at2001-2.htm

There is no doubt that some of the US stations will be copied in Europe this coming DX season. Since the first few years of this century a number of new weak signal modes have appeared such as WSPR2 and WSPR15 and OPERA. Also, with GPS locked systems and superb frequency accuracy, it is possible to run very slow CW and DFCW modes knowing that the TX frequency can be very accurately set, so the RX can look for the signal in uHz bandwidths to dig it out of the noise over a period of hours. All we now need is for a limited number of 73kHz permits to be again allocated in the UK.

Please note this is NOT a general allocation in the USA: it is a special research permit to a limited number of stations in much the same way as some access to 500kHz and 136kHz has been granted over there. Their FCC does seem to be incredibly slow at getting new bands like 472kHz allocated. I don't know why this is such a problem: perhaps they fear allocating these LF bands will be a threat to homeland security?

2 Aug 2013

New Address with OFCOM

This evening on-line I notified the TV licence people of our upcoming address change as well as notified OFCOM of my new address.  It is now unlikely I shall make any further QSOs from my current QTH as the last remaining antennas will be coming down next week. Getting my VHF/UHF vertical up is a priority at the new QTH although there are a few more pressing issues to deal with first - like getting some carpets on the floor!

On the front cover of Practical Wireless this month

Well, I had quite a surprise when the Sept 2013 edition of Practical Wireless (PW) magazine dropped on the mat in the post this morning. Although I knew my review of the Wonderwand Wonderloop was inside, I did not expect my bald head to be the subject of the main cover image! My wife Lis took the photo in the back garden of our current home.

I hope those reading the Wonderloop review will think it a fair one. The loop is tiny and uses thin 1mm wire, yet the performance was actually pretty good considering its size, averaging a couple of S-points down on a decent back garden antenna. As the review shows, some good results were obtained.

May I recommend you buy PW as there is a reasonably decent selection of articles in it most months. It is now the only independent amateur radio magazine published in the UK. I do miss the old Short Wave Magazine which was a good magazine in its heyday back in the 1950s and 1960s.

31 Jul 2013

20m WSPR with 0.5 to 2W

As I wind down activity from this QTH before my move, I have been allowing my WSPR beacon to run on 20m using an indifferent wire antenna strung to a low tree at the bottom of the garden. At its lowest point is is only about 2m above ground. Power out has been 500mW or 2W. The results below speak for themselves: WSPR spots from across the planet.
20m WSPR unique spots in last day or so
These are just some of the unique spots: the actual list goes on and on down the page. I am a real fan of WSPR for checking rigs, antennas and propagation. It is also a way to still enjoy the hobby whilst packing up books, CDs, DVDs and other household rubbish in preparation for a house move!

26 Jul 2013

Reflex Receivers

In the days when semiconductors were very expensive parts, the reflex receiver was a very popular design for AM broadcast and simple amateur AM receivers. The basic idea is to use a single transistor is several different ways: as an RF amplifier, possibly a detector and then finally as an audio amplifier by clever feeding of the RF and AF signal back around the transistor. Even today they are fun circuits to try. For example, see the schematic at http://www.ke3ij.com/reflex.htm . Rick has a number of novel circuits on his site.

http://www.ke3ij.com/reflex.gif
In Rick's circuit, Q1 first acts as an RF amplifier. The 1N4148 rectifies the signal which is again applied to the base of Q1, which is now used as an AF amplifier stage. Although adaquate level is available on the collector of Q1 to drive a high impedance earpiece, Rick added another low cost stage to drive an 8 ohm speaker.

Another example of a reflex circuit is at http://www.sm0vpo.com/rx/reflex_rx.htm . Perhaps the most famous reflex circuits came from Sir Douglas Hall in a series of circuits in Radio Constructor back in the 1960s and early 1970s. Some of these are collected at http://www.spontaflex.free-online.co.uk/ . Sir Douglas was a UK overseas diplomat and a very nice gentleman. One of my old school friends lived in the same Devon village and visited him to try some of his prototypes.

24 Jul 2013

Speech processors

Earlier today someone asked me to forward them some links I had on speech processors. This reminded me of a VERY effective speech clipper I built many years ago for a 2m AM QRP transmitter. The audio pre-amp had 2 stages of 6dB/octave pre-emphasis followed by very hard clipping and an active low pass filter to keep >2.5kHz audio levels to very low levels. The signal sounded remarkably punchy and allowed this little 100mW AM transmitter to punch well above its weight. It sounded like a rig running several watts. At some point, after we move, I'd like to replicate the design and give it a go again. It was based around the audio stages I used in the Pye PF8 PMR handheld but with value changes to increase the gain and add the second pre-emphasis stage. Double pre-emphasis meant that there was less clipping at lower audio frequencies and more at the higher end. Compressors are meant to be better, but honestly this little circuit took some beating.

Satellite tracking app (free)

The always interesting Southgate ARS News page has a link to a free app by Tom W9KE for iPhones, iPads and iPod Touch devices to allow tracking in real time of satellite passes. The app has a nice user interface and looks to be extremely useful if you enjoy tracking satellites and the ISS as well as want to work through some of the amateur radio satellites up there.  The App is available from https://itunes.apple.com/us/app/satellite-explorer-pro/id669039200. The only thing the app seems to miss is a list of the amateur satellite frequencies (up/down) and their modes of operation. I guess one has to look this up somewhere else. 

23 Jul 2013

Thunderstorms and Es

Sporadic-E (Es) is an exciting propagation mechanism that allows contacts on the HF and VHF bands out to around 2000km regularly (with multi-hop Es MUCH greater ranges can be covered) in the April-Sept period in the Northern Hemisphere. There is another smaller peak around Dec/Jan too and propagation by Es can occur at others times of year, but much less frequently. Exactly what creates good Es conditions is open to debate still but some believe thunderstorm activity in the troposphere can impact it.
http://images.blitzortung.org/
A way of checking on thunderstorm activity is to look at the map at http://www.blitzortung.org/Webpages/index.php?lang=en .  Right now there are plenty of thunderstorms over northern Europe with lots over the UK earlier, spreading northwards. Looking at the map one might expect good conditions towards Italy and Greece on Es if whatever rises from the tropo region reaches the E layer mid-path.

22 Jul 2013

My internet saga continues - positive outcome on cable at new QTH

Yesterday I reported that at the new QTH our new home was the only one on the close that was unable to get fibre optic broadband, phone and TV services from the provider I currently have used for over 12 years: Virgin Media.

Well, today their field engineer surveyed the road and has confirmed that we WILL be able to get cable services at our new place after all. They were very quick checking this - I only asked yesterday - and it looks like everything will be ready for when we move mid-August.

21 Jul 2013

KX3 purchase?

For the last 6 months I have been saving the pennies in my amateur radio kitty towards the purchase of a new transceiver for general use at the new QTH. I am still very tempted to splash out on a new KX3 from Elecraft, despite the high UK cost when fully loaded with auto-ATU, narrow roofing filter, battery pack, charger and mic. As I tend to hang on to gear for a LONG time, this may be a good investment. All the www.eHam.com reviews are very good and it does appear to be a first class radio. What bothers me though is that for the same price I could buy 2 FT817 transceivers and still have change! My main interest is e weak signal mode experimentation and I am not sure that the KX3 is an ideal radio for use as a base rig for this application: there seems to be a need for lots of cables to connect to a PC, whereas the FT817 is easy using a Signalink USB interface.

As was the case when pocket calculators came on the market in the 1970s, the default position here is to "wait and see", which means I buy nothing and hope that a clear winner becomes obvious in the months ahead. In the 1970s I ended up not buying a scientific calculator at all, HI.

Ending operations at this QTH

Nearly the end of an era (37 years) at this QTH. I will resist taking down the antennas until the last moment in a few weeks from now, but already my mind is turning to the new QTH.

Would you believe it, but every house in Mill Close, Burwell is able to get Virgin Media apart from ours! Even next door they have it.  I contacted Virgin Media who have agreed to send out a field engineer to check why this is. The CATV box on the pavement is about 4m from our drive. It is not the end of the world: I can revert to Sky (or BT) phones, TV and broadband and get over 10M download speeds but I will wait until the VM engineer feeds back his findings as it would be preferable to stick with our current provider. Virgin's broadband is VERY reliable and fast.

I now have a firm plan on where to erect the VHF/UHF antennas. The earth electrode antenna for VLF/LF/MF will be installed in the next few weeks. I have still to decide on the location of HF wire antennas in a way that is "sleuth" i.e. low profile and not obvious. Our new patio is right outside my new shack, so operating in the garden should be very easy and fun.

18 Jul 2013

Going batty

We are spending a few days with our son and family near Canterbury where he lives in an 18th century cottage not far from the school where he teaches. In the last few months their home has become an hotel for a colony of tiny pipistrelle bats who have taken up residence under the centuries old tiles on the side of the cottage. A bat expert estimated there are at least 300 living there.

This evening, as the light faded, we watched as they  flew out from what appeared like impossibly small gaps in the tiles. Bats are a protected species, so they are not allowed to get rid of them, but apart from their tiny droppings they are not a nuisance. It was quite amazing watching them fly off for food this evening.

IC-7100 UK price: £1249.99 from Martin Lynch


The IC-7100 multi-mode multi-band 100W radio is now available for £1249.99 including VAT from Martin Lynch. Although not yet in stock this is the price advertised, which is some £500 less than I was expecting. Considering it includes all the HF bands, 6, 4, 2 and 70cms this is not bad value. I just hope the touch screen is not tacky and unreliable. See http://www.hamradio.co.uk/amateur-radio-main-equipment-mobile-radio-icom-mobile-radio/icom/icom-ic-7100-pd-5020.php .

New VLF tests from Germany

News from Germany of an upcoming VLF test at 8.970kHz using earth electrodes as the TX antenna with an ultra-stable Spectrum Lab derived signal.

Hello Group,
 
We are planning some VLF-activity at 8970Hz during a meeting of  electronic hobbyists nearby  Kassel / Germany (JO40vr) on this weekend.  The plan is to run a VLF-PA between some ground electrodes. Due to other activities we have no exact time plan, when to start. Depending on internet access i will inform you about the details. 
 
Thanks for looking for our signal in advance.
 
73s
Eike DL3IKE



14 Jul 2013

HF activity - the weakest maximum in 100 years?

Space.com reports that the peak of cycle 24 is likely to be the weakest for 100 years with the next one likely to be even worse. See http://www.space.com/21937-sun-solar-weather-peak-is-weak.html .

Although I venture onto the HF bands every few days usually, I've not found the level of activity, excitement or interest that I had in previous solar cycle peaks. On 10m back in the 1979 peak the band was filled with stations at any time in the day, even outside of contests. There just doesn't seem to be the same level of activity these days? Perhaps it is because having worked over 100 countries with just a few watts, many on SSB, there is, for me, less interest in chasing DX now. Also, I tend to enjoy more creative parts of the hobby whether on VLF, lightbeams, etc. and don't have the time (as much) for HF operating where the competition is often from ill-mannered, QRO stations more interested in their egos than the ham radio spirit.

Crystal Set DX log from 1991

As I clear out my stuff ready for our move, I've discovered my Crystal Set DX Log from 1991, which was 2 sunspot cycle peaks ago. Looking through the entries in the log (all received with a VERY simple shortwave crystal set using a toroid, a germanium diode, a resistor and a crystal earpiece and a longwire antenna about 15-20m long) it is quite astounding how the HF world has changed.
Shortwave Crystal Set DX log - from 1991
For a start, many of the coast radio stations used to transmit in CW on HF and these could often be read due to the cross-modulation from other stations. This was the technique used to detect those shown in the log above.

Also, the shortwave bands were still filled with English language broadcasts. In the few days covered by this log I managed to receive broadcast stations from Cuba, UAE, India and Australia directly (not via relays) as well as plenty of Europeans. Before this date I had no idea that worldwide reception on a crystal set would be possible.

There is no doubt that conditions were very good back in 1991 and I am not so sure that it would be possible to repeat this in 2013, but I would be delighted to hear of success by others with crystal set DXing on HF in more recent times.

I still enjoy crystal sets: they are simple and fun to make yet there is still something unbelievably good about using the electricity from the TXing station to hear them, not my own, especially when the signal comes from very far away.


12 Jul 2013

IC-7100 UK launch July 17th at Martin Lynch

A few hours after I commented on the price in the US of the IC-7100, I had an email from Martin Lynch and Sons announcing the UK launch on July 17th.

There is still no information that I've seen that gives the likely UK price although I doubt one will be in my new shack.

The IC-7100 is bound to cause a lot of excitement as it is one of the first commercial multi-modes to include 4m (70MHz). The press release seems to indicate that D-star will be supported in the standard product i.e. my understanding is this is NOT an optional add-on, but you get it with the basic product you buy.

The pdf leaflet on the IC-7100 is now available.

11 Jul 2013

Weather boots for coax plugs?


I'm looking for what I believe are called "weather boots" to slide over the end of PL259 and BNC coax plugs to help protect them up the mast from water ingress. I guess it is still necessary to add a smear of silicone grease. There are such items for Sky dish F connectors (see eBay item 251296277220) but I have not yet found a source for the common 50 ohm plugs.

Anyone know where such rubber/PVC boots can be obtained please?

2m big wheel antennas on 70cms?

Just wondering if anyone has checked what a horizontally polarised 2m big-wheel antenna looks like (gain, match, directivity, polarisation) on 70cms?

At the new QTH, the most likely antenna on the apex of the bungalow will be a 2m big-wheel (for 2m datamodes, SSB, CW) with a V2000 fitted above it (for 6m Es, 2m and 70cm FM) with suitable spacing between them (>1.3m). It would be useful if the big-wheel behaved well as a half decent horizontal omni on 70cms too so it could be used in UKAC contests.

IC7100 prices

Image at http://www.hamradio.com/images_manuf/H0-011766A.jpg
The new multiband, multimode mobile/base radio from Icom is now available in the USA for $1,824.90 from Ham Radio Outlet store with a 2 year warranty. It is available for $1,664.95 without the extended warranty. See http://www.hamradio.com/detail.cfm?pid=H0-011766.  If importing from the USA don't forget VAT and import duty.

The usual UK price is about the same in pounds as it is in the USA in dollars, so I guess around £1800-1900 is likely to be the going price, although I don't think the UK dealers have them yet.

At the time of writing there are only a couple of reviews of the IC7100 at www.eham.net

Antennas start to come down and wi-fi range tests

Today marked the beginning of the end for amateur radio at the present QTH. We've lived very happily here for 37 years, bringing up our 2 boys and welcoming our 4 grandchildren. Now we are just a few weeks away from our move to the bungalow 300m away up on our local "hill" next to the windmill, the latter currently undergoing a £417k refubishment courtesy of a National Lottery grant. The new home is a nice place and we are looking forward to the move, but it won't be without a few sad moments: closing a chapter in our lives but also opening a new one. The last time we moved, the removal van cost just £11 - it was a LONG time ago, HI.

Today I removed the first part of the antenna system: my 20m spaced earth-electrode wire running in the back garden. Next to come down will be the coax feed from my workshop to the upstairs shack where I operate. The V2000 vertical and the Par 10/20/40 end fed will come down in a few weeks time. I also de-cluttered the bedroom shack to some extent, clearing out all manner of the "I may need this some day" rubbish that fills drawers and cupboards. It is just unbelievable how many SMPSU wall blocks I have that belonged to equipment like routers and scanners long gone. The worst is always the stuff you've kept because, "I may need this one day".  I am trying to be ruthless and give it to a local charity store, recycle centre or the dump if it has not been used, read, looked at for several years. For certain something that goes will be needed next week.

I did a test at the new bungalow tonight on the internet wi-fi coverage: I took my Virgin Media wireless super-hub and set it up (locally, no internet connection) and walked around the new home with my iPod Touch 4g to see how strong the signal was in the shack, bedrooms and garden. Results were promising: I think I may get away without a range extender.

10 Jul 2013

WonderLoop antenna

If you have just bought a copy of the August 2013 copy of Practical Wireless you may have noticed that in the next edition (September) I'm doing a review of the WonderLoop antenna, although the editors managed to give me a new callsign by mistake in the "Coming next month" column on p77, HI.

Confidentiality prevents me saying anything yet until the edition is published, but I much enjoyed carrying out my tests.  I have absolutely no affiliation with the manufacturer or supplier. As a keen blogger I find it hard not to blog about something radio related that I have played with!

The Wonderwand page is at http://www.wonder-wand.co.uk/WonderWand/WW_Homepage.html .

If you are interested in reading my review, please buy the Sept 2013 copy of PW on sale August 8th.

Birdlip in the Cotswolds


The distant Malvern Hills from near Birdlip
There have been no posts for a few days as my wife and I have been away from home staying a couple of nights on the western edge of the Cotswolds at Birdlip. The occasion was a gathering with cousins I'd not seen for around 50 years. The gathering was excellent. We stayed at the Royal George Hotel (3 star rating) which was superbly located right next to the Cotswold Way path with good rooms, large gardens and excellent value meals.  I am please to report that everyone had a great time and got along fine!

This part of the Cotswolds would make an excellent VHF-microwave location with the Cotswold escarpment meaning the ground falls away dramatically towards Wales and the west. I didn't take any radio gear, but will do so if I stay there again. The hotel was a good find.

6 Jul 2013

472kHz in Canada - getting closer

From Joe VO1NA:
Dear Group,
Last week, Industry Canada published its Proposed Revisions to the Canadian Table of Frequency Allocations. It includes the 630m band for the amateur service.  So we wait with much anticipation...

73
Joe VO1NA

VHF/UHF QRP DXing with weak signal digital modes?

When there is a decent contest with some portable stations with decent antennas about, it is surprising how far can be covered with QRP kit on 2m and 70cm. This makes me wonder just what sort of ranges could be covered with QRP and modest antennas on these bands using WSJT digital modes.

Going from SSB to one of the more effective weak signal modes is like gaining another 30dB, i.e. far more that the antenna gain of a big contest station, suggesting that ranges of 200-300km should be ALWAYS possible on 70cms with quite modest QRP stations with small yagis or colinear vertical antennas in flat band conditions.

I am speculating what sort of ranges should be possible under flat conditions (no lifts) with 5W and a small omni or broad beam yagi such as a Moxon or HB9CV.  When I move to the new QTH I think some 70cm skeds are called for with stations out to 300-400km using WSJT modes using 5W or less.

70cm VHF NFD with a simple QRP station

4 ele 70cm yagi on car
Just for a little fun in the sunshine I took my FT817 and "coathanger" 4 el yagi onto a local high spot (actually nothing is high here in East Anglia!) to try just over an hour of operating on 70cm SSB during VHF NFD. Conditions were average, but I heard EI, F, GM and PA and worked 12 stations in just 70 minutes of casual operation with the best DX 262km.  Power output was either 2.5W or 5W.

The 4 el yagi is mounted on a 22mm PVC pipe mast that is simply wedged in the car rear window and manually rotated. The whole set-up can be erected and taken down in about 2 minutes: I don't take contests THAT seriously you see :-)  The map shows the stations worked before going back home for tea.
70cms QSOs in 70 minutes with 5W to a 4el yagi

After tea I parked the car outside my new QTH and erected the 4 el as shown in the photo. Signal strengths from DX stations (PA0 and a station in SW England) were very similar to those on my local /P site, suggesting the new QTH, on a local bump, is promising for VHF/UHF/microwaves.

70cm is a great band and sadly under-used these days on SSB. It is also sad that there are so few 70cms beacons on the air in the UK now. I believe the Bristol 70cms beacon - it was a good conditions indicator here in East Anglia - has recently gone QRT too?

4 Jul 2013

30 line TV

It is a long time since the Baird 30 line TV system was replaced by 405 line and then 625 line TV here in the UK. However, there are still enthusiasts building mechanical 30 line TV systems and getting respectable results. At one time I joined the NBTV group (does it still exist?) who promote(d) hobby activity with 30 line TVs, particularly mechanical versions with scanning discs etc. Bandwidths needed for such systems are very narrow (audio) so the signal can be transmitted using a standard voice transmitter. These days it is possible to produce 30 line TV using a PC, but this not quite the idea: one can after all communicate worldwide by Skype video or FaceTime.
 This video (linked from its original location on You Tube) gives some idea of what is possible.

Wellbrook LF RX Loop

http://www.wellbrook.uk.com/antennashop/image/cache/looponfence-250x250.jpg
A Wellbrook ALA1530 loop antenna for VLF-HF reception is now in my plans for the new QTH. This is not a low cost antenna - currently around £200 in the UK - but its performance is excellent judging by reports from people I know and reviews. It looks like the very best choice of RX antennas for the 136kHz and 472kHz bands where local noise can be a real issue. It does not need to be mounted high, just about 5m from the house. The photo above (linked from the Wellbrook site) shows the antenna mounted on a fence.

The technical specification speaks for itself: truly excellent OIP2 (+90dBm) and OIP3 (+49dBm) figures and a 1dB compression point of +28dBm in the Medium Wave band. It can stand a local field strength as high as 400V/m. As a loop, this antenna has a figure of eight pattern, so local noise sources can be nulled in many cases. It covers from 20kHz to 30MHz.

This looks like a good investment before the LF DX season.

VLF kit at PA3CPM

Henny PA3CPM has been continuing his 8.270kHz VLF transmissions, on and off, for some weeks now and is getting reports from several stations in western Europe despite his modest antenna. Paul Nicholson in Todmorden and Eddie G3ZJO regularly receive his signals using integration over several hours and extremely narrow bandwidths to dig the signal out of the VLF noise.

8.270kHz VLF loading coil at PA3CPM
This is a photo of Henny's huge loading coil used to bring his 40m sloper to resonance on 8.270kHz. The loading coil uses a LOT of wire (several kms) and building such a VLF loading coil is not for the faint hearted! I suspect that a large wire loop may be an easier TX solution?
PA3CPM's VLF PA unit
Henny is using a 200W PA and this is shown here. Note the fans to cool the unit.

To radiate an amateur signal at VLF requires special dedication, yet Henny has shown that even a modest 40m antenna can get a signal hundreds of km on VLF with quite modest powers. It is indeed a new and exciting area of the hobby.

3 Jul 2013

Analysis of the PA0RDT E-field probe RX antenna

Image of miniwhip on VK1OD's website

VK1OD has done an interesting analysis of the PA0RDT E-field probe miniwhip receiving antenna. This is very popular as an effective antenna from 8.9kHz right through to the HF bands. I have used my own versions on the VLF, LF and MF bands with great success, but I commend the PA0RDT design to you. His design uses readily available semiconductors to give excellent IP2 and IP3 figures. You may be surprised how something this tiny and simple can work so well if mounted away from the house on a small pole. Remember, you do NOT need big antennas to receive on the lower bands: it is S/N that matters not very low noise figures. VK1OD's analysis is somewhat harsh: in my view it works as a true E-field probe should, even at VLF.

More loops

HF TX loop in the bedroom
Small TX magnetic loop performance continues to astound me. This evening I erected my little loop antenna made with 6mm diameter copper pipe and tuned with a standard 365pF air-spaced variable as used in my regen receivers. The loop has a diameter of just 65cm (about 2m circumference) and is mounted on a piece of PVC pipe as a support. The 365pF is attached to the hi-Z part of the coil with a couple of crock-clips. Matching is with a coupling loop about 1/5th the diameter of the main loop.
The simple tuning unit - a 365pF airspaced variable
Without any effort, apart from the tuning sharpness,  it tunes from 10-28MHz and got loads of spots on WSPR. I then tried with 2W CW on 14MHz and received several European reports via the reverse beacon network. The loop is just resting against a wall in the shack. Overnight on 20m WSPR the best report was from 8338km with 2W indoors. On 10m this morning (July 4th) it is already exchanging WSPR spots with CN8LI despite being orthogonal to him i.e. in the worst orientation, 2W and indoors.

According to my loop calculator the efficiency should be around 12% or 9.3dB down on a "proper" dipole antenna on 14MHz. This is less than 2 S-points difference. Results bear this out. On 28MHz the efficiency is better.

Purists will point out that the crocodile clip connections will have a few milliohms resistance and this will reduce loop performance. At 2W there is no sign of arcing across the plates. The point is with QRP one can get away with simple circuits that would not be possible running 100W.