Earth-electrode "antenna" in the ground

Until our son accidentally cut it, I used this antenna extensively from VLF to 60m. On 630m (472 kHz) it consistently got reports from Norway with a measured ERP  of just 10mW using WSPR. 

My theory is that at low frequencies it acts as a loop in the ground. As you go higher in frequency the loop gets smaller, so the antenna gets worse. 

If my theory is correct, the loop will get larger as frequency is lowered making it very effective for sub-10 kHz communications. Indeed, such an antenna has been used to great effect by DK2FC and others at VLF.

For use on LF and MF it has worked well for me.

See https://sites.google.com/view/g3xbm4/home/antennas/earth-electrode-antennas .

Remarkable - the earth-electrode "antenna" in the ground on 160m FT8 RX

As reported last evening, 31 stations across Europe spotted my 2.5W FT8 to the earth-electrode "antenna" in the ground on TX.

Overnight I left it connected on 160m FT8 RX. In all, 328 stations were spotted including very many in N. America as shown on the map. 

UPDATE 1024z: Apart from VE3PJ (5492km) at breakfast time (0722z), all spots now are UK on 160m FT8 RX.

Earth-electrode "antenna" in the ground

At VLF, LF and MF I have used this at 2 QTHs with great success. My own theory is this acts as a loop in the ground which gets bigger with rising skin depth i.e. as frequency is reduced. I am sure a full sized antenna would be better, but this works way beyond expectations.

See https://sites.google.com/site/g3xbmqrp3/antennas/earth-electrode-antennas

Earth-electrode "antennas" in the ground

Quite often I hear people tell me they have no space for LF or MF antennas. Rubbish!  

For many years I have used my earth electrode "antenna" on VLF, LF and MF. It won't be as good as a big antenna, but it works remarkably well.  Even my wife does not know it is there!  Neither do the neighbours. 

On 472kHz WSPR I get copied in Norway most nights with less than 10mW ERP with mine.

See https://sites.google.com/site/g3xbmqrp3/antennas/earth-electrode-antennas

Earth-electrode "antenna" in the ground details

Several people have asked for more details of the "antenna" I use on 137kHz, 472kHz and 1.84MHz.

The far end is a ground rod (copper I think) about 1m long. The wire back to the shack is about 12m long and runs along the garden fence (about 1.5m off the ground). At the near (shack end) it connects to the mains ground.

At the old QTH I tried a separate ground just outside the shack and running the "return" wire along the ground. Results were much the same. At 137kHz, 472kHz and 1.84MHz I am pretty sure this structure acts as a loop in the ground.

On VLF earth mode, I suspect the "antenna" is not acting as a loop.

                               --- Sketch and photos to be added on a later post, probably Feb 15th? ---

Earth-electrode "antenna" at MF and LF

Several people have asked me about my somewhat unconventional "antenna" at LF and MF. Let me say from the outset, if you can erect a "proper" antenna and ground at LF and MF you will do better, but at 2 QTHs the earth-electrode "antenna" worked for me. No-one knows it is there yet it regularly gets my 5mW ERP WSPR copied over 1000km!

See https://sites.google.com/site/g3xbmqrp3/antennas/earth-electrode-antennas

Earth Electrode Antennas

For some years, I have used earth-electrode antennas of the lower bands such as VLF/LF/MF. I have also tried these on 160m and 80m with less success. I have never claimed they work wonders, but if you are stuck for an antenna on the lower bands it will enable you to get out. On the lower bands you may be surprised how well this "antenna" works.

See https://sites.google.com/site/g3xbmqrp3/antennas/earth-electrode-antennas

472kHz - directionality of earth-electrode "antenna"

Last night and today, my 5mW ERP on 472kHz WSPR from the 12m baseline earth-electrode "antenna" was copied by 9 unique stations with best DX being F6GEX (590km) in IN97 square. In a crude attempt to plot the directionality of the "antenna" I have shown the QTH squares in which I was received as purple coloured squares marked with a cross. Other purple squares shows where I received stations from too.

5mW ERP 472kHz - crossed + coloured squares shows where spotted

This is crude, but the directionality is roughly E-W I think, which makes sense. The reception by F6GEX (590km) in IN97 is south of west, but not orthogonal to the loop. DK7FC is very strong and I would expect to copy Stefan off the side of the loop.

I shall leave 472kHz running with the earth-electrode antenna again tonight.

Sunspot count over 200, VLF earth-mode, and my stroke

Today I have taken a day off from 10m, but I see the sunspot count is 202 and the transatlantic path is well open with lots of EU stations being spotted in the USA and Canada, and vice versa. There are good spots from Europe to S.America too and the band was open EU to Australia again this morning.

VLF  earth-mode beacon TX

Later today, if my energy levels improve (very low currently because of my stroke after-effects) I want to match my 8.97kHz VLF earth-mode TX  into the earth-electrodes better. At 472kHz they look quite a bit different here compared with at the old QTH (here more like 200-300 ohms with some capacitive reactance whereas at the old QTH it was more like 40-60 ohms resistive. At VLF it might be a lot different, of course. My initial earth-mode VLF results from this new QTH last August/Sept (before my stroke) were disappointing and this may have been due to poor matching?

If I can get more power into the ground I may ask my wife to help me with some drive tests locally to check earth-mode VLF performance. This is where I REALLY miss my health and fitness. I tire SO easily at present, but have been told this should improve given time and more healing.

Guess I have to slow down and let things take their time and not expect instantly to get better. Apparently I was VERY poorly last autumn - my heart stopped at one point and the first 4-6 weeks in hospital are just a blur -  and feel I am almost living a new "second chance" life. Certainly I have never seen a more beautiful springtime.

UPDATE 2045z:  In the end the VLF work will have to be later as I am too tired right now. The simplest way of increasing the output impedance is probably to reduce the PRIMARY turns on the 3C90 output toroid s long as the frequency response is OK. This is currently set for a 4:50 ohm step up. Reducing by a few primary turns may be all that is needed. We'll see tomorrow.

Proposed new 474.2kHz Earth-electrode baseline

The yellow line shows the approximate 15m baseline used currently on MF WSPR.

The red line shows the proposed new earth-electrode baseline which should place the northern electrode well clear of buried pipes and wires. It should be better, but you can never be sure until you try it! I (or a friend) need to hammer in some new ground rods first at either end of the baseline wire.