Showing posts with label aircraft scatter. Show all posts
Showing posts with label aircraft scatter. Show all posts

29 Aug 2020

2m aircraft scatter?

As many will know, I frequently try 2m FT8.  What puzzles me is that even will 10W and the big-wheel omni antenna (3dB over a dipole maximum) I seem to get great ranges at any time.  

This could be aircraft scatter, but I am puzzled why this is there all the time. If it was just at certain times I would be more inclined to think this is aircraft scatter. Just maybe, there are enough aircraft in the sky to allow brief 15 second periods of FT8 to be reflected at any time.

Another possibility is that FT8, with its additional sensitivity, allows other scatter modes to be possible. Whatever, 2m FT8 seems to allow me to reach incredible distances every single day, even with my very simple antenna and low power. If I had a big beam and 400W, some amazing distances should be possible.

22 Jun 2014

6m - no Es here this afternoon

Just locals and GDX here this afternoon, with no sign of Es since before lunch on 6m. I shall stick with 6m in case things change later. Much GDX is via aircraft reflection.

With regard to 10m, sunspot count is 75 and 20-30MHz conditions are "normal" so F2 DX on 10m should be likely. Es is more likely on 10m (than 6m) too but that is not related to sunspot activity, at least not directly.

6m - CN8LI again and more local DX

The path to CN8LI (2113km) is there again today, but not as strongly as yesterday. So far a single spot in each direction mid-morning. You will recall I use 1W ERP  with a vertical V2000 antenna with about 0dBD gain on 6m. My coax is CB RG58, so quite lossy.

There is quite a bit of inter-G/GDX and aircraft scatter activity with G4FGJ (44km), G4IKZ (18km), G0OQK (98km), G4BRK (134km), G0LRD (25km), G4FFC (45km), G3WKW (134km), G8JNJ/A (184km), as well as ON0VA (280km) with the latter with 3Hz Doppler so almost certainly aircraft reflection.

6m is an interesting band!

20 Jun 2014

6m GDX - there if stations are active

Today there have been a good number of G stations active on 6m WSPR allowing a really good opportunity to explore GDX paths out to 134km. It seems that if stations are active out  to close to 200km (and probably further) then even a few watts of WSPR (polarisation probably unimportant?) will be decoded at the far end of the path eventually, depending on aircraft reflections and favorable Doppler.

This probably means JT65 or JT9 ranges on 6m probably extend to around 200km at least if the stations know the most favourable alignment of aircraft. The same probably applies on 10m, 4m and 2m ,as well as 70cms and microwave bands.

What I'm not (yet) clear about is the normal tropo range without aircraft reflections. For true tropo, polarisation is more likely to be important: one does not want to throw away valuable dBs with cross-polarisation losses. I don't think this matters where signals are randomly scattered off aircraft bodies.

14 Jun 2010

6m WSPR - and tropo?

In between other things tonight I've been running WSPR on 6m. Interestingly I seem to be able to consistently copy G8JNJ 184kms away, presumably by tropo? He's also decoded me once. Don't think it is aircraft reflection as no Doppler evident on the WSPR display. Also managed to see and be seen by EA1FAQ. I use a V2000 triband vertical on 6m.

18 Jan 2010

10m WSPR

This morning I've been WSPRing on 10m again. G4IKZ 18kms away is a good signal and he has been heard in Italy. G4IKZ is copying me, but no DX reports yet. There is a great deal of aircraft Doppler on local signals. We have the Mildenhall and Lakenheath airbases some 20-30kms away, so I expect it is because of aircraft taking off, circling and landing.

2 Sept 2009

6m aircraft scatter

Just been WSPRing on 6m and spotted G3ZJO, who is 79kms from here, by aircraft scatter. This is clear from the WSPR waterfall display which shows all sorts of Doppler shifted traces as well as the one that was successfully decoded. I suspect this is aircraft stacked over, or approaching or leaving, Stansted or Luton Airports.