WSPR non-reciprosity?

Sometimes my software give some stations on WSPR quite decent reports as the signal decodes well. In these situations I am surprised not to be decoded myself as, even allowing for power difference, I should still be well above -30dB S/N. The reasons could be many:

• The other station is just on TX only
• The other station has a very high noise floor
• The other station has a deaf RX.

Apart from these, I cannot think why I should not be copied.

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.

Lightning damage risk

I am always nervous about lightning strikes.

The excellent Southgate News today told the (true) story of a local CBer who had his vertical and CB rig destroyed by lightning. See http://www.huntspost.co.uk/news/latest-news/
huntingdon_cb_radio_user_almost_electrocuted_after_lightning_
bolt_strikes_aerial_1_3648368http://www.huntspost.co.uk/news/latest-news/
huntingdon_cb_radio_user_almost_electrocuted_after_lightning_
bolt_strikes_aerial_1_3648368

I usually disconnect antennas when there is lightning about but I am still nervous.  One of my friends (not a radio ham and with no big antennas in the air) who lived in a normal estate home had his home struck years ago and it took out lots of his household wiring. The chances of a direct hit are rare, but I am always bothered and never quite sure what the best advice is.

Email from space?

Just had an email with this at the end:

"Sent from the ISS ...-.-"

I am assuming this came from the International Space Station (ISS).

If correct, this is a first for me.

6m Es today here on WSPR

This is being written at 1740z and so far today just one 6m Es opening, which was to IW1PAK (1092km) around 1100z today. Spots were exchanged in both directions. No other 6m Es see today at all, but things could change later.

Sunspot count is 108 but 20-30MHz propagation is only "fair".  I have not been checking 10m for F2 DX but there would have been a reasonable chance today.

UPDATE 1940z: No further Es seen today, as yet. At this time there are 40 stations active on 6m WSPR including some in the eastern USA. I am always hopeful! This is the highest number so far this DX season.

6m Doppler

On 6m it is amazing how much Doppler there is on longer distance GDX stations. The screenshot shows just how much Doppler there is on G4BRK's signal today.  There were something like 6 aircraft involved at times with WSPR managing to decode when the Doppler is low. On more local signals (e.g. G4FGJ) there is much less (or nil) Doppler. Clearly aircraft reflection plays an important part in long GDX paths. I have no idea where these planes are located.

6m - yet more GDX this evening

Even if Es is not around for me on 6m WSPR, then GDX certainly is.

Just a few moments ago G4BRK  (134km) was spotting me at -18dB S/N with low Doppler (1Hz). I seem to regularly get GDX stations in the log, most usually as a result ( I think) of favorable aircraft alignment. If the planes are moving along the path between me and the other station then Doppler is normally too bad and no decodes occur. If the plane crosses the path then Doppler is usually low and there is a better chance of WSPR decoding. Clearly, modes that are sensitive and more Doppler tolerant would mean such long GDX paths would be workable - JT65 or JT9-1 maybe?

There are software packages used by microwave guys that show aircraft movements in relation to paths between stations, allowing one to work out when planes en route would be most favorably aligned to allow a path to be worked.  My memory fails me on the package name, but it was mentioned in a blog post earlier this year by G3WKW.    UPDATE 1925z Friday:   Bob has kindly reminded me of the software (see comment below too) http://www.airscout.eu Airscout.

134km (83.5 miles) is a very decent distance on 6m inter-G with QRP. I wonder if a horizontal halo would be better or worse? If signals are being scattered off aircraft, then polarisation is less important. A halo would probably have less gain than my V2000 vertical 2dbD omni for halo(?) and 0dBD omni for V2000(?). I guess it will also depend on the other station's polarisation. For pure tropo, I suspect a halo would be better to other stations equipped with horizontal beams, but few GDX paths seem to be pure tropo on 6m.

Just now G8DOR (103km) and G8JNJ/A (184km) were spotting me on 6m WSPR.

Concentrating on one or two bands?

With limited space for antennas, it seems sensible to concentrate efforts on just a couple of bands only. As my favorite band is 10m, I am tempted to erect a more efficient antenna for this band and maybe put up the 6m V2000 only during the Es season. My problems are (a) a lack of mobility because of my stroke and (b) choice of compact, efficient antennas. At present I can cover 40, 20, 10, 6, 2 and 70cms, plus 630m rather inefficiently with my earth electrode antenna. Perhaps, whilst my health is not too good, I am better sticking with what I've got? I know that on 10m my antenna could be better but the Par end-fed covers 3 bands (10, 20 and 40m) and my 2W QRP has reached VK on WSPR on all these bands and doesn't do a bad job.The Par is is almost impossible to see in the air.

Back on 6m WSPR

After a couple unsuccessful attempts on 20m and 40m JT65, I have returned to WSPR on 6m again this afternoon. So far just locals and GDX (DX within G land) and no signs (yet) of any Es. At least one east coast USA station is now monitoring 6m WSPR (Gary KC1AWS). Hopefully there will be more.

Stations copying my 1W ERP today so far on 6m are G4IKZ (18km), G4FFC (45km) and G0OQK (98km). I am still hopeful of 6m Es.

40m WSPR - a total change

Just for a change I QSYed firstly to 20m for a few WSPR spots and then on down to 40m for the morning. Spots (both of me and others) are easy at the 2W level. No great DX seen, just EU stations. The antenna is the Par 10/20/40m end fed which is also used for 10m and 20m. It has an average height of around 4-5m above ground, so probably quite a high angle on 40m. I have been copied in VK on 40m with this set-up though and with just 1W RF.

40m unique WSPR spots this morning