WSPR on 28 MHz...4th and 5th of Oct 2012

I left the rig listening to WSPR signals on 10 metres over the last two days and both were reasonably similar.  These were the individual stations heard on the 4th of October.....


2012-10-04 19:32 CX2ABP 28.126071 -27 0 GF15wc 10 EI7GL IO51tu 10705 27 
2012-10-04 19:24 EA8FF 28.126110 -9 0 IL18pc 2 EI7GL IO51tu 2730 12 
2012-10-04 18:32 N6OIL 28.126066 -28 0 DM14fl 0.2 EI7GL IO51tu 8212 37 
2012-10-04 17:44 KK4XO 28.126006 -20 1 EL96uf 5 EI7GL IO51tu 6527 43 
2012-10-04 14:48 UA6AAK 28.126084 -13 0 KN96dq 5 EI7GL IO51tu 3374 297 
2012-10-04 14:48 W3PM 28.126123 -10 0 EM64or 0.5 EI7GL IO51tu 6298 46 
2012-10-04 14:44 KE7A 28.126077 -17 0 EM12kx 5 EI7GL IO51tu 7109 43 
2012-10-04 13:30 HS1ZKM 28.126114 -22 -1 OK03gr 5 EI7GL IO51tu 10058 324 
2012-10-04 13:06 AI4ZN 28.126125 -19 -3 FM02 2 EI7GL IO51tu 5949 46 
2012-10-04 13:02 SV1FXO 28.126027 +1 0 KM17ux 5 EI7GL IO51tu 2925 312 
2012-10-04 11:16 OZ7IT 28.126142 -26 0 JO65df 5 EI7GL IO51tu 1410 263 
2012-10-04 09:06 VK5AKJ 28.126045 -23 1 QF02id 5 EI7GL IO51tu 17156 313 

The 5th of October was a little better for Australia with four stations making it through between 7:18 to 9:58 UTC. According to an online calculator, sunset in Sydney was at 08:02 UTC.

WSPR signals heard on 28 MHz...Friday 5th Oct 2012

There were some Sporadic-E signals around Europe again. EA8FF who is one F2 hop to the south (2730 kms) was the most consistent signal again and the band opened to the USA again.

These were the individual stations heard on the 5th of October...


2012-10-05 20:08 K7UEB 28.126063 -19 0 DN06tb 5 EI7GL IO51tu 7248 40 
2012-10-05 18:54 EA8FF 28.126110 -2 0 IL18pc 2 EI7GL IO51tu 2730 12 
2012-10-05 18:02 KC4LE 28.126093 -20 1 EM63nh 5 EI7GL IO51tu 6412 46 
2012-10-05 17:58 W3PM 28.126115 -24 0 EM64or 0.01 EI7GL IO51tu 6298 46 
2012-10-05 17:38 KK4XO 28.126008 -6 1 EL96uf 5 EI7GL IO51tu 6527 43 
2012-10-05 16:40 W9HLY 28.126018 -17 0 EN70mt 1 EI7GL IO51tu 5727 50 
2012-10-05 16:38 K9AN 28.126168 -10 0 EN50wc 0.5 EI7GL IO51tu 5982 49 
2012-10-05 16:06 4X1RF 28.126169 -24 0 KM72ls 2 EI7GL IO51tu 4063 315 
2012-10-05 13:52 OZ1PIF 28.126132 -24 0 JO65an 5 EI7GL IO51tu 1400 261 
2012-10-05 13:50 DB0ZDF 28.126085 -17 -1 JN49cx 5 EI7GL IO51tu 1178 287 
2012-10-05 13:48 GW7PEO 28.126189 -20 -1 IO83gh 5 EI7GL IO51tu 370 246 
2012-10-05 12:18 F6HCO 28.126107 -22 0 JN19bg 10 EI7GL IO51tu 794 295 
2012-10-05 10:30 SA6BSC 28.126121 -24 0 JO67ts 5 EI7GL IO51tu 1546 254 
2012-10-05 09:58 VK5AKJ 28.126092 -25 0 QF02id 2 EI7GL IO51tu 17156 313 
2012-10-05 09:34 VK2KRR 28.126133 -22 0 QF34mr 5 EI7GL IO51tu 17333 321 
2012-10-05 09:24 R3LW 28.126022 +10 0 KO54mq 5 EI7GL IO51tu 2605 279 
2012-10-05 07:20 VK2FLR 28.126074 +1 0 QF56od 10 EI7GL IO51tu 17430 327 
2012-10-05 07:18 VK2MEV 28.126152 -25 1 QF57ua 5 EI7GL IO51tu 17373 329 

Interesting enough, the last signal heard was K7UEB which is a club station at a university in Washington State in the north-east of the USA.

GW7PEO........The most unusual signal of the day is again, GW7PEO. I heard his signal three times on the 5th of October.

Timestamp Call MHz SNR Drift Grid Pwr Reporter RGrid km az
 2012-10-05 13:48 GW7PEO 28.126189 -20 -1 IO83gh 5 EI7GL IO51tu 370 246 
 2012-10-05 12:34 GW7PEO 28.126133 -23 -1 IO83gh 5 EI7GL IO51tu 370 246 
 2012-10-05 10:46 GW7PEO 28.126137 -24 -3 IO83gh 5 EI7GL IO51tu 370 246 
 2012-10-03 13:44 GW7PEO 28.126137 -21 -1 IO83gh 5 EI7GL IO51tu 370 246 
 2012-10-02 14:52 GW7PEO 28.126146 -24 0 IO83gh 5 EI7GL IO51tu 370 246 
 2012-10-02 14:30 GW7PEO 28.126146 -23 0 IO83gh 5 EI7GL IO51tu 370 246 

The question is how? I presume it is F2 backscatter as I often hear EA8FF at the same time (as can be seen from the bright trace in the WSPR display above) but why haven't I seen any other spots from other UK stations in the three days?

I sent Phil, GW7PEO an e-mail to enquire about his working conditions on 28 MHz and he very kindly replied. Power = 8 watts......which after compensating for coax losses gives about 5w at the antenna which is a multi-band vertical. Good low take off to the mountains to the south/south-west....i.e. in my direction.

If the signal was direct via tropo then I'd expect to have seen more spots. Backscatter via F2 is probably the most likely explanation. It got me thinking though if it was at all possible that it might be from aircraft scatter? GW7PEO is very close to the flight path for planes going from Dublin/Belfast to London.

The problem with the aircraft scatter theory is that there will be a certain amount of doppler shift on the signal, even at 28 MHz. The maximum amount of drift allowed on a WSPR signal is about 4 Hz. If I understood the figures correctly with an online calculator, the maximum amount of doppler at 28 MHz from an aircraft doing about 800 kph is about 19 Hz. Unless of course if the plane was going at right angles to the direct path between the two stations in which case, the doppler shift would be a lot less.

F2 backscatter? Aircraft scatter? Tropo? Hard to tell with just 6 spots.