QRM from a Chinese satellite on 145.725 MHz

After my four year absence from the radio, the main task now is just to get some of the gear working again. Over the last two weeks, I managed to locate the microphone for the 2m/70cm dual band rig and I have put up a vertical half-wave in the attic of the house. Not perfect but at least it gets me on the air again.

Even though the aerial is indoors, I can hear some signals from repeaters and simplex stations from about 100kms away. One of those is the Limerick repeater on R5 (145.725 MHz) which is just over 100kms to the North.

The signal is about S3-5 which means it's clear and easy to listen to but I'd probably need the full 50w to work through it.

I have also managed to get the rig set up to scan both 145 MHz and 433 MHz bands which lets me see who is about. The level of activity is pretty low so it spends a lot of time scanning.

I have noticed though that it sometimes stops on 145.725 MHz with the unmistakable sound of CW coming through. It's not CW on FM but I can hear the white noise on FM getting pulsed by a CW signal. Sure enough, when the repeater opens I can hear the CW beating with the signal and the sound of the CW frequency changing slowly....a sure sign of a satellite.

I came across this a few weeks back when I went looking for info on the Cornwall beacon on 50.042 MHz. I ended up watching a video for the AGM of their Beacon/Repeater group...as you do :o)

During the presentation, someone mentioned that there was interference to their local repeater GB3NC on 145.725 MHz from a new Chinese satellite.

Sure enough when I heard the signal today, I looked up the N2YO satellite tracking website and it was out over the Atlantic and within range. If you want to see where it is at any time or to see when it might be visible, go to http://www.n2yo.com/?s=40911

It seems that a bunch of Chinese satellites were launched in September 2015 and their up links and down links are shown below....

As you can see, the XW-2B has a beacon on 145.725 MHz which is the one I was hearing. The image below shows what it looks like with some specs...

 XW-2B
– Micro-satellite architecture
– Dimensions: 250Lx250Wx250H mm
– Mass: 9kg
– Stabilization: three-axis stabilization system with its +Y surface facing the earth
– Antenna: Deployable antenna, one 1/4λ monopole VHF antenna with max.0dBi gain is located at +Z side and one 1/4λ monopole UHF antenna with max.0dBi gain is located at –Z side, close to the each edge of satellite 
CW Telemetry Beacon: 50 mW, 22 wpm

Essentially it's a 25cm cube with 50mW into a quarter wave whip on 145 MHz. It's pretty amazing to hear it with just a half-wave vertical in the attic.

I presume a lot of others must have noticed this?

Silent Key...Bernie EI6AX...RIP

I heard today that Bernie O'Sullivan EI6AX has passed away (Notice). Bernie used to be a regular on the HF bands and always called into the IRTS News on 40m every Sunday morning. Maybe it was because of his location but he was always one of the strongest signals on the band.

Living in Cahermore on the Beara Peninsula, he was also one of the most remote EI calls in the country.

The ARRL have a piece in their audio archives about Bernie recounting his contacts with King Hussein of Jordan.,,, http://www.arrl.org/library-oral-history

Ar dheis Dé go raibh a anam

CB Divisions on 27 MHz

It can often be useful to listen on the 27 MHz CB band to see if propagation is likely on 28 MHz, especially when the 10 metre band seems dead. The fact that it is slightly lower in frequency can mean that the CB band will open before 10 metres for F2 and Sp-E propagation.

Many of those CB operators who are into DX-ing use 'Division' numbers. For example, if you heard '26 AB 123' then that person would be from England.

The full list is shown below.

Getting back on the radio after 4 years

Four years....Yes, four long years since I posted anything on this blog let alone turn on the radio.

It's hard to exactly why I was off the air for so long but the main reason is that there are so many other things happening. In a world of Facebook, Twitter, YouTube, TV and all the other stuff, there seems to be less time for things like radio. I guess the biggest single reason is that I just got out of the habit of turning on the radio and using it.

In the last two weeks, I had to do some paperwork for something else and this get me to sort out all my Comreg and IRTS paperwork and notices. That single act alone got me thinking about the radio again.

On the Comreg front, I managed to find my PIN number and I was glad to see that I still had a licence when I logged onto their site! :o)) I wasn't sure if it had lapsed or not but the renewal is still a few years off.

With the IRTS, I rejoin every year but I'm always late. It was always a case of rejoining...looking back through a years worth of newsletters online...and then forgetting about it again. Looking back through the newsletters this time, one thing that struck me was the number of people who had passed away.

Antennas.......On the antenna front, the four years have taken their toll. I no longer have any external antennas as they have been damaged in various storms and I've taken them down. The only antennas I have are the two in the attic of the house....a 2 element beam for 50 MHz and a vertical half-wave for 144 MHz. The next step will probably be to get a vertical up again for 28 MHz.

Conditions on 28 MHz...Tues 23rd Oct 2012

Another good day on the 10 metre band with the solar flux at 144. The photo above shows the 57 WSPR stations heard on 28 MHz between the time the band opened at 7:34 UTC and closed at 19:56 UTC.

Points to note....
1) Lots of spots from Australia including Tasmania :o)
2) I heard a station in Japan for the first time on WSPR on 10m! Note the Northerly path. Japan on 10m was pretty common at the peak of the last solar cycle back in 2001. Those northerly paths are still proving difficult at the moment with the flux at 144.
3) Absence of signals from Africa and South America has more to do with a lack of stations using WSPR rather than a lack of propagation.
4) The band opened to the NW coast of the US which again is a Northerly path and a good sign. It was open to the same area the previous day as well.
5) Backscatter.......every day now, I am hearing stations in the UK. A while back, I was wondering if the mode of propagation was tropo, aircraft scatter or Sporadic-E? Now I'd be almost certain that it's F2 backscatter. It seems to be remarkably consistent day after day. If the band is open then the backscatter is present. The thing is that WSPR is hearing signals that are normally buried in the noise.

These are the stations in the UK heard on the 23rd of Oct via backscatter. Most are using 5 watts. G4ILO had 2 watts into an attic dipole...

Timestamp Call MHz SNR Drift Grid Pwr Reporter RGrid km az
 2012-10-23 16:24 G4HZW 28.126086 -25 0 IO83uh 2 EI7GL IO51tu 442 251 
 2012-10-23 13:32 G3JKF 28.126153 -23 1 JO00bs 5 EI7GL IO51tu 603 285 
 2012-10-23 11:12 G4ILO 28.126172 -23 0 IO84hp 2 EI7GL IO51tu 455 229 
 2012-10-23 10:32 G4FDD 28.126065 -20 0 IO93kx 5 EI7GL IO51tu 540 247 
 2012-10-23 10:32 M5DND 28.126142 -19 1 IO82ll 5 EI7GL IO51tu 370 261 
 2012-10-23 10:30 MW0BYS 28.126099 -23 0 IO71mr 5 EI7GL IO51tu 235 275 
 2012-10-23 09:52 GW7PEO 28.126167 -18 0 IO83gh 5 EI7GL IO51tu 370 246 
 2012-10-23 09:14 G8JNJ/A 28.126049 -20 0 IO90hx 5 EI7GL IO51tu 495 284 

Some of the WSPR stations heard using less than one watt...

Timestamp Call MHz SNR Drift Grid Pwr Reporter RGrid km az
 2012-10-23 14:58 K9AN 28.126185  -20   0   EN50wc   0.5 EI7GL IO51tu 5982 49 
 2012-10-23 14:40 VE3EWW  28.126095   -9   0   FN03gv 0.2 EI7GL IO51tu 5160 54 
 2012-10-23 14:38 N4AU 28.126151  -9   0   EM62vp 0.05 EI7GL IO51tu 6420 46 
 2012-10-23 14:16 W8AC 28.126186   -14   0  EN91jm   0.05 EI7GL IO51tu 5434 52 
 2012-10-23 13:22 K3DCW   28.126110   -7   0   FM18qt 0.5 EI7GL IO51tu 5319 51 
 2012-10-23 10:36 OK2SAM   28.126145   -19   0 JN99du 0.5 EI7GL IO51tu 1874 287 
 2012-10-23 10:18 LB9YE 28.126055  -16   0   JP54pu 0.5 EI7GL IO51tu 1829 227 
 2012-10-23 08:34 VK2GEL   28.126146   -25   0 QF56oc 0.5 EI7GL IO51tu 17434 327 

50 MHz.......I also noted that there was an opening from the UK and Ireland to South Africa according to the DX cluster. No sign yet of any F2 East/West conditions.

Mystery WSPR signal on 28 MHz....

Over the last week or so, I have at times seen an odd looking signal while using WSPR on 28 MHz. It starts off about 10 Hz too low in frequency and then drifts upwards for about 30 seconds and then stays reasonably steady for the remaining 90 seconds of the WSPR two minute time period.

When I first saw this signal, I wasn't getting any decodes but eventually, it came through.....it was GW7KNF in West Wales on backscatter. I have no idea as to why his signal drifts at the start but it is unique to his signal.

Normally, I think a signal needs to drift less than 4 Hz to be decoded. Considering that at least 20% of his signal exceeds this then perhaps you don't need to hear the full two minutes of the signal to decode it? Going on the above example, it looks about 90 seconds.

New Zealand heard on 28 MHz...Sat 20th Oct 2012

Loads of signals on WSPR on 28 MHz today.....

While it's nice to see the stations coming through from Australia and the West coast of the US, the one that really caught my attention was ZL3PX from New Zealand. Considering that it is at the opposite end of the globe as viewed from Ireland, it's reasonably rare on 28 MHz.


Timestamp Call MHz SNR Drift    Grid   Pwr Reporter RGrid km az
 2012-10-20 08:28 ZL3PX 28.126130  -20 1  RE66hm 5   EI7GL   IO51tu   19081 4 
 2012-10-20 08:16 ZL3PX 28.126130  -20 1  RE66hm 5   EI7GL   IO51tu   19081 4 
 2012-10-20 08:06 ZL3PX 28.126131  -21 0  RE66hm 5   EI7GL   IO51tu   19081 4 
 2012-10-20 07:48 ZL3PX 28.126132  -20 1  RE66hm 5   EI7GL   IO51tu   19081 4 
 2012-10-20 07:38 ZL3PX 28.126132  -23 0  RE66hm 5   EI7GL   IO51tu   19081 4 

But how did the signal get from New Zealand to Ireland? Short path over the North Pole? I have my doubt's. Long path over the South Pole? Or skewed path?

New tower at EI7M...

I got an e-mail this morning with the link to new IRTS newsletter. Looking through some of the news items, I came across a link to this video showing the new tower for the East Cork Radio Club contest station, EI7M.

Some serious metal in the sky here....

Skewed path on 28 MHz???

This morning (~8:45 UTC), I heard NH7O in Hawaii on SSB on 28 MHz.

His signal was very weak, maybe 4/1 to 4/2 at best. He was working a pile up and it was obvious that he was getting into the UK and Ireland pretty well. I gave him a call towards the end......managed to get a EI7?? back but then he dived into the noise. I think it was probably just at the end of the opening.

But I was curious. How did the signal get from Hawaii to Ireland?

This is the short path shown above. It almost certainly wasn't short path as the band hadn't opened to the US and the North-West yet. What about long path? Did the signal travel over the South Pacific, over Antarctica and then over Africa???

Or was it a skewed path? From somewhere over the Indian Ocean? I have heard of this before whereby European stations work Japan on 50 MHz by beaming at the Indian Ocean. Not long after hearing NH7O, I could hear the Australian beacon VK8VF/B near Darwin. Earlier, I was hearing the Phillipines on WSPR so the band was certainly open to that part of the world.

Wonder what way people were beaming when they worked him? It's kind of hard for me to tell with my vertical ;o)

WSPR on 28 MHz...Wed 17th Oct 2012

Some more good conditions on 28 MHz on the 17th again. Started off with WSPR station being heard in Australia and finished with ones near Los Angeles in California...

Two Australian stations were heard, VK5AKK near Adelaide and VK2FLR near Sydney.

VK5AKK was being heard or was hearing a lot of stations in Europe

In contrast, none of the stations in the UK were hearing VK2FLR.
His signal  went over the UK and landed in Ireland instead.

There was no shortage of backscatter? signals as well with lots of the stations in the UK being heard. GW7PEO and G4HZW were the most consistent.......

Signal to Noise of the UK stations heard on the 17th...
G4ILO.....-25dB (1 spot)
GW7PEO.....-22dB to -26dB (18 spots)
G4HZW......-20dB to -25dB (31 spots)
G4KPX.......-25dB (1 spot)
G4FRE........-23dB (1 spot)
GW3LEW......-25dB (1 spot)
G8JNJ/A.......-21dB to -26dB (5 spots)

All pretty weak signals buried in the noise. Typical of what might be expected for back scatter.

WSPR on 28 MHz...Tues 16th Oct 2012

Over the last week or so, the solar flux had dropped down to around the 100 mark and there was a distinct lack of good East-West propagation. On the 16th, the flux was back up to 137 and the band really opened nicely to the USA...

There seems to have been some Sporadic-E signals from Europe as well. In fact, there seems to be plenty of weak Sp-E around most days.

Almost every day as well for the last week, I have heard WSPR signals from stations in the UK. The only pattern is that they seem to coincide with good Sp-E conditions to Europe or good F2 conditions. I would say at this stage that I am pretty sure that they are via back scatter rather than some other mode.

Back issues of 73 Magazine...

I came across this amazing resource recently. 73 magazine was an amateur radio publication that ran from October 1960 to September 2003. In total, there were 513 issues and they are all available now for free in PDF format.

Click HERE

No decode on WSPR spots...

One of the main reasons I have this blog is to act as a scratchpad for myself. If something happens that I want to make a note of, then it's a handy place to keep a record of it and if it helps someone else fix a problem that they are having then so much the better.

On the morning of the 11th of October, I was receiving a station as shown above but I was getting no decodes. Looking at the database on the WSPR website and the spots from other stations, it seemed as if the station was EA8FF, someone who I have heard and decoded over the last few days.

I switched the rig to 30m and left it listening to the WSPR signals there for about 10 minutes. No decodes. So obviously, WSPR had stopped working.

Solution.......it turned out that the sound card in the PC seemed to have crashed or at least the micropart part of it. It was a simple case of rebooting the PC and everything worked fine again.

Wartime Radio : The Secret Listeners...

I came across this video clip recently from the BBC about the vital part that radio amateurs played in wartime Britain by listening in to coded German traffic on the short wave bands.
The programme was broadcast in 1979 which was 33 years ago, about the same amount of time from when the events happened in WW2.

The 29 minute video clip can be seen HERE

The LED is 60 years old this month

The Light Emitting Diode started life in October 1962, as a single red illumination in a General Electric research lab in New York state.

In this video clip, the LED inventor Prof Nick Holonyak Jr look back at how it all began........click HERE

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.

28 MHz...Wed 3rd Oct 2012

Another day with some good conditions on the 10 metre band. I left the radio on the WSPR frequency for most of the day........which is great as I don't have to be there! ;o)

I had a quick listen at various times as well and it was different from the previous days. No Australians heard this time but DU1MGA did make it through with one spot on WSPR...

2012-10-03 10:48 DU1MGA  28.126068  -28  1  PK04lc 5   EI7GL   IO51tu 11213 331

On SSB, I heard VU3RAZ in India and A4 and A6 stations in the Middle East. Also, lots of Russian and Ukraine stations at one F2 hop distance.

As the map shows above, there was some Sporadic-E as well with some of the closer European staions in Germany and Spain making it through. Later, it opened to the USA again, the first time really since last Sunday and the aurora on Sunday night. The one of interest here was N6OIL making it through from California...


 2012-10-03 18:08 N6OIL 28.126067 -28 0 DM14fl 0.2 EI7GL IO51tu 8212 37 
 2012-10-03 17:50 N6OIL 28.126068 -22 0 DM14fl 0.2 EI7GL IO51tu 8212 37

Another point of interest was GW7PEO made it through again, presumably on back scatter?...



 2012-10-03 13:52 DB0ZDF 28.126080 -24 -1 JN49cx 5 EI7GL IO51tu 1178 287 
 2012-10-03 13:44  GW7PEO 28.126137   -21  -1   IO83gh 5 EI7GL IO51tu 370    246 
 2012-10-03 13:44 EA8FF 28.126107 -12 0 IL18pc 2 EI7GL IO51tu 2730 12 
 2012-10-03 13:44 DG2NBN 28.126031 -24 0 JN59nr 5 EI7GL IO51tu 1387 287 
 2012-10-03 13:40 CX2ABP 28.126066 -24 1 GF15wc 10 EI7GL IO51tu 10705 27 
 2012-10-03 13:38 EA8FF 28.126107 0 0 IL18pc 2 EI7GL IO51tu 2730 12 
 2012-10-03 13:38 DF6MK 28.126047 -24 0 JN68ik 5 EI7GL IO51tu 1544 292 
 2012-10-03 13:38 KK4XO 28.126004 -13 -1 EL96uf 5 EI7GL IO51tu 6527 43


Again, EA8FF was being heard at the same time with a reasonable signal indicating good conditions to the south. In reality, the back scatter could be from anywhere....south? south-west? south-east? Today, the spot from GW7TEO was at 13:44 UTC. The two spots from yesterday were at 14:30 and 14:52 UTC.

Overall.....some notes...
1) Over the last few days that I have been listening on the 10 metre band, the Solar Flux index has been around the 120-130 mark.
2) Lot's of multi-hop F2 conditions but very variable. Open to different areas on different days.
3) The most consistent signals as expected are the single hop F2 ones....East Mediterranean, Russia.
4) The most consistent beacons are those around the 3,250 to 3,750 km mark. e.g. 5B4CY/B in Cyrus, SV5TEN/B in Rhodes.
5) When conditions on 28 Mhz got very good, the skip distance shortened and the beacons around 2,400 kms were heard.
6) There is a fishing buoy on the WSPR frequency! It ID's itself as 'DJ' but seems a bit low in frequency so is not a issue.
7) Using WSPR to measure band conditions is somewhat limited by the number of people using it. For example, there is a lack of WSPR stations in the mid states of the USA. All you can use the WSPR map for is to gauge where the band is open to, not where it is not open to. The band can be wide open to southern Russia and there can be no WSPR spots.

Backscatter.........For anyone not familiar with the principles of back scatter, it works as follows....

A signal from a transmitter 'bounces' off the ionosphere and lands in a target area. A small percentage of that signal may be reflected back towards the TX due to mountains, waves on the oceans, etc. Received signals tend to be very weak.

P29VR on 28 MHz...

Interesting conditions on the 10 metre band today. After starting off listing on WSPR for about two hours and then having a quick listen around the band, it was soon obvious that the conditions were better than the map on the WSPR website might suggest.

Came across P29FR in Papua New Guinea. He was weak but I could hear him giving 5/5 reports which was a sure sign he was working weak stations. So after a quick scramble in the drawer for the microphone.....one call....and P29FR was in the log! My first QSO since May 2011 ;o)

Conditions seemed to be pretty good around 11am with signals coming through from South-East Asia and Australia even though they were weak. I heard VK6APZ on the West Coast of Australia, HS0ZEX in Phuket Island in Thailand and later, I heard 9M2CQC in Malaysia on WSPR.

Timestamp Call MHz SNR Drift Grid Pwr Reporter RGrid km az
2012-10-02 14:44  9M2CQC  28.126119   -16   0  OJ03tb  10   EI7GL  IO51tu  11089  324 

Signals heard on WSPR on 28 MHz...Tues 2nd Oct 2012. Red dots are some of DX stations heard.

I also heard 5Z4/LA9PF in Kenya as well as the ZD9UW expedition on Tristan da Cunha in the South Atlantic....just about audible but way too weak to work. There were also plenty of signals from Eastern Europe...Ukraine and Russia as well as some strong signals from Cyprus and the Canary Islands.

I was kind of expecting it to open later to the US but it never happened. I heard some weak beacons from Argentina and Brazil but that was about all. I was hearing EA8FF on WSPR up until 18:48 UTC, some 40 minutes after local sunset here.

GW7PEO.......Of the European signals heard on WSPR on 28 MHz, one struck me as strange...GW7PEO in North Wales.

Timestamp Call MHz SNR Drift Grid Pwr Reporter RGrid km az
 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 

At 370 kms, it's an odd one. It's very close for Sporadic-E and I didn't seem to hear any of the other UK stations active at the time. It might have been via tropo?.......although I have my doubts. If he was on the west coast then I might think maybe but he is on the coast of North Wales with some high mountains to his south-west. Meteor scatter?.......although the requirement for a two minute burst and the lack of other UK stations tends to rule that one out. The only other possibility that I can think of was that it was via back scatter? F2 or Sp-E?

2012-10-02 14:52 GW7PEO  28.126146   -24 0 IO83gh 5 EI7GL IO51tu 370  246 
2012-10-02 14:50 EA8FF 28.126116 +9 0 IL18pc 2 EI7GL IO51tu 2730 12 
2012-10-02 14:40 EA8FF 28.126116 +8 0 IL18pc 2 EI7GL IO51tu 2730 12 
2012-10-02 14:36 EA5EHS 28.126164 -23 1 IM99wv 2 EI7GL IO51tu 1473 337 
2012-10-02 14:32 EA8FF 28.126116 +7 0 IL18pc 2 EI7GL IO51tu 2730 12 
2012-10-02 14:30 GW7PEO 28.126146 -23 0 IO83gh 5 EI7GL IO51tu 370  246 
2012-10-02 14:26 EA8FF 28.126116 +8 0 IL18pc 2 EI7GL IO51tu 2730 12 

Looking at the WSPR spots above, GW7PEO at -23dB is buried deep in the noise. At roughly the same time, EA8FF is flying in with +8dB......obviously good F2 conditions to the south. My guess is backscatter via F2 but it's impossible to be sure.