As we move further into April, the F2 layer propagation in the northern hemisphere is getting worse on the higher HF bands but in contrast, things are improving in the southern hemisphere.
On the 16th of April 2024, short-wave listener Tony Mann in Perth, Western Australia reports reception of the ZS6WAB/B in South Africa on 40.675 MHz. The distance was in the region of 8320kms.
Tony writes... "To my surprise the 40.675 MHz ZS6WAB beacon was received here in Perth, W. Australia again this autumn, on 16 April 2024, from 0630 to 0750 UTC. I guess his antenna must be beaming eastwards to be audible in CW mode. IC-R75, broadbanded horizontal 6m dipole (s) at 5m agl."
While this beacon in South Africa has been heard recently in Europe over similar distances, what makes this one of interest is that it's more of an east-west path and is a sure sign of improving F2 layer conditions in the southern hemisphere.
Link... 1) See my 40 MHz page for more information on the 8m amateur band.
In a previous post, I looked at the Low Interference Potential Devices (LIPD) Class Licence in Australia and how it allowed individuals to transmit with very low power in parts of the low-band VHF spectrum.
Tony Mann is a radio experimenter in Perth, Western Australia and has over the last 12-months been operating four beacons in the low-VHF bands with each one running 100 milliwatts.
The frequencies were 30.8761 MHz , 36.6073 MHz, 39.1467 MHz and 40.6864 MHz.
In 2023, several stations heard the beacons and there are shown on the map above.
Short wave listener Hugh Cocks (HC02) is in the south of Portugal. Phil, EI9KP is located in the west of Ireland. Paul, G7PUV is located in the SE of England. All three are in the region of 15,000 kms.
Otto, VK4OTZ in Queensland, Australia is about 3,700kms to the east which is pretty much ideal for one F2 layer hop.
Tony informs me that he initially made a single frequency “beacon” on 36.860 MHz for the southern hemisphere F2 season in March-May 2023. It was simple crystal oscillator modulated by a PIN diode.
By July 2023, he had a second beacon on 30.876 MHz which was still heard in Sydney via F2 up until September 2023. By that time, Hugh Cocks in Portugal was interested in trying, so he ran 30 MHz after late Sept 2023, quickly added 36 MHz, then 39 MHz by 10 Oct and finally by 29 Oct had a 4th, 40 MHz beacon running.
The 36.860 MHz frequency was changed to 36.607 to avoid DX radar interference in Europe. The 40 MHz beacon was never received as by mid-Nov 2023 conditions had deteriorated.
Tony's antenna is shown below...
Tony uses two vertical dipoles: On the left is a single dipole for 30.9 MHz and on the right is a folded dipole for 36-41 MHz (which works adequately on 30.9 MHz).
The beacon signal is alternately switched on for 0.5 seconds, then off for 1.5 seconds. The cycle repeats every two seconds. There is a 0.5 second gap where no power is going out.
The screen grab above from Hugh, HC02 in Portugal shows what the 39.1467 MHz signal looked like on the 11th of March 2024.
Videos... This clip from Paul, G7PUV shows reception of the 30.876 MHz signal...
The video clip below shows reception of the 36.860 MHz signal by VK4ATZ...
Current Status - March 2024: Tony is currently carrying out propagation tests as we're close to the equinox.
Tony writes... "I am ready to resume the 07-11 UTC tests for Europe in March 2024 and I anticipate adding 00-04 UTC for the autumn F2 season in Australia."
It would be interesting to see more reports of people hearing Tony Mann's beacons. Perth to North America? Perth to South America?
If you hear anything then you can leave a comment here.
Over the last few months, there have been plenty of long distance propagation paths reported on the 40 MHz band but nearly all involve at least one station in the northern hemisphere. In this post, we'll look at a recent East-West path in the southern hemisphere.
5th April 2023: Short wave listener Tony Mann in Perth, Australia reported reception of the ZS6WAB beacon in South Africa on 40.675 MHz. The distance was about 8320kms.
Tony Mann writes... "To my surprise the South African 8m beacon on 40.675 MHz, ZS6WAB, made an appearance here for over 2 hours after 0615 UTC. I am amazed it was detectable, and for so long here.
The receiver is an Icom IC-R75 with audio via usb mode. The beacon was first heard around 0615 UTC on a north facing 6m broadband dipole at 5m agl. When I rotated the dipole around to face east-west the signal was much stronger.
The signal was audible for over an hour, peaked again 0645-0655 UTC and was visible on Spectrum Lab past 0800 UTC. The decoded morse revealed the callsign ZS6WAB and grid locator KG46RB. The great circle distance is 8320 km (5200 miles)."
Tony posted this video on his YouTube channel...
In response to this reception report, Willem ZS6WAB reports... "All my beacons from 40.675mhz /50.025mhz /70.025mhz /144.400mhz is beaming to Australia for the last month now. Ure report is the very first report since my antenna are turned to VK land."
I think there was a report of a VK8 station in the north of Australia hearing this beacon in the last 12-months but it wasn't really documented or reported on.
Analysis... While this opening was ongoing, Tony Mann took a screenshot from the Australian Bureau of Meteorology website which shows the predicted F2 layer critical frequency. This is the frequency that is returned from the F2 layer in the ionosphere when a signal is sent straight up.
The actual maximum usable frequency (MUF) is roughly three times the critical frequency i.e. a signal at perhaps an elevation of about 5 degrees above the horizon. The map suggests a MUF of maybe 3 x 11 MHz / 12 MHz = 33-36 MHz. It's not exact but it suggests that a path in the low VHF spectrum (30-40 MHz) might be possible.
The second thing to note from the graphic above is that conditions in the ionosphere are now better in the southern hemisphere now that we have passed the equinox.
If we consider how many good east-west paths there were in the northern hemisphere in January to March then there should be similar east-west paths on the 40 MHz over the next few months from South Africa to Australia and South America and from Australia to South America.
It really is just a case of getting more people transmitting and listening.
Link... For more information on the 8m band, see my 40 MHz page.
