Outstanding VHF Tropo propagation
The year 2020 started with outstanding tropospheric VHF propagation here in southern Germany. For the first time, I was able to copy the VHF beacon GB3NGI from Northern Irland at a stunning distance of 1300km. Read more about this great opening and listen to the audio recording I made.
VHF propagation phenomenons
Radio signal propagation on VHF is normally limited to a few hundred kilometers, at most. However, sometimes extraordinary physical effects extend temporarily the effective range well above 1000km. The two most common effects are:
- Sporadic-E, when radio waves are reflected on small patches of unusually dense ionization within the E-layer of the ionosphere.
- Tropospheric propagation, when layers of hot/cold air create ducts or cause refraction.
Beacons
In a nutshell, radio beacons are automated transmitters with a known location. They are used heavily in navigation, but also Amateur radio operators rely on them as indicators for extraordinary propagation. In Europe, we, fortunately, have a respective amount of active VHF/UHF/SHR radio beacons. Most amateur radio beacons operate with modest power (1 - 20 watts) and omnidirectional or large beamwidth antennas.
My setup
My setup for 144 MHz is average. I have a single directional 11el Yagi antenna on a 6m long boom just two meters above the roof. The station is located in the Maidenhead locator JN48QM at 700m above sea level. I am lucky to have a free takeoff with no obstacles in all directions.
Figure 1: My 11el Yagi antenna for 144MHz on top of a 2el Tribander for HF (FB-23)
My lucky morning
While on a normal day I copy between 2-3 beacons, in the early morning hours of 01.01.2020 I was able to copy a total of 8 radio beacons at the same time.
Figure 2: 144MHz spectrum view with 8 visible radio beacons as copied in JN48
Here is the list of the beacons I was able to copy:
| Frequency | Beacon | Location | Distance |
|---|---|---|---|
| 144.404 MHz | DB0THE | JO51EL | 336km |
| 144.414 MHz | DB0JW | JO40EK | 303km |
| 144.435 MHz | DB0LBV | JO61EH | 377km |
| 144.444 MHz | DB0FGB | JO50WB | 249km |
| 144.454 MHz | DB0MMO | JN49RV | 153km |
| 144.463 MHz | DF0ANN | JN59PL | 175km |
| 144.474 MHz | DB0HRF | JO40FF | 175km |
| 144.482 MHz | GB3NGI | IO65VB | 1290km |
GB3NGI was the biggest surprise at a stunning distance of almost 1300km. Find below the recorded audio:
I’m licensed now for more than 20 years, but this was the first time that I was able to observe such outstanding VHF Tropo propagation. I guess 2020 started great for me!
