Бразильская FM-радиостанция на частоте 77,9 МГц слышна в Португалии - 7 марта 2023 года

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Brazilian FM radio station on 77.9 MHz is heard in Portugal - 7th March 2023

This is a pretty amazing reception report. On the 7th of March 2023, SWL Hugh Cocks near the city of Faro on the south coast of Portugal managed to receive the FM radio station Radio Justica from Sao Paulo in Brazil on 77.9 MHz!

Just to explain the unusual frequency, Brazilian authorities are currently migrating radio stations from the Medium Wave band (AM) to a new eFM or extended FM band which goes from 76.1 до 87.3 MHz. This is just below the usual 87.5 to 108.0 MHz FM band i.e. Band 2.

The FM station on 77.9 MHz is actually Radio Cultura which is obliged to carry some of the Radio Justica programmes and it runs 5KW from the city of Sao Paulo.

You can listen to the reception report below and Hugh reports that it’s about Brazilian employment law.

Hugh reports using a 3-element antenna with a low noise narrowband FET amplifier. The signal was at its strongest between 22:20 and 22:40 UTC.

Hugh writes… “The evening TEP starts around 2145gmt with Ch A2-A4 TV, fluttery signals as usual. Then if good 2210 or so tiny carriers from Ch5 TV 77.25MHz and then it may appear, often lower quality than this. Last night conditions were less but there was a new station on 76.9MHz playing non stop music, very weak.

Анализ… As the map shows above, the FM signal on 77.9 MHz from Brazil traveled about 7880 kms to reach the south coast of Portugal. While a signal at around 78 MHz is likely to propagate better than the usual 88-108 MHz Band 2 signals, it’s still a remarkable distance.

As Hugh indicates, it looks as if the mode of propagation was TEP – Trans-Equatorial Propagation. The time of about 22:30 UTC is about right for evening TEP.

What seems unusual though is that the signal path doesn’t seem to cross the Geomagnetic Equator at a right angle. Normally, FM radio stations from this part of Brazil might be heard in the Caribbean as the signals cross the Geomagnetic Equator at close to 90 degrees.

The lower the frequency then the higher the signal can deviate a lot from that required right angle. This often happens at say 28 Mhz or 50 MHz. Still though, it does seem to be quite far off 90 degrees for a signal around 78 MHz.

I’m also quite sure that the radio engineers in Brazil didn’t expect the signal from their FM transmitter to reach the shores of Europe!

Further experiments… As this band is largely unused, it should be largely uncongested and quiet in other parts of the world. If these eFM radio stations in Brazil can reach Europe, can they be heard in the USA? Most of the south-eastern states in the US are closer to Sao Paulo than Portugal. Is anyone going to try?

Could it be heard further north in Europe? Say in late April or early May when the Sporadic-E and TEP seasons overlap? It only requires one Sporadic-E hop to reach the UK or Ireland but 22:30 UTC isn’t the best time of day for Sp-E. Can it be done?

Ссылка… For other long distance FM reception reports, see my 88-108 MHz page.

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