I’ve been asked by our fellow Polish DXer to comment a little on his reception of a distant Ukrainian station in OIRT band. So, this time it’s not my DX, but someone elses. Alan’s report went unnoticed on Radiopolska Forum, but there’s a chance it will contribute the history of Polish FM DXing. That’s the reason to give it some attention here…
Alan’s antenna is 88-108 MHz Korner 19.3, with reflectors working as directors for OIRT, installed for horizontal polarisation. His OIRT tuner is Diora AS-502, produced in the 80s in Poland. The reception appeared shortly before noon, November 19th. after the whole morning with strong reception of Ukrainian OIRT stations that are located along PL-UKR border (Lviv, Lutsk/Rivne). The tropo must have been strong then, since these OIRT stations broadcast vertically.
Eastern and norteastern direction at Alan’s QTH – Skalbmierz was also dominant on 88-108: 93,7 semi-local Planeta overriden by R.Opatow and 93,8 Tok FM from Lublin instead of Złote Przeboje. Well, only Polish DXers would know that must indicate something going on. Apart from this, nothing else was indicating SUCH a great conditions for FM DXing that day. Maybe 88-108 MHz Ukrainian station were making it’s way into Polan too, but were covered with PL locals? OIRT band is empty in our country, so it’s perfect area for DXing with the East.
Alan Received “Piershiy Natsyanalniy Kanal Ukrainskokho Radio” on 68,75 MHz presumably at a distance of over 1000+km and a number of other Ukrainian stations.
The tropo that day wasn’t exceptional, as based on the observations of all other stations – especially in CCIR (88-108) band. What mode caused such distant reception? To try to answer that, we must assume two things:
- 68,75 MHz is not broadcasted from anywhere else closer to Poland. There are only two transmitters carrying Ukrainian Radio 1 on 68,75: in Trostyanyets, which was presumably received – 1025km from Alan’s QTH; and Lughansk – even further in easternmost Ukraine – that would be as far as 1370+km. No other txs are listed anywhere.
- Alan’s tuner is selective and provides sharp filtering and proper frequency readout. Otherwise, this could be a closer neighbour-channel station. He says he’s tuner’s fine. Moving on then…
Sporadic-E comes to mind as first. No wonder – Eastern Ukraine has ever been received in Poland only via Sp-E, and even I myself got UR1 on 68,75 at an occasion. November 19th might have been an off-season opening, not that uncommon for the lower bands. But it’s not a clear Sp-E skip in my opinion.. if you listen distinctly to the recording, you will hear the fading which helps peak the signal to quite fine mono reception. The signal peaks twice throughout the recorded time. Such schematic fading is significant to another mode of propagation…
Aeroscatter Recent research by Konrad with hi-end antenna and tuner, pushed max DX via scatter from commercial aeroplanes at 12km agl. to as far as 830kms. This Ukraininan tx is significantly further. Was it caused by aircraft at an altitude over 12km a.g.l.? -Like military? Sadly Alan didn’t follow radars by then and we don’t know if it was commercial flight. But of course, online radars won’t indicate high alt military flight… One important detail is, that prior to 68,75 Alan received 72,35 from Ukraine – faint but steady for over 3 minutes.
Mixed mode So, it was defenately some sort of scatter, probably linking with other mode of propagation. Was tropo over Ukraine such strong at that time, that a commercial plane scatter boosted it and carried additional kilometers to let Polish DXer finally receive it at 1025km? Checking logs in DXmaps.com showed some tropo traffic in Kiev area. Also Hepburn indicated some light tropo (of 2nd degree) stretching latitudinally over Ukraine – but we always treat it only demonstratively, potentially. Baric maps claimed 10hPa difference between QTH and DX.
What about Es+scatter? I’ve heard scatter disturbance of ionosphaeric signals. A shortskip that was boosted by a plane passing by. What about the preceeding 72,35 signal?
Maybe MS/FAI? Leonid meteor shower peaked only two days before the reception, so still provided some ionisation, especially in the morning. Some MS I heard, especially those probably being FAI, performed flutter that sounded just like scatter’s fading. But I wouldn’t say this one. We discussed this phenomenon, and it realised us that tropo over huge distances towards East is still the topic to study and research on. Only recently we received mainland Russia via 900+km ducting and now this… I enjoy our hobby is so scientific!