Third order IMD is typically something like 2f1 - f2 so if f1=105Mhz and f2=90Mhz then the 3rd order IMD = 120Mhz which is smack in the middle of the aeronautical band. You can also get 5th orders(3f1-2f2) which gives 135Mhz. FM power amps are typically wideband Class C which make great mixers and common FM antennas are broadband too, so you really need to keep received RF out of your transmitters with a filter of some type or via a narrowband port on a combiner. Most Pirates are not that technical of course.
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Received a Whittington FM pirate this afternoon. This is what they played.
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Canāt recall if this has been posted at all, there seems to be a pirate on the south side of Sydney playing dance musicā¦ on 108.0 ā¦ heard it in the car around Taren Point and San Souci areas.
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Have you ruled out a car mp3 tx, possibly from the P-plater in front who you followed for most of that video?
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Nothing heard here in Melbourne with the yagi on 90.5
Edit: Actually there is some faint music there but super low signal strength
Further Edit: Its actually Triple M Mt Gambier iām picking up
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It was actually coming from someoneās home within the area. I would normally hear some sort of āwaiting for connectionā message if I detected a car transmitter. But the faint electrical noises heard in the background proves that this is not a car transmitter.
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In car FM transmiiter reception always gives me a chuckleā¦ Iāve heard sat nav instructions, dial tones and bits of conversations on them!
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Iāve picked up some of those too when scanning the FM band, and have picked up music, phone calls, and podcasts. And yes, Iāve received sat-nav (GPS) instructions from those transmitters too. They were so hilarious. Many have said āwaiting for connectionā at times, most likely Chinese imports, due to the fact theyāre probably buying these off Temu or Aliexpress.
Perhaps I should maybe start a new thread where we cover various reception of random car transmitters?
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The Whittington pirate was on-air again as of 2:42pm this afternoon. Possibly operating on a daily basis. Not sure how long that FM operation will last given the transmission distance and the ability to receive it a fair bit away from the TX. Must be at 1 watt power, maybe a tiny bit more.
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That 89.5 around Blackheath which others have reported is still around, but was carrier only today when I passed through. For the record, no āFluckin Good Bangazā or anything at all was received in Penrith.
The Blackheath 89.5 was also received on the TEF from Hassans Walls, Lithgow. So itās putting out a decent amount of power.
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