"If my calculations are correct an aircraft would have to be moving at 700 kts to give a Doppler shift of 60 Hz. Metro area airports are usual in Class B airspace with a speed limit of 250 kts. Maximum speed on the BRUSR ONE is 250 kts reducing to 210 kts as they pass my house. At 250 kts I calculate a shift of 22 Hz. I assume one of us has a math error. I'll be happy to correct my spreadsheet if my numbers are wrong.
I couldn't find any screenshots of Doppler shifted FT8 signals. I'll look out for some next time there is activity on 6 m." That frequency shift calculation was for a signal transmitted at 50.3 MHz. Sorry I missed that in the original message. Two others have independently calculated doppler shift with compatible results so I think the math is correct. However, I captured several images of prominent doppler shifted signals on 6 m yesterday morning. One signal had two shifted images and the approximate maximum shift was 110 Hz. I'm now wondering if reflection between several aircraft can cause additive shifts. I'd like to share the referenced image but that doesn't seem to be possible here. 73, Andy, k3wyc ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
