OK, one more question. If the frequency has to be above the MUF, what's the point ? If the selected frequency was above, but close to, the MUF would we not expect " regular " terrestrial propagation to work ? I have assumed that MS makes '"sense" because it is making propagation possible that would not be possible terrestrially?
Andy. On 5/18/07, Tony <[EMAIL PROTECTED]> wrote:
Andy, > How do you know it was genuine MS versus sporadic terrestrial propagation? That's a good question and the answer is that meteor burst signal characteristics are unique to other propagation modes. Meteor trail ionization peaks suddenly and falls quickly causing the signal to pop-out of the noise and fade fast (underdense radio meteors). "Regular" propagation modes via the ionosphere would take on a steady state compared to this and would be unlikely at the time Colin and I had the 21MHz and 28MHz QSO's (after midnight). I've found that in general, the criteria for HF meteor scatter is: the frequency needs to be above the MUF, the noise levels need to be low to detect the signals and the distance between stations is no more than 1300 miles (the maximum distance for radio meteors). Have a listen to the attached mp3. The meteor bursts you hear were recorded during the Leonids meteor shower in November 2005. I used W4MQ's Internet Remote Base to record my 15 meter carrier. Notice there's no carrier signal between bursts. The clip is a more exaggerated version of what's heard with random meteors on a daily basis, but it gets the point accross about HF radio meteors. Also see the attached image file. It illustrates how the radio meteor rate and signal strength increases as you go lower in frequency. Notice the steady 80 meter trace at the top. It represents the MUF between W4MQ and I at the time (about 2AM local). The samples for each band were taken a few minutes apart and the record time for each band was about 1 minute. Tony KT2Q s you go lower in frequency. I created this using W4MQ's IRB between Tony KT2Q ----- Original Message ----- From: "Andrew O'Brien" <[EMAIL PROTECTED] > To: <[email protected]> Sent: Friday, May 18, 2007 4:40 PM Subject: Re: [digitalradio] HF Meteor Scatter > Fascinating Tony. I saw your Ping Jockey chat record and thought you and > Colin were on the wrong site. > > How do you know it was genuine MS versus sporadic terrestrial propagation ? > > Andy K3UK > > > > On 5/18/07, Tony <[EMAIL PROTECTED]> wrote: >> >> All: >> >> Was able to demonstrate HF meteor scatter to >> Colin, K4CML last night. We worked 10 and 15 >> meters between midnight and 2AM local time with >> WSJT. >> >> Meteor pings were especially loud on both bands >> and we were able to hear them on every sequence at >> times. See attached for one of Colin's 21MHz >> pings... >> >> Tony KT2Q >> >> >> >> > > > -- > Andy K3UK > Skype Me : callto://andyobrien73 > www.obriensweb.com >
-- Andy K3UK Skype Me : callto://andyobrien73 www.obriensweb.com
