Andy: > I have assumed that MS makes '"sense" because it > is making propagation possible that > would not be possible terrestrially?
Right... Meteor scatter allows distant VHF contacts when ionospheric modes like Sporadic-E are not available; which is much of the time. The same can be said for the upper HF bands during sunspot lulls and nighttime closings; why not meteor scatter on 10 and 12 meters when the bands are dormant? Of course, you could just go to a lower band that's still open and make contacts, but there's something about bouncing signals off a space rock that's been flying around for millions of years! Tony KT2Q ----- Original Message ----- From: "Andrew O'Brien" <[EMAIL PROTECTED]> To: <[email protected]> Sent: Friday, May 18, 2007 10:29 PM Subject: Re: [digitalradio] HF Meteor Scatter > 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 >
