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Re: (meteorobs) Radio Arietids Peaks?
Dear Thomas.
Thomas Dorman wrote:
>>I have had my FM meteor scatter system
>> running all daylight hours and late
>> into the night since Saturday June 1st
>> working 89.5 Mhz.
Congratulations for tuning into radio meteors.
>>increase Monday June 3rd and appeared to
>>me to peak out somewhere between 11UT-14UT
>> June 5th. Could not count this peak, to
>> many events
This can happen from May to August and is normal "sporadic-E" propagation. Sporadic-E gives you either continuous reception, or reception at continuous intervals (sometimes, not every time). In the minutes before sporadic-E and after the start of sporadic-E there are *sometimes* very reqular intervals observed, at a rate of 3-20 per minute. The echo strength and echo dip (short noise break) are quite exact, and vary slowly over minutes. If you compare this to the Quadrantids or Geminids (which are my "standard" meteor shower), the meteors come at irregular intervals, never on the same second(s) interval. I have recordings of this "regular echos" available, if you wish, and there is surely no visual meteor counterpart.
Ongoing sporadic-E is monitored on the dx-cluster: http://oh2aq.kolumbus.com/dxs/50.html
or
http://oh2aq.kolumbus.com/dxs/144.html
It may be hard to read for non radio amateurs, but you might find a note on MUF which is the highest usable frequency. If there is a "spot" reported in your continent, there is a good chance, that there is also sporadic-E for your receiving path.
>>This I know is called overdense activity by some..
"overdense" is a term/definition for one meteor echo. The electrons in the ionosphere, which are normally not interacting with eachother, are forming an ionized column, which gives some 10seconds to several minutes of echo. Sporadic-E is always like "overdense" and strong, as the electrons interact with eachother. But the term overdense is IMHO not used with sporadic-E.
>>band and also an outburst I observed on January 15/16
>>1999 which I never saw a posting on.
Yes, Jan 15/16 1999 is most likely Sporadic-E, because it falls within the Sporadic-E Cycle, see my Sporadic-E report from January 1999 at: http://www.qsldot net/oe8fnk/sporadic-e-1999.txt (more on the cycles: http://www.cn-training.at/sporadic-e/es_forecast.htm )
>>If this is spordic E layer then it
>>mimics identically radio meteors in the FM band
>>observed audibly with the human ear.
100% YES.
FM gives only the signal level, no more information. But Sporadic-E is more often continuous (e.g. for minutes). Really good sporadic-E completely covers the real meteor echos, with the typical rise and fall times (look for more information about overdense vs. underdense meteor echos).
>> Now if you wish to make the case that
>>some spordic E layer is induced by
>>increased meteor activity as it passes
>>through the ionosphere this I could believe
>>as an outside possiblitiy.
YES, i have only very rare observation for "induced": e.g. sporadic-E was induced by meteors during the Leonids 98, but the regular case is that a meteor or fireball *triggers* sporadic-E. Read more on my sporadic-E forecast page (see above).
>>I may except such explanation for the
>>activity I observed, but I would still
>>be very suspicious.
I do not *listen* for the meteors, but record 2 distant tv video carriers with fftdsp means on the PC, which gives much more information and a crystal clear distinction, repeat, a CRYSTAL CLEAR DISTINCTION between radio meteor echos and sporadic-E, even with the Leonids 1998. Usual rate is some 10000/day since 7 years, and still stunning images. See it on the explanation on my realtime pages: http://www.cn-training.at/fftdsp_samples.htm (currently offline).
Hope this helps. I appreciate any feedback about "sporadic-E" and radio meteors, via the list or direct. Could be even on-topic?
wish you all clear skies and interference free reception of the Arietids
Werfried,
www.qsldot net/oe8fnk
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