Radio Meteor Forward Scatter Observations during Leonids 2002

Notes on an amateur observation. Please bear in mind that these results are not peer reviewed in any way. Last modified, 18th Oct 2003.
Frequency: 55.25 Mhz
Transmitter: TV signal from Liege Bol d'air, Belgium.
Receiver: Todmorden, UK. 53:42:00 N, 2:04:00 W. 
Path:  Approx 500kM.
Recording: from 18/11/02 12:00 UT, to 19/11/02 18:00 UT.

Reception Method

Zenith pointing wire turnstile with ground as reflector. AR8200 scanner receiver, upper sideband mode, 55.2493 Mhz, audio output to PC soundcard. Data recorded in unsigned bytes at 8018.609 samples/second.

The setup is identical to previous year's recordings, 1999 and 2000.

Mean Relative Signal Strength

Using 300 secs integration per point. This is the raw signal with no allowance for radiant elevation.


The two large spikes at around longitude 236.67 and 236.79 were each due to single very strong overdense returns lasting several minutes.

Peak signal for the 1767 trail occured at 04:02 UTC +/- 3 mins.

No sign of a single strong peak corresponding to the 1866 trail. Instead a number of separate well defined peaks of modest average signal strength containing a large number of weak pings and head echoes.

A second TV carrier within the passband comes from Bagn, Norway, on 55.2513 Mhz and delivers a weaker signal, shown below.


The graph below shows both signals together.


Lack of correspondence between the sub-peaks of the two signals suggests that they don't carry meaningful information about the detailed density of the dust trails.

Sounds samples

leo02-236.960.mp3 (215kB, 70 seconds) - A sample from near the end of the 1866 peak. Pings, head echoes, and overdense returns from at least four distant TV transmitters are audible in a 4kHz passband based at 55.2493MHz.

References

Armagh Observatory, The Leonid Meteors 2002.

For those interested in turning their scanners to the skies, the following European band 1 TV transmitters deliver a reliable stream of background meteor pings in northern England. All are horizontally polarised.

Greipstad, NOR, 48.2528 Mhz, 50kW, 07e51/58n13, 795km.
Melhus, NOR, 48.2564 Mhz, 100kW, 10e22/63n59, 1340km.
Hemnes, NOR, 55.2487 Mhz, 70kW, 13e44/66n13, 1635km
Liege Bol d'Air 55.2500 Mhz, 05e33/50n35 100kW, 625km. (*)
Lousa, POR, 55.2500 Mhz, 06w11/40n25, 60kW, 1510km (*)
Bagn, NOR, 55.2513 Mhz, 09e37/60n49, 55kW, 1055km (*)
Kobenhavn, DNK, 62.0573 Mhz, 50kW, 12e30/55n44, 960km, (*)
Raichberg, D, 62.1927 Mhz, 100kW, 09e00/48n18, 980km, (*)
Lopik, HOL, 62.2135 Mhz, 05e03/52n01, 100kW, 510km (*)
Bremanger NOR, 62.2539 Mhz, 80kW, 05e00/61n53, 1000km (*)
Vuokatti, FIN, 72.1771 Mhz, 40kW 28e16/64n08, 2061km.

Data for the above list came from http://www.ukwtv.de/de/publikationen/tvlist/EU1.pdf . Those marked (*) are strong enough to be audible, the others are only visible on a spectrogram under normal conditions.


Paul Nicholson paul@abelian.demon.co.uk   Comments and suggestions are welcomed.