(meteorobs) Radio Forward Scatter

[David Entwistle]

In message <6.2.3.4.2.20090612164757.036d0928 at pop.west.cox.net>, Lake 
Hodges Radio <LakeHodgesRadio at Cox.net> writes

>
>There are also VHF AM audio carriers on the aircraft band between 108
>and 135Mhz... these are low power automated traffic (and weather)
>information stations (ATIS), and there is one at just about every
>mid- to large-size airport.
>
>Can you use any of those signals to detect ionized trails?
>
>-- Kurt, K6SDO/N6MD

Hi Kurt and radio meteor observers,

It's a interesting suggestion. The advantage of the analogue TV vision 
carrier is that it contains a large un-modulated carrier component - 
ideal for meteor work. There isn't any other common service, which 
replicates this high-power un-modulated component, but that isn't to say 
the transmissions can't be used.

I've put together some details of the aeronautical allocations - if 
anyone can correct, or add to these it would be useful.

For those that don't know it, ATIS is Automatic Terminal Information 
Service.

<http://en.wikipedia.org/wiki/Automatic_Terminal_Information_Service>

I think it's worth broadening the discussion initially to include all 
aeronautical allocations. These include the following bands:

190 - 1750 KHz NDB
108 - 112 MHz ILS (localiser)
108 - 118 MHz VOR & GBAS*
118 - 137 MHz - Civil VHF voice communications*
236 - 282 MHz - Military UHF voice communication
328.6 - 335.4 MHz - ILS (Glide Path)
590 - 598 MHz Ground Radar (50cm)
960 - 1215 MHz DME, TACAN, Secondary radar (1030/1090 MHz)
1215 - 1350 MHz Primary radar
2700 - 3100 MHz Primary radar
4200 - 4400 MHz Radio Altimeters
5000 - 5150 MHz MLS
5350 - 5470 MHz Airborne Weather Radars
9000 - 9500 MHz Ground movement and airborne radar
13250 - 13400 MHz Doppler navigation aids
15400 - 15700 MHz Ground movement radar

* ATIS uses these allocations and possibly the military UHF voice 
allocation?

Of these, the following are of a frequency which may be of use for radio 
meteor work:

108 - 112 MHz ILS (localiser)
108 - 118 MHz VOR  & GBAS
118 - 137 MHz - VHF Communications
236 - 282 MHz - Military UHF voice communication
328.6 - 335.4 MHz - ILS (Glide Path)

ILS (localiser) - Instrument Landing System (localiser)
<http://en.wikipedia.org/wiki/Instrument_landing_system>

VOR  - VHF Omnidirectional  and Range
<http://en.wikipedia.org/wiki/VHF_omnidirectional_range>

VHF Communications - uses Amplitude Modulation, but isn't a continuous 
transmission. The airline operators also uses this allocation for their 
information services.

GBAS - Ground Based Augmentation System (GBAS)
<http://www.eurocontrol.fr/Newsletter/2002/November/GBAS/GBASv0.32.htm>

ILS - Instrument Landing System (Glide Path)
<http://en.wikipedia.org/wiki/Instrument_landing_system>

Of the above, although not ideal, VOR looks to be the best candidate for 
meteor work.

Best wishes,
-- 
David Entwistle