Which FCC table is applicable to ...

[Phil]

Only the lower frequencies would be reflected, i.e. depending on angles, those cited as “maximum usable frequencies” (MUFs) and below. Higher frequencies would pass through as they do from earth, disappearing into space forever. Hence the use of 30 MHz and up (VHF / UHF for most modern amateur low-earth-orbit satellites). The USA and USSR had agreed to the international use of VHF frequencies (150 MHz?) before either had launched a satellite in 1957; USSR reneged on the deal as soon as Sputnik 1 was launched, transmitting on roughly 20 and 40 MHz; they wanted radio amateurs to be able to hear the transmissions before the US Government could claim that the launch announcement was a fake. The Sputnik 1 beacons were credited with advancing understanding of the ionosphere.

Interestingly, when Heaviside and Kennelly predicted the existence of an ionosphere in 1902, their arguments were so persuasive (they did not consider the effect of frequency) that all research into radio astronomy ceased for nearly 25 years!

Phil M1GWZ



> On 25 Feb 2021, at 17:39, <samudra.haque at gmail.com> <samudra.haque at gmail.com> wrote:
> 
> Thanks Dick, I guess a beacon would be just another carrier in an assigned band, but considering that FCC couldn’t give me a direct answer, I had to ask.
>  
> What I am wondering (given the few pieces of information available) is historically, what were the mode/types of beacons that were downlinked in the HF range that were sent down from Satellites?
>  
> What’s the principle behind the beacons coming down to Earth stations, through the ionosphere? I though they would get trapped by the ionosphere as being reflected ? It’s fascinating know how.
>  
> samudra
> From: Dick <w3hwn at comcast.net> 
> Sent: Thursday, February 25, 2021 12:34 PM
> To: samudra.haque at gmail.com
> Cc: Tacos <tacos at amrad.org>
> Subject: Re: Which FCC table is applicable to ...
>  
> There are a number of satellite downlink bands. Which ones you're entitled to use it depends on the service you are providing. Amateur satellite bands are, of course, in the amateur bands. The ones that Noaa uses are in the middle meteorological bands.
>  
> On Feb 25, 2021 11:35 AM, samudra.haque at gmail.com <mailto:samudra.haque at gmail.com> wrote:
>> Could anyone help me understand:  If  a satellite were to send a beacon transmission to a ground station, which FCC regulated sub-band would be applicable?
>>  
>> All I found for ‘identification’ was:
>>  
>> 30.005-30.01
>> SPACE OPERATION (satellite identification)
>> FIXED
>> MOBILE
>> SPACE RESEARCH
>>  
>> That is 30.005-30.01 MHz !
>>  
>>  
> 
>  
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> https://lists.amrad.org/mailman/listinfo/tacos

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