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RE: Re: Thoughts on future "FM birds" (was: proposal for maximizing fm le o contacts)



On Fri, 18 Aug 2000, Tony Langdon wrote:

> But is SSB the be all to end all? ...
> Surely there are other modes that can be tried...

Yes, Actually, we began our search for a new "easy-sat" by looking for
a way to do 10 channels of FM ...  So we looked hard at how to do FM
right... and just could not come up with anything viable...

1) 2m is out, due to not enough bandwidth
2) 70cm has the bandwidth
3) But then you need 1.2 or 2.4 GHz as the other band.  ANd we can only
   use 1.2 Ghz for transmit uplink

Now then you get all kinds of baggage encumbering an "easy" solution:

  = 70cm downlink of 10 FM channels to OMNI receivers requires at 
    least 40 Watts of continuous transmit power.  This needs a BIG
    satellite, at least 1 meter square

  = Fortunately we are beginning to see some 1.2 GHz FM HT's, but they
    would need handheld dishes or long yagis to get into the bird.
    Sort of what we do with the Arrows now.

  = No easy off the shelf 2.4 GHz transmit capability ...

  = etc...


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