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Re: lower frequency downlinks cont.



At 12:40 PM 1/31/06 -0800, "Scott Avery WA6LIE" <wa6lie@msn.com> wrote:
>Pat,
>
>Having the technical ability of building a satellite is one thing.
>Having the ability, contacts and funds to launch is another....
>So, I assume, since you don't know how to build one, you have a couple
>million
>dollars laying around to launch one?
>
>Step one is to at least have a ground station capable of "communicating"
>with the bird.
>That is the "easy" part!
>
>As for HF and LEO/HEO satellites, 10 and 15 meters can be a problem with LEO
>satellites,
>and difficult at best for a HEO scenario. The RS series of satellites were
>primitive, but useful.
>
>Did you ever take an Amateur exam where they talk about propagation?
>The invisible D to F2 layers? When there "is" propagation on these bands,
>that means the signals are not going out into space anymore, and thus
>reflected
>back to earth. Some call it DX. So, when there is propagation, signals from
>space may not
>make it to earth, bounce around or killed with QRM. With "weak" signals
>(QRP) from a spacecraft,
>one needs to have a decent antenna and receiver. Remember.. it's all in the
>antenna!
>Amps/preamps help.
>
>Oh... I just threw KISS out of the equation.
>Cans and a string would only work for a limited amount of orbits.
>
>Back to the drawing board...
>
>73, Scott


This thread got interesting. :-)

I remember some weird propagation effects when RS-10/11 was in KT 
modes.  The band openings on 15 & 10 meters made for some interesting 
contacts.  I remember working the bird when it wasn't in-range "line of 
sight".  HF propagation made things strange, yet very interesting, when you 
sat back in your chair and tried to figure out was happening.  Guess it's 
just one of those things hams find interesting.

I don't recommend or want to see HF frequencies on HEO's.  If someone wants 
to experiment with it on a new LEO though...

73
KB7ADL
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