[sarex] Re: Future ISS amateur radio modes

[Robert Bruninga]

> The ISS is a sufficiently large mass of metal that 
> tremendous same-band isolation should be achieveable 
> by simply mounting antennas on opposite sides of the 
> station,...[etc]

Unfortunately, Not really.  I am sure that if we had two
magmounts and could crawl all over the outside of ISS with long
enough cables, that two mutually isolated locations could be
found (kind-of-a- can you hear me now? Kind of test).  But NASA
does not allow us the resources for that kind of approach.

But even if you did find such a location, or even if you did
spend a few millions of dollars doing an RF analysis of such an
arrangement, it would all change when ever anything moved.  And
things are always moving up there.

Also, not only does one not even attempt to plan weak signal
same-band operations from the same Field Day site, one would
never risk several years of planning and millions of dollars of
effort on something that critical that might be desensed as soon
as the solar arrays moved 10 degrees..

We had several amateurs do tests of several 2 meter radios to
discover how much power on one 2m radio was needed to descense
another 2m radio and the power level was down around 10
milliwatts at 100 foot separation and it still caused 10 dB
desense. (I think I remembered those right)...

Unfortunaly then, we simply cannot plan on up and downlinks in
the same band while hoping for independent operations without
constant crew intervention with every single mode change that
affects that band.

Bob Bruninga