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ISS radio Filter





Hi all:

One of stations Andre PE1RDW asked if there is a radio filter on ISS.
The answer is no , not yet.

On the Mir station, we had a problem that when the Mir commercial
transmitter was active, it would de-sence the 2-meter amateur radio
receiver on 145.985 FM Simplex.  The commercial VHF radio would
effectively disable the Amateur radio station until the VHF transmitter
shutdown.
This was not the fault of the any equipment, its just the facts of
radios,
you can not put a powerful transmitter next to a receiver and space the
channels
a few megs apart with out special filters.
The MAREX-NA team, had DCI custom design a filter which solved the
problem.

http://www.siliconpixels.com/marex/DCI.htm

We believe a similar problem may exist on ISS, so we have been working
on a 
design for possible use on ISS. The old filter weighed 4 pounds and
was 15 inches long and required
5 chambers which were a combination of Notch and pass band chambers.

The new filter will be similar, yet 1/3 lighter and smaller.
The Amateur Radio currently being used on ISS is a commercial grade HT,
which
has a little better selectivity than a typical amateur radio HT.
However we believe that even the good built in filters of the HT
we may have difficulty fighting off the ISS commercial VHF transmitter
which is only 30 feet away in distance and only 800khz in frequency
from new Amateur Radio ISS uplink channels.

We hope to have a protoye completed by the end of the year, and if the 
project is needed and approved, be flight ready by summer 2001.

Miles WF1F  MAREX




> 
> No that I think of it did the bring a simular filter to iss as they have in
> mir to prefent the downlink tx deafening the ham station?
> 
> 73 de Andre PE1RDW
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