[amsat-bb] R: RE: R: Re: ISS SSTV frequency

[Armand SP3QFE]

Dear Carlo,

I heard about similar troubles over the Western part of Europe, however, 
I think it happens not very often. The ISS appears only a few times in 
the region of the terrestrial repeater. Moreover, the directional 
antenna system for your ground station should help you to separate 
signals from different sources (except in a few exceptional situations). 
For the part of orbit between TCA and LOS, you can try to use a 
horizontal antenna, then you should decrease interferences from the 
vertical polarization from terrestrial repeaters.

You can also ask the local repeater coordinator to move its frequency to 
avoid interferences, especially in the case, when the repeater is not 
local, but with a wide range! You can also ask to change the FM to 
Narrow-FM mode for this repeater. Good luck.

Do you know the callsign and the location of this repeater (locator)?

73, Armand SP3QFE

W dniu 2020-11-30 22:53, ik5jrz--- via AMSAT-BB napisał(a):
> Thanks Frank,
> saying to move to 145.825 in fact I forgot all the other problems but
> it is certainly a local problem in some areas. So our only hope is
> that these repeaters will not be renewed or converted to digital.
> Thanks anyway for the reply.
> 73 Carlo IK5JRZ.
> 
> 
> ----Messaggio originale----
> Da: ka3hdo at gmail.com
> Data: 30-nov-2020 22.29
> A: <ik5jrz at tin.it>, <fabrizio.carrai at gmail.com>, <amsat-bb at amsat.org>
> Ogg: RE: [amsat-bb] R: Re:  ISS SSTV frequency
> 
> All,
> 
> We CANNOT move the ARISS SSTV frequency to 145.825.  This is being
> used for other satellites employing APRS and we would interfere with
> their operation.
> 
> Prior to their being an ARISS station on ISS, we conducted an
> extensive, international effort to ensure ARISS had a clear downlink
> on 2 meters.  We worked with all IARU regions and concluded that the
> best world-wide downlink frequency for Human would be 145.80 MHz.  At
> the time (1997) the United States had terrestrial APRS on 145.79.  In
> the USA we worked with the APRS community in a collaborative fashion
> to QSY APRS terrestrial from 145.79 to 144.39 (where it is today).
> This was a HUGE effort and required many digipeaters, several on snow
> covered mountains, to be modified or replaced.  Donations were
> collected.  And AMSAT-NA and TAPR worked together to make it happen.
> 
> Again, please note that IARU region 1 agreed with this downlink
> frequency for human spaceflight many years ago so we could have one
> common downlink.  I am very sorry you are experiencing this.  I think
> this will take local coordination to resolve this.  Similar to what we
> did for terrestrial APRS.  Trying to move ARISS around in the very
> small OSCAR 2 meter sub-band (145.8-146) is virtually unworkable,
> given the many 2 meter satellites that are employing this band.
> 
> I hope this helps explain things from an ARISS perspective.  Back in
> the day, I was given the unenviable task of working these frequency
> coordination issues for human spaceflight.  To be clear, we are much
> better today than some of the issues we were experiencing in the past.
>  And changing things around will probably make it worse for ARISS and
> other users in the satellite community.
> 
> 73,  Frank Bauer, KA3HDO
> Chair, ARISS-International
> 
> -----Original Message-----
> From: ik5jrz at tin.it <ik5jrz at tin.it>
> Sent: Monday, November 30, 2020 2:36 PM
> To: fabrizio.carrai at gmail.com; amsat-bb at amsat.org
> Subject: [amsat-bb] R: Re: ISS SSTV frequency
> 
> Thanks for answer,
> The repeater is R7a (Monte Secchieta), it's not only an Italian
> problem unfortunately, I have read many complaints in other areas as
> well. I don't question the correct spacing between frequencies, but
> I'm afraid it's only on actual paper. I don't want to doubt that the
> repeater is working correctly, but I think that if the ISS transmitted
> at 145.825, since when it transmits in SSTV APRS is disabled, the
> problem would be solved. The video demonstrates the proximity between
> the frequencies even if I admit to being in the high area and to
> receive the repeater very well.
> https://www.youtube.com/watch?v=nsoSjh54a3A&amp;ab_channel=IK5JRZThanks
> again.
> Carlo IK5JRZ.
> 
> 
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