[amsat-bb] the SATgate donut effect

[jeff_griffin]

Bob,
I think it would get you a lot more Igates if you/we could convince the APRS
s/w authors to put in my simple fix. I mean really, how many people are
going to put in a 9 square foot ground mounted vertical? I couldn't in
either of my homes, the landscapers would take it out in no time, the only
place for a small vertical is mounted off the ground...

73 Jeff kb2m  

-----Original Message-----
From: AMSAT-BB [mailto:amsat-bb-bounces at amsat.org] On Behalf Of Robert
Bruninga
Sent: Sunday, June 28, 2015 3:05 PM
To: amsat-bb at amsat.org
Subject: Re: [amsat-bb] the SATgate donut effect

The donut hole is a problem...  With two more APRS satellites to launch this
year, we need -more- Omni Satgates with *lower* antennas.  The vertical omni
1/4 or 3/4 wave satgate vertical antenna needs to be as low as possible (to
minimize the donut hole null and to reduce lightening
risk) while still seeing sky above 30 degrees.

See: http://aprs.org/aprs-satellite-igate-antennas.html

Once I deliver the last of these next two transponders, I hope to build such
a satgate with a D7 HT and document its performance.  I can place the HT at
the base of the antenna with near zero coax, and being low, it is not
vulnerable to lightening compared to surrounding structures.

Bob, WB4APR

-----Original Message-----
From: AMSAT-BB [mailto:amsat-bb-bounces at amsat.org] On Behalf Of
kb2m at arrl.net
Sent: Sunday, June 28, 2015 10:02 AM
To: amsat-bb at amsat.org
Subject: [amsat-bb] the donut effect

Is there anyway to get any APRS client to not Igate a packet with a path of
ARISS in it. I run a satgate here in NJ and the donut effect is causing
problems for several hams in the area that can't get a packet Igated after
it is digi'd by the ISS because it's a dup. My Igate hears the first packet
direct that then causes the ISS digi'd packet to be a dup.  It would seem to
be a simple thing to  set a filter to ignore a path of ARISS, and accept
everything else. I would think that this would fix the problem of people who
want to run Igates, but don't because of this. I recently moved to Florida
for the winter and had to shut my igate down in NJ for this reason. Also,  I
noticed when down there that there is a lack of satgates along the
eastcoast. ISS,PSAT, and PCSAT are hearing stations fine but no satgate's
available until the bird's footprint move well inland.





73 Jeff kb2m



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Sent via AMSAT-BB at amsat.org. AMSAT-NA makes this open forum available to all
interested persons worldwide without requiring membership. Opinions
expressed are solely those of the author, and do not reflect the official
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Subscription settings: http://www.amsat.org/mailman/listinfo/amsat-bb