[amsat-bb] AISAT-1 PS4 antenna configuration ?

[Nitin Muttin]

There are seperate antennas for the AiS and the APRS payloads and there is no interference between the two payloads. 

73
Nitin [VU3TYG]

--------------------------------------------
On Fri, 12/4/19, KC9SGV via AMSAT-BB <amsat-bb at amsat.org> wrote:

 Subject: Re: [amsat-bb] AISAT-1 PS4 antenna configuration ?
 To: amsat-bb at amsat.org
 Date: Friday, 12 April, 2019, 4:01 PM
 
 Sharing the 2m antenna...
 (APRS and AIS)
 IF this is the
 case, then...
 Hope suitable design and
 testing went on before the launch.
 
 Even if two separate antennas are used, they
 might heavily interfere with each other on the same band.
 And if hundreds of AIS ship customers are
 beaconing through the sat, then the APRS system might be
 deafened by same band, close frequency interference.
 Maybe the reason why lots of RF power is
 required to work this sat on APRS.
 
 Repeater builders know this...
 
 http://www.repeater-builder.com/projects/2m-dup/dupfig13.jpg
 
 http://www.repeater-builder.com/projects/2m-duplexer.html
 
 One other solution might be to
 alternate the systems on and off.
 Thus no
 interference takes place system to system.
 If this is the case, then we simply do not know
 the APRS "on" schedule.
 It could
 be off over NA today and on again over NA tomorrow.
 
 Where can we find better
 guidance ?
 
 KC9SGV
 
 Sent from my iPad
 
 > On Apr 12, 2019, at 10:19 AM, KC9SGV
 <kc9sgv at gmail.com>
 wrote:
 > 
 > If they
 use one antenna for both AIS and APRS...
 > (APRS was added as an afterthought,
 completed in six days, just a box, no antenna, no battery,
 no power panels.)
 > If this is the case,
 AIS has thousands of ships all trying to work the antenna
 automatically.
 > There are only a few
 hams trying to work APRS through the same antenna per
 pass.
 > Without proper diplexing, how
 would this system not be blind to APRS ?
 > AIS is ~160 MHz for ship to shore
 connections.
 > Not sure what the sat
 connection freq would be for AIS.
 > Maybe
 it is time for AMSAT India and Exseedspace to inform us hams
 here ?
 > 
 > KC9SGV
 > 
 > Sent from my iPad
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