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AO-7 Mode B "Interlopers"




I received an interesting email message from one of the regular users on 
AO-7 who indicated that there may have been "interlopers" on AO-7.  They 
were transmitting on the "wrong" sideband, never identified themselves and 
just chewing the rag for a long time.  At first I wasn't sure what was 
going on but after confirming that it happened in Mode B the answer because 
clear.

AO-7's Mode B uplink (432.150MHz) is technically not in the Amateur 
Satellite Service band (435-438MHz), but rather in the Weak Signal (SSB) 
portion of the Amateur Radio Service (432-433MHz).  The other key here is 
that the "interloper" was using USB to uplink, not the normal LSB uplink 
AO-7 users use.

There are a few important points to be made here:

1) AO-7 Mode B Uplinks are technically using Weak Signal bandwidth, so 
operators should be careful to conduct themselves according to the 
regulations of that band.

2) When uplinking in Mode B, AO-7 operators should take care to avoid 
interference to local 70cm propagation aids (beacons) and other 70cm weak 
signal services.

3) Remember that the USB/LSB conventions are by gentlemen's agreement and 
not enforced by the satellite.  So it is possible for operators to uplink 
on USB and downlink on LSB (though you may not get many QSOs.)

4) Don't freak out if you hear someone operating in the weak signal 
band.  It is their primary service in 70cm.

73,

Emily




W0EEC - CM87tm
ARRL - AMSAT - MSARC - ARCA - Project OSCAR
http://www.projectoscar.net
http://www.emilyshouse.com/W0EEC
http://www.experthams.net/ao7


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