[amsat-bb] Re: Half-duplex on the Kenwood TH-F6A

Zach Leffke zleffke at vt.edu
Tue Apr 16 13:48:26 PDT 2013

I have had some luck using the HT's SSB mode to listen to some of the
"Beepsat" beacons.  This was done for educational purposes to show the
effects of polarization to non-believers.  Using an arrow style antenna
(homebrew version) mounted on a tripod, we would dial in the CW beacon of a
bird with linear polarization.  After matching up polarizations by twisting
the arrow to maximize the volume out of the TH-F6A we would have the
"onlookers" mentally note the volume of the beacon then quickly twist the
beam 90 degrees (while maintaining azimuth and elevation the same).  The
previously clear and strong beacon would all but disappear from the audio.
We would then twist back 90 degrees and the beacons would come right back
nice and strong.  

The onlooking non-believers jaws would drop, eyes would widen, and learning
would occur.

I have yet to try it out with the SSB voice transponders, mainly because you
can't transmit SSB so there's no chance of making a QSO with just the HT.  

However, the future of the Amateur Satellites is evolving and we will "soon"
be seeing more software defined radio technology being incorporated into the
transponders.  This technology will allow previously unheard of modes of
operation that could allow these types of HTs to complete a QSO.  Imagine a
software defined transponder that receives an uplink in FM and downlinks
SSB.  Piece of cake for the SDR wizards.  A satellite that can do that is
good news for owners of these types of HTs.  As mentioned by Patrick below,
these types of HTs will not match the performance of the work horse
satellite radios (FT-817, FT-847, FT-857, IC-910H, etc.), but for those good
high passes, with a decent antenna, I bet it will probably work.

-Zach, KJ4QLP

-----Original Message-----
From: amsat-bb-bounces at amsat.org [mailto:amsat-bb-bounces at amsat.org] On
Behalf Of Patrick STODDARD (WD9EWK/VA7EWK)
Sent: Tuesday, April 16, 2013 4:41 PM
To: amsat-bb at amsat.org
Subject: [amsat-bb] Re: Half-duplex on the Kenwood TH-F6A


> My experiences though are with the FM easysats (including AO-51 of 
> happy memory). Has anyone had any luck with this radio's SSB receivers 
> for the linear birds?
I have a TH-F6A, and have used it as the downlink receiver when working SSB
via satellite.  I use an FT-817ND as my uplink transmitter, and will
occasionally use the TH-F6A as the downlink receiver in place of another
FT-817ND.  The all-mode receiver in the TH-F6A is not as sensitive nor as
selective as the receiver in the FT-817ND for SSB and CW, but it can work.
I don't work the lowest passes on VO-52 with the TH-F6A as my receiver, and
only look at the higher passes for FO-29 - but it can work this way.

I have recently purchased the 2m/70cm broadband preamp from AMSAT, but have
not had a chance to try it out.  As long as I don't swamp the front end of
the TH-F6A's receiver, that HT with the preamp may be my ticket to a better
receive setup with the HT.  Even without the preamp, I have done
demonstrations using an FT-817ND with a TH-F6A, making for a very small and
portable all-mode satellite station.


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