[amsat-bb] DJ-G7T and full-duplex satellite operating

Patrick STODDARD (WD9EWK/VA7EWK) amsat-bb at wd9ewk.net
Mon May 25 22:21:04 PDT 2009


I spent this afternoon using my new DJ-G7T HT on a few passes, with 
mixed results.  Working with the incomplete manual that came with 
the HT has been a challenge.  I still need to use it more, and be 
ready to make more changes to settings.  So far, I'll say it is a 
good radio for satellite work.  Not great, but good. 

I first tried this HT on the satellites during the weekend of the 
Dayton HamVention.  The first report I received on it related to my
transmit audio - sounding quiet and compressed.  There is a mic gain
setting in the firmware, which I put to the maximum setting.  Over
this weekend, I received the EDS-10 speaker/mic adapter cable to go 
into the speaker/mic jack on the top of the HT - a 4-conductor 1/8"
(3.5mm) plug with threads around the base of the plug.  Without this
cable, I did not want to risk trying full-duplex operation on the 
birds.  With this, I could feed audio through a splitter to my 
earpiece and audio recorder.  

I tried AO-27 and SO-50 passes this (Monday) afternoon around 2120-
2140 UTC.  The 5W transmitter and change to the mic gain setting 
meant I could be heard, but I had difficulties hearing the satellite.
Also, I could not hear myself while transmitting.  I tried another
AO-27 pass at 2301 UTC, and part of the pass was covered up by a
loud bout of intermod (Phoenix Fire Department VHF dispatch channel
swamped the receiver).  Not good.  

Before the first AO-51 pass I had this afternoon at 0027 UTC, I 
talked with John K8YSE about the radio and the problems I had.  He 
suggested I turn off the extended-receive capability of the HT, 
limiting it to just the ham bands.  I did that, and then tried the 
AO-51 pass.  Things went much better.  I had an easier time hearing
the satellite, and could hear myself through the satellite while 
transmitting - something I've never been able to do with my IC-W32A.  

I still need to go back to AO-27 and SO-50, to see if limiting the 
receiver to just the ham bands yields any improvement when working
those satellites.  I can't wait to see a new and improved version of
the instruction manual, and improvements to the firmware to fix some
of the idiosyncracies I've seen in trying to get this radio set up.
Even with those issues, I'm glad I bought the radio.  I plan to 
continue working with this radio, to see if I can improve on what I
heard this afternoon on AO-51.  This may turn out to be a nice radio
for the satellites.  For now, it's a work-in-progress.  Maybe others
who picked this radio up at Dayton - or have ordered it since then -
will chime in with their comments about the radio.  



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