Patrick,
The DJ-G7T does appear to be unsuitable for full duplex U/v operation. In limited testing (only 3 passes - 2 with a whip, 1 with an Elk), I experienced desense. I could still hear my own signal a bit, but it was not clear. I even keyed up with a whip on 1.2 GHz during a pass of AO-92 when it was in high speed mode and the 1.2 GHz signal mostly wiped out the satellite reception.
Even just listening, the receiver performs poorly for satellite operation.
That said, I have used the DJ-G7T as my transmitter to make contacts on three passes of AO-92 in mode L/v.
73,
Paul, N8HM
On Thu, Jan 25, 2018 at 1:50 PM, Patrick STODDARD (WD9EWK/VA7EWK) amsat-bb@wd9ewk.net wrote:
John,
"(O)n current HTs"? Other than some reports I have seen about the Alinco DJ-G7T and its poor receiver for FM satellites in general, it appears that the HTs that have been previously reported as capable of full-duplex operation with V/U FM satellites like AO-51 and SO-50 would be fine with the mode B (U/V) satellites like AO-91 and AO-92. With the uplink on 70cm, you avoid issues with harmonics which can be an issue on some radios capable of full-duplex operation when you transmit on 2m - keeping in mind that frequencies in the 435-438 MHz satellite subband can be very close to the third harmonic of the 2m uplink frequency.
After AO-85's launch in October 2015, I tested a few Chinese- made 2m/70cm FM HTs that were advertised as being capable of full-duplex operation. None of them could work SO-50 full- duplex due to receiver desense, but could be used with AO-85. I wrote a series of AMSAT-BB posts about those tests at that time, and a link to a summary with other links to the specific models is in the AMSAT-BB archive:
http://amsat.org/pipermail/amsat-bb/2015-December/056269.html
I have been using the Wouxun KG-UV9D with AO-91 on a regular basis, either with my Elk log periodic or an MFJ-1717 2m/70cm long duckie. This radio, along with other HTs like my TH-D72 and an old TH-D7 I had for a little bit, is capable of full- duplex operation with mode B (U/V) satellites. I have seen other reports online of hams using a Wouxun KG-UV8D (or one of its variants) to successfully work AO-91 full-duplex.
73!
Patrick WD9EWK/VA7EWK http://www.wd9ewk.net/ Twitter: @WD9EWK or http://twitter.com/WD9EWK
On Thu, Jan 25, 2018 at 6:30 PM, John Geiger af5cc2@gmail.com wrote:
Does desense on 2m occur with using Mode B FM satellites in full duplex on other current HTs?
73 John AF5CC