[amsat-bb] AO-92 L/V with an Alinco DJ-G7T full-duplex (long)

Wed Mar 6 02:23:08 UTC 2019

Which Yagi 1.2 GHz that you use ?

73 de Yono YD0NXX 

Sent from my mobile device

> On Mar 6, 2019, at 6:23 AM, Patrick STODDARD (WD9EWK/VA7EWK) <amsat-bb at wd9ewk.net> wrote:
> 
> Hi!
> 
> I have written a bit about the Alinco DJ-G7T and using it on satellites on
> this list over the years. I wrote about using it on AO-92 in both U/V and
> L/V modes last year:
> 
> http://amsat.org/pipermail/amsat-bb/2018-February/066923.html
> 
> Until the past weekend, I had always worked AO-92 L/V with two radios -
> transmitting on 1.2 GHz from the DJ-G7T, and receiving the 2m downlink
> with my Kenwood TH-D74 (which can also record the downlink). I have used a
> couple of different antennas, but have wondered if the DJ-G7T could work
> the L/V mode full-duplex like it can work U/V (with some caveats) full-
> duplex. Now, I have tried this for myself, and will ask the question...
> 
> Can the Alinco DJ-G7T work AO-92's L/V mode full-duplex? Yes.
> 
> Before the past week or so, I was aware of the triplexers offered by
> Diamond that included a 1.2 GHz port. Those are noticeably larger than the
> diplexers from Diamond and other manufacturers, and a larger price tag as
> well. I saw something online that mentioned the Diamond MX-37 diplexer,
> having one port for HF through 470 MHz, and the other port for 800-1300
> MHz. Physically, the MX-37 diplexer is similarly sized with other
> diplexers, and it has two coax pigtails for those two ports - coax with an
> N connector for the 1.2 GHz port, and a PL-259 on the other pigtail for
> use with the lower frequencies. The common port is an N socket. After I
> received this diplexer in the mail, I was ready to fit it into my portable
> AO-92 L/V station.
> 
> I have been using a 10-element 1.2 GHz Yagi for AO-92 L/V in the past few
> weeks, and I tie that to the PVC handle of my Elk log periodic. I decided
> to tie the MX-37 diplexer to the PVC handle behind the antennas. This
> allowed me to connect the 1.2 GHz side of the diplexer directly to the coax
> pigtail from the Yagi's driven element. I used a 3-foot/1m length of coax
> from the PL-259 connector on the other side of the diplexer to the Elk's
> coax feedpoint. From the common port on the diplexer, I ran another
> 3-foot/1m length of coax to the DJ-G7T.
> 
> To keep from causing audio feedback while transmitting, an earpiece or
> something like that needs to be plugged into the DJ-G7T. The DJ-G7T uses
> a single 4-conductor 3.5mm jack for speaker/mics. To split out the speaker
> jack so I can use an earpiece and an audio recorder, an adapter is needed.
> I use Alinco's EDS-10 adapter, which provides a 3.5mm speaker jack and a
> 2.5mm microphone jack (don't need anything in the smaller jack for this).
> Alinco also has an EDS-14 adapter, which looks very similar to Yaesu's
> CT-91 adapter used with a few HTs (VX-6R and VX-7R, among others) - where
> the two jacks are on short pigtails from the 3.5mm plug. The Yaesu CT-91
> adapter works fine with the DJ-G7T.
> 
> The DJ-G7T only allows transmitting from VFO A, the upper VFO on the HT's
> display. I put the 1267 MHz uplink frequency in this VFO, along with
> encoding the 67.0 Hz CTCSS tone. I use 5 kHz tuning steps on this radio for
> 1.2 GHz. I set the volume for this VFO to 0, and tightened the squelch to
> the maximum. For the lower VFO (B), I put 145.880 MHz with the squelch left
> wide open, and adjusted the volume to a reasonable level using my earpiece.
> 
> I used this setup for 3 passes over the weekend. The antennas were a little
> heavier with the diplexer on the handle, but I could still control them
> with one hand. I held the DJ-G7T, along with the splitter and patch cable
> to my audio recorder. I could still adjust the knob for the transmit VFO,
> and made some contacts on those 3 passes. It was fun to be able to use just
> one HT for AO-92 L/V.
> 
> There are some tradeoffs when going from a two-HT setup for AO-92 L/V to
> just the DJ-G7T. The 2m receiver isn't as good as with other HTs, certainly
> not as good as the TH-D74 I have normally used when working L/V. I heard
> some other signals mixing with the AO-92 downlink on parts of a couple of
> passes. Of course, the DJ-G7T does not come with a built-in recorder like
> the TH-D74. There may have been a little less power going to the 1.2 GHz
> Yagi, passing through the coax to the diplexer's common port and then out
> from the diplexer to the Yagi, but I still got through. During one of the
> L/V passes, I was still able to get through AO-92 transmitting at low power
> from the DJ-G7T (rated at 300mW for 1.2 GHz).
> 
> I posted some pictures of this setup on the QRZ satellite forum, in a long-
> running thread "Where's AO-92???", starting at:
> 
> https://forums.qrz.com/index.php?threads/wheres-ao
> -92.614536/page-34#post-4986044
> 
> Audio from my recorder on the 3 passes I worked last weekend with this
> setup is in the "Satellite_Audio-2019" folder in my Dropbox space:
> 
> http://dropbox.wd9ewk.net/
> 
> The direct link for the pass I worked Saturday evening, where the recording
> started at 0537 UTC Sunday (3 March), is:
> 
> https://www.dropbox
> .com/sh/v3byggtuqw33fkk/AAA_gyTts4RpjT3jZa8GJI5ha/Satellite_Audio-2019/20190303-0537UTC-AO92-DM43bl.mp3?
> dl=0
> 
> Audio from the 1709 UTC pass Sunday morning is at:
> 
> https://www.dropbox.com/sh/v3byggtuqw33fkk/AACeV6R0Bjh-RRPXTrNpblAca
> /Satellite_Audio-2019/20190303-1709UTC-AO92-DM43bl.mp3?dl=0
> 
> and the late-morning pass at 1843 UTC Sunday:
> 
> https://www.dropbox.com/sh/v3byggtuqw33fkk/AADmbAfFYtHARDfULAR
> _J5eSa/Satellite_Audio-2019/20190303-1843UTC-AO92-DM43bl.mp3?dl=0
> 
> It is nice to see that the DJ-G7T is capable of L/V full-duplex operation,
> just as it is capable of U/V full-duplex operation, in line with Alinco's
> advertising for the radio - with some caveats. I can now alternate between
> a one-radio setup and a two-radio setup for AO-92 L/V. More fun with
> radios... :-)
> 
> 73!
> 
> 
> 
> 
> Patrick WD9EWK/VA7EWK
> http://www.wd9ewk.net/
> Twitter: @WD9EWK or http://twitter.com/WD9EWK
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