[amsat-bb] AO-85 and Puxing PX-UV973, full-duplex - report (not so long)

Skyler Fennell electricity440 at gmail.com
Sat Nov 28 10:56:07 UTC 2015

Thanks for that information. 

I am looking into the woxun radios, and see the kv9d at the top of your rank.

Is this an adequate radio for full duplex satellite operation, how far does it fall behind the American radios?

Skyler kd0whb

> On Nov 27, 2015, at 12:23 PM, Patrick STODDARD (WD9EWK/VA7EWK) <amsat-bb at wd9ewk.net> wrote:
> Hi!
> Another day, another radio to try on AO-85. I woke up early, and decided to
> try another HT on a high AO-85 pass starting at 1350 UTC. I wanted to see
> if it could work the satellite full-duplex. The radio, this morning: the
> Puxing PX-UV973. After working AO-85 with it this morning, my (low)
> expectations were met.
> The Puxing PX-UV973 has been on the market a couple of years. It is
> supposed to handle cross-band full-duplex operation. This radio is still in
> production, and I picked mine up from Amazon for about US$ 78. It is less
> expensive than the other radios I have tested so far for full-duplex
> operation on AO-85, and it shows.
> First, the simple question. Can the PX-UV973 work AO-85 full-duplex?
> Yes, more or less.
> The radio comes with a duckie antenna, and a 7.4V/1200mAh battery pack. The
> battery pack is smaller than the standard packs supplied with the other HTs
> I have tested so far. It is also a little bit smaller than the other HTs.
> As with the others, I did not program any memory channels to work AO-85. I
> used the two VFOs, putting the uplink into the upper (A) VFO, and the
> downlink into the lower (B) VFO. Uplink and downlink can be done from
> either VFO.
> I used these VFO-specific settings with this radio, similar to what I have
> been using with the other HTs:
> Uplink VFO:
> SQL (005): 9
> N/W (014): WIDE
> T-CDC? (019): 67.0
> STEP ? (020): 2.50
> Downlink VFO:
> SQL (005): 0
> N/W (014): NARROW
> STEP ? (020): 2.50
> Another setting I had to enable for full-duplex operation was:
> DUPLEX (031): ON
> With the smaller tuning steps, I could get the AO-85 downlink lined up
> easily on my PX-UV973. It was about 5 minutes into the pass before I made
> my first QSO, with Glenn AA5PK in west Texas. A couple of minutes later, I
> made another quick QSO with Ed N7EC north of the Phoenix area. The receive
> audio while I transmitted was not really good - despite the satellite's
> elevation heading up to 56 degrees at the midpoint of the pass. The HT was
> able to operate full-duplex, but the other HTs I have tested with AO-85
> have done much better. I could still hear myself through AO-85 a couple of
> minutes after these QSOs, until the trees in a neighbor's yard started to
> make it tougher to hear. The CW beacon from XW-2F was also starting to
> overlap with the AO-85 downlink, also.
> Using my SDR receive setup (SDRplay receiver, HDSDR on an 8-inch Windows 10
> tablet, AMSAT-UK VHF crossed dipole), my transmitted audio sounded OK. Not
> loud, but it was fine - similar to what I've heard from the other Chinese-
> made HTs I have tested. I have uploaded the audio recording I made from the
> HT, the RF recording from the SDR receive setup, and some photos, to my
> Dropbox space. You can get those files at http://dropbox.wd9ewk.net/ - look
> for the folder "20151127-AO85_Fox1A_XW2F-DM43". I also heard XW-2F near the
> end of the AO-85 pass, and I let HDSDR continue writing the RF recording to
> cover XW-2F until its LOS.
> Since the PX-UV973 has been on the market for a couple of years, I did not
> have high expectations for it working AO-85 full-duplex. I was not
> surprised to see that it was a poor performer. If I had to rank this with
> the other 3 Chinese-made HTs I previously tested, this one would be at the
> bottom of the list by default:
> 1. Wouxun KG-UV9D
> 2. AnyTone TERMN-8R
> 3. Wouxun KG-UV8D
> 4. Puxing PX-UV973
> Don't be drawn in by the low price of the PX-UV973. If you already have it,
> it can be used as one radio of a two-radio setup, probably as the uplink
> radio. Or use it for terrestrial repeaters, where it would probably serve
> that purpose adequately. I now understand why one dealer was hesitant to
> offer an opinion about this radio's performance for FM satellite work, when
> I asked about it early last year.
> 73!
> Patrick WD9EWK/VA7EWK
> http://www.wd9ewk.net/
> Twitter: @WD9EWK
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