Hi!

Starting just after the launch of AO-85 last month, I have been using different radios to work this satellite. Some of my experiments have been with HTs, along with my Icom IC-2820H mobile radio at different power levels. During the first weekend we had AO-85 in orbit, I had used my Wouxun KG-UV9D to work the satellite, and found that it was usable to work AO-85 when it was above 20 degrees elevation. The KG-UV9D can also work U/V FM satellites like AO-85 full-duplex, although the reverse is not true (there is too much desense when trying to work SO-50 or LilacSat-2, two V/U FM satellites, full-duplex). After working AO-85 over the past 6 weeks or so, I wanted to see if I could refine my suggestions from posts I made here on the AMSAT-BB and on the QRZ satellite forum last month. Here goes...

When I did my tests last month, I set the tuning step for the uplink VFO to 5 kHz, and the downlink VFO at 2.5 kHz. Most Chinese-made HTs have sharper receive filters than the HTs from the traditional ham equipment manufacturers, so I have used the smaller tuning step for the downlink frequencies when working FM satellites. For this weekend, I went with the 2.5 kHz tuning steps for both VFOs. This means still more adjustments when working these passes compared to other radios that have 5 kHz as their smallest tuning step in FM, but I think being able to make smaller adjustments on the uplink VFO helps get through. I started with the uplink VFO at 435.165 MHz, and then prepare to tune this VFO higher throughout the pass. The downlink VFO is usually set to 145.9825 MHz initially, but it does not take long for me to tune it down to 145.980 MHz, on its way down to 145.975 MHz near LOS.

At the time I did my tests last month, I had set the KG-UV9D to "wide" FM in both VFOs. Since then, there have been suggestions on working AO-85 in narrow FM. Transmitting to AO-85 in narrow FM ensures the uplink signals aren't overdeviated, and for the downlink it filters out most of the noise that comes with the data being transmitted with the FM voice downlink. With the KG-UV9D, it seems that its "wide" FM setting doesn't transmit a signal with deviation that matches what comes from radios made by the traditional ham manufacturers. The "wide" FM setting for the transmit VFO made a big difference for me getting through and making more QSOs during the passes I worked last weekend.

As with my tests last month, I did not program any memories. The KG-UV9D's VFOs are ideal for this type of operating. Since operators can transmit from one VFO and receive with the other VFO, memory channels aren't really needed. An earpiece plugged into the speaker jack ensures no receive audio feeds back into the microphone. There are moments where I have to switch VFOs, so I can tune the downlink VFO down to the next tuning step, and then switch back to the uplink VFO. This is not a huge issue, as I have had to do this with my Kenwood TH-D72A.

Here are some key menu settings I have used with my KG-UV9D, for each VFO:

Uplink VFO:

STEP (03): 2.5 W/N (04): WIDE SQL-LE (08): 9 Tx-CTC (17): 67.0

Downlink VFO:

STEP (03): 2.5 W/N (04): NARROW SQL-LE (08): 0

I normally put the uplink frequency in the upper VFO, and the downlink frequency in the lower VFO. This is my preference; it does not appear that I have to use the VFOs in a particular way for full-duplex operation. I set the squelch as tight as possible on the uplink VFO, and wide open on the downlink VFO, to ensure I am hearing only the static from the downlink VFO.

Since many Chinese-made HTs use menus that are similar to what I have in the KG-UV9D, I plan on using these settings in the other Chinese-made dual- band HTs I plan on trying with AO-85 (Wouxun KG-UV8D, AnyTone TERMN-8R, Puxing PX-UV973). I already had a successful test of full-duplex operation on AO-85 with the KG-UV8D, and hope to try the other two HTs soon and see how they handle full-duplex operation on this satellite. I have a couple of other HTs that I'll try on AO-85 from "traditional" ham manufacturers (Icom IC-W32A, Alinco DJ-G7T). I will also try my Kenwood TH-D72A, a radio that should have no issues working AO-85 full-duplex, as it can be used with SO-50 full-duplex.

Now, the AO-85 passes I worked with the KG-UV9D...

I worked three AO-85 passes from my back yard this weekend with the KG-UV9D and my Elk log periodic antenna - a Saturday afternoon pass to my west with maximum elevation of 61 degrees, a western pass Sunday morning with maximum elevation of 70 degrees, and an eastern pass Sunday afternoon with maximum elevation of 37 degrees. All 3 passes had several minutes where AO-85's elevation was at least 20 degrees. I plugged an audio splitter into the KG-UV9D's speaker jack, and split the receive audio between an earpiece and my Sony digital audio recorder. This allowed me to have MP3 recordings of the audio received by the HT while I heard the downlink, safe from having receive audio feeding back into the HT's mic. For the two passes on Sunday, I made an RF recording from my SDR receive setup - SDRplay SDR receiver, 8-inch Windows 10 tablet, HDSDR software, and the AMSAT-UK VHF crossed dipole on an 8-foot mast and tripod. I forgot to make an RF recording of the pass I worked on Saturday afternoon, or I would have had 3 RF recordings to go with the 3 MP3 recordings from the HT. Oops. The SDR receive setup allowed me to hear myself through AO-85 from an independent receiver, as well as upload telemetry to the AMSAT server.

I logged 3 QSOs on the Saturday afternoon AO-85 pass, 6 QSOs on the Sunday morning pass, and 3 more QSOs on the Sunday afternoon pass. The KG-UV9D did a great job, even at 5 watts. The last QSO I completed on the pass Sunday afternoon, with Drew KO4MA in Florida, was made with AO-85's elevation down to 21 degrees. Shortly after this QSO, I was not able to hear myself through the satellite. My audio from the satellite sounded OK on the HT and my SDR receive setup, although not as loud and strong as other stations. I had to twist my Elk antenna around, which helped to improve the downlink signal and (when transmitting) improve my chances of AO-85 hearing me. I was also able to upload telemetry to the AMSAT server from the two Sunday passes I worked with the HT from the SDR receive setup out in the yard.

If you want to see pictures of my setup for these passes, or hear the audio and/or RF recordings I made from these passes, you can visit my public Dropbox space at http://dropbox.wd9ewk.net/ and look for the folder named "20151122-AO85_Fox1A-DM43". If the folder listing doesn't appear when going to that link, press F5 or Refresh to force your web browser to make another try at accessing the link.

I'll post more to the -BB, and upload more files to my Dropbox space, as I test other HTs for their ability to work AO-85 full-duplex. I plan on trying the KG-UV8D again, with the same settings as I used on the KG-UV9D, to see if it does any better than it performed last month. The upcoming Thanksgiving holiday weekend should allow for many passes that are usable with 5-watt radios.

73!

Patrick WD9EWK/VA7EWK http://www.wd9ewk.net/ Twitter: @WD9EWK