Hi!
Because I had to be awake for a 5am/1200 UTC conference call with my office this morning, I only worked two passes last (Saturday) evening. Both were AO-85 passes, with different radios for each of the passes. It is amazing that we have access to this satellite's FM transponder, so soon after its launch.
The first pass I attempted was around 0215 UTC. This pass was an overhead pass, so I took advantage of that to try another one of my Chinese-made dual-band HTs (Wouxun KG-UV8D) with this U/V FM satellite. The KG-UV8D was connected to my Elk log periodic. I had my SDRplay receiver out in the yard for this pass, connected to the VHF crossed dipole sold by AMSAT-UK, with HDSDR running on my 8-inch Windows 10 tablet to make an RF recording of this pass. After the pass, I would play the RF recording from HDSDR into the FoxTelem software, so the telemetry I captured would be uploaded to the AMSAT server.
I had previously written a lot about the KG-UV8D in a thread on the QRZ.com satellite forum last year. I had tested it against the Fox-1A engineering model at two events in 2014, and it was able to work the transponder on the engineering model without suffering from receiver desense when transmitting on 70cm. I was working the transponder at the low-power setting (1W), and would move the HT around to shield the radio from the model, all in attempts to simulate working an actual satellite in orbit. Not hearing any desense, I was hopeful this HT would be one that could work Fox-1A (now AO-85) full- duplex. The answer...
YES
There are issues with the KG-UV8D's receiver, where you'll occasionally hear what might be more static coming through on the receiver. The noise level increases, even when receiving a stronger signal like from a local 2m or 70cm repeater, or other non-amateur transmitters. I had to be more diligent in orienting my Elk log periodic, so I could hear the AO-85 downlink clearly. When I was able to get through the transponder, I could clearly hear my voice in the earpiece I plugged into the HT. I also heard myself in the RF recording written by HDSDR on my tablet. It helped that I changed both the receive and transmit VFOs to use narrow FM, instead of "wide" FM. My transmitted audio seemed better, when I heard myself on the RF recording from HDSDR, and I could hear the downlink better on the HT during the pass. I worked K8YSE/7 here in the Phoenix area and KO6TZ in southern California just before the satellite was directly over my head. This is in line with my previous test with the KG-UV9D, where lower power levels were not sufficient to get through AO-85 until the satellite was up from the horizon a bit.
For the uplink, I was able to get through using 435.165 MHz for my two QSOs with the KG-UV8D. Downlink... I started on 145.9825 MHz, then tuned down to 145.980 MHz, and later I tuned down to 145.9775 MHz. Just like I saw when I used my KG-UV9D Friday evening, the sharper receive filters in the Chinese-made radios made using the smaller tuning step (2.5 kHz) useful.
After this pass, I played the HDSDR RF recording into FoxTelem, and uploaded 9 packets to the AMSAT server. Had I used the Elk with the SDR setup, I am sure I would have collected many more packets from that pass.
The second pass I worked, around 0400 UTC, was a shallow pass. AO-85 was only up to a maximum elevation of just over 11 degrees. I used only my Icom IC-2820H for this pass. I had used the IC-2820H as the uplink radio for a pass I worked Friday evening with my SDRplay receiver and HDSDR handling the downlink, but wanted to try the mobile radio by itself this time. it had no problems hearing the downlink, once AO-85 rose above the nearby mountains and houses.
I started the radio on 435.160 MHz for the uplink (with 67.0 Hz tone activated for this VFO), and 145.980 MHz for the downlink. Both with narrow FM, a suggestion that had been tweeted earlier by Peter 2E0SQL. I was not able to get through using 435.160 MHz, but was able to when I tuned my uplink to 435.165 MHz. Later in the pass, I could get through when transmitting on 435.170 and 435.175 MHz. I had to use 15W, and at times 50W, to get through. The pass was too shallow for me to get through at 5W. Around the midpoint of the pass, possibly just after that, I had to tune my receive VFO down to 145.975 MHz to hear the rest of the pass. I mostly heard stations in California, along with W7JPI in southern Arizona and WQ3U in Oregon, and logging a total of 5 QSOs (working all I heard, except for WQ3U).
The later pass was more orderly, probably a function of the footprint covering more of the Pacific Ocean. All stations allowed time for others to make (or complete) their calls. Fading is still an issue, and we all experienced the fades while trying to complete QSOs.
Some observations...
Now that I have a KG-UV9D HT, I probably won't use the KG-UV8D much. The KG-UV9D's receiver is probably the best receiver for satellite work from any of the Chinese-made HTs I have tried. The KG-UV8D *is* capable of full- duplex operation on AO-85, something that I had been told last year would not be possible with this radio (and before we had a U/V FM satellite to test radios against).
While working the earlier pass with the HT, I kept an eye on HDSDR on my tablet. Once again, with AO-85's downlink, the AFC function tracked the downlink from start to finish. I would not have had to make any manual adjustments to the downlink frequency, had I used the SDR setup as my downlink receiver.
After installing a virtual audio cable on my laptop, I was able to feed the RF recording I made with HDSDR into the FoxTelem software. I think this is how I will send telemetry to the AMSAT server, unless I have an occasion to use the FUNcube Dongle Pro+ and FoxTelem to send telemetry to the server automatically. When I am able to work the passes, I will use the SDRplay, which appears to work a little better for working satellites, and in making a RF recording that FoxTelem is able to extract more data packets from.
As I have been doing recently, I uploaded files related to last night's AO-85 passes to my Dropbox space. You can get to that using this link:
(press F5 if the folder/file listing doesn't appear immediately)
I have only one RF recording from last night, since I didn't use an SDR receive setup for the later pass. I have MP3 files from each pass, to show what I heard on the KG-UV8D and IC-2820H as I worked each pass. Photos and screengrabs, too.
Thanks again to AMSAT for allowing us to use the FM transponder on AO-85 so soon after the launch! I have a few radios, and combinations of radios, I want to try with this U/V FM satellite. I have used different setups for each AO-85 pass I have worked, and hope to continue this for a while. This effort may take a pause while I attend the upcoming AMSAT Symposium, but I will certainly continue this after the Symposium.
73!
Patrick WD9EWK/VA7EWK http://www.wd9ewk.net/ Twitter: @WD9EWK