Hi!
I have been busy this week, and haven't been able to finish this sooner. Better late than never...
Having the 1.2 GHz uplink active on AO-92 last Sunday was fun! I tried to work 4 different passes, heard myself on one of the two morning passes, and worked stations on the two passes in the evening. It was fun to dust off a radio and some antennas for the uplink, and end up with a few QSOs by the end of the evening.
The first of the 4 passes was a nice 25-degree pass Sunday morning at 1638 UTC. To avoid the houses and other things around my house, I went to a city park on the DM33/DM43 grid boundary. This was my setup:
TX: Alinco DJ-G7T @ 1W, Diamond RH951S 2m/70cm/23cm whip (on Diamond BNCJ-SMAP adapter) RX: Kenwood TH-D74, Elk Antennas handheld 2m/70cm log periodic
The 145.880 MHz downlink was easy to hear, of course, but I never heard myself through the satellite. Between using an omni antenna on my uplink and playing whack-a-mole trying to find the right uplink frequency, I was a spectator. With the next pass 90 minutes away, I went home to regroup.
Before the second pass, I went looking through some boxes for more stuff I could use for the L-band uplink. I found a very old Comet CY-1205 5-element Yagi for the 1.2 GHz band. This antenna has a BNC connector on the bottom of the driven element, and was originally sold in two versions (BNC and TNC connectors) to be compatible with the radios available in the early 1990s. The listed gain for the CY-1205 is 11.0 dBi, which was an improvement over the 5.5 dBi gain for the Diamond RH951S whip used earlier. Gain figures aside, a directional antenna should be a better performer than an omni antenna for satellite work - even a directional antenna sitting on top of the radio.
The last pass for the morning was at 1812 UTC, to the west. It was lower, with maximum elevation of 14.4 degrees. I went outside with a slightly different setup...
TX: Alinco DJ-G7T @ 1W, Comet CY-1205 5-element Yagi (on Diamond BNCJ-SMAP adapter) RX: Kenwood TH-D74, MFJ-1717 2m/70cm long duckie
For a few minutes, there was no activity on the downlink, and I heard the voice ID followed by more static. Around 1817 UTC, I heard the downlink come on, and Tom N6NUG in San Diego appeared. Now I was trying to find a combination of uplink frequency and antenna orientation to hear my signals through AO-92. I finally did, around 1818 UTC when the satellite was just under 14 degrees elevation. By that point N6NUG was nowhere to be heard. I heard later that N6NUG's 1.2 GHz setup was for terrestrial operation, and he wasn't able to catch up with the satellite after the point I heard him. I was able to get through a couple of times, and this gave me encouragement for at least one of the two passes coming up in the evening.
For the evening, I saw a couple of passes - a shallow 7-degree pass at 0314 UTC, followed by a 61.4 degree pass around 0445 UTC. From home, I didn't think the 7- degree pass would be a good one to try. I drove to a rest area along I-17 about 50 miles north of Phoenix, a location I use for low eastern passes. One problem there - all parking spaces at the south end of the rest area, the highest part of that location, were occupied. I think people, and especially truck drivers, were taking a break for the end of the Super Bowl game. I have never seen that rest area that full of cars and trucks, and went back to I-17. Ten miles further north, there is a junction for the AZ-69 highway to Prescott. I did not go up AZ-69, instead parking in a large lot on the east side of the freeway behind a McDonald's near the interchange. This spot, in grid DM34wh, turned out to be a good spot.
For the evening passes, I used the following setup:
TX: Alinco DJ-G7T @ 1W, Comet CY-1205 5-element Yagi (on Diamond BNCJ-SMAP adapter) RX: Kenwood TH-D74, Elk Antennas handheld 2m/70cm log periodic
I recorded these passes using the audio recorder function in the TH-D74, which stores the audio as WAV files with the time (hour/minute/second) the recording started in the file name - helpful to know when in each pass different events happened.
The first pass at 0314 UTC was very low to the east. I thought it would clear the hills east of the freeway, and I was able to hear the downlink about 30 to 40 seconds after the predicted AOS time. I heard a few stations, and I started trying to get through. A couple of minutes into the pass, I was able to hear myself. Glenn AA5PK in west Texas also heard me, and gave me a quick call. At this point, AO-92 was almost at the midpoint of the pass, with elevation around 6 degrees. I was getting through! Jeff WB8RJY in Michigan also heard me, and gave me a call. Now the satellite was at its highest, just under 7 degrees elevation. Alan WA4SCA also called me, but I was not able to get back to him before LOS.
From comments I saw online during the day, it was apparent that the nominal
uplink frequency was higher than the published 1267.350 MHz. Most reports placed it about 8 kHz or so higher than that. With my DJ-G7T and its 5 kHz tuning, I went with 1267.360 MHz as the nominal uplink, and that helped to get through.
For the last pass of the evening at 0445 UTC, things started out well. I heard Jerry N0JY initially. Between tuning and twisting my HT/antenna combination, I wasn't able to get lined up in time for a QSO with him. I was eventually able to get through, and after a few minutes Greg KO6TH in northern California appeared. We started to chat slowly, mainly due to my need to tune and move the radio around to get each transmission through the satellite. During this time, AD5MT in southern California appeared. I made a quick QSO with AD5MT, but KO6TH wasn't able to do that. No other stations showed up during the pass, which allowed KO6TH and me to call out our uplink frequencies and the satellite's elevation on its way to LOS.
I put the audio, pictures, and other files related to all of this in a couple of folders in my Dropbox space at http://dropbox.wd9ewk.net/ . Files from the two morning passes are available in the "20180204-AO92" folder, and files from the two evening passes are available in the "20180205-AO92" folder. Each of those folders has a PDF file with a 2008 article from CQ VHF magazine by Kent Britain WA5VJB for smaller 1.2 GHz Yagis with 4, 6, or 10 elements. The 4-element Yagi might be enough with a 1W HT to use the AO-92 1.2 GHz uplink. Since I was able to get through with a 5-element Yagi, it seems like the 6- and 10-element versions in the article should be good options for 1.2 GHz and AO-92.
Looking forward to more time to use 1.2 GHz...
73!
Patrick WD9EWK/VA7EWK http://www.wd9ewk.net/ Twitter: @WD9EWK or http://twitter.com/WD9EWK