Discussion in 'Satellite and Space Communications' started by K6LCS, May 28, 2018.
That 1st-place medal in the picture looks nice. Congratulations, Marissa!
Thank you! She is so proud! She's been texting me like crazy and now gets to progress to the district level of competition. Who would have know that her getting an amateur radio license a couple of years ago could lead such great STEM education for her!
Sorry I missed the big announcement (New Year's resolution was to ditch Twitter). Congrats to W4AQT!
I have posted more lately about working AO-92 in L/V mode than U/V, but here's a little something about working AO-92 in U/V. Yesterday (Friday, 18 January 2019), I met Ruth KM4LAO along with a couple of other Arizona hams (Chris K7TAB, Fernando NP4JV) at the Titan Missile Museum south of Tucson AZ. Ruth is in Arizona for a few days for a family reunion in Tucson, and wanted to work some satellite passes. Friday was an open day in her schedule, and she - along with her parents - wanted to tour the museum, so we took the opportunity to help Ruth get on the air from outside the museum.
There were a couple of AO-92 passes in the morning. Ruth worked them both. First, an eastern AO-92 pass around 1647 UTC:
Then she worked the western AO-92 pass at 1821 UTC:
For AO-92, Ruth used her portable station: Arrow Antennas dual-band Yagi, and two radios - an Icom ID-51, and a Kenwood TH-D74. Working full-duplex, Ruth did a great job from outside the museum.
In addition to working AO-92, Ruth worked passes on NO-84 (digipeater) and AO-91 in between the two AO-92 passes. After touring the museum, KM4LAO was heard on the HF bands for a couple of hours. Ruth used my Elecraft K3S at 40W connected to the large HF discone next to the museum, before heading back to Tucson.
It was fun seeing Ruth have so much fun working satellites and HF. I worked her on NO-84 (her first packet satellite QSO), and later on 20m (I used one of my Yaesu FT-817NDs and a telescoping whip for 20m to work her). The weather was perfect for being outside in southern Arizona and playing radio.
Since it was posted here about W4AQT's winning science fair project at school. I wanted to let everyone know that she progressed to the district level of competition and today her satellite science fair project won the district competition. Now she will progress to the state level. Once again, win or lose, she's a winner because she is using amateur radio and satellites to further her STEM education.
This thread has definitely taken a turn for the best. I wish all the threads here could end up as festive as this on has become.
Still getting L-band activity on weekends, and more stations are gearing up for the challenge. Since I switched from the small 5-element Yagi to the 10-element Yagi from eBay, I have been able to do more with my Alinco DJ-G7T on 1.2 GHz. On many passes, I'm able to get through on its low power (300mW).
Endaf was on AO-92 this morning, and he was using something that might be a museum piece for his uplink radio - a rare Yaesu FT-911 HT. Endaf tweeted a picture of the radio:
I remember when these radios were on the market, about 30 years ago when the ham manufacturers were making hgear for the 222 MHz & 1.2 GHz bands, after the "Novice Enhancement" in the mid-1980s where US Novice licensees gained voice privileges on those two bands. I've never seen an FT-911 in person, and never saw one in the HRO store here in Phoenix when they were on the market. Then again, I never saw new 1.2 GHz radios in the Phoenix HRO store back then. I bought a Kenwood TH-55 1.2 GHz HT from AES in Las Vegas back then, when Phoenix had two analog FM repeaters on the band. One of those two 1.2 GHz analog FM repeaters is still alive, along with one or two D-Star repeaters on that band.
Until next weekend's L-band activity...
After a year or so of working AO-92 L/V using a two-radio setup (Alinco DJ-G7T, Kenwood TH-D74), I tried working the L/V mode with just the DJ-G7T. Alinco advertises this radio as being capable of cross-band full-duplex operation, and it does OK for U/V full-duplex with AO-91 and AO-92. It's no good for V/U full-duplex operation, with SO-50 or previously with AO-27 and AO-51 many years ago, since transmitting on 2m desenses the 70cm receiver. After ordering a diplexer that should work for L/V operations, I tried working AO-92 L/V tonight with just the DJ-G7T.
The diplexer I ordered is Diamond's MX-37 diplexer.
One of the band ports is rated for 1.8-470 MHz, and the pigtail on this side has a PL-259. The other band port is rated for 800-1300 MHz, and has a male N connector on its pigtail. The common port has an N socket. Here is the specifications sheet that is included with the diplexer:
Mostly in Japanese, but the important details should be readable.
I used the same two-antenna setup I have been using on AO-92 L/V for a while; a 10-element Yagi I ordered from eBay for the 1.2 GHz uplink, and my Elk 2m/70cm log periodic for the 2m downlink. The diplexer's pigtail with an N connector went directly onto the coax pigtail off the Yagi's driven element, with no other coax or adapters needed. I had to run a short bit of coax (3 feet/1m) from the diplexer's pigtail with the PL-259 to the Elk's feedpoint. With an adapter, I used another 3-foot/1m length of coax from the diplexer's common port to the DJ-G7T.
On the DJ-G7T, there is a single jack for the speaker/mic. To get a normal 3.5mm jack for speaker output I can use with an earpiece or a splitter, I used Alinco's EDS-10 adapter in the HT's speaker/mic jack.
Alinco has (had?) another adapter for the single speaker/mic jack on the DJ-G7T, an EDS-14. This adapter has two pigtails, with separate jacks for the speaker (3.5mm) and microphone (2.5mm). Yaesu has a CT-91 adapter, used with their HTs that have a single speaker/mic jack like a VX-6R, VX-7R, FT-270, and FT-277. The CT-91 is identical to the Alinco EDS-14 adapter, if either of the Alinco speaker/mic adapters are not available.
On the 0535 UTC (9.35pm PST) pass tonight, I had a nice pass that went up to almost 27 degrees elevation to my west:
I heard only one other station on the pass, Craig N6RSX in southern California. We made a contact early in the pass, and I proceeded to make transmissions through AO-92 for most of the pass. At one point, I was getting through on the DJ-G7T's low power setting for 1.2 GHz, 300mW. I have posted the audio I recorded from this pass in my Dropbox space.
I don't know if anyone else has tried working AO-92's L/V mode with the DJ-G7T full-duplex. After trying it tonight, I now know that the HT can handle L/V full-duplex, although the 2m receiver can be affected by intermod (noticeable in the recording at the link above). I may still prefer to use two radios for AO-92 L/V in the future, but for this weekend I will go with just the DJ-G7T for the two passes on Sunday morning to see how I do then...
I worked the two AO-92 L/V passes this morning, using the same setup as I illustrated last night. From my tracking app, the two passes (times in these screenshots are local time for Arizona, UTC -7 hours):
The 1708 UTC pass was basically a coast-to-coast pass, with stations heard from all over the continental USA. I was able to make some QSOs on that pass (AA5PK and W5RKN in Texas, N6RSX in southern California). The later pass for the west coast at 1842 UTC wasn't as busy - I worked W7QL in Utah, and heard K7TAB near me in central Arizona along with N6RSX. I posted audio recordings from both passes: one recording starting at 1709 UTC for the eastern pass, and another recording starting at 1843 UTC for the western pass. These recordings are fine for updating my log, but the recordings I made from other passes with my Kenwood TH-D74 sound better - in part due to the so-so performance of the DJ-G7T's receiver, and also in part due to the TH-D74's recording function writes 256kbps WAV files (higher quality than these MP3s).
The DJ-G7T is capable of working AO-92 full-duplex in both U/V and L/V modes. Many other radios would do a better job hearing the 145.880 MHz FM downlink than the DJ-G7T, but for these combinations of bands the Alinco advertising is accurate. This HT just isn't up to the task of working SO-50 full-duplex. We won't ever see V/L or U/L configurations on satellites, as the 1.2 GHz band is only used for amateur satellite uplinks. Regardless of the shortcomings in the DJ-G7T's receiver, it does work as an FM transmitter on these 3 bands, including the AO-92 L/V mode that a few of us work regularly with a DJ-G7T as part of our station.
I used the DJ-G7T with the Diamond MX-37 diplexer once again for this weekend's AO-92 L/V passes, the same setup as illustrated in the pictures from last weekend's posts here. I worked two passes, and made at least one QSO on each pass, but it was very clear that the DJ-G7T's receiver just isn't as good as other radios. I worked Craig N6RSX in southern California last night, and heard Rick VE4AMU in Winnipeg late in the pass. This morning, I worked 3 stations (W7QL in Utah, W9TWJ & W5RKN in Texas), and heard 3 others (WA6DNR, N6RSX, and N6NUG - all in California). I heard W7QL work KA7FVV in Washington state, but I never heard KA7FVV. Maybe I would have heard both sides of that QSO, had I used a different receiver.
The DJ-G7T is a good transmitter for satellite work, including 1.2 GHz even with 1 watt, but the receiver has always been the weak part of this radio when it comes to satellites. At least I have been able to confirm the DJ-G7T is able of working L/V satellites full-duplex, which was the reason for getting that diplexer and trying this out.