Yesterday my new TYT TH-9000 (220 MHz band) radio arrived, along with my 3-element 220 MHz Yagi.
While I did programme the radio, I need to use lug terminals on the power supply connections, so I didn't get to try out the radio on the air. Instead, I set up the beam and connected my TYT 440/220 hand-held to it to give the antenna a trial run.
The antenna is nice. I got it from Centerfire Antennas for about $50 (including shipping), and it was shipped very quickly. The elements are short whips held by set screws, so the antenna can be dis-assembled easily for portable use. My only concern is that the set screws mount into a short aluminium bar, and over-tightening could strip out the threads. I used a Procomm coaxial cable with lug terminals already installed, which made connecting the beam very easy.
My original intent was to mount the beam on my portable 13-foot tripod mast and aim it at the 223.940- (PL 100.0) repeater on the other side of the metro in Arden Hills. I don't see a lot of point in omnidirectional coverage on the 1.25M band, since I'm not working simplex. While I could hit the .940 and the .540 (Burnsville) repeaters okay with the "rubber duck", I wanted a solid signal. The beam is not large at all. The boom is only about 20" long, and the longest elements extend about 28" total. I can leave it set up on the tripod mast, only about 6' high, and it can't be seen from the ground -- though it can still reach both the 223.940 and the 224.540 repeaters quite well. It's a much better solution than swapping out a mobile whip (which is visible) whenever I want to use the 1.25M band.
So I set up the beam and pointed it to the north-east. It was already dark, so I hoisted the mast about ten feet up and connected the other end of the cable to the TYT UVF9 (70cm/1.25M) HT. I wasn't expecting much from the HT (which has been a general disappointment), but I was hoping that a good antenna would make up for the radio's deficiencies.
I hit the .940 immediately, and it came back with full quieting. On top of that, the SWR was totally flat and the meter was showing 5W output. This is something that I've noticed about the Chinese HT's: the power output seems very dependent on the antenna being used. It might be more an anomaly with the meter, but that's what it showed. Whatever the case, the HT was working very well. I even switched it over to UHF (440 MHz), and the SWR was quite reasonable - though the power output was the typical 2W. I haven't really explored the possibility of using the beam on UHF, but it would very convenient if I didn't have to swap between the UHF and the 1.25M Yagis.
After checking a map and making a slight adjustment to the direction, I threw out my sign again on the .940 machine. This time, someone came back. It was KG0BP (Chris), who was one of the trustees for the machine. He was using an HT with a rubber duck, so he wasn't getting in to the repeater very well. I struggled to hear him, but the repeater's signal was full-scale. I really wanted to talk to him about the future of the repeater, and the .850 (UHF HandiHam) repeater that he also ran, but I just couldn't pick him out of the noise. I got back to him the next morning on the .450 (VHF HandiHam) repeater and got that info, and he also said that my audio was good into the .940 1.25M machine the previous night. So, with that, I'm "officially" on 220 MHz even if the new TYT 1.25M mobile doesn't work out!
But there was more good news. With the beam, I found that I was able to reach two new repeaters that I had believed were down. Both the 224.880+ (no tone) in Maplewood and the 224.900+ (PL 100.0) in Mounds View came back with a squelch tail! That makes four operational repeaters on the band that I can hit with the beam. The "low" power setting on the new TYT mobile is 10W, so when it's all set up I should be able to reach all of them with full quieting. I don't plan on doing simplex on 1.25M, so all that I need to do is hit the repeaters well.
My quandary now is what to do about a power supply for the TH-9000. The manual says that full power (55W) draws 12A. I have a 7A TrippLite 13.8V supply and a 30W Yaesu supply. I'm using the Yaesu for my FT-897D, but I would never be transmitting on both of them at the same time. The 7A TrippLite should be able to handle the "low" setting of 10W easily, which is all that I need. Besides, I think that the TYT will get really hot on full power.
I think that I'll stick with the TrippLite for now, and start shopping around for a 12 to 15A supply next year. With that, I could use the "middle" 25W setting, and also hook up my old SSB CB radio just for fun. The CB will work on 7A, but it would like 10A better. Neither of these things are high priority, but it would be nice to have a solid arrangement at some point. I have a FireStik for the CB that I think would work really well, even though there's about as much activity on CB as there is on 220 MHz. The SSB CB is just gathering dust, so I might as well hook it up at some point.
I'll report more on the new TYT 220 MHz mobile when I get a chance to put it to the (low power) test.
No comments:
Post a Comment