Repeater Update 9/12/22
On Saturday I replaced my Diamond X51 with the Diamond F718 that was donated to me. One of the first tests was to determine with my antenna analyzer, what the SWR curve was. The antenna has best resonance at 445MHz, right in the middle of the band. My transmitter being at 440MHz, SWR at that frequency came in at about 1.5:1 The built-in SWR meter in the Quantar repeater reports 1.8:1, with about 2W reflected back. I want to pull down the antenna, take it apart and see if there’s any way to adjust it so that the resonance is at a lower frequency.
There’s one thing however that really improved, and that is the sensitivity. During the morning commute, I talk with K7CWA who lives in Apache Junction. We erected a small 440 beam at his place and pointed it toward my place, hoping we could communicate without static and path noise. Over the past three or so years since, communication would be hit or miss. Some days there would be almost no path noise, and others would be so bad that we have to go to another repeater just to communicate. Warren keeps the radio on 50 watts in any case. Last Friday was an off day as we had to go to the alternate repeater. After the antenna replacement, On Monday morning, Warren was full quieting, and as a test, he put his radio on 10 watts and was still 95% quieting. I call that a major win.
If you’ve been frustrated with the performance of my repeater lately, please give it another try. The sensitivity problem seems to be solved now, and so far I hear no crackling like I did before.
Right now the repeater is up. I’ve had increasingly bad desense, increasing SWR and static. SWR used to be 1.2:1 when everything was working optimally, and in testing, on the very weakest signals, no difference in receive was noticed whether the transmitter was on or off. Now the SWR is just a hair under 2:1 and when testing desense, signals crackle and drop out when turning on the transmitter. At first I thought it was due to coax wearing out so I replaced the coax with high quality Messi & Paoloni brand coax, and unfortunately nothing changed. I then thought maybe the high SWR was causing arcing within the duplexer. In the past I used to be able to tweak the duplexer a little to bring down the SWR and audibly tune out the desense, but this time when trying I made it worse. I borrowed a spectrum analyzer with tracking generator in order to tune the duplexer back to its old glory. That worked well but didn’t address the issue. I put on an antenna analyzer directly on the feed line to the antenna, and found the SWR is all over the place. I pulled the antenna down in order to take it apart to check all the internal set screws and connections. All looks good, but as you can see the SWR is all over the place.
Problem is, my health is such I don’t do well in 115 degree heat with Monsoon humidity. Please be patient while I work through these issues and the repeater will be back in no time.
My next step is to replace my Diamond X510 dual-band with a Diamond F718 antenna that was generously donated, but the mounting sleve was missing, and I need to go find an appropriately sized tube.
If you’re in the east valley, try to access my repeater on 440.675 MHz (+) with a PL (CTCSS) of 107.2 Hz. It’s on AllStar node 29600, and it’s usually tied to the Western Inter-tie Network (WIN system). The WIN System is a link of over 100 or so full time repeaters all connected to each other from all over the USA and the world. Some are connected using RF, others use the Internet on Allstar or IRLP (Internet Radio Linking Project). My repeater is built on Asterisk, the Open Source Telephony Project. Asterisk is much more than a telephone system, it’s a communications tinkerer’s playground; a great platform from which to build a repeater. When you talk on my repeater, you’re being heard on local ham repeaters all over the world!
I run my repeater on 100% solar, with a backup battery at night.
Here is the link describing my solar system.
Click here to hear my repeater on streaming audio
Click here to find out more about ham radio.
Baofeng UV-82 dual band hendheld, 5W
TYT TH-9000 UHF Mobile radio
Here are some things I have for sale including amateur radio equipment.
More coming soon!
Contact me at john at qso daught com