Click here to jump down to recent updates on my antenna system

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.

Here’s a view of the basic map coverage of my repeater:

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.

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Antenna System update Sunday Oct. 9th, 2022

Today I want to report total happiness with how everything has turned out.
I have great reception with no desense noise, 1.1:1 SWR, and I’ve up’ed my transmitter power to 32 Watts.

On last report, since the antenna replacement, the SWR reported on the repeater came in at about 1.8:1 with 2 watts reflected back. Ron (WB6IAG) on the WIN system has been telling me that the addition or subtraction of just a few inches of the feedline makes a big difference in obtaining a correct match. Used to be, there was a watt meter (never was very accurate) connecting the main run from the antenna to the jumper that feeds through the wall to the duplexer. With it inline, it I got about 1.5:1 SWR as read from the repeater. Without it, it jumped to 1.7. I started experementing with various amounts and combinations of adapters and couplers. I have about 12″ worth of adapters and couplers when in the right sequence, can lengthen the feed line.

With all but 2 adapters, I was able to get the match down to 1.1:1. However that ties up all those adapters and for each one, it also introduces insertion loss. For UHF, you want as clean of a path as possible, and zero dissimilar metals mating with each other for repeater purposes. Messi & Paoloni cable and connectors meets those needs. Here’s a cut-out of the M&P cable:

So I measured the length of my jumper including the length of the adapters, and found I needed to order a jumper with Messi & Paoloni .400 cable at exactly 40″ to get my desired match. Here is a pic of my M&P cables mating with proper M&P connectors.

Buytwowayradios.com web page only let you order in increments of feet, so I ordered 4 feet and emailed them to cut it to 40″. Well they sent me 4′ anyway, I hooked it up and found a 1.7:1 match with about 2 watts reflected. Here’s a screenshot of the Quantar RSS metering screen:

I cut the coax to 40″, re-applied the connector, and waddoyouknow… it was a solid 1.1:1. I think I’m leaving it alone.

Repeater Update 9/12/22

On Saturday I replaced my Diamond X510 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.

Antenna Update 10/6/22

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 I tried, 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.

Update 3/17/23

Well I’ve had the Diamond F718 antenna up since September, and it improved over what I had up before, but in even the slighest wind, I heard crackling and sometimes it would drop out the received signal altogether. On the SWR meter, it would go from 1.25:1 to bad intermittantly. I really thought my new coax was the issue.

In February, I pulled down the antenna again, completly took it apart, and was astonished as to the design. Turns out it’s an Omni-Gain Vertical Collinear Antenna. The entire antenna is made of 14 sections of 6″ peices of coax, decreasing in diameter as you go up, end to end, put together as thus:

So what I noticed was that at the very top of the antenna, where they used RG58 for the last segment, it was just chopped off, and the braid was slightly touching the center conductor.

This is what I discovered was making the noise and static:

This is what I did to fix it:

Problem instantly solved. The antenna system is now stable, and very sensitive again.
Thank you for taking the time to read this.

Contact me at john at qso daught com