Since around 2018, we have had our 440 repeater in North Chili at Roberts Wesleyan. It was a Yaesu DR1X machine capable of FM and C4FM. Additionally, it could do D-Star as well. Dave, N2OA made it happen by adding a Northwest Digital Universal Digital Repeater Controller (UDRC).

The coverage was not great. We don’t have a lot of members on the west side. It did not get a lot of use. Additionally, access to the repeater site was difficult.

Earlier this year, we received an opportunity to relocate the repeater to Bristol at an excellent repeater site. There were a couple of requirements, the main ones were that we enable DMR and P25 along with Fusion and D-Star. I discussed the idea with Dave, though he is not a big fan of DMR and P25, he agreed that it might be a better location, though probably not for him personally. It also would dovetail nicely with the XLX927 Multiprotocol reflector I had been working on for a year. Dave was finally able to extract the repeater from its old location, and wanted to update the UDRC before relocating.

The one casualty in the plan is FM mode. FM does not play nice with digital with the MMDVM board as implemented. Since there are already several FM repeaters at the same site, including another 440 machine, providing a digital-only repeater is the reason for this to even happen.

Finding time was a problem with Dave’s schedule, and when he did try doing some updates, he ran into technical problems with the UDRC. The UDRC was no longer made, Northwest Digital’s owner had passed and the company was barely still afloat. After talking it over with Dave, we made the decision to convert the digital side to an MMDVM type controller. Because of Dave’s difficulty to find enough free time for the project, he handed off the repeater to myself and Steve KA1CNF, to finish getting it ready.

I purchased the Repeater Builder STM32-DVM (https://www.repeater-builder.com/products/stm32-dvm.html) and Steve supplied a Raspberry-Pi 3 for the project. Steve loaded up the Pi with Pi-Star software, and when I received the new hardware, we spent a couple of afternoons at Steve’s place getting it working. Once we were fairly sure things were doing what we expected, I took the machine back to my place to continue with testing and setups.

I had wanted to check the duplexer, since it was over 30 years old and the performance of the machine at Roberts seemed a bit underwhelming. A 2 meter machine at the same site had been strong at my house, yet I could not hear the 440 machine.

I did have a NanoVNA, and I knew that the dynamic range was not adequate to a complete tuning, but after watching a few videos, especially from W2AEW, I thought I could at least get an idea. I spent several days testing and re-testing. I was suspecting a problem with my NanoVNA (a known issue with my model). So I tried another one. Same problem, I could get a Bandpass response reading, but the band reject measurement seemed flawed.

I finally decided to spend some serious money and buy a spectrum analyzer. Hopefully I could find more uses for other than a one-time duplexer tuning. Anyway, when it showed up I was able to get measurements that looked reasonable and I was able to get it tuned up properly.

Dave had supplied a rack at Roberts, but he had other plans for it. Mike, W2HYP, had given us two small Motorola racks back in 2015, one of which is still being used for our 2 meter machine. The other rack was not in great shape, so at the same time I was working on the duplexer, I was cleaning up the rack and gave it a few coats of new paint. The rack is much smaller depth-wise than a DR1X, such that it sticks out the back several inches. The duplexer as well protrudes slightly. So the back cover will probably not be used. I ordered a support bracket to hold up the back of the DR1X. Hopefully mice won’t be an issue. The front cover should still be able to protect the front side.

At some point I might try to find a deeper rack But this one should do for now.