Searching the website, I’ve just realized that I haven’t written about the ARR Preamps I’ve added for VHF (2 meters) and UHF (70 centimeters). They arrived in the shack in January and April, respectively. With the initial installation I connected them directly to the back of the IC-910H transceiver. They do a good job of amplifying the weak received signal and they are set up to automatically switch out of the circuit when I transmit.
They are meant to be installed near the antenna, directly on the mast. This way they can grab the signal before it goes through all that coaxial cable and, as a result, drops its strength. With my set up, however, I have lightning arresters installed at the bottom of the mast that don’t allow DC power to travel along the coax all the way to the antenna to power the preamp.
Recently my satellite elmer, Clayton, W5PFG, suggested that I mount the preamps somewhere along the coax to avoid overpowering the receiver. So, my weekend project was to mount them right by the lightning arresters. This gets them as close as possible to the antennas while still allowing them to be powered via DC on the coaxial cable.
You can get a glimpse of the installation in the nearby photo, note the nearby lightning arresters. I used a PVC pipe as the pretend mast, along with a couple of wooden shims to make everything work. I still need to make one of the connecting cables. I use Davis RF Bury Flex for most of my outdoor work. The needed cable is on the 2 meter side, which uses PL-259s from the receiver to the antenna, so I’ve ordered some Amphenol PL-259s. Once that’s in place, I’ll do the tape wrap water-proofing.
Everything is working well on the satellites. I’m now thinking about ways to move the antennas from 10 degrees elevation and vertical polarization to zero elevation and horizontal polarization for the VHF-UHF contests. That’s perhaps the next project – needed in time for the January VHF contest.
Have fun in your ham radio adventures. I hope to work you on the air.
how much did the preamps help?
i get the FM birds at s-2 to 3 on my ts-2000 and need some gain just to hear them on my little antennas.
Hi Brad, it is a balance of antenna, coax cable loss, and receiver sensitivity. I found that with my IC-9100 I didn’t really need the 2 meter preamp but the 70 cm preamp is very helpful. I’m currently using a 10-element yagi on 2 meters and 15-element yagi on 70 cm. Good luck. 73, Jim, K5ND
also you could use a ground rod or pipe to mount them on and kill two birds with one stone…
Nearby to the preamps is a groundrod with Array Solutions lightning arrestors mounted on it. No room for the preamps.
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