Overhaul Phase 3: Amps, Feed Lines, and January VHF Contest

I had shared that the amplifiers I was shopping had been on perpetual back-order since 2020. The supplier continually moved the availability back another few months each time that their expected ship date approached. I found another brand of amps that is arguably better. However, I lack confidence in their follow-through since they haven’t responded to e-mails or catalog requests, seldomly answer their phone, and their website’s pricing info is sorely out of date. As luck would have it, I tripped over a deal on a used Mirage B-5018-G 160-watt 2m amplifier at HRO and made a new plan.

I like Mirage amps, not because I think they’re the best, but because I’m intrigued by their remote control heads. Remotes would allow me to operate the amps without having to physically access them under my trunk floor. That’s especially beneficial if I’m carrying cargo. I picked up the used amplifier and a new remote control head from my nearest Ham Radio Outlet while I was in northern Virginia to pick-up my Yagis from DSE. Next, I ordered a PA-80U 70cm amplifier by Toptek Communications. The PA-80U outputs 20 watts less than the Mirage equivalent and it does not have provisions for a remote control. Still, 20 watts is not a huge deficit and the amp will be ON throughout any contest… remote not required!

But there’s one small problem: I use a switch near my seat to disconnect power to my communications equipment when I leave the car. The PA-80U defaults to OFF anytime power is interrupted. That’s probably not a terrible, but I’ll have to remember to NOT turn-off my remote switch during contests. As for the 2m amp, I operate on 2m SSB from time to time; plus, I may exercise the option to connect the amp to my ID-5100 for FM operation. With that in mind, I absolutely appreciate the ability to control the amplifier remotely.

Okay, I’m getting ahead of myself. Let’s get the amps installed first, okay? 😉 My first task was to mount the amplifiers on the electronics panel so that I could figure out how much feed line I needed. My setup demands A LOT of feed line. As a result, I chose LMR-240UF throughout the project, except for two outdoor runs of LMR-400UF on my 432 MHz feed lines. With my short paths, I use LMR-400UF more for structure than coaxial performance. Notice how the feed lines are held away from the car’s paint in this photo and away from the tower structure in photos below? I credit LMR-400UF’s stiffness for that. This photo also shows a pass-thru panel that I made to support up to eight Type-N feed lines. I could have made my own cables, but I don’t want to manage the small bits and supplies to make that happen, especially with cats in the house.

Instead, I paid extra to have mine built by The Antenna Farm. That inserted some delay into my project. Still, it was nice to have over 250 feet of expertly crafted cables arrive ready to install. I used a Dymo Rhino 4200 label maker to label my wires and cables. The labels provide an extra touch of professionalism and should make chasing cables easier in the future. Pro Tip: Labeling each end of a cable is almost a no-brainer. However, long cables that pass thru different areas of the car can benefit from additional labels in the middle, too!

You may recall that I drew an outline on the top side of the electronics panel to show an outline of the channel that’s created between the spare tire and the tub in the trunk. I decided to draw the boundaries on the bottom side of the panel, too. The power leads for the amplifiers and ALL coaxial feed lines travel beneath the trunk floor for concealment and management. Drawing the boundaries allowed me to fasten the cable runs to locations under the electronics panel that clear obstacles when the floor is closed. It also made it easier for me to decide where to put the diplexers, coaxial relays, and other equipment in the spare tire tub. I think it turned out fairly well, although it’s not quite as tidy as my work on the top side of the panel. It is, after all, still a “cellar.”

“Diplexers, coaxial relays, and other equipment?” What’s going on in the spare tire tub? Well, I have nine full-time antennas and three alternates, namely the Yagis on the rotator, but “only” six transceiver bodies. So, there’s a bit of antenna sharing, redirection, and switching, depending on my needs. The diplexers split signals to send to specific feed lines, the relays allow me to select different antennas from the driver’s seat, and a pair of dummy loads ensure that none of my transceivers are accidentally left without a load on its coaxial port. Is it a thing of beauty or a convoluted mess? It’s hard to say; but it’ll be worth it if I never blow up a transceiver or amplifier!

My ultimate goal of “doing it right the first time” wound up taking A LOT of my time, time that was also eroded by cold temperatures and rain… even the snow in this photo. I severely underestimated the time that I would need to get everything done before the January VHF contest, especially with the weather and supply delays. As a result, I did not finish in time to participate in the contest. However, I did manage to activate three parks as part of Support Your Parks event for Parks on the Air over the same weekend. I’ll write about that separately. While it’s easy to feel as though I failed to contest, I also recognize that I’ve undertaken a huge task with this Rover build; I want it to be RIGHT! The next VHF contest is in June… that’s the big one. I’ll be ready!

Getting There,

Scott, KE4WMF

About Scott

I grew up near Houston, TX and served in the U. S. Coast Guard ordnance and electronics communities for over 35 years. I became involved with ham radio and computers in 1995. The explosion of technology made my jobs and hobbies quite interesting. My hobbies include Volkswagens, bicycling, photography/videography, electronics, ham radio, and web management.
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