Last Updated on 11/5/2025
I decided to try my hand at VHF contesting in 2022. Being a mobile-only operator, what better way to contest than as a “Rover?” Rovers move from one Maidenhead grid square to another during the course of a contest. This allows stations to work each Rover as a new station because each new grid means a new contact, even with repeat stations. A team of Rovers can accumulate a load of contest points by moving between the squares, then working each other and the other same stations after each line crossing, a process known as “grid circling.”
ARRL has three categories for Rovers: Classic, Unlimited, and Limited. I focus my efforts in the Limited category, which operates only on the “low four” VHF/UHF bands of 6m, 2m, 1.25cm, and 70cm (50MHz, 144MHz, 222MHz, and 432MHz) and has power restrictions (200W at 50 and 144MHz; 100W at 222 and 432MHz). Most successful Rovers have directional beams to focus their signals toward their intended contacts. They also have a large e-mail lists that they use to promote themselves ahead of time. I have not yet developed such a list of contacts; but I suspect that I will make some connections as I gain more experience.
I started my contest build by reinstalling my discontinued Yaesu FT-857D multi-band/multi-mode transceiver. Choosing a radio that I already own was the least expensive way to start using SSB modes on VHF/UHF. In case this photo has you curious, the 220-band is NOT native on the FT-857D! It has a transverter setting that allows transverted frequencies to display, a feature that’s apparently extinct on modern mobile HF rigs. I use my FT-857D to drive a 222 MHz 50W transverter on SSB and FT8 during contests and as my 220-FM rig outside of contests.
I started my journey with horizontally-polarized 50, 144, and 432 MHz loops by M2Inc.com. I added a 222 MHz loop in 2024. My “loop module” is a modest setup and less effective than what most Rovers use, but it was quick and easy to buy, build, and install on short notice to get started. Each loop is tuned for the SSB portion of its respective band. I used CQ’s World Wide VHF Contest in 2022 as a training run for ARRL’s larger VHF contests, which occur each January, June, and September.
Later, I constructed a “micro-tower” to support a Yaesu G-450ADC rotator and four horizontal beam antennas. Most rotators require household 115VAC to operate. I have an inverter in my car, but prefer to minimize its use because it produces radio frequency interference (RFI) on some frequencies. I eventually replaced the rotator controller with an RT-21DC by Green Heron. It’s powered by 20VDC, the same voltage that’s used by the rotator motor and my laptop, and allows me to leave my 115VAC inverter turned off. The RT-21DC has a lot of optional features that I do not use, but I have great appreciation for the knob that allows me to just dial-in a bearing and let the mast rotate without having to hold a “Left” or “Right” switch. Sure, it’s lazy; but it’s also wonderful! 😀
My micro-tower features a 5-foot tall 1.5-inch schedule 80 (1.9″ O.D.) aluminum mast, a Yaesu GS-065 thrust bearing, and four horizontally polarized Yagis. I use a “Stressed Moxon“ by Par Electronics for 50 MHz. The Moxon is a folded two element Yagi-Uda antenna that claims ~3.7 dBd of gain. My other beams are “Rover Specials” by Directive Systems & Engineering and feature 8-ft booms. The DSE144-6RS is a 144 MHz 6-element Yagi with 10.1 dBd of gain, the DSEFO222-10RS is a 10-element Yagi with 11.4 dBd of gain, and the DSEFO432-15RS is a 432 MHz 15-element Yagi with 13.5 dBd of gain. All of these antennas will accept 1000 watts or more, which is far more than I will ever use in a mobile application.
Getting thick feed lines out of the car and to the roof is an unusual challenge! At first, I simply fed the coaxial cables into the car through a rear window and sealed it using a piece of pipe insulation. Soon thereafter, I created a pass-thru panel with ³⁄₁₆” HPDE (plastic) that mimics the shape of the window and has weather-sealed Type-N connectors, making the setup completely modular and easy to remove. I have eight ports and still have use of the rear door. I chose eight ports because I used to run with both loops and beams during VHF contests. Today, I operate with either beams OR loops, but not both. I could fill these eight ports very nicely with 50, 144, 222, 432, 902, 1296, 2304, and 3400 MHz. However, I have intentionally limited myself to the “Limited Rover” bands to restrain myself. 😀
Having two amplifiers and a transverter can lead to a key line failure due to over-current. Naturally, I want to protect my accessory ports! I also wanted a way to protect the receivers of whichever radios are not transmitting. My solution started with a key line combiner that takes all transmitter outputs and converts them to a single signal. Next, I added a solid state relay that takes the combined low-current signal and then outputs high-current key signals from a separate 13.8V source. That output goes to a key line splitter which splits the signal for use by each amplifier. A benefit of having ALL amplifiers key at once, even if only one is going to actually transmit a signal, is that all receivers are blanked and protected from front end overload during transmit. The only downside is that all three amplifiers keying at once, even if only briefly, results in a 50-70 amp spike at the battery. This is not a problem for my 12VDC distribution setup, but those who copy my efforts should beware.
My car usually has its roof rack mounted since I mount the 6m/2m loops several days per month. Having the rack mounted full-time provides the option to go completely nuts! I have nine antennas mounted in this photo, though the count is closer to five on most days. Learn more about my rooftop setup on my Antenna Farm page. See the photo album below for more photos as well as a functional block diagram of my RF paths.
See You on the Air!
Scott
