One of my toys these days is a Jeep Wrangler (TJ) which we use for playing in the mountains. I finally got around to installing some ham radio equipment in it a few weeks ago. I mostly wanted to have good old 2 Meter FM – the amateur radio utility mode - in the vehicle. These days, it makes sense to include 70 cm (440 MHz) as well.
The first priority was to pull the old AM/FM receiver and put in a new Sony CDX-GT430. Crutchfield supplied excellent installation instructions and soon I had the center portion of the Jeep dash pulled out and the receiver installed. This work gave me valuable experience in pulling the Jeep’s dashboard apart. Not surprisingly, the Wrangler disassembles quite nicely with just a few screws here and there and a handful of those snap-in-place trim fittings to undo.
The next job was to get a dual-band Yaesu FT-7800R 2M/70 cm transceiver installed. This is a one-frequency-at-a-time dualbander, very easy to use with all the required FM features. Originally, I thought I would just bolt the unit down in a convenient spot and call it good. As I surveyed the Jeep, I realized that I could do much better using the detachable control head approach (using YSK-7800 separation kit). The control head was mounted to the main plastic piece that covers the center of the dash using a pair of angle brackets from the hardware store. The radio box went under the back seat… somewhat protected from weather when the top is down and definitely not in the lower part of the Jeep floor. With the hardtop off, a hard rain can cause a small lake to accumulate inside the Wrangler. (I know from experience.)
The most challenging decision turned out to be what antenna to use and where to put it. Mobile antennas are always a trade off between radiating effectiveness, ease of installation and overhead clearance. The Wrangler has a removable hardtop, made of fiberglass. This presents two problems: the fiberglass makes for a lousy ground plane and there will be times when we go topless. So a roof mount was not looking very attractive. Another choice was on the spare tire mount, which hangs off the back of the vehicle. I’ve seen a few installations like this that look good. It looked like a more complicated installation and I was not sure how well the antenna would radiate off the back of the vehicle.
In the end, I chose to mount a short dual-band antenna on the hood near the driver’s side, using an NMO-style mount with one of the L-shaped trunk mount brackets. This is not the best location for antenna efficiency but it would be “good enough” for most use. The antenna is a 1/4-wave on 2 Meters, about 19 inches long, also tunes to 70 cm. The low profile has the added advantage of not getting pounded down by tree branches on the back roads. And I can take the hard top off without changing the antenna configuration. Did you spot the antenna in the first photo?
The Jeep had a obvious rubber plug that I poked through to get the DC power and antenna connections through the engine firewall. Per the usual guidance from the transceiver manufacturer, I connected the power cable directly to the 12-volt battery (with fuses in line). The antenna seems to pick up a bit of ignition noise due to the close proximity to the engine, but it is tolerable.
Off to the mountains to have fun.
73, Bob K0NR