The idea of hood-mounted antennas had not appealed to me. With my sedans, I would either use a trunk lip mount or, eventually, a hole mount. Trunk lip mounts are not compatible with my GTI because of the plastic cladding on the hatchback. I went with a replacement for my factory sharkfin antenna on the roof. See how I did it here. Eventually, I decided to keep my roof rack mounted full-time and populated it with antennas. The latest configuration of my my contest rover’s “micro-tower” has lowered the Yagis by about 12 inches. That brought the lowest Yagi within easy striking distance of two of my rack-mounted vertical antennas. In some cases, I can replace those verticals with shorter variations. But I also concluded that mounting some of my verticals to the hood would lower their overall height and eliminate the collision hazard altogether.
I almost purchased a pair of trunk lip mounts, but I wasn’t certain that a lip mount would fit over the thick roll of my hood’s sheet metal; nor, did I want to risk damaging the paint protection film that’s on my hood. I quickly realized that I had another solution in my garage. I had purchased a pair of “ditch light“ brackets and used them to help guy my first micro-tower. The idea was short-lived; so, I put the brackets in a box. I didn’t have any plans to mount ditch lights, but I thought that they might come in handy someday.
The main challenge with these brackets is that they’re not wide enough to allow for boring the light’s mounting hole to the ¾-inch holes that are required by the vast majority of NMO antenna mounts. But there’s a better option with Diamond Antenna’s C213SNMO NMO mount. It features a slender center that fits in a ⅜-inch hole! The included star lock washer is good for a surface that exceeds one square inch. However, my ditch light brackets are narrow enough that I opted to use a ⅜-inch replacement star lock washer. This photo shows the slender profile of the bracket. You can see that I routed the feed line with enough slack to allow it to articulate with the hood when I open it.
Rather than clamping to the hood’s sheet metal, these mounts use factory hardware to clamp within the hood’s mounting hardware in the hinge. This allows the antennas to move with the hood. They even clear the A-pillars when the hood is open. Better yet, the mounts are bonded to the car’s body since I had already bonded the hood when installing HF equipment. Each antenna that I’ve mounted has tuned just as well as if it was on a body-mounted NMO mount! They function well enough here to consider them as permanent mounting locations.
Speaking of my choice of antennas, two key antennas collide with the Yagis when they’re mounted: My ATAS-120A and a tri-bander that’s used primarily for 223.5 MHz FM and my D-STAR hotspot (446.XXX MHz). During a VHF contest, my only need for the ATAS would be on 52.525 MHz FM for stations that do not have horizontal polarization. That seems like a rare need, but I have a 52 MHz vertical antenna and have mounted it to the the driver’s side hood mount. I could even mount an NMO-27, should I decide to have a dedicated 10m or CB antenna. I mounted the tri-bander on the passenger side. If you’re wondering about RF safety with hood mounted antennas, the driver’s side antenna is 4 feet from me and the passenger side antenna is 4.5 feet away. According to ARRL’s RF safety calculator, I’m beyond the compliance distance for 52 MHz 100W SSB by a good margin and right at the edge of compliance for 144/222/446 MHz 50W FM for my particular antennas.
See a video about these mounts HERE. For now, I plan to use these mounting positions only during contests and exhibitions or, stated differently, whenever the micro-tower and Yagis are mounted. I don’t think I’ll have a need any other time unless I decide to add an APRS transceiver. Until then, can I find a reason to mount…
More Antennas? 😉
Scott, KE4WMF
