Honda Ridgeline NMO Antenna Mount Installation

Ray installs a NMO antenna mount on Stuart Gorsky's (K9STU) 2010 Honda Ridgeline

Stuart's Choice for Mobile Radios
Yaesu 8800r

I have always wanted to drill a hole and mount an antenna in the center of my roof in order to take advantage of the many benefits provided but like many "hams", I have always been very apprehensive in doing so. The reasons for not drilling a hole in the roof of my vehicle are well know to all. The value of the vehicle will be diminished on trade-in and water will leak in through the hole in the roof. Others worry that a permanently mounted antenna advertises the presence of electronics making you a target of theft.

All of the reasons listed above for not drilling a hole in your vehicle roof seem valid but lets take the time to discuss them. What follows is my OPINION and not proven fact so don't come back to me at a later date and complain to me that you lost money in trade in value because of this article...

If your are leasing a car forget it! End of discussion. There will be no drilling of holes for you! If you purchase an expensive Jaguar, Lexus, Mercedes, Porsche or any other vehicle of this kind, drilling a hole is not something I would do. For these cars I would purchase a good quality hatch back or trunk lip antenna mount along with a "Diamond NR Series" mobile antenna. The "Diamond NR Series" antennas that I have used are top of the line in workmanship with great "ears" and transmit range. The "NR" series of antennas are advertised as being ground independent and in my experience I find that placement of the these antennas is far less critical than other antennas that I have used. As a note, no matter how hard I try, when using a magnet mount antenna I always find a way to scratch the paint.

Lets go back and address some of the issues listed above for not drilling a hole in your vehicle. I have done lots of volunteer Emergency Communications with the Los Angeles County Sheriffs Department as well as other organizations and in my travels I have met many of the professionals that install the complicated radio systems found in the modern police car. What I find from these professionals is that they drill holes and mount antennas in there own vehicles just like they do on police cars. When asked about trade in value of their vehicles the consistent answer is that when they go to trade in there vehicle, they put on a "cap" to cover the hole and never does a car salesman bring it up. How about the roof leaking during a rain storm or car wash? Modern NMO or UHF mounts manufactured by Motorola, Larsen, Diamond or Comet are first rate and when installed by a professional or experienced and competent individual they do not leak. As a regular practice I check my SWR in my vehicle every two years but baring any premature hardware failures I plan on replacing the cable and mount at the ten year mark. Finally, worrying that a permanently mounted antenna advertises the presence of electronics making you a target of theft is not something that overly bothers me. I make sure I have a very low insurance deductible on auto break in and theft and when I find myself in a bad area I remove the removable head from my Yaesu 8800r and take it with me.

Installation

The decision was made to put one of the "Larsen NMO" mounts in the center of my Honda Ridgeline roof at its highest point. This antenna will be connected to my analog Yaesu 8800r VHF/UHF radio. The second NMO mount was placed to the rear of the roof and will be connected to my Motorola MotoTrbo XPR-4550 digital mobile radio with GPS. Next, in order to make room for running the coax and dropping the headliner, we removed the rubber molding along with roof and side panels. Measurements were taken to determine the precise point where the holes were to be cut and a protective ring of tape was placed around the area where the holes were to be drilled. The tape had a two fold mission, (1) to precisely mark the spot to drill and (2) to keep any metal filings kicked up by the drill bit from scratching the paint that surrounds the drilling area. Next, from the inside of the truck we put a large piece of wood between the roof and head liner so the drill bit would not penetrate too far and ruin the headliner. After the holes were drilled the edges were smoothed over with a file and left over metal particles were vacuumed out.

Antennas to be used:

Larsen 2/70b NMO Collinear Antenna. black coil - open coil black whip

The 2/70 is listed as a a UHF collinear and a center loaded VHF. The loading for VHF comes from the coil placed in the center of the whip. This coil, however, is also designed to phase the top and bottom sections for UHF. Both the top and bottom sections of the whip are 5/8 wavelengths (roughly) at 445 MHz. The base coil helps impedance match both VHF and UHF. This antenna design is very tricky - and picky in terms of mounting because of the narrow tuning characteristics.

UHF: Low Profile Antenna.

More to follow....

Click here for several pictures of the installation process.