my mobile installation

Before I get into some current projects, I will add a few posts related to past projects I have completed. This was originally printed in my club’s May 2009 newsletter.

FT-7800R control head

Yaesu FT-7800R installation in a 2000 Honda Civic EX
By John Shadle, W4PAH

This past September I began a job in RTP which led to more time spent in my car on a daily basis than my previous status as a bus-riding student—and potentially more time to “play radio” on a regular basis. This began an evolution of my reality of mobile operations, as well.

My first mobile station consisted of a Yaesu VX-7R handie-talkie and its rubber-duck antenna. The frustrations of a poor radiating antenna led to the installation of an Austin 500C dual-band (2m, 70cm) antenna on a Comet CP-5NMO mount on the lip of my trunk. Then, I added the earpiece mic (VC-27) to the mix, to keep from having to hold the radio while driving. This worked well for a while, but I soon realized that I wanted to place a higher power radio in my car “permanently”.

Since I had already solved the antenna side of things, I began my search for the perfect radio for mobile operations.

My car is a 2000 Honda Civic EX with a manual transmission. Because most of my travel would be short trips to work from my house and back, and because of the need to shift gears, I decided against an all-mode, all-band transceiver and for an FM dual-bander, instead. After reading the reviews on eHam.net, and based on my own positive experience with Yaesu rigs, I purchased a FT-7800R on special from one of the online dealers which included the head separation unit. I knew that I would not have room for the full transceiver in my dashboard, so having the ability to place the bulk of the rig elsewhere was very attractive to me.

Now that I had almost all the pieces in place, I began sketching out plans of how I could run wires in my car to get power from the battery to wherever I placed the transceiver, from the transceiver to the control unit, from the transceiver to the speaker, and from the antenna to the transceiver. Lots of wires going different places in this installation!

DC, control head cable, and speaker output under passenger-side of dashboard

Running wires from your battery to your transceiver through the firewall of the car is not the easiest task. This, above all else, caused the most trepidation because I didn’t want to destroy any wiring currently in my car or create unneeded holes in the firewall. I headed over to K0BG’s mobile installation site to view other hams’ installations, based on a recommendation from KZ1X. I read on the eHam forums, too. I finally decided that I would run #10 AWG red/black power wires from my battery to the trunk, where I would place the transceiver. The #10 was probably overkill, but I thought that it would allow the most flexibility if I ever decided to put anything else in the trunk in the future which required more “juice”.

First I tried simply pushing the #10 through a hole through the firewall I had located behind the glovebox. While the #10 is pretty stout wire, it would not make it through on its own.

Next, I tried taping a straightened wire clothes hanger to the #10 and pushing it through. I had made it through the firewall successfully, but once I started pulling the hanger through on the engine side, the hanger snapped in half. Finally, I decided to take advantage of the nature of the twin-lead wire and make a few small slits in the thick plastic separating the red and black wires (NOTE: Be very careful not to breach the insulation of either the red or black wires and create a possible short!) and “weave” the coat hanger in and out of these slits. I tightly wrapped electrical tape around it and I was in business. This technique allowed me to get the wire through the firewall to the battery. Success!

Scosche pocket, plastic from The Scrap Exchange, faceplate mounting bracket

The next step was to figure out a way to fasten the control head to the dashboard. Below the AM/FM radio there is a small pocket where papers, CDs, or the like can be stored. I found a replacement pocket kit on eBay which was manufactured by Scosche. I wanted to preserve the resale price of my car as much as possible, so I decided to purchase the replacement pocket and save the original pocket to re-install once I removed the control head at some point in the future. Thanks to a tip from N2JFP I headed down to Durham’s Scrap Exchange to search for something to cover the pocket and attach the control unit to. Success once again, as I found just what I was looking for in a rectangular plastic piece for $0.10!

I drilled a hole in the rear of the pocket and in the new plastic faceplate for the control wire to pass through, pulled the wire through, and grommetted the front hole (to keep the wire from passing back through the opening if I ever removed the control head). Next, I used super glue to attach the plastic rectangular panel to the pocket and waited. Once the glue was dry, I then measured and installed the control head mount with the included screws.

Installing the pocket in the dashboard is another topic completely, but if you are lucky enough to find a service manual for your particular car, then this becomes much easier to do.

Once the pocket was installed, I began the process of routing the power cord, speaker cord, and control cord from the front of the car to the rear of the car, where I was going to install the actual transceiver. I bundled the three wires together with wire ties and used split-loom tubing to protect them from potential nicks. Using the handy service manual I had found on the internet, I removed the interior side paneling to pass the protected wires to the trunk. (Again, I’m making this sound easier than it really is, but each installation will be different depending on your automobile.)

transceiver in trunk

I decided to install the transceiver on the back of the passenger-side rear seat. I first removed the backing of the seat to reveal the metal where I would drill through to attach the transceiver mount. A Dremel came in handy for this task, then I used a cordless drill to drive the screws into the metal.

On each end of the #10 AWG I attached the ubiquitous Anderson PowerPole connectors. This allowed easy attachment of my transceiver to the power cable, using replacement VHF/UHF “T” connectors from PowerWerx, as well as to the Littelfuse (yep, that’s how they spell it!) ATO/ATC fuse holder (attached to my car’s battery on the other end).

I was finally ready to apply power and try it all out. Lucky for me, the result was a clean, alternator warble-free sound. Thanks to all the club members who offered encouragement and experience along the way. I couldn’t have done it without you!

As far as I’m concerned, the installation is complete. I decided on the Vertex Standard MLS-100 speaker, which plays perfectly with my FT-7800R. The speaker is loose in the floor at the moment as well as the hand mic. I may eventually fasten them to the interior of the car at some point, but I’m quite happy with their locations at this moment.

References
http://www.eham.net/reviews/
http://www.K0BG.com/
http://scosche.com/
http://www.scrapexchange.org/
CARQUEST: split-loom tubing, Littelfuse fuse holder, fuses, battery terminal connections
http://www.powerwerx.com/oem-connectors-filters/

High resolution photos of the install are available at
http://www.flickr.com/photos/shadle/sets/72157613559691280/