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The Mobile Ham Installation

from Andy D. Crouch N5NDD on May 17, 2000
View comments about this article!

As a ham of many years, I know that many of us would like to do our own installations. Whether in our cars or our homes, there is nothing like doing it yourself. Looking from the outside, as an installation manager for an electronics retailer, I can point out some common mistakes made during the course of an installation.

I'll start with a couple of stories about some of these "hack" home installs. About 2 years ago, a ham stopped by the shop to inquire about a problem he was having with his vehicle after he performed his own installation. His mobile setup consisted of a 2m ht with a Mirage 100w amp mounted under the passenger side dash of his Regal. His complaint was that any time he would key up with his amp on, the car would shut down.  Upon further inspection, it was determined that not only was the vehicle computer directly above the amp, but approximately 10 feet of extra rg58 was coiled up next to the factory module. Relocating the amp, rerouting the coax and trimming the excess solved his problem.

Customer number two is more of a horror story. A budding radio hobbyist (a cb'er) came into the shop to have a stereo installed.  As we were looking at his car, I noticed the 5/8 antenna and a shiny silver box mounted under the Camaro's dash.  It turned out that he had a linear on his 40 channel CB and that it shouldn't affect having a stereo put in. True enough, there was no problem installing his stereo, but afterwards was another story.  One week after he left, we received a call from the customer saying that we "burnt" up his car. When I went to the salvage yard to inspect the vehicle with our insurance adjuster, we found that the customer had routed his #10 gauge power wire for his amp through the door area and had neglected to fuse the wire at the battery. After a few weeks of being rubbed, the insulation was broken and the wire became a giant heating element burning everything between the battery and the short including the hoses, carpeting and the ac ductwork.

The bottom line is that a few basic precautions will save you from having any of these potentially fatal problems.

"be sure to use the right tool for the job"

1. Fusing and current draw. Anything more that 10-15 amps of draw should have the power line run directly to the battery.  Make sure that when routing these battery lines that you use either an existing factory grommet on the firewall or have the pros drill a hole thru for you.  There also should be a fuse within 18 inches of the battery on that power line.  You may say "well there's already a fuse at the radio".  Well the gent with the Camaro had a fuse at his amp as well, but the short happened before that fuse. Right?

2. Antennas. Most of us are familiar with the typical mag mounts and nmo hole mounts. They are very simple to install and are very low maintenance. The glass mounts can be another story. Some of the newer vehicles such as the Ford Explorers and Expeditions are coming with factory metallic tint in the rear glass making an antenna mounted on these windows perform as well as a wet matchstick.  On most vehicles, the front window is a safe bet, but one hint, "check your wiper clearance".  Also when running your coax cable, use the lowest loss cable as possible.  In addition, make sure that when running one of these mag or gutter mounts, that you allow for a drip loop before the entry point. Rain can (and will) follow that coax line into the vehicle whenever possible. A man named "Murphy" set up a set of laws regarding this and similar situations.  As with the guy in the Regal, make sure that you run you coax line as far a way from anything electronic in the car.  Not only can you produce interference problems with the car, but the car can also increase the amount of ground noise during a QSO. This also includes the infamous "whine" that you hear on the other end of your conversation.

3. Connections: When making any electrical connection, use either solder and heat shrink, (or 3m super 33 tape) or a high quality crimp type of terminal. The old "twisty and tapey" with the dime store roll of "no-name" electrical tape just will not cut the mustard.  In addition, when using the crimp type connectors, be sure to use the right tool for the job.  An old set of diagonal cutters trying to install a crimp is as easy as putting an 80m 1/4 wave vertical on the bumper of your old Chevy truck. (catch my drift ?). I would also recommend using only solder type coax connectors for both interior and exterior connections. A little connector sealant tape from radio shack helps to keep the water out of your feed line.  Water in your coax results in corrosion and signal loss which in turn decreases your output and increases your SWR. The higher the frequency, the more severe the impact.

4. "I MUST HAVE A SCREW LOOSE!" When mounting the gear inside your vehicle, make sure that you know what is on the other side of the panel that you are screwing through. You have a lot of things to look out for. Wire looms, vacuum lines, and fuel lines are a few of the obstacles to look out for.  If you can't see or feel what's on the other side, then don't screw into it.

Well, I hope this information has been of use to you. As a reminder, please ask for help if you get into trouble on an installation. Help is only a radio call away.


Andy D Crouch

Installation Manager

Member Comments:
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Mobil Installations  
Anonymous post on May 18, 2000 Mail this to a friend!
Fuse? Fuse? I don't need no stinkin' fuse! It's just something else to go bad!
Mobile Installations  
by K5MAR on May 18, 2000 Mail this to a friend!
Reminds me of the college kid who had his new Camaro towed into the Chev. dealer I used to work at. Seems the wiring under the dash caught on fire. While pulling the dash apart to get an estimate for warranty purposes I found a 1/4-20 bolt in place of the cig. lighter fuse (this was back in the '70s). When asked, the owner said he'd installed an amplifier for the radio and it kept blowing fuses, so he cut off the bolt and stuck it in there 'cause he got tired of replacing them. Warranty disallowed.
Mark K5MAR
by W9JCM on May 18, 2000 Mail this to a friend!
Good advise i installed cellular equipment in a very high end store in downtown chicago for some time. But when ever u go through the fire wall no matter if you have a "professional do it" or not you ALWAYS use some type of gromet. Drilling a hole is ok but u have to gromet it even if u file it down that can 1) wear a hole in that wire. 2) add road noise in the car. 3) get your feet wet..
by N8VW on May 19, 2000 Mail this to a friend!
I love my vw vanagon. Battery is under the front passenger seat, so I don't have to drill to install my ham gear.
Old Cars are best  
by N3PRZ on May 21, 2000 Mail this to a friend!
I've got a 1970 Ford Galaxie 500 which is perfect for ham radio among other things. The firewall is full of holes, the engine bay can fit upto two additional batteries (three total) and have plenty of pick-up power to get you moving. It also has so much room inside that you don't have to skimp out on one of these new Icom 706 or Yaesu FT-100 mini HFs, you can have a full blown HF and have leg room to spare. Plus there's a huge back seat that if your 5'-10 or less you can fully stretch out on. A trunk that will swallow all your gear and weekend stuff. It's a blast to drive. Even the SUV drivers stay clear the thing is so big.

Jason Foster, N3PRZ
HF Mobile Antenna installation  
by KB8AIZ on May 22, 2000 Mail this to a friend!
I have a 1999 Ford F-350 pickup and pull a fifth wheel camper. My TS-50 is under the dash (fed with 8 gauge wire and fused in both leads - 25 amp). I want to use the rig while driving on 10-20-40-75 (have a Hustler with these resonators). I will not drill holes in the body, thinking of mounting it in the bed of truck between my toolbox and the hitch assembly - there is sufficient room for trailer tongue to swing when turning. Easiest way my be to fabricate a mount that would also attach to my hitch rails! Anybody done this? I welcome all suggestions - thank you.
Motorolla's first install  
by ZL1TSC on May 23, 2000 Mail this to a friend!
The story of the second guy and his car catching on fire, reminds me of a story I heard about the first radio the founders of Motorolla put in, caught fire and was a total write-off the next day, because the power lead was only protected through the firewall with insulation tape, instead of a grommet.
RE: HF Mobile Antenna installation  
by N5NDD on May 23, 2000 Mail this to a friend!
If your tool box is made of metal, like diamondplate or steel, Simply attack some ground cable to link the metal of the tool box to the body of your truck. As long as the antenna does'nt react to your trailer, this should provide an excellent groung plane. The higher freqs will perform slightly better than lower ones due to the obvious lack of a larger ground plane area. Hope it works well for you.

N5NDD = Good Install Man, too!  
by MCRAM on May 25, 2000 Mail this to a friend!
I have used this guy Andy D Crouch (N5NDD) to install remote alarms on my Chevy Cavalier convertible (my last two Cavaliers, as a matter of fact!). I found him to be extremely courteous, diligent and professional, a perfectionist, too! He left my car sparkling clean (no snippets of wires left under the dash or seats). And most importantly, he was very patient explaining how to operate all the buttons on my remote (the several times he had to go over it with me again!). I am glad to know there are quality installers out there who are really "craftsmen" - those who know and care enough to do a job right the FIRST time! Thanks Andy. I appreciate your fine workmanship! ~m
RFI from 2000 Subaru Instrument Panel  
by N4OWG on May 28, 2000 Mail this to a friend!
Has anyone out there had any luck suppressing RFI generated by the instrument panel in the 2000 Subaru Outback Wagon while operating HF mobile?

Pulling the instrument panel fuze fixes the problem, but presents it's own set of problems (like no speedometer, tachometer, odometer, trip meter, and temp guage).

If anyone has solved this problem, please let me know. I'd hate to sell this car so soon.
RE: RFI from 2000 Subaru Instrument Panel  
by KB8RBD on May 29, 2000 Mail this to a friend!
first thing you need to know is is the noise coming in thru antenna or power find out ,set radio to situation that causes noise and disconncet antenna and see if noise goes away,if it does then noise is entering from antenna.if not then noise is entering thru power feed.if noise is entering thru power feed,consider do you have power cord hooked directly to battery? it NEEDS to be .if you do you might try routing a temporary feed to battery say out the door on oppsite that you have it now to see if this eleminates noise.if it does you might consider rerouting power cord,or adding chokes to power severe cases you can wrap power cord its length with some hi tech stuff,but this is a last resort.hope this helps.gregg
RE: HF Mobile Antenna installation  
by W4SIH on June 1, 2000 Mail this to a friend!
I also pull a fiver with antenna mount.I use a screwdriver mounted near the l/front corner of bed on a 99 F250 (I dont mind holes )How about one of those stake mounts it should hold a Hustler. I would try to get the antenna as far away from the front of the trailer as possible and as high as possible .The screwdriver and the 706 works great for me.
Chrysler 300M mobile installation woes  
by W8ZR on June 17, 2000 Mail this to a friend!
I'm the owner of a new Chrysler 300M, but am beginning to doubt my choice as I contemplate installing my h.f. Yaesu FT-100. My problem is that I can't figure out how to get a 12V DC cable from the battery into the passenger compartment. The engine compartment is so full, I can't even SEE the firewall! And the battery is also hard to get to. One has to take out a cover in the wheel well to get access to it. Anybody know some tricks of the trade that would be helpful. Tnx. 73,
Jim W8ZR
Mobile installations  
by W6AMH on June 24, 2000 Mail this to a friend!
When I was in high school in Palmdale, CA I worked for a Muntz dealer for a short time installing 8-track players (what do you mean Paul McCartney had another band before Wings?). The boss was extraordinarily persnickity about installations and taught me a lot about "faking it" or otherwise making something work, look good and cause no problems that appears impossible to accomplish from first glance.
My real education came during a 2 year-long stint as flight-line electrician on F-16 aircraft at Edwards AFB. The electrician "owns" the cockpit on the F-16 and is even responsible for all switch settings and fuel transfer responsibilities before the pilot climbs in and takes off.
My real education came during an instrument panel mod for a demonstration for all the NATO countries that fly the F-16. I had to add new instruments, lighting and glare shields and route new wiring into existing looms without disturbing the looms or removing any old wiring since it would be returned to original configuration after the demonstration. After I had done my best to podge the job up, a grizzled old solder burner from the General Dynamics factory in Ft. Worth showed me how to do what had escaped me. I had to make nooses from stainless safety wire and snake the new wires into all the appropriate places. The job was finally finished perfectly and bought off by the inspector with compliments. Most importantly I learned something about installation which serves me well today as a ham:
1. Make it as safe as possible.
2. Make it look like it was designed to be installed there.
3. Do it right the first time and you don't have to do it over again.
When I make installations now in my own vehicles I always get a warm feeling of self-satisfaction when other hams and otherwise technically astute people compliment my work. I favor Mil-Std equipment and installations that are just as sturdy!
Now if I can just convince my wife that a couple of holes in the new Lincoln won't look that bad...
Alan Heaberlin W6AMH

PS: Don't put the mike clip on the passenger air bag door!
RE: Chrysler 300M mobile installation woes  
by RICK on June 26, 2000 Mail this to a friend!
W8ZR - James:

Please E-Mail me, I have a 300M too and would like some information about how you installed your mobile.
RE: Chrysler 300M mobile installation woes  
by K3FT on October 12, 2000 Mail this to a friend!
I have a Dodge Caravan 1998- same problem. NO firewall access, no engine compartment access. Wanted 8 GA wire to run HF, VHF with no voltage drop and sufficient safety margin for 20+ amp service. WHAT TO DO?!

Ponder and scratch head. Arrive at answer.

Buy a plastic tubing junction feedthrough that is sold at Home Depot, etc. This is a gray plastic threaded unit that has a nut at one end and a flanged end with a neoprene seal. Make sure the inside diameter of the hole is sufficinet to allow your cable(s) to pass through unobstructed. Allow air gap for movement and cooling. Remove the front driver's seat of the vehicle. Drill a hole through the floorpan. Lift the carpet and install the threaded feed through through the hole. Attach the nut and tighten it SECURELY! Route wires to battery and secure them under the vehicle and in the compartment. Feed your wires through. Put Coax-Seal (TM) in the hole to seal it up from the outside world. Replace the seat and tighten seat bolts. YOU ARE DONE.

You now have weatherproof, flexible under all conditions, direct connex from battery to passenger compartment. No muss, no fuss. an no firewall holes to worry about. Plus you can feed other wires through simply by removing the coaxseal and feeding new wires through and repacking it.

Works fine with my van and best of all,when I'm done with power cables, I stuff 'em under the seat and they are out of sight.. out of mind. Neat, tidy, ready for action.


Chuck k3ft
by K3FT on October 12, 2000 Mail this to a friend!
Vehicle - 1998 Dodge Caravan.
Need - HF (160-10M), VHF (2M), UHF (3/4M)

PROBLEM! Radiated pulse noise (from computer, natch!) on DC power lines. 1mHz - 20 mHz then drops off and picks up again at about 26 mHz. 18kHz square wave pulse train, high rep rate.

Daimler Chrysler - talked to RF engineer who worked on RFI. No help, but lots of suggestions.

THE FIX! (What you've waited to read anyway!)

Build filter box in DC line. How? OK.

Get 20A or better 'hash filter' choke. This is several turns LARGE diameter bare copper wire around tubular iron core. This goes in SERIES with PLUS lead.

Parallel following capacitor values together.

1600 microfarads,
.1 microfarads,
.01 microfarads,

(If you use electrolytics WATCH THE POLARITY!!! PLUS TO PLUS.. MINUS TO MINUS!!)

This can be anywhere in the passenger compartment, closer to the radio the better.

IT TOTALLY eliminated the hash.

schematic follows PUT IN METAL BOX!!!!!!!! I used a 6x3x3 minibox I happened to have around. FUSING MANDATORY!!!!!!!! FIRE HAPPENS!

====== (hash filter, 20A or more)
from the battery PLUS 12VDC + 0----^^^^^^^^^-o-----------------o---------------o-------FUSE-------0 +12VDC to the rig
(the box is INSIDE THE CAR | | |
| | |
------ ----- -------
1600uf .1 uf .01 uf
------ ----- -------
| | |
| | |
from the battery NEG 12VDC - 0-----------------o------------------o---------------o------FUSE---------0 - neg to the rig

This will cure hash. Cap values not critical. Play with them if you like. Can go all way down to .001 ufd if wish. Again, if using electrolytics WATCH POLARITY!


CHuck K3FT
The Mobile Ham Installation  
by KB9RPD on May 21, 2001 Mail this to a friend!
Very good article. I'm glad I'm OVER cautious!

I've owned an HT for several years and that's been my only rig. However, I just purchased a new mobile Yaesu and I want it installed correctly.

What would you recommend for looking for a good radio installer in the Indianapolis area? What things should I look for, look out for, etc.? Actually, where do I start? I've looked in the yellow pages, but perhaps I'm not looking for the right item.

I could do this myself, but frankly, I want it done right the first time and I'll admit that I'm no expert and want a bang-up job done the first time, not something that would take me weeks on end to complete...and wonder if I did it right.

Any recommendations on finding a reputable installer?


73, Ted
RE:GMC Suburban Mobile Ham Installation  
by KD5CZM on December 5, 2001 Mail this to a friend!
I bought a creampuff 1985 GMC Suburban, big V8 engine, rebuilt by the lifetime mechanic who owned it. He retired after 40 years in the business. I would dearly love to install a 2-meter rig here as there is plenty of room. Your help appreciated if you installed a rig in your similar vehicle. Where did you route the pwr and antenna leads? How did you get through the firewall?

73 de KD5CZM

Joe Guerra
RE: Chrysler 300M mobile installation woes  
by KD5CZM on May 3, 2002 Mail this to a friend!
Do you think your solution would work on a 1999 Chevy Malibu? I installed a 2M rig in a Suburban the traditional way using a preexisting grommetted hole. The previous owner cobbled a GM stereo amplifier to go with the stock AM/FM radio.

When the time comes for a rig for the Malibu, well. . .

Joe Guerra
73 de KD5CZM
RE: The Mobile Ham Installation  
by KD5CZM on May 3, 2002 Mail this to a friend!
My friend,

I am the same way: persnickety about drilling holes in an important investment--your vehicle. Got tired, though, about going mobile with my 5W Alinco HT. This year, when the IRS refunded my taxes, I purchased Yaesu's FT1500 2M rig. Built like a fireplug. The mount looks like an iron butterfly which bolts right through the radio.

I can use a drill for the occasional chores but I asked my brother in law to do the honors. He's installed car stereos in all kinds of vehicular environments. Four holes through the sheet metal underdash. Shimmed two bolts so the radio is suspended evenly with the adjoining stereo amp. The rig and the mount aren't going anywhere.

I live in a small town and luckily, I worked for the County where I got to know the radio repairman. He did 'civilian' jobs between government repair orders. Paid attention to detail, did things right.

My advice? Get to know your local law enforcement personnel. Soon you'll find out who does the repairs on their rigs. If he doesn't do "installs," he'll point you in the right direction.

73 de KD5CZM
The Mobile Ham Installation  
by KG4OJN on July 28, 2002 Mail this to a friend!
Thanks for all the tips, I know they will all come in handy.

73 de KG4OJN
RE: Chrysler 300M mobile installation woes  
by N2YPH on May 8, 2003 Mail this to a friend!
I was going to comment - If you think the 300M is bad, try a V6 Caravan later than '96, but others beat me to it. :) My mom has one, I would NOT want to install a radio in it. I wouldn't want to do any major engine work on it either, it is a CRAMPED engine compartment.

I'm glad my '95 LeBaron convertible and old '93 Spirit both have lots of engine compartment room. (Moreso on the Spirit, the 'barons V6 is larger but still far better than the minivan.)

As to RFI - Ferrite is your friend. There is no such thing as Too Much Ferrite. Fuel pump power lines are a good place, same for the computer's power supply. I've even heard of 1-2 people putting ferrites on their *ignition* wires. (I'm a little iffy about this one, but it might work well, since the important signals in the ignition lines are low-frequency. Heck, some premium wires are essentially ferrite-core wirewound inductors...)

There was a good article on eHam a few months ago on mobile RFI suppression.
RE: HF Mobile Antenna installation  
by HUDSON on August 25, 2003 Mail this to a friend!
Hi Jim W8ZR,

Any chance at all you might be able to e-mail a few pictures of your antenna install? I also have a Ford F-250 Super Duty and recently bought a new High Sierra HS-1800 HF mobile and wanted some ideas on wher the best place might be.

Also curious to know if the position of the antenna is working well (or will work well ) for you.

Thanking you in advance,

Hudson Vallieres
Labrador City, Labrador

RE: The Mobile Ham Installation  
by WE4Q on August 9, 2004 Mail this to a friend!
I've been working at the local police radio shop for 16 years, mostly doing installs.
It's been getting harder to find places to put everything because cars are
getting smaller, and the list of equipment is going up. (radio, lights, siren,
cameras, computers...)
There is usually a friendly grommet to be found. If not, a drill and a grommet
can be added.

And if you are driving a Ford Crown Victoria, do not put any screws on the back
shelf in the trunk. (That's where the gas tank is... ask me how I know.)

RE: The Mobile Ham Installation  
by FBCMBR on August 9, 2005 Mail this to a friend!
Hi Mike:

I'd like to use some of your police installation expertise. I'm installing electronic equipment in a 2002 P71. Where the heck is the firewall pass through? I'm using a Federal Power Distribution Center in the trunk and it requires direct wiring to the battery. Should I install a fuse on the lead ?

If you can help, I'd greatly appreciate it - you're obviously the expert I need !!!

Thanks !

by KI6LO on January 23, 2006 Mail this to a friend!
Reply to K3DT hash filter...

====== (hash filter, 20A or more)
from the battery PLUS 12VDC + 0----^^^^^^^^^-o------------[Short]-----o---------------o-------FUSE-------0 +12VDC to the rig
(the box is INSIDE THE CAR | | |
| | |
------ ----- -------
1600uf .1 uf .01 uf
------ ----- -------
| | |
| | |
from the battery NEG 12VDC - 0-----------------o------------------o---------------o------FUSE---------0 - neg to the rig

What happens when the +12VDC line get shorted to ground halfway to the fuse (see the [Short] point above in +12V line)? Recommend in your drawing to move the fuses to be at the battery and then the hash filter and rest of stuff after that. Any short on +12V line will blow fuse at battery instead of melting wire and maybe causing a fire.

Otherwise good idea.

Gene KI6LO
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