Last Modified: May 7, 2013
Contents: Basics; Doing it Right; Equipment Placement; Antennas & Things; Odds & Ends;
If you don't take time to do the job right the first time, how are you going to find time to do it over?
Anyone planning on installing radio gear in their vehicles should read (at least) the Bonding, Noise ID, Antennas, Antenna Mounts, Radio Mounts, and Wiring articles. The latter is especially important if your vehicle is equipped with a Battery Monitoring Systems (BMS) and/or Voltage Quality Modules (VQM). Thus the Wiring article should be reviewed before the actual installation begins. It should be noted that BMS and VQM are acronyms used by Ford Motor Company, and other manufacturers may use different acronyms for these devices.
There seems to be a lot of misinformation about installing amateur radio in vehicles with respect to interference (RFI) of on-board electronics . Contrary to information found across the web, no automobile manufacturer prohibits the installation of radio gear, amateur or otherwise. Nor do any deny warranty claims on vehicles so equipped. In fact, they offer guides on proper wiring. Here at the ones for Ford, and GM. The ARRL web site has information on other makes, here. Perhaps there could be a case made wherein factory wiring was used, and a wiring fire resulted as shown in the left photo. But even that scenario would be hard to legally support. The point being, if you follow the recommendations herein, you'll never have a warranty problem. This said, there have been instances where dealerships have refused to work on vehicle (warranty or not) because the radio and/or ancillary hardware made access too difficult. Their position is easy to understand, especially if the problem at hand is being warranted. The best way to handle situations like these, is to discuss the issues with the dealership personnel first!
Very few amateurs go out searching for a new vehicle with the idea of mounting an antenna on it, or a transceiver in it. Typically, they already own a vehicle, and they decide to operate mobile. Either way, it always presents a problem in some fashion. Minivans, SUVs, RVs, Jeeps, station wagons, crossovers, and plastic-skinned vehicles present the greatest challenges. As a result, I receive a lot of emails asking me for suggestions about mounting all-things mobile. This article is an attempt to answer the questions. In the end, it might be a feeble attempt, as what I'm willing to do, isn't necessarily what everyone else is willing to do. Drilling holes in sheet metal, is a prime example.
Whatever your stance on drilling holes, the performance you ultimately end up with is directly dependent on how much time, and effort you're willing expend. Or spend, as the case may be. I must say, in almost every mobile installation I have ever done, there ends up being something I could have done better. What seemed like a wonderful idea up front, wasn't so good after the fact. This is of extra concern for those who have never done a mobile install before. Hopefully, the information presented here will minimize the amount of rework.
Speaking of doing it right, look at the photo on the left (click to enlarge). The owner, D. H. Gieskieng, K9CFE (sk), drilled several holes in the roof of his new vehicle to mount his version of a remotely-tuned antenna. Would you do this to your new vehicle?
The Photo Gallery's Other Installs album is a good resource for finding a spot to mount antennas, transceivers, and all manner of ancillary hardware. They are listed in alphabetical order by the call I received them from. In some cases, the calls have changed and/or the vehicle has been traded. If you're looking for a specific call, use the album's search function.
If you've been reading the other articles on this web site, you'd know this important antenna mounting point; It is the metal mass directly under the antenna, not what's along side, that counts! Typically, this requires drilling holes!
Note the arrow in the photo at right. It is pointing at what's left of an accessory socket (cigarette lighter) plug, after it started a wiring fire. This is the exact reason why you should never, ever use existing vehicle wiring to power any amateur radio gear, no matter what it is!
I have always been amazed at the amount of work some amateurs will go, to avoid doing their installations correctly, as the left photo will attest to! The HOS album of the Photo Gallery has many more examples. These installation faux pas go well beyond the mechanical, and include every facet of the installation, especially wiring (look closely on the left side of the photo at the dash board).
Another wiring faux pas is using an isolated battery charged by the vehicle's existing wiring. The usual (moot) excuse is that they couldn't find an easy way through the firewall. If you think this is your best solution, you're wrong! And think about this. A lot of amateurs receive flak from the spouses about their amateur radio extravagances. The main reason is simply because of the haphazard methodology they're so used to seeing in amateur-related venues around the house. Doing installations correctly is always a mitigating factor in reducing flak from a spouse.
Make everything as automatic as possible. This is one reason why I like automatic antenna controllers so well. Once setup, a single button push finds the correct antenna resonant point. No meters, no switches, just the existing Tune button on the radio. How much simpler can it get?
If you're planning to run an amplifier, now is the time to wire for it, not after you buy it. Remember, rework is always more costly in terms of time and money. The SGC and HL450B have automatic band selection built in—use it! If you use manual control, no matter how careful you are, sooner or later you're going to transmit into the wrong bandpass filter with predictable results. Better yet, with automatic band switching, all you really need to control the amplifier is a switch to turn it on/off, and an LED to tell you when it is on. Incidentally, the Ameritron ALS-500® does have automatic band switch option (ARI-500). Unfortunately, all of the cabling comes out the front of the unit, and it you need a remote on/off, you have to opt for the ALS-500RC as well (or add one to the ARI-500 yourself). Finding room for all of these devices is difficult in most vehicles.
Lastly, make sure you notify your insurance company and/or agent that you have installed radio gear in your vehicle. In some cases, the notification must be in writing. Most of the time, coverage riders are not necessary, but that is not a given. It is always best to check first, not after a loss. By the way, most automobile insurance companies will not cover radio equipment that is not permanently installed. This rules out mag mounts among other temporary mounting schemes.
If there is but one theme to follow when doing any mobile installation, it is Safety. Far too many amateurs get in too big of a hurry installing their mobile equipment. Haphazard and improperly fused wiring, inconvenient transceiver mounting locations, or mounting too close to an SRS device are dangerous practices. Please! Take time to plan your installation, and execute the plan in a diligent manner. While none of us want to be involved in a vehicle crash, statistically one in seven will be at sometime in their lives. A minor knowledge of high school physics is all it takes to understand what damage an unsecured remote head or handheld can do during a crash.
The rule of thumb is, if it is loose, bolt it down! And, contrary to popular belief, there is always a place to properly screw down radios and/or remote heads. If you have to resort to Velcro®, double-sided sticky tape, suction cups, bungee cords, magnets (no matter how strong they are), wedged in blocks of wood, and rubber bands, you haven't studied the issue long enough!
Wherever you mount the your radio or remote head, it should be within easy reach, and easily viewable—not always an easy task to accomplish. Speaking of mounts, don't buy one, and then try to figure out how or where to mount it. That should be done first, and then a suitable mount selected based on the established criteria.
While I realize some folks don't like to drill into plastic interior pieces, if you plan well they won't be easily visible once the radio is removed. The photo at left is a good example. The flexible goose neck is screwed down inside the cup holder. Once the rubber protector is replaced, the holes will not be visible. Note that the controls can be adjusted while resting the forearm on the top of the console. This is an ideal situation for obvious reasons. There is more information in the Radio Mounts article.
If there is one point about mounting locations that needs to be driven home—The top of the dashboard is not it! Modern Supplemental Restraint Systems (SRS or airbags) virtually cover the whole top of the dashboard, and they literally explode in less than 200 milliseconds! That's about 200 mph! Obviously, any hardware within reach of an SRS (including the suction cup-mounted control head at right), will be flung far and wide when it goes off. As further proof of the dangers, here is a 2.7 MB wmv movie (used with permission of the NHTSA, National Highway Traffic Safety Administration) of an actual deployment. You need to play the movie several times to get the full effect. Note how many frames it takes for the air bag to explode to full size, and how far it reaches across the dashboard.
Some mobile operators disregard the aforementioned, and continue to mount their transceivers within reach of the passenger side airbag. Their reasoning is often based on the fact that some airbags deploy from the center of the dash, rather than the top of the dash. They ignore the fact that airbags must meet fed guidelines with respect to coverage area. Don't be fooled! Any hardware mounted atop the dash to the right of the steering wheel, is within reach of the passenger airbag!
There are several other places in the interior of a vehicle which should be avoided and/or where extra care should be exercised. One of those is under the seats. It is not uncommon for the side Supplemental Restraint System (SRS or airbags) impact sensors to be mounted within the seat(s) framework, and in some vehicles, the side impact airbags themselves. These devices are directly interfaced to their control system using secured connections. It is possible, albeit remote, to set off an airbag if these connections are mishandled. Disconnecting the vehicle's battery is not a workaround, as these systems have their own internal power source!
Further, cubby holes, center consoles, and storage boxes should not be used. Remember, modern transceivers rely on fans to stay cool, and thus require air flow all around them. This is one of the reasons factory-supplied mounting brackets should be used. In other words, don't place any transceiver directly on any surface.
Because it is tough finding room for all the requisite goodies, even microphone hooks, some folks use the foot wells to stash gear. If you have to resort to using the foot well, maybe you should ask yourself if that ancillary goodie is really needed.
Do yourself a favor, and resist the temptation to install hardware you really don't need. A good example is a SWR/wattmeter for an FM radio. By the time the meter tells you anything, you'll no doubt already know something is a miss. The only case for installing one on an HF transceiver, is for manually tuning a screwdriver antenna. Even then, the one in the transceiver should be adequate. The same goes for some amplifier remote controls. A good example of that is the one sold by SGC. Since the SG500 amplifier can automatically select the correct band filter, a simple remote control switch is all that's needed. It pays to remember the KISS principle!
There are exceptions, but even some of those can be avoided. For example; One unique feature of the IC-7000 is its video out. In my case, the video is fed to a TVandNav2Go converter, which displays the front panel on the Navi screen. Therefore, there is no need for a separate video screen. It is considerably safer due to the Navi screen's near perfect mounting location.
If you own an IC-7000, and you don't have a Navi, then opt for a rearview mirror monitor. The unit shown at left is made by the AudioVox division, but others are available. Some models clip to the existing mirror, and may not be suitable for some vehicles. All current models are composite video in, and are compatible with the Icom IC-7000. Retail averages about $200, and some models come with a backup camera as well.
If there is one item you should have on board, it's an accurate voltmeter (in dash units aren't very accurate) like the two-wire Martel Electronics QM-100V shown at left. Its current draw is a scant 2 mils, so it need not be switched off.
Here's something to think about before you buy an antenna, or at least your next one. The vast majority of e-mails I receive deal with RFI issues. The on-board devices affected are all over the board. However, there are two common threads that crop up far more often than any of the others.
The first one is stubby antennas. There are currently five manufacturers I'm aware of, but there could be more. Folks buy them because they're unobtrusive, and apparently easy to mount. The most common mounting method seems to be the Diamond® K400®. The K400® series is an adjustable trunk lip mount, typically supplied with a 6 foot long RG174 type coax cable terminated in a crimped on PL259. Regardless of the advertising hype, the lip of an average trunk has enough flex that the mount needs to be retightened quite often. Remember, the coax shield needs to be securely connected to the body of the vehicle (which acts as a ground plane). If the connection loosens (a regular occurrence when using clip mounts), common mode currents will flow over the outside of the coax with abandon! A separate ground strap isn't a cure! Even when the coax connection is secure, there will be more common mode currents than there would be if a full-sized antenna were mounted in its place. Overcoming this problem is not an easy task, as outlined in the common mode article.
If you're having a radio or sound shop install your antennas as well, educate yourself about the various types of mounts. For example, the only VHF mount that is truly waterproof, even with the antenna removed, is a real NMO (New Motorola), and not some Pacific Rim knockoff! Incidentally, the various versions of the NMO produced by these Pacific Rim antenna companies, are not compatible with real, NMO mounts, so don't try to mix and match them.
While we're on the subject of mobile antenna mounts. Every single antenna mount, based on a UHF connector (PL259/SO239), will leak water to some degree. Remove the antenna, and they're virtually a sieve! Further, all clip mounts route the coax around the trunk's (or hatch, door, etc.) weather seal. If you live in a rainy area of the country, you'll discover their worth!
All remotely controlled HF mobile antennas will have RF flowing over their motor leads when transmitting. The basic reason is, the motor operates above RF ground. Therefore, the leads have to be bypassed (RF choked). The Antenna Controller article has a complete description about the requisite chokes. Again, the level of RF on the leads of stubby antennas are much higher than a full-sized one, all else being equal. Add insult by using a clip mount, and RFI issues will abound.
Forget about mag mounts. Just about an equal amount of folks have told me theirs has never come off as opposed to those who have. When your mag mount decides to dislodge, it will undoubtedly be during the worse driving conditions imaginable. I don't like trunk lip mounts either, but they're better than mag mounts especially in a crash. Read my VHF Options and Antenna articles for more information on safe antenna mounting.
Mag mounted antennas often cause another problem, and that's a ground loop. Typically in this case, the ground loop manifests itself as alternator whine impressed on the transmitted signal, and to a lessor degree the received signal. While a brute-force filter on the power cable may mask the malady, it is nothing more than a voltage-reducing band aid!
Note the bent sheet metal in right photo. This type of repair is much more costly than that caused by a drilled hole. I also suspect a lot more folks would drill holes to mount their antennas if they weren't so afraid of botching the job. As a result, some folks seek professional help from two way radio dealers and/or mobile sound shops to install their gear. Unfortunately, some of them don't know anymore than you do! If this is your tact, educate yourself with respect to proper wiring. And insist that you be allowed to watch the work being performed. If they say no, go elsewhere.
There is one mounting location you don't want to use, and that is inside a bed-mounted storage box, no matter what it is, or how it is made. The reason is simply moisture condensation. Storage boxes are typically not vented since they're made to be weatherproof. In most areas where there are large variations in moisture and temperature extremes, condensation builds up inside the boxes with predictable results—rust in other words.
Bed boxes are often used as antenna mounts, although there are better solutions. If you do use a bed box, make sure they are properly bonded to the bed. If in doubt, run short (!) bonding straps to the bed on both sides of the box.
As a parting thought.... Neatness counts!