Contents: Basics; Auto Off; A Better RF Mousetrap; Bluetooth; SWR; Amplifier Interfaces; Antenna Analyzers; Coax Cutter; FT-857 Meter; Mini-Manual; Passive Audio Filter; Two Wire Voltmeter; Video Display;
Since my first foray into HF mobile operation in 1972, I have always looked for things that would (or could) make my operation safer and easier. Over the years, I've built, bought, and sought just about every type of gadget you can think about. If you have a favorite gadget which makes your mobile operation safer and easier, send me an e-mail and let me know about it.
Please note that I am in no way connected to any of the manufacturers, or their dealers. The products are here because I (or my readers) found them useful. Also note that some of the gadgets appear elsewhere on this web site, and if there is a more complete description, I'll post a link to it.
Unfortunately, not all amateur radios have an auto off feature, especially VHF/UHF ones. This fact causes a lot of amateurs to bypass proper wiring practices (using vehicle wiring for example) just so the radio can't be left on. Well, now there is a solution.
The PowerWerx APO3 is more than just a timed (0, 5, 10, 20 minutes), auto off device. There are four pre-programmed voltages (11.8, 12.1, 12.7, 13.05 volts) settings. Properly programmed, the APO3 will turn off, and on, your radio just by monitoring the battery voltage!
It can handle up to 30 amps making it compatible with almost any radio. It comes equipped with Anderson Powerpole connectors, making wiring simple, and quick! At $60 (MSRP) it is also affordable. Visit their web site for more information.
Once in a while, something new comes along that is heads above the competition. Referring to the photo above right, the black box is the Better RF Screwdriver Controller. It will work with almost any remote controlled HF mobile antenna, including the HiQ. It has some very unique features, including non-volatile memory!
There are two parts. The Tuner Control Plugs into the tuner port of the 7000, and a short jumper plugs into the CI-V port. A 2.5 mm stereo cable interconnects with the Screwdriver Controller. Except for the antenna's motor, all power comes from the radio. All cables are included, and all that's necessary is to provide a 3 amp fused circuit. The only modification required, is changing a jumper located inside the tuner unit.
The factory SWR default is set at 1.5:1, but can be easily adjusted. The stall current is automatically set to twice the run current, and it too may be changed. You can manually operate the antenna if needed, but you won't need to as this unit works perfectly, every time! There's even an amplifier bypass relay (both NO and NC).
The programming is fairly straight forward, and utilizes the Lock function, and the QS menu. Setup takes all of 5 minutes. If you use a HiQ antenna (and some off-beat screwdriver antennas), the motor leads need to be flopped. Even if you don't get it right, they can be reversed in software.
Once set up, when you QSY all that is necessary to do is to push the Tune/Call button, and the controller takes over, always moving the antenna in the correct direction. If the motor overshoots the programmed SWR (a rare event as dynamic braking is used), the controller detects this, and reverses. To further minimize overshoot, the controller switches to PCM (pulse-code modulation) when the SWR drops below 4:1, and the motor runs at about half speed.
I've personally tried 6 different commercial controllers: manual and automatic; SWR and turn counting; and so far, this is the best yet. At a total cost of about $150, it is indeed a Better RF mousetrap! You can download the manual here.
Just about every cellphone made these days, is equipped with Bluetooth capability. Unless you live under a rock, you'll know it allows fully handsfree operation. The headsets (if you can call them that), are small enough to fit into, or hang from, one's ear. Quality suffers in most cases, especially when they're used in a noisy mobile environment.
Until just recently, when Yaesu introduced their FTM-10R, there were no amateur transceivers equipped with Bluetooth. I'm sure the rest of the pack will follow suit, but that leaves the rest of us wanting; in two aspects.
Current model Bluetooth headsets are just barely adequate for cellphone use, and certainly don't qualify for any measure of amateur communications. We don't need (contrary to some opinions) high fidelity response from our microphones, they certainly need some improvement over current cellphone requirements.
The quietist of vehicles are still noisy when compared to the average living room. Unless, of course, you have teenagers around! In any case, when operating mobile, we need a good level of noise cancelling, we need an even level of audio, and we need convenience. Well, guess what? Things are about to change!
RPF Communications has awarded Heil Sound as their US distributor! Bob Heil and his engineers are busy converting their Traveler headset to Bluetooth connectivity. What this means is, amateur mobile operators will have the best of audio, coupled with the best in wireless technology, with interconnection to almost any currently available transceiver.
Although pricing is still up in the air as I write this (October 2007), I suspect it will be in the $350 range complete, and ready to go. While this may sound expensive, the freedom from dangling cords, and associated driving distractions, is well worth the cost of admission.
There are a lot of ways to measure Standing Wave Ratio, but when you're mobile, the options diminish. Several different companies manufacture remote SWR bridges so you don't have to run coax hither and yon if your radio is remotely mounted. I don't know about your installation, but I had problems finding a place to mount the head of my Icom IC-700o, much less finding space for a 4 inch square meter. Well, it turns out you don't have to, thanks to LDG Electronics.
This is a picture of their TW1 talking wattmeter. There is a review of it in the November 2005 issue of QST starting on page 77. It runs on a nominal 13.8 VDC, and draw less than 90 uA on standby so a power switch isn't needed. You should properly fuse it however.
There is something special about the TW1, and if you've read the review you would know that it not only talks, it squeals. Well, actually it's a tone you hear which changes in pitch to indicate forward or reverse power, or SWR. This means you can tune your antenna by just listening; a great way to minimize distraction.
By the way, the TW-1 has been discontinued by LDG, but are still available from their retailers.
Amplifier interfaces are a prerequisite for high power mobile operation as none of the late model miniaturized transceivers will directly switch one. The MFJ 704 shown is one of many sold to the amateur market, and it will switch just about any amplifier including grid blocked ones. This is overkill in a mobile installation.
The fact is, a very simple circuit can be built in less than an hour that will easily switch any solid state mobile amplifier I am aware of. The plans are on Bob Wolbert's (K6XX) web site. As you can see from the schematic, it requires just two resistors and two transistors. I built one of these onto the accessory jack plug that came with my 706; it's that small and that easy. While I on this subject, here's a tip. The accessory plug which comes with both the Icom 706 and 7000, comes with a pigtail which makes wiring difficult especially if you only need to bring out two or three of the 13 pins. The accessary jack Kenwood supplies for the TS-2000 is identical, and it comes unadorned. Most amateur dealers carry the Kenwood part which sells for about $7.
There was a time when one of the most sought after devices for the ham shack was a directional coupler; nowadays called an SWR bridge. As time passed, affordable directional wattmeters become available. Both of these devices were invaluable in finding and solving antenna problems. However, if the resonant point of a high-reactance mobile antenna is out of band, it is all but impossible to to find out where it's resonant using the aforementioned. That is no longer the case as affordable, computer controlled, antenna analyzers are now almost ubiquitous. Probably the most affordable ($210 street price) is the 
This is a Ripley Tool UT-8000 coax cutter. I have a complete story about this tool in my 
Anyone who owns a menu-driven, miniaturized mobile radio, knows how difficult some of them are to program. Adding insult, far too many are written in ambiguous English. Here's the best answer I've found.
No matter which mobile transceiver you use, DSP notwithstanding, passive audio filters have their place. You might be asking why add a passive audio filter to a radio with a decent IF based DSP? If it were a radio primarily designed for base station use, that question might be difficult to answer. But for a mobile installation, no matter how good the DSP, some high frequency rolloff increases readability. While passive filters are easy to design, having all of the right parts in one plastic bag is a benefit. The 
The filter's SSB curve is just about right for most mobile installations, as the chart indicates. Building the filter is easy enough, and about the only thing not included in the kit, are any plugs, jacks, an a box (if needed). If your mobile speaker is large enough, you can even put it inside.
Some things just aren't small enough to fit where you want them to fit. This goes double for voltmeters which seemingly are large, and usually ugly. Here's one that isn't.