Neat Gadgets
Last Modified: August 31, 2010
Contents: Basics; MiniVNAPro; Speech Clipper; Active Audio Filter; LCRZ Meter; Auto Off; A Better RF Mousetrap; Amplifier Interfaces; Antenna Analyzers; Coax Cutter; FT-857 Meter; Mini-Manual; Passive Audio Filter; Rescue Tape; Two Wire Voltmeters; 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.
Affordable antenna analyzers have been with us for some time. They're invaluable for finding resonance, and the impedance (X and R), if they're within the analyzer's range (typically <650 ohms). What they can't do is give you a picture (a graph really) of the reactance over a given frequency span. This is the forte of a VNA (Vector Network Analyzer).
There are several versions of miniaturized VNAs on the market these days, and choosing one might seems daunting. However, there is one feature which sets the miniVNAPro apart from it's lessor competition; it has Bluetooth connectivity! Heretofore, either the data was stored in the VNA, or a CAT5 interconnecting cable was required. But with Bluetooth, the VNA can transfer live data to its host computer. The implications should be obvious.
Its frequency range is from .1, to 200 MHz, with a range of Z from 1 to 1,000 ohms. It's built in Li-ion battery is recharged through its USB connections, and offers 4 full hours of continuous testing. Since it has two ports, you can even use it to do IMD testing!
Software versions cover not only Windows, but MacOS and Linux. The data can be exported in several formats, including jpg, PDF, and Excel. At $650 including it's SMA adapter kit, it's a bargain its competitors can't match.
The announcement of this (future) mobile device is a bit premature. However, whetting one's whistle is what this hobby is all about. So what you see here is really a base-station device, but it will be available as a mobile device in the coming months, so stay tuned!
It was designed by Dave Haupt W8NF, of Idiom Press fame. Speech clipping is not the same as speech compression. The latter constantly adjusts the audio input gain as you speak. They're hard enough to adjust properly in a home station scenario, and in a mobile one, almost impossible due to the high background noise level, the use of a noise canceling microphone notwithstanding.
Speech clipping is a whole new animal, and one which does not increase the background noise level. From their web site: RF clipping is simply the most effective way to increase the average power of your SSB signal. LogiKlipper® works by converting your audio to SSB at an IF of 125 kHz, amplifying the signal, and then clipping it. This results in a signal with higher average power, but also with harmonics. Fortunately, the harmonics don't fall within the passband, and are easily filtered out. The signal is then downconverted back to audio to be sent to your rig. The result is clean, splatter-free audio that sounds louder on the other end.
Pricing for the base unit (as shown) is $300, but the mobile might be a bit less. The price, and its size, may be a drawback for some, however, if you want to be heard, this is one more tool toward that goal.
If there is a real drawback, it's the fact the average SSB power increases by 6 dB. In some cases, this can over-tax a vehicle's electrical system, especially if high power is being used. It should be mentioned, that using a clipper in combination with speech processing, is a sure-fire way to create massive amounts of splatter (IMD products).
A little further down is a paragraph or two on a passive audio filter. I've used passive filters for many years, to cut back on the high-frequency hash we all have to deal with. They do work well, and don't require any power. However, they do rob a little power in that they do have insertion loss. Depending on the design, that can be as much as 4 or 5 dB. Some transceivers meant for mobile use, lack sufficient audio power in the first place, and a passive filter just adds insult.
A good example is Icom's IC-7000. It's audio amplifier is rated at 2 watts RMS, but it has a hard time doing 1.5 watts, and if you remotely mount the head, the loss in the interconnect cable takes an additional toll. Well, there is a solution, and it's from Idiom Press.
The SCAF-1 is an adjustable, lowpass, active filter with some very impressive specifications. How does 96 dB per octave rolloff sound to you (excuse the pun)? The cutoff frequency is adjustable from 3.5 kHz, down to 450 Hz. It uses an LM-386 amplifier chip, and at first blush I didn't think the audio output (about half a watt RMS) would be enough, but it is. In fact, it is as loud as the IC-7000's built in audio amplifier.
The fact that it is adjustable adds a lot of value, and although it was designed with the contester in mind, it does have a place in a mobile installation. If you don't operate CW, you can order one (kit only) specifically for SSB. This makes the rolloff a bit less touchy to adjust.
It sells for about $100 (including shipping) in kit form, and takes about four to eight hours to assemble, depending on your skill level. Assembled units are available too.
The M3 Electronix digital LCRZ meter comes in kit-form only, and sells for just under $200. I should add, it is not a kit for beginners. Depending on your kit-building skill level, the average assembly time hovers around 12 hours, but may take twice that. If you follow the detailed assembly instructions, you'll be rewarded with a high-quality, lab-grade, LCRZ meter with .2% accuracy!
Inductance can be measured from 0.01uH, to 99.99H, and Q ratings from .0001 to 100. Capacitance values are from .001pF, to 99,999uF, and resistive values from 1 milliohm to 99.9 Megohms. To be sure, there is a lot more to it than just a few specifications, and a neat-looking black box replete with back-lit LCD.
If you're a serious builder and/or designer, or just want an exacting LCR measuring device, this is the answer to your prayer. Fact is, to better its capabilities requires a very substantial layout of cash with Agilent.
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 (or your ancillary equipment) 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. 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.
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.
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 accessory 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.
By the way, the SGC SG500 and the Tokyo HyPower HL-450B, are the only mobile amps which can be safely switched by the Icom IC-706 and IC-7000, and the Yaesu FT-857 mobile transceivers without the need for an interface. All others require one.
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 MFJ 259B.
It would take several pages to describe its various uses. A quick visit to MFJ's web site will fill you in, and you can even download a copy of the owners manual. From tuning matching coils, to finding resonant points, it is an invaluable tool which should be in every ham shack, right next to the wattmeter and dummy load.
This is a Ripley Tool UT-8000 coax cutter. I have a complete story about this tool in my Coax article. Designed for RG 8 sized coax (.405"), it has a street price is $20, and is available from Sunset Enterprises. There is also a model for RG58 size coax. With the soldering iron already hot, I can install a PL259 in under two minutes.
There are other coax cutters on the market, but they all require you to properly place the cutter at a specific length from the end of the coax. With the UT-8000, this isn't necessary as all of the measuring is done for you. I'll never be without one.
If you use a Yaesu FT-857 mobile (it'll work with a FT-897 too), you know how hard the LCD S meter is to read. The folks at LDG Electronics have come up with an answer. At just $50 retail, it is an elegant solution to the problem. On receive it becomes an S-Meter, discriminator indicator, or voltage monitor. On transmit, it measures RF Power, SWR, modulation, ALC or voltage. The only drawbacks are finding room for the meter, and home brewing a mobile bracket.
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.
Nifty Accessories offers a line of Mini-Manuals and Mobile Cards for all of the popular mobile radios, and most handheld as well. They have all of the important programming information clearly defined, easy to read, and in plain English!
They won't break your budget either, as prices range from $5 to about $25. These photos don't do them justice, so you should visit their web site for full details. While you're there, look at their other nifty stuff.
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 Xtal Set Society offers such a filter, tailored for either CW or SSB. It sells for $20 plus shipping.
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.
If you need more information on building the filter, look here, or go to the manufacturer's web site.
Rescue Tape is a self-fusing silicone tape. It comes is a rainbow of colors, but that's not what makes is special. It is incredibly strong, it will adhere to any surface, thus effectively sealing out moisture, and dirt. It is an ideal produce for sealing all manner of connections exposed to the elements, especially in a mobile installation. It is perfect for sealing coax connections too, and when properly applied, it makes them virtually submergible. You can even use it to seal high voltage connections like those used in auto-coupler applications. It has a myriad of other uses too.
It makes a great emergency bandage, and you can even use it to repair a radiator hose leak. The best part is, when you need to remove it, it leaves no residue, period!
Your local Ace Hardware is one source, but it can be ordered on-line directly from Rescue Tape.
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 two that aren't.
Martel Electronic's meter division makes the QV100 series of 2 wire voltmeters at left. They're not only small physically (.84 x 1.71 inches), at about $50 each, they're also small in cost. Current draw is just 3 ma, and really don't need to be switched. They're unlit which might be a drawback for some users. I solved the problem with a shielded LED. In a mobile application, the meter should be shunted with a Zener diode (18-24 volts) to protect the meter from transients. Check out their web site for other versions of the meter including time-elapse, temperature, and analog readout styles.
The LED voltmeters shown at right are from Datel. They are available in both red (preferred, see below), and blue LEDs. They sell for about $60 plus shipping. The good part is, they're weatherproof! Like the Martel they are two wire which simplifies wiring. They also sell back-lit LCD voltmeters, but they're not weatherproof. Datel also sells AC meters, as well as ammeters. Downloadable data sheets are on their web site.
As noted above, if you're going to use these inside a vehicle, it's best to use the red color LED versions. The reason is, human color persistence is much longer for blue than red. The last thing you need is blurred vision especially at night.
If you have an Icom IC-7000 and a factory installed navigation system, here's just the gadget you need. TVandNav2Go makes video adapters for just about every factory installed navigation system ever made. The best part about the unit is, it reduces the distraction we all contend with. The photo depicts the unit in my Honda Ridgeline.
The device itself is in a metal box about 1 x 3 x 4 inches. The manual is rather lame, but installation is easy enough to figure out. You have to supply switchable DC power to the unit, and a SPST switch or two for controlling it, and select the display sync mode. There's even a second, switchable input for a backup camera, or DVD player. But, before you decide on the latter, remember there are laws about watching video while in motion.
