You can try www.qrpkits.com for their AWG26 and 28 wire, but orders won't be taken for a few more days due to a SK in the family.

Stew

It should take 3hrs 51min to charge a completely discharged battery with your system, but you want to be careful! Go over it by a few minutes and you could overcharge a cell or two and ruin the battery.

The best way to charge a NiCd battery pack is slowly, and at 1.1C over 10 hours. That means a 700mAH battery should be charged at 12V with a current of 77mA for 10 hours, or 70mA for 11 hours. In the olde days, we sometimes hooked up a timer to the charger to make sure we didn't overcharge the battery.  Charging at rates much lower than 70mA meant we could leave the battery connected for longer than the recommended time, but one still didn't want to "overcharge" a battery pack.

A simple experiment is to remove the scanner's antenna and/or replace it with a dummy load.  It's just a shot, but it might work.  Another idea, make an extra long headphone cable.... GL

Explain your balun--if it's a choke balun (unun), that's good; but if its a voltage or current balun, then it shouldn't be used with an off-center fed antenna. A choke unun will keep (most of) the common mode currents off the coax so that only the antenna radiates.

The other suggestions are valid; you probably could use chokes on the WiFi Cat5, speaker, and touch lamp cords to minimize stray RF. (Touch lamps are especially sensitive to oddball RF and static problems). Radio Shack and other outlets sell clamp-on chokes (RS273-104 is their best, at around $10 each, and is what I'd recommend for the speaker cables; but 273-105, 273-069 and 273-067 are possible substitutes). GL in solving the problem.

   Don't you know you're suppose to call "CQ," and not "CO?"

Here is an idea for a fairly realistic battery test: First, determine the average current you expect to draw from the rig. This will be the transmit current x transmit time + receive current x receive time. Next, find some filament lamps that in series/parallel combination will equal, or come close, to that figure. Charge up the battery, connect a voltmeter across its terminals, and connect the lamps. Note the difference between the start time and the time the battery reaches 11 volts, and that gives you a fairly good estimate of operating time with your particular radio.

Let's say you have a radio that consumes 1 amp in the receive mode, and draws 4 amps when transmitting. And let's say you spend about 50 minutes listening and 10 minutes transmitting out of every hour. That means, every hour the rig draws 5/6 x 1 + 1/6 x 4, or 5/6 + 4/6 = 9/6 = 1.5 amps.

So you need a lamp bank that draws 1.5 amps. An 1141 or 1142 bulb comes awfully close (1.44 amps at 12.8V), so wire one across a fully charged 12V battery and start your timer. When a voltmeter attached to the battery's terminals reads 11V, stop the timer. The time from start-of-test to end-of-test will give you a reasonable expectation of the amount of time you can get from using that particular gel cell. GL

I remember that story, too. The version I heard was that a farmer-ham heard the foreign-talk on his receiver, didn't know it was German, bud did know that hams were under radio silence during the war.

I suppose you could ask the editor of the QCWA Journal to query his readers about the veracity of the story. The Quarter Century Wireless Association's web site it www.qcwa.org, and its general manager is Jim LaPorta, N1CC, n1cc(at)qcwa-hq.com.

Auto parts stores and hardware stores should have something that will work. I recently bought some GB Ox-Gard at an Ace hardware store fairly inexpensively. While there, you can buy copper, brass or stainless steel hardware for mounting the ground wire to he plate. In your environment, I'd pack or spray some weatherproofing material on the completed connection.

Ring terminals are good for static protection, but not so good as lightning protection. A better way is to use a copper plate (aluminum will do, too) and mount your SO239s through it. Also bolt your low-impedance ground strap to the plate and tie that in to your electrical ground system.

I've had good luck finding plate stock at metal salvage yards. Copper is very hard to find, aluminum is much easier. Painted steel would work, but you need to ensure that the SO-239 or feedthrough is in electrical contact with bare metal, then protect the metal against corrosion or rust. Others will have hints as well. GL

I agree with Dale; trying to tune a mobile antenna while standing next to it is somewhat frustrating. The ideal way to do it is from inside the vehicle, while it's tooling down the highway, primarily because that's where it will be used most!

Typical mobile antennas should have low r (radiation resistance) and low feed point resistance. The loading coil is there to cancel the capacitive reactance of short mobile antennas, so reactance should be as close to zero as possible. When you get zero X, then you can start matching the feed line to the antenna's r.

Try to find an open area away from other vehicles and overhead utility lines to run your tests. You also need to be inside the vehicle, with the doors closed, when you measure the antenna's parameters. I would start with the whip almost fully extended and the matching coil bypassed, then start adjusting the loading coil tap until you get close to zero reactance.  From that point on you can fine tune the matching coil and loading coil to get close to 1:1 SWR at the rig end of the feeder.

I would also recommend you use a mobile antenna design program to find good starting points for loading and matching inductances. The ARRL Antenna Book is a good starting point as well.

I would also suggest that you not "short" out turns with your tap wire--the shorted turns will change the coil's inductance and will waste power. Keep one end of the coil open-circuited if at all possible. And, if you're using a capacity hat, mount it as far above the loading coil as possible.

If you can find it, Don Johnson's,W6AAQ's, book. 40+ Years of HF Mobileering is an excellent reference for building, testing and using mobile antennas. GL

Here's another thing to think about; I once heard that a direct lightning strike directed through a ground rod in very wet soil resulted in a steam explosion that caved in part of a basement wall. Since I cannot vouch for the veracity of this story, I only pass it along as "thought material."

Something I read on N1FN's home page this morning: "I just got lost in thought. It was unfamiliar territory."

It appears you are OK. It wouldn't hurt to go to http://www.arrl.org/files/file/Technology/tis/info/pdf/rfex1_2.pdf, print out Worksheet A on page 2, and fill in the form, in case anyone asks if you have complied with the FCC's exposure rules. If you have a log, you can annotate in it the date you did the evaluation.

Although I've never known anyone to experience RF exposure complications, I do know there is a movement to caution cell phone users of unnecessary exposure, and to opt out of wireless utilities metering. And contrary to what some people may think about the safety of VHF frequencies, the reason the evaluation is for 50 watts and above on those bands, and much higher on frequencies above and below VHF, is because the government thinks VHF is riskier than the other bands. It is sometimes cited that tall people approach resonance in the 2-meter band, where a full wavelength in the human conductor is in the vicinity of six feet!

High-dollar tuners often contain extras not found in lower-priced units, such as gear-reduction controls and turns counters, baluns, power output or SWR metering, silver-plated inductors, bypass switches, etc. And some of these extras don't come cheap; tapped air inductors don't cost very much to make, but roller inductors are a lot more complicated, which increases the man-dollars required to make and install them; cheap baluns are common, but teflon-insulated "optimized" baluns are not; nickel-plated sockets and plastic switches are a dime a dozen, but good silver-plated brass sockets and ceramic switches cost somewhat more; and there's a similar difference in the quality of meters and other components, and in the skills of those who assemble and calibrate them.

Then, too, there's the "name brand" recognition and manufacturer's reputation that are sometimes factored into the costs. The old saying, "You get what you pay for," pretty much applies to tuners as well.

To expand on Dan's answer, some radios, like my old Yaesu FT101, will only receive on the ham bands and the 30-meter WWV band. Many radios now permit reception on all the popular shortwave frequencies, including commercial and government bands, making it easy to listen to foreign commercial and propaganda broadcasts, aviation radio, numbers stations, ship-to-shore, maritime weather reports, etc.

When I was stationed overseas, I used my rig's "general coverage receive" connected to my Commodore C-64 computer to receive news service teletype dispatches in the commercial bands. My colleagues were amazed that I seemed to know of news events several days in advance of the Stars and Stripes newspaper, and several hours ahead of Armed Forces Radio. I even had the Intelligence Officer stumped over where I was getting my information. It was great fun!

Light exists either as photons or electromagnetic waves. In ancient times (late 19th and early 20th Century), scientists wondered how photons could penetrate transparent substances and, at the same time, dislodge electrons from the surfaces of many elements. The real conundrum was; how can light, as photons, pass through a lamp's solid glass envelope, and strike a elemental target to knock electrons free? And, if light is a wave how could it pass from the Sun and stars, through the emptiness of space, to illuminate the Earth? To answer the second question, they invented "ether" as the invisible substance that exists everywhere to convey the "waves" of light. The current belief is that electromagnetic energy can manifest itself as "solid" photons that can travel through the emptiness of space and 'bump" into atoms to release electrons, but those same photons can revert back into electromagnetic energy when they need to travel through transparent materials.

Velocity factor is based on the electromagnetic definition. Just as sound waves can speed up or slow down, or even stop, in various substances, electromagnetic waves can, too. That ""Donald Duck" voice that helium induces is because sound travels nearly three times faster in helium than in air. Water speeds up sound velocity more than 4 1/2 times faster than in air, and solid aluminum can give sound waves a velocity more than 15 times greater than in air!

Electromagnetic waves, likewise, exhibit various velocities in various materials. Water slows the velocity of light to about 75 percent of its velocity in air; glass may slow it to around 60 percent; and diamond to as slow as 41 percent! But, when it exits these materials, it isn't slowed by their density anymore, so it reverts back to its original speed.

Let's say you are a jogger, and your normal jogging speed is 20 m.p.h. You encounter a river or pond along your route, but when you try to run through it, it resists your efforts and you might find yourself going only two or three m.p.h. while exerting the same effort that you used on dry land. However, once you're out of the water hazard, and without increasing your effort, you easily pick up your 20 m.p.h. pace.

In physics, velocity is defined as distance divided by time, so it has nothing to do with energy. A sound or light wave that changes velocity when going into one substance from another, changes back to the original velocity when reentering the original substance.

Likewise, electromagnetic waves are slowed by whatever they have to travel through or along, from the conductor itself to the insulation that might surround it. Consequently, everything the wave has to traverse is analogous to the pond the jogger has to wade through. Once out of the pond (off the wire, out of the insulation), the normal (air, vacuum) velocity will be reestablished without the expenditure of new energy.