---   Sundry Odds & Ends   ---




METERS

One of the most conspicuous signs of BigRig’s old age was the appearance of the several meters. The grease, grime, and general crud, and in some cases even rust, had not only covered the external surfaces of the meters, it had actually penetrated the cases and wreaked its havoc on the interiors, too. Take a look at the “before” picture of the modulator front panel. The meter is a good example of one needing help, although all 8 meters of the transmitter are likely candidates.

My first attempt at a meter restoration was woefully unsuccessful. The speech amplifier’s VU meter, used to set the modulation level, was the first meter-rejuvenation guinea pig. The housing was cleaned uneventfully, but the meter face needed much help. So much help that my over-aggressive approach succeeded in wiping not only the dirt, but also some of the ink, right off the face. That meter now needs repair.

The next meter to be subjected to my shaky cleaning skills was the 0-800 milliameter used to show modulator plate current. Look again at the “before” picture of the modulator front panel. The meter was disassembled. The glass was removed by loosening the internal retaining ring, and all of the case parts were cleaned in warm water and a mild detergent. Some grease that curiously resided on the inside of the case and even more curiously on the meter magnet itself, succumbed to a Q-tip and some 90% alcohol.

The meter face was in bad shape. After the speech-amplifier experience, I was nervous about cleaning a meter face, so I took a precautionary measure. I placed the faceplate in my scanner and did a high-resolution scan. I opened the resulting file in Photoshop and cleaned it up using common Photoshop techniques. Next, I printed the resultant image at such a size that it could be placed on the meter faceplate, cut to fit the plate, and affixed with rubber cement.

To see the Photoshop results, look at the accompanying pictures. One shows the original faceplate as removed from the meter. The next one shows how it can be “restored” using Photoshop, and the final picture shows how a meter appearance can even be modified in Photoshop. In this example, I removed some “extraneous” markings and added the all-important call sign.

In the end, it was a unnecessary exercise for this particular meter. It turned out that the original meter faceplate cleaned up satisfactorily in warm water and mild detergent, so the face-replacement technique was unnecessary and the modulator plate-current meter remains original.

There are though, 5 more meters to be cleaned up, and one to be repaired, so the face-replacement technique may yet become necessary.



ANTENNA CHANGE-OVER RELAY

A radio amateur of ostensibly sound mind might ask what on earth could be so interesting about a relay that warrants discussion here. Well, perhaps nothing to most, but I found it interesting so here's the story.

Going back to the days of yore, when men were men and radio amateurs built transmitters, it was unusual to see an antenna change-over relay built into a transmitter. Generally, such peripheral gizmos were external to the transmitter and so it was with BigRig. The hamshack antenna relay was mounted on a wall several feet from the rig, and feedlines of various types ran from rig to relay, relay to receiver, and relay to antenna. Of course, a power line also ran from the rig to the relay, to cause the relay to contribute to the satisfying clunk of the various relays energized when entering the transmit mode.

Well, BigRig will not occupy space in the W8VR hamshack for a long time and all of those wires would be obtrusive. So, with apologies to the gods of yesteryear's transmitter design, I decided to build the relay into the transmitter, as is done in these modern times. Not exactly build it in in a permanent sense, but instead to construct a module that can easily be attached to the side of the transmitter and easily removed when necessary.

The first problem was, where on earth would I ever find an appropriate relay? An antenna changeover relay before the post-World War II days of the popularity of coaxial cables was different. It was a wide-spaced affair to allow substantial spacing for the high voltages perhaps present on high-impedance feedlines and to minimize stray capacitance, and it had healthy contacts to allow for the substantial currents of low-impedance feedlines. Unfortunately, as far as I know, such relays disappeared with auto-radio vibrators and selenium rectifiers.

Enter eBay. One day, an eBay ad offered an antenna relay. I bought it, and I was surely a delighted camper when it came. It was probably 50+ years old, and it was brand spankin' new. In it's original box. Untouched. A gorgeous Magnavox RF relay with gleaming metal parts and a splendid ceramic base. I'd like to ask K8GTO just what it means to be in love with a relay, but I'm afraid to. If though, you'd like to take a look at this eBay surprise, there's some pictures in the Sundry folder.

As you look at the pictures, please shed a tear for the hours I spent fiddling with all those little tiny brass interconnects that had to be measured, cut, ground, filed, punched, drilled, soldered, fitted, buffed, and usually made eleventeen times each before I got it right. And, why is it that I had to undertake this project when I no longer have easy access to a shear, brake, or a mill, but I do have lousy eyesight, ever-present fatigue, consistent impatience, and shaking hands? And, why is it that the hardware store is never open when I need more brass?


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