WACOM

[W3WN]

Had a great time at the WACOM hamfest today. Would have done better if I'd sold a few more things, but what the heck.

Saw KB3LIX, but I don't think Bill saw me. Oh well.

But... I picked up an interesting item, and I will post a picture of it...

I was looking for a roller inductor for a future tuner project. Found two. One's a standard roller, but the other... I'd never seen anything like it. Two rollers, and as you turn the mechanism, a ribbon moves from one to another.

I'm told that this is military surplus... and that the ribbon is silver and the one roller is silver plated. There are no markings on the unit to indicate a part number or what type of rig it's out of.

I was made an offer I couldn't refuse... $3. (I got the other one for $2). With the vernier dials thrown in.

I've since been advised to sell this on eBay, it might be worth some real money. Of course, I've heard THAT before...

This ring a bell with anyone?

[KJ6BSO]

I was looking for a roller inductor for a future tuner project. Found two. One's a standard roller, but the other... I'd never seen anything like it. Two rollers, and as you turn the mechanism, a ribbon moves from one to another.

I'm told that this is military surplus... and that the ribbon is silver and the one roller is silver plated. There are no markings on the unit to indicate a part number or what type of rig it's out of.

I was made an offer I couldn't refuse... $3. (I got the other one for $2). With the vernier dials thrown in.

I've since been advised to sell this on eBay, it might be worth some real money. Of course, I've heard THAT before...

This ring a bell with anyone?

Ron, what you've got there is the Cadillac of roller inductors. The conductive drum on a ribbon-type roller inductor shorts out the unused turns, canceling any magnetic coupling with the turns in use. From a purely technical point of view, it's the best way to design a variable inductor; unfortunately, it requires a complicated and expensive mechanism, which is why you rarely see one. They are rare enough to command a decent price but if you want top-notch performance from that tuner you're building, you might want to hang on to it.

Here's a site with more info:

http://www.g3ynh.info/comps/Vari_L.html

[W3WN]

Carl, that was a very informative site. Especially the last picture, the Collins 180L-3A inductor. I think that's exactly what I have.

I'm not ready to build the tuner yet... I need one more capacitor, two big ones would be better (and I have a source for them) and I have to find a chassis. So my immediate inclination is to put this up for sale somewhere and use the proceeds to fund other pieces of equipment for the shack... assuming it's really worth something.

All I can figure is that the ham who sold it to me was just cleaning out his shack & junque box. I don't think price was that important to him; he sold a working Motorola VHF-HI HT with charger for $5, for one. But! I asked him his price, he told me what he wanted, I didn't quibble, and he was happy. Therfore, I feel no guilt if I should turn it around for more...

We shall see.

After all, if there are four items and five collectors, the items are all very valuable -- to the collectors. But if there are five items and four collectors, one item is worthless...

[KJ6BSO]

It's a pretty interesting site. I found it when I was doing the research to build my own tuner---then someone offered me a "good enough" unit for fifty bucks so I never did. But I still want to build a better one, so I'd be happy to take that roller inductor off your hands for ten times what you paid for it ($30) if you want to sell it.

[W3WN]

Ten times what I paid for it, hmmmm?

Seriously, I'm not sure what I'm going to do with it. As I said, we'll see...

[W1GUH]

Get yourself another one and build a twin-T balanced coupler!

The problem with roller inductors is they don't lend themselves to link-coupling. Kinda make 'em useless in a balanced coupler. The Twin-T works well, but adds mechanical complexity.