What's this thing?

[WX7P]

I think I know, but I don't want to embarrass myself.

It's a variable something. 140341403514036

It came from Lithuania. It must be commie no goodnik radio hooligan device.

[W2NAP]

what ever that thing is... its 250pF

>_>

[n0km]

Jennings or similar vacuum variable capacitor.

[w2amr]

I think I know, but I don't want to embarrass myself.

It's a variable something. 140341403514036

It came from Lithuania. It must be commie no goodnik radio hooligan device.I like it.:agree:

[NA4BH]

Did it come from Adam and Eve?

[WØTKX]

Yup, looks like a vacuum variable cap.
Great for tuners at the feedpoint.

[PA5COR]

Or a nice loop ;)

[WX7P]

Or a nice loop ;)

Yes.

That's what the guy I got it from said he was going to do with it. He was a real talker, we got sidetracked and I never got exactly what he was going to build with it. I'll have to dive into intertubes and find out what I can build with this thing.

I got a bunch of other junk to play with all for not much money, so it was worth the drive to Seattle.

[NQ6U]

Ees gud Soviet diesel-powered personal vibrator, tovarisch. Not affected by EMP.

Seriously, it's a vacuum variable capacitor, as others have already pointed out. Probably worth at least a C-note on eBay.

[K7SGJ]

It can also be used as a cooker cutter.

[KG4NEL]

New, they're expensive as hell.

[W2NAP]

New, they're expensive as hell.

only 5,000 Rubles

[KG4CGC]

Everybody's right. Everybody's left.
I used to drool over those things at hamfests thinking about what a righteous crystal radio you could make with one or two. Then the guy selling them told me to step away from his table.

[WØTKX]

Making friends and influencing people as always, eh bartender? ;)

[KG4CGC]

Making friends and influencing people as always, eh bartender? ;)

Yes. Yes I am.

[koØm]

what ever that thing is... its 250pF

>_>

Yup, it's a 250uuf (micro-micro farads) vacuum cap but, it's only rated at 5,000 volts. If one were going to use it, it would be on the Tune side of the output Pi-Network; for my work, I would want a value 4 times that of the maximum plate voltage. I would not use that in an 8877 amplifier that ran 4500 volts on the plate.

.

[n2ize]

I have one of those (but with higher) ratings) that I planned to use in the RF Deck of a modified Globe King 500 transmitter a few decades ago. Turns out there was no way I could fit it into the deck without building a whole new and larger rf deck. So I decided to just go with a higher rated air variable. So far its worked, no arc overs. I paid about $100.00 for the cap back in the late 1980's. Let's just say that that price was a "steal" compared to what they cost these days.

[kb2vxa]

"...what a righteous crystal radio you could make with one or two. Then the guy selling them told me to step away from his table."
He was being kind, lucky you didn't walk away with it sticking out of your....... ear. (;->)

"Let's just say that that price was a "steal" compared to what they cost these days."
Steal? I'll go you one better. For nothing and nothing trumps a steal I scrounged dozens of them and huge inductors from an electronics scrap yard in town along with Frankenstein type 12in surface mount meters, Edison base neon indicators and knife switches. I made a breadboard tuner out of them that could handle 50KW AM easily, a friend mounted it on the wall to match his Valiant to an inverted L, of course it worked great and was very impressive. I put the rest of the junk on the front of a large box with a Jacob's Ladder on top and a CB set inside. That was Crusher Radio, how does plate readings of 500A @ 25KV grab ya punkie? UUUUHHH!!!

[WØTKX]

However, it would be likely be good for a mag loop antenna running 100 watts, eh?

Jealous, I am. :)

[n0iu]

It came from Lithuania. It must be commie no goodnik radio hooligan device.

Lithuania gained its independence from the Soviet Union in 1990 and has been a sovereign country ever since. They hold free and open elections and have no ties whatsoever to Communism. I know this. My wife's grandparents were from Lithuania.

[N8YX]

Lithuania gained its independence from the Soviet Union in 1990 and has been a sovereign country ever since. They hold free and open elections and have no ties whatsoever to Communism. I know this. My wife's grandparents were from Lithuania.
The Vilnius Schoolmaster also hailed from Lithuania.

[n0iu]

The Vilnius Schoolmaster also hailed from Lithuania.

Be very careful if this man offers you a cup of tea!

http://rs1img.memecdn.com/and-marko-ramius_fb_2806367.jpg

[KG4NEL]

The Vilnius Schoolmaster also hailed from Lithuania.

Good, because he was godawful at speaking Russian.

[N7YA]

Did it come from Adam and Eve?

I have no idea what that is...and last i heard, Eve is living with a used car salesman in Ohio or something. Im a married man now, and for some reason, people keep asking me about bombs and ants.

[kb2vxa]

So who is this guy Atom Ant I keep hearing about?

[WØTKX]

No. It's Adam Ant. :cool2:

[KA9MOT]

Ya' know, I've been curious as hell about these. I've not seen one until I became a ham and I know what they do... what I am wondering is do they use Vacuum to change the value (vary) or is the Cap kept under a vacuum? How does one vary the capacitance in either case. Looks like a knob on the end, but I keep seeing these used remotely and it doesn't make much sense if a person has to keep running out to the antenna to turn the knob.

Who can clear that up for me?

[NQ6U]

I suppose you could rig something up to tune it remotely using a stepper motor but, otherwise, you have to run out and turn the knob.

[KA9MOT]

I suppose you could rig something up to tune it remotely using a stepper motor but, otherwise, you have to run out and turn the knob.

Again, thank you Carl!

[KG4NEL]

Ya' know, I've been curious as hell about these. I've not seen one until I became a ham and I know what they do... what I am wondering is do they use Vacuum to change the value (vary) or is the Cap kept under a vacuum? How does one vary the capacitance in either case. Looks like a knob on the end, but I keep seeing these used remotely and it doesn't make much sense if a person has to keep running out to the antenna to turn the knob.

Who can clear that up for me?

The primary advantage is that they can offer a redonkously high breakdown voltage in a pretty small package. Voltages at the base of some end-fed antennas can get pretty hairy.

[PA5COR]

Look on the net for circuits that will tune the vacuum C with stepper motor and remote control, a m8 has one running like that in his 10 foot loop working 160 - 40.
One reason I use an Autotuner at the feedpoint of the inverted L here, no need to zip around to tune the damned thing from 160 - 10 ;)

[KG4NEL]

Look on the net for circuits that will tune the vacuum C with stepper motor and remote control, a m8 has one running like that in his 10 foot loop working 160 - 40.
One reason I use an Autotuner at the feedpoint of the inverted L here, no need to zip around to tune the damned thing from 160 - 10 ;)

Autotuners and open-wire feeds have made me supremely lazy.

[PA5COR]

For that I still have to tune the Heathkit SB - 1000 ;)