EMRFD Message Archive 8856
Message Date From Subject 8856 2013-07-30 09:41:59 Bob L Sourcing Variable Capacitors and Reduction Drives Those of us who still build classic VFO's or tunable front end band pass filters still need variable capacitors.
Today I found 298 listings on ebay under Radio Communications-variable capacitors. This includes trimmers; and some that have been pulled out of the barn where they have wasted away since World War II.
Very usable capacitors can be found for $5.
The Xtal Set Society is producing new 365 uf variables for about $11. With built-in 8:1 reduction drives they are $20. Dual 365's are about $20. They also sell what appear to be Jackson Bros. 6:1 drives for $11.
Their web page is:
John Kolb, KK6IL, sells used reduction dial capacitors. They run $15-$20.
His web page is:
Note that I have no financial interest in either of these companies.
For the true homebrewer here you can learn to make your own variable caps:
8857 2013-07-30 12:25:44 William Re: Sourcing Variable Capacitors and Reduction Drives Bob,
I have bought the caps from the Xtal Set Society and they are most excellent.
8971 2013-08-16 20:48:37 Bob L Re: Sourcing Variable Capacitors and Reduction Drives Crystal Radio Supply is going out of business. They have variable caps here:
A 14-400 pf 8:1 reducti
8972 2013-08-17 04:43:27 Ashhar Farhan Re: Sourcing Variable Capacitors and Reduction Drives But, why are they going out of business? I thought there was enough
interest in crystal radios et al to keep them going for a long time!
On 8/17/13, Bob L <email@example.com> wrote:
> Crystal Radio Supply is going out of business. They have variable caps
> A 14-400 pf 8:1 reducti
8976 2013-08-17 20:00:05 Bob L Re: Sourcing Variable Capacitors and Reduction Drives He is a "one man" business, apparently. Its very comm 8977 2013-08-17 23:26:24 Robert Bennett Re: Sourcing Variable Capacitors and Reduction Drives Hi Bob
>>>I keep wondering where these crystal radio shops are getting their new stock of variable capacitors.<<<Maybe from here:
Very best regards
[Non-text portions of this message have been removed]
9064 2013-09-03 11:38:45 bob_ledoux Re: Sourcing Variable Capacitors and Reduction Drives There is a nice Mil-Spec variable capacitor on ebay for $14 delivered. He has more than ten available. It was supplied under a 1995 purchase order. I bought one and it is a bit larger than some of the traditional caps we use. Its made of brass and has a sealed ball bearing 9068 2013-09-04 12:50:23 Jim Scott Re: Sourcing Variable Capacitors and Reduction Drives I have been getting 365pf variables in small quantities from
Home of the XTALSET Society in Lawrence Kansas USA
9069 2013-09-04 18:13:49 Ashhar Farhan Re: Sourcing Variable Capacitors and Reduction Drives Unavailability of variable capacitors is making it impossible to
publish and kit designs that need them. Each source is temporary and
As a result, certain topologies like wide range narrowly tuned
front-ends, free-running mechanically tuned oscillators, antenna
tuners, are vanishing from ham literature.
Sourcing of variable capacitors is far tougher issue in India. Though
the polyvaricon is available in the market, it is rapidly vanishing.
It is a bad part anyway. It has horrible Q, bad thermal and mechanical
stability, it mounting screw are rarely available and it needs a brass
shaft that is no longer manufactured.
The larger 365 pf air spaced part used in broadcast sets is available
through friends and junk boxes. I started accumulating the$ some time
ago and now I have a sizable collection. I almost regret having
collected them : they could have been useful to other hams instead of
lying in my junk.
On 9/5/13, Jim Scott <firstname.lastname@example.org> wrote:
> I have been getting 365pf variables in small quantities from
> Home of the XTALSET Society in Lawrence Kansas USA
> Jim Scott
9070 2013-09-04 21:27:24 Kim, VK5FJ Re: Sourcing Variable Capacitors and Reduction Drives 9071 2013-09-04 21:31:23 e_trician Re: Sourcing Variable Capacitors and Reduction Drives I have one of those variable capacitors and I would like to find out what are the frequencies of the RF section and OSC section it was designed for.
9072 2013-09-05 00:47:55 blumu Re: Sourcing Variable Capacitors and Reduction Drives With some basic skills and tools, it would appear possible to make
a tuning capacitor - even if getting it linear might be more challenging ...
PS : hope friend NEO lets the link work :-)
----- Original Message ----- From: Kim, VK5FJ
Subject: Re: [emrfd] Sourcing Variable Capacitors and Reduction Drives
9075 2013-09-05 14:44:45 bob_ledoux Re: Sourcing Variable Capacitors and Reduction Drives
The River City Amateur Radio Communications Society (N6NA) is working