I am in the process of designing an ATU yet am having difficulty in locating
a company who can supply a suitable Variable Capacitor.

At the moment the only ones I seem to find are trimming capacitors and I
require an item which is somwhat larger than that - E.g in the region of
about 680pF.

Any suggestions as to a suitable supplier would be grately appreciated.

Failing this if anyone knows of a circuit diagram available on the net which
may be constructed from components more readily available then I am more
than happy to hear from you.

Many Thanks.

There are several US manufacturers still in business (a google search will
turn up at least 3), one option is Oren Elliott Products (OEP) in Ohio.
http://orenelliottproducts.com/index.html

OEP was the original supplier for many Collins, Drake and Heath capacitors
(and planetary drives).

Oren Elliott Products, Inc. is the largest US domestic manufacturer of
air-dielectric variable capacitors.
Producing capacitors since 1925, the OEP Plant I was first known as American
Steel Packaging Company and then as All Star Products. In those early years,
their applications and major products were almost exclusively focused on the
broadcast and short-wave radio industry (which was a huge market in late
1920s and 1930s - Hammerlund, Hallicrafters, Zenith, etc.).
During World War II, ASP supplied the Allies with 3500 capacitors per day,
and by the end of the war the company was the world's largest producer of
air trimmers.
In 1983, Oren Elliott Products Inc.(name change from ASP to OEM) was created
and expanded into new facilities (Plant II) to include CNC lathes, CNC
vertical machining centers, CNC and conventional Swiss screw machines, and
all of the support equipment necessary to enable OEP not only to produce all
of the machined subcomponents for their capacitors.

Another option (UK based) is Jackson Brothers which was founded in 1923 to
manufacture variable capacitors and accessories such as tuning drives and
dials. Today, distribution and production facilities are owned by the
Mainline Electronics Group.
http://www.mainlinegroup.co.uk/jacksonbrothers/

For Jackson Brothers orders:
Mainline Electronics
Unit 1A Cutters Close
Coventry Road
Narborough
Leicester LE19 2FZ
UK
Tel: (+44) 116 286 5373
Fax: (+44) 116 286 7797
Email:

============
w9gb


"S C" wrote in message ...
I am in the process of designing an ATU yet am having difficulty in
locating
a company who can supply a suitable Variable Capacitor.

At the moment the only ones I seem to find are trimming capacitors and I
require an item which is somwhat larger than that - E.g in the region of
about 680pF.

Any suggestions as to a suitable supplier would be grately appreciated.

Failing this if anyone knows of a circuit diagram available on the net
which
may be constructed from components more readily available then I am more
than happy to hear from you.

Many Thanks.

http://orenelliottproducts.com/index.html



S C wrote:
I am in the process of designing an ATU yet am having difficulty in locating
a company who can supply a suitable Variable Capacitor.

At the moment the only ones I seem to find are trimming capacitors and I
require an item which is somwhat larger than that - E.g in the region of
about 680pF.

Any suggestions as to a suitable supplier would be grately appreciated.

Failing this if anyone knows of a circuit diagram available on the net which
may be constructed from components more readily available then I am more
than happy to hear from you.

Many Thanks.

A little ally-bashing and you have your own capacitor to your
own specifications! A trivial matter for a _REAL_ Radio Ham; perhaps
more difficult for a CBer who buys his station from the shops and
takes it back to be mended?

"S C" wrote in message ...
I am in the process of designing an ATU yet am having difficulty in
locating
a company who can supply a suitable Variable Capacitor.

S C wrote:

I am in the process of designing an ATU yet am having difficulty in locating
a company who can supply a suitable Variable Capacitor.

At the moment the only ones I seem to find are trimming capacitors and I
require an item which is somwhat larger than that - E.g in the region of
about 680pF.

Any suggestions as to a suitable supplier would be grately appreciated.

Failing this if anyone knows of a circuit diagram available on the net which
may be constructed from components more readily available then I am more
than happy to hear from you.

Many Thanks.


* Hamfests
* Surplus Sales of Nebraska
* MFJ (I think -- or maybe it's their roller inductors)
* Antique Electronics Supply

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

In article , "S C" writes:

I am in the process of designing an ATU yet am having difficulty in locating
a company who can supply a suitable Variable Capacitor.

At the moment the only ones I seem to find are trimming capacitors and I
require an item which is somwhat larger than that - E.g in the region of
about 680pF.

Any suggestions as to a suitable supplier would be grately appreciated.

Access the Ocean State Electronics website at www.oselectronics.com
and you will find a number of variable capacitors (two pages worth in
their printed catalog). Their VC-250 and VC-2502 models are good
for just over 3 KV voltage breakdown. Quarter-inch shafts, almost
10 1/2 inches long. Inexpensive, no. Price is $70 and $80,
respectively.

Smaller (lower voltage breakdown) single to multi-gang units are
available including a 4-gang which can be paralleled to get
800 pFd maximum.

Ocean State also has a number of hardware components for
rotary components from shaft couplers through panel bearings
through flexible shafts and on into vernier reduction drives.

I have bought many many items from Ocean State and I have never been let
down.

I have several of their dual gang 365pf air variables here for monkeying
with crystal receivers and the like. Put them in parallel and add a series
gimic cap and you could be at 680pf pretty quickly.

(730 * X) / (730+X) = 680
(730 * X) = 680 * (730 + X)
(730 * X) = (680 * 730) + (680 * X)
(730 * X) = 496400 + (680 * X)
(730 * X) - (680 * X) = 496400
50 * X = 496400
X = 496400/50
X = 9928pf

So go with a .010 uF cap in series and you'll be cooking with gas.....if I
did my math right.


73 de KB9BVN


"Avery Fineman" wrote in message
...
In article , "S C" writes:

I am in the process of designing an ATU yet am having difficulty in
locating
a company who can supply a suitable Variable Capacitor.

At the moment the only ones I seem to find are trimming capacitors and I
require an item which is somwhat larger than that - E.g in the region of
about 680pF.

Any suggestions as to a suitable supplier would be grately appreciated.

Access the Ocean State Electronics website at www.oselectronics.com
and you will find a number of variable capacitors (two pages worth in
their printed catalog). Their VC-250 and VC-2502 models are good
for just over 3 KV voltage breakdown. Quarter-inch shafts, almost
10 1/2 inches long. Inexpensive, no. Price is $70 and $80,
respectively.

Smaller (lower voltage breakdown) single to multi-gang units are
available including a 4-gang which can be paralleled to get
800 pFd maximum.

Ocean State also has a number of hardware components for
rotary components from shaft couplers through panel bearings
through flexible shafts and on into vernier reduction drives.

S C wrote:
I am in the process of designing an ATU yet am having difficulty in locating
a company who can supply a suitable Variable Capacitor.

At the moment the only ones I seem to find are trimming capacitors and I
require an item which is somwhat larger than that - E.g in the region of
about 680pF.

Any suggestions as to a suitable supplier would be grately appreciated.

Failing this if anyone knows of a circuit diagram available on the net which
may be constructed from components more readily available then I am more
than happy to hear from you.

Many Thanks.


http://www.rfparts.com/products.html
look under Capacitors, Variable Tuning & Load

Kind regards, Eike