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:

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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.