Found a cheap source of quality air variable capacitors in the UK - Page 1
Forum section: electronics / rf-microwave

author: MrSlack
author_rank: Frequent Contributor
timestamp: March 15, 2016, 01:39:10 pm
content: £16.49 inc delivery for the following (Clansman TUAAM ATU):http://www.ebay.co.uk/itm/321860429348Nice bit of kit by the looks. It's an ATU for HF bands that operates automatically.Made by Racal, it has three motor driven air variables in it with suitable measurement and servo circuits.Someone did a tear down here:http://sigmatechnica.com/clansman-tuaam-antenna-matching-unit-teardown/I'll do another tear down and work out the capacitance when mine arrives. If they're good I'm going to buy a few!

author: m100
author_rank: Regular Contributor
timestamp: March 15, 2016, 02:14:13 pm
content: Yes, that works out quite a bit cheaper than thesehttp://mainline-group.com/collections/5720-tx5-high-power-airspaced-variable-capacitor-by-jackson-brothers

author: MrSlack
author_rank: Frequent Contributor
timestamp: March 15, 2016, 02:22:06 pm
content: Exactly!If they're not the right values you can pad them out easy enough as well.

author: Gyro
author_rank: Super Contributor
timestamp: March 16, 2016, 12:22:24 pm
content: Wow, that takes me back!

author: SeanB
author_rank: Super Contributor
timestamp: March 16, 2016, 07:14:29 pm
content: 10 quid for the unit and 40 postage to me..........

author: MrSlack
author_rank: Frequent Contributor
timestamp: March 16, 2016, 07:21:00 pm
content: Ouch. 6.50 for postage for me.

author: SeanB
author_rank: Super Contributor
timestamp: March 16, 2016, 07:27:18 pm
content: Scary thing is I ordered a Ham radio from China, and it came as courier delivery, for no extra charge. Our regular courier guy arrived in the morning, and gave it to me, and I thought it was for the company and not my parcel, which was at that time still marked as in customs. No charge, and very fast as well.

author: MrSlack
author_rank: Frequent Contributor
timestamp: March 17, 2016, 03:14:59 pm
content: It arrived!Teardown in progress...

author: wkb
author_rank: Super Contributor
timestamp: March 17, 2016, 03:16:58 pm
content: Quote from: MrSlack on March 17, 2016, 03:14:59 pmWhere are the photographs!

author: MrSlack
author_rank: Frequent Contributor
timestamp: March 17, 2016, 03:44:13 pm
content: Right herehttps://www.eevblog.com/forum/rf-microwave/racal-clansman-tuaam-military-antenna-tuner-unit-teardown/

author: voltz
author_rank: Frequent Contributor
timestamp: March 18, 2016, 01:39:49 am
content: Nice find!Here's some info on the unit:http://www.vmarsmanuals.co.uk/newsletter_articles/prc351pt2.pdfLooks like its designed for VHF. 30 to 76Mhz. Max power is 20 watts during tune, 50 watts once tuned. 22 to 32v operation.Those caps look too small for HF use.This could make a fantastic auto tuner for 6 and 4 metre bands.

author: MrSlack
author_rank: Frequent Contributor
timestamp: March 18, 2016, 06:48:55 am
content: Excellent - thanks for the info. I'm extracting and measuring the capacitors today. Will drop a list of salvageable parts out.The plan is to nick at least one of the capacitors to pull a 7030khz xtal a bit for QRP use in my perpetually unfinished VXO that was a terribly drifty VFO about a month ago.