Single Coil Z Match Balanced ATU

The tuner is a VK5BR single coil balanced tuner which I threw together and after it proved itself was boxed and is a real treat to use!

If you follow the instructions on the linked page you won't go far wrong but here are a few pointers:

• Measure 3 times and cut once

• Variable capacitors were ebay a while ago so no idea of cost, they are quite close spaced but work up to 100 Watts from 30 m up (not tested on 40, 80 or 160 m yet)

• The project case was from ebay member gadjets4you and cost £16

• Angled aluminium from B&Q extortionate price (£4) but I will use it all one day

• Plexiglass left over from HB1A screen protector job - when drilling drill at high speed and press lightly - going slow will crack it. To cut it a very sharp Stanley knife and repeated scoring does work

• Vernier dials are like gold-dust, I got mine from A1 Factors for £5.99 each, they are not the smoothest but they do work well. I went for the small version (to save money) and they are about 4:1 reduction.

• The insulating shaft is 6 mm plastic rod

• The couplings are aluminium tube drilled with 3mm holes and use self-tapped screws, I filed down the tip of the thread so they bound on better to the shafts.

Total cost - £40'ish and well worth it.

As may see I've extolled the virtues of auto tuners and my MFJ-902 but this beats them all.

Now if you have come this far you will obviously enjoy radio but what is better than looking at copper coils, air spaced capacitors and vernier dials?

Enjoy....

The prototype....