Coil Coverage Test Unit

[Yorkie]

I too have got that design somewhere Al. Raymond Haigh also designed a similar 'Q' meter, which again I have details of somewhere.

Right back to my schooldays in the mid 1950s I've always been fascinated by simple test gear projects (and sometimes not so simple, such as a 1976 Radcom 200MHz nixie tube counter, and the Robin 1 GHz counter, and PW Purbeck 'scope). I was in the habit of copying articles and adding them to my 'do list' and one such article was for a Mosfet High Impedance Voltmeter in PW (11 MOhm input impedance, compared to AVO 8 at 20k, and Avo 7 at just 1K). It will measure up to 500V DC, and has an AC probe to measure up to 28V P-P at frequencies up to 200MHz, so is ideal for peaking RF circuits. It uses a 100uA meter, and I came across a meter for £2.00 at a rally which has a 5" x 3.5" scale - ideal for the project. I recently turned up the article again and the PCB (7 x 5 cms), and was quite shocked to note that it was in Dec 1985 PW. It seems like only yesterday, and is yet another example of the long gestation period that some of my projects have!