Golborne quiz

[Keithstv]

At todays talk I had a small quiz, What was this meter used for? Several people got it right but before I reveal the answer I'll let others have a go. No prizes just the satisfaction of getting it right.

The meter is enclosed in a perspex case and there is a single cable connected to it and one socket.

I'll let it run for a few days before I put you out of your misery.

Keith

[tiv48]

to measure rf output of some kind?
Rob T

[Refugee]

Currant in the output feed on a hefty RF amplifier of some kind. The loops look like 1/2 wave.

[Skywave]

Usually, a meter is mounted in a metal case - to provide screening. That one is in an 'anti' metal case - so presumably this item is deliberately designed so that the case does not disturb the circuit within it: that carries connotations of high-frequency tuned circuits. I also see what looks like two very low inductance coils, which, in turn suggests a VHF transformer. The primary can be seen to be connected to the single wire and the socket, thereby possibly providing a pick-up loop for collecting EM energy from a radiated field. Then by transformer action, the resultant voltage is coupled into the transformer secondary and then connected to the two diodes - which can be clearly seen. The FSD of the meter, 2 mA, is suggestive of the item's application, too

So, put all that together: I reckon it's a field strength meter - probably for VHF use.

Al. / Nov. 03, '13 //

[pwdrive]

Are the copper rings anti corona rings?
The red wire looks like EHT cable.

Lawrence.

[Keithstv]

Well out of the 4 replies so far one is very warm.

Keith

[pwdrive]

Schematic?

Lawrence.

[Keithstv]

I'll post the schematic tonight.

Keith

[Skywave]

Well out of the 4 replies so far one is very warm.
Keith

Hmm; I see. Although I wrote my guess after that of Refugee, upon reflection, I do believe that Refugee's suggestion is the correct one. Further idea though: a standing wave detector for use with transmission lines. Field strength measuring device? Nah!

Al. / Nov. 04, 2013 //

{Subsequently edited: poor grammar; unclear remarks! }
Al.

[pwdrive]

The diodes look similar to the old BY100 types.
The perspex maybe for EHT insulation as it looks thick.
So far as I can see there's nothing tuned, unless it's very broad tuning.
There appears to be another loop/ring on the back of the meter case (Tinned copper wire?)
Looks like HV/EHT in via the red cable.
To measure current?

Lawrence.