[jamesinnewcastl]

Hi Richard

Thanks for your comments. The resistors will soon be undergoing the two tests, will they (some) melt and will the additional capacitance be an issue? Along with, of course, will any of it work?

Currently I am building up the test rig around the receiver. I need the control panel, indicator dial and power supply to be mounted and wired in.

I'm not familiar with valve circuits (or radio come to that) and I note that this design has an HT supply that connects between the anodes and a line called 'bias resistors', not earth (what I would call 0V common). I had originally thought to ask a question about this on here but decided after some thought that this is how it was intended to be and not just a mistake in the documentation. So it seems that the HT supply negative will fluctuate below 0V common in order to supply the negative bias for the valves - this value being controlled by the AGC requirements of the circuit. The AGC for this system being switched ON when flying generally and looking for the airfield and switched OFF when on the final glide and using the actual field strength to guide the pilot down.

I was OK with this until I looked at the HT supply of a later system to see the HT supply connected to the 0V! Sadly I don't have the receiver circuit of this later system so I can't see how they are generating the bias.

In any event I will have to suck it and see!

I'll post the results when I get them!


Cheers
James