13-11-2012, 08:54 PM
Last lap, at least for now.
First I set it up connected to the 81A, and dialled up 600R and 1mW.
The scope says that the output is within 10%. Having said that I'm relying on an uncallibrated scope and a thick line on the 81A.
Next I connected it to the J-2 on the 600R output. Apart from a bit of hum - must look at the smoothing - the results were much the same as above.
Finally I connected it to the 5R output of the J-2 set to 100mW, and dialled up 5R on the Marconi - that's the part that didn't work before. The scope says it's 2V p-p, which is correct.
A couple of comments:-
The measurements were at 1kHz.
I could/should have got my super DVM out but I couldn't be bothered because it would have taken a long time to warm up.
The Marconi Manual does admit that the Impedance is mainly Resistive, but doesn't define the other part, although I have to think that it's Inductive. It's measured using a Bridge, and the fourth arm includes a Capacitor - RTFM - which no doubt explains the odd readings I got before.
Alan
First I set it up connected to the 81A, and dialled up 600R and 1mW.
The scope says that the output is within 10%. Having said that I'm relying on an uncallibrated scope and a thick line on the 81A.
Next I connected it to the J-2 on the 600R output. Apart from a bit of hum - must look at the smoothing - the results were much the same as above.
Finally I connected it to the 5R output of the J-2 set to 100mW, and dialled up 5R on the Marconi - that's the part that didn't work before. The scope says it's 2V p-p, which is correct.
A couple of comments:-
The measurements were at 1kHz.
I could/should have got my super DVM out but I couldn't be bothered because it would have taken a long time to warm up.
The Marconi Manual does admit that the Impedance is mainly Resistive, but doesn't define the other part, although I have to think that it's Inductive. It's measured using a Bridge, and the fourth arm includes a Capacitor - RTFM - which no doubt explains the odd readings I got before.
Alan
