GR-1602 and some accessoires.
In the time befor VNA’s were invented there were instruments to measure things like antennas at high frequencies. General radio made this ” bridge” for that purpose. It is not realy a bridge but because it uses a zero detector, it looks like it is.
Measuring a tv antenna
Thanks to Gerard , a GR collector, I finally have an Admittance meter.
A close up from the rear
It is a very nice build instrument.
Inside the cute cabinet
And build in a very cute box.
Close up
In action,
All bridges together with the GR1602 in action
You need a lot of things top use it. Two unit generators, the mixer, cables, a variable reactance and things like a short and load, linestretchers ect. Here you see a set up.
A typical set up.
It is not a bridge. There is a voltage source that feeds 3 loops. If all is equal the signal currents cancel each other. For that the bidge is connected to a variable reactance, a fixed resistance, a generator, detector including mixer and LO, and the DUT, for instance a component or an antenna. The bridge gives admittance Y and split up in conductivity G and susceptance jB.
Principle
14-70pF variable capacitor
Variable capacitor 14-70 pF.
An accessoire for the GR-1620 and 1602 to shield components
This cup is made to measure components in a shielded holder. The thing on the chain is a short you can mount in the middle position instead of the banana bus.
The “screw” is a short
Innerside of the 874-MR
