Posting Comment for "VHF Impedance Bridge"

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8th August 2014 23:10

EA1TY wrote...

Hi Alan

I am building your Meter, so please could you said to me minimun signal level for use in 122.3 Mhz ??



3rd September 2008 00:24

Alan Yates wrote...


Yes you can use a 1N4148, but it won't be as sensitive. You could use a 1N34 or similar Ge diode too. Most any small signal device will work, but power rectifiers won't work very well.

The diode is reversed in the bridge because the meter is connected the other way (because it was physically easier or I stuffed up assembling it - can't remember which). It doesn't matter too much, if the meter deflects the wrong way reverse the diode or the connections to the meter.



2nd September 2008 23:32

ken potha wrote...


as for your circuit 1n5711 ,Can i use 1n4148?

and why the picture 1n5711 the position A ,K show not same the circuit?

please let me know