On 2 jun, 07:58, "Antonio Vernucci" wrote:
The Bird actually measures a combination of capacitive coupled voltage and
inductively coupled current. *There is a app note on the Bird website..
Find: *"Straight Talk About Directivity".

Thanks for pinpointing that nice document.

However the document dwells on the directivity of the meter, and I could not
find there any mention of the impedance tolerance issue I had raised.

73

Tony I0JX

Hello Tony,

If you think cable impedance deviation from 50 Ohms is the problem in
your situation, why not making a resistor bridge type of VSWR meter
(wheatstone bridge)?

By changing the resistor that goes from the source to the output
connector, you can change the reference impedance of the resistor
bridge. For HF and VHF, accuracy is very good when using surface
mount components.

One example is given he
www.w1ghz.org/QEX/A_UHF+_VSWR_Bridge.pdf

Best regards,

Wim
PA3DJS
www.tetech.nl
don't forget to remove first three letters of alphabet in case of PM.