Hi Bob . . .
You are venturing into the "operating impedance bridge" (OIB)
idea. An
article with some information is "Building an Operating Impedance
Bridge"
in
QST, Nov 1979, pp 11-17.
I think this same OIB was published by ARRL Handbook from 1984 or
something
like that. Uses a linear sampler + some metal hardware assembled
properly
..
I gather that the OIB can work while the
transmitter is in normal service, and R and jX can be read from
calibrated
knobs on pots on the secondary side, after a null is found by
adjustment.
Yes, I remember that.
But I'm trying to make it similar to Kachina SWR bridge. And there
they use
this kind of directional coupler (2 ferrite transformers) and a TTL
Dual D
flip flop to detect phase and transform this in voltage. So there is 3
voltages and no need to operate anything. A SBL1 mixer can detect
phase
differences with LO/RF between 3 ... 7dBm within 1° or less from 1 to
500MHz. Ok, that's not LF but the Dual D Flip-flop can be used from
some
Hertz to 35MHz.
The idea is a bench bridge + some micro-controller / portable bug and
running from some mW to a watt or so ...
Thanks on the info. May be for now a RX noise bridge can do the
job :o)
73
Marcus, PY2PLL(Base) / PY3CRX (Mobile)
GG66rf - S. B. do Campo - SP
hampage => http://py.qsl.br
e-mail => [email protected]
Active from DC to 24GHz
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