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To: rsgb_lf_group@blacksheep.org
From: py2pll@py.qsl.br
Subject: LF: Re: SWR X phase X reactive components
Date: Wed, 7 Feb 101 23:55:25 +0000
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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 => py2pll@py.qsl.br
Active from DC to 24GHz