Message-ID: <002f01c0913f$8b1a55e0$a4b21bca@xtr743187>
From: "Vernall" <vernall@xtra.co.nz>
To: rsgb_lf_group@blacksheep.org
References: <00a901c0910c$d7b3e520$0d0e0805@globocabo.com.br>
Subject: LF: Re: SWR X phase X reactive components
Date: Thu, 8 Feb 2001 08:50:25 +1300
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----- Original Message -----
From: "PY3CRX PY2PLL" <py2pll@py.qsl.br>
To: "LF Group" <rsgb_lf_group@blacksheep.org>
Sent: Thursday, February 08, 2001 2:49 AM
Subject: LF: SWR X phase X reactive components


> I need a help:
>
> I have an SWR bridge - 2 X 1:40 transformers on a conventional circuit and
> from this bridge I have two rectified voltages: forward and reflected.
>
> On the other side, if I have any reactive component at load side, there
will
> be difference between source signal phase and load signal phase.
>
> Using a DBM I'm able to convert this phase difference into voltage.
>
> The question is: how can I convert degrees in reactive component value? My
> phase measurement ranges from -180 to +180 degree on a linear basis, e.g
the
> phase comparator delivers some mV proportional to degrees.
>
> Knowing this I'll be able to measure SWR, R and J at the same time.
>
> Thanks in advance for any help ...
>
> 73
> Marcus
> PY3CRX/PY2PLL
> S. B. do Campo - GG66rf
> http://py.qsl.br
> Active from "DC" to 24GHz
>

Marcus,

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 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.

73, Bob ZL2CA