"Try to make a "

'cause this technique works, is perfectly
valid AND works from DC to as high as your
construction techniques will allow (making
it largely 'frequency independent') ...

Jim

----- Original Message -----
From: "Peter L. Peres" <plp@ACTCOM.CO.IL>
To: <PICLIST@MITVMA.MIT.EDU>
Sent: Tuesday, July 09, 2002 12:13 PM
Subject: Re: [EE]: Directional couplers & T/R test sets


> On Mon, 8 Jul 2002, Jim wrote:
>
> >10 - 20 MHz?
> >
> >Ouch!
> >
> >I've got directional couplers that are 'effective'
> >as low as 100 MHz - amd as most of my work in
> >the past has dealt with this range I've been
> >okay.
> >
> >I've got some on-going work (a filter) in the range
> >of .5  to 5 MHz right now.
> >
> >I am able to measure S21 (Insertion Loss) using a
> >spectrum analyzer and signal generator, but shortly
> >I've got to measure S11 (Return Loss or 'VSWR')
> >as well.
> >
> >I'm going to use a crude 'bridge' in combination with
> >a dual-trace scope or a Vector Voltmeter to accomplish
> >this in a round-about fashion (measure complex Z and
> >then compute the Return Loss/S11).
> >
> >http://www.dallas.net/~jvpoll/tech/ph_mag.html
>
> Try to make a bifilar wound directional coupler on a toroid or
> snap-together ferrite transformer for 5MHz. It will very likely work for
> you. 30 turns at 5MHz would be too much I think. Surely you have a core
> like this in the junkbox.
>
> Peter
>

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