[Wswss] Re: Simple 432 MHz return loss bridge

[John B. Stephensen]

#77 ferrite is very lossy at 432 MHz. #67 or #68 will work better. Another
method is to mount two 1/4-wavelength striplines next to each other.

73,

John
KD6OZH
.
----- Original Message -----
From: "Cliff Buttschardt" <cbuttsch at kcbx.net>
To: "Microwave Reflector" <microwave at lists.valinet.com>; <WSWSS at mailman.qth.net>
Cc: "Weak Signal eMail Remailer" <wsvhf at mailman.qth.net>
Sent: Thursday, 06 January, 2005 01:48 UTC
Subject: [Wswss] Re: Simple 432 MHz return loss bridge


> Hi all.  Seems some simple problems can get awfully complex.  I would like to
> build a small signal----that is signal generator operated----return loss
bridge
> for the 420 to 450 band.  Most of the publications show complex microstrip
> designs.  I visualize two panel mount type "N" connectors spaced by the width
> of a BNC panel mount connector, that is about one inch, all soldered together.
> Then possibly a #16 wire between the type "N's" and a ferrite bead suspended
> between the two, with pickup loop of teflon coated wire of say #28 size.  The
> loop is terminated on one side with a fifty ohm resistor.  I've used ferrite
> #77 material which should be good to 440 MHz, but maybe this is wrong.
>      The best directivity I can get is only 8 db or so using a spectrum
analyzer
> as a detector.  Is this the problem?  From the RSGB handbook is appears a high
> impedance detector should be used but so far that has not improved things.
> There has to be a way of putting a small device such as this between a signal
> generator and an antenna rather than a complex directional coupler.
>      If I am trying too hard that is just as valuable an answer as any BUT
> HP has a small device such as this and we should be able to duplicate it!!
> Cliff K7RR
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