[Wswss] Re: Simple 432 MHz return loss bridge

[Cliff Buttschardt]

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