[amsat-bb] Re: Possible SWR problems with 70cm antenna
domenico.i8cvs at tin.it
Wed Jun 4 10:56:28 PDT 2008
----- Original Message -----
From: "Michael Tondee" <mat_62 at netcommander.com>
To: "amsat-bb" <amsat-bb at amsat.org>
Sent: Wednesday, June 04, 2008 2:33 AM
Subject: [amsat-bb] Possible SWR problems with 70cm antenna
> I'm having some problems with a homebrew lineasrly polarized "cheap yagi"
for 70cm. I don't have any success hearing myself on VO-52 or AO-7. This
antenna used to work reasonably well for both. The way the power out meter
on my radio acts, it leads me to believe I may have an SWR issue.
Unfortunately I don't own or have access to an SWR meter or anylyzer capable
of working at 70Cm.
> I'm going to take a wild shot in the dark here and ask the bb because I
sure don't know. Would it be possible to put my 2 meter SWR meter in the
70cm line and at least get a ballpark figure of SWR? Or would the reading be
so far off, it would be useless?
> I'm not intending to try and tune the antenna in this manner, I just want
to get some indication as to if SWR is indeed the problem.
> I must confess I don't know what the frequency range determining elements
of an SWR bridge are. I must have missed that at some point or the other.
> Any other ways to determine if I have an SWR problem without a meter? It's
just not in the budget to buy one right now.
> Any suggestions are appreciated.
> Tnx and 73,
> Michael, W4HIJ
Hi Michael, W4HIJ
To measure the VSWR with accuracy you can build by your self a set of
inexpensive directional couplers ranging from 100 MHz to 10 GHz using
semirigid coax cables as described into the RSGB Microwave Handbook Volume 2
pages 10.13 to 10.18
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