[amsat-bb] Re: Possible SWR problems with 70cm antenna

Sebastian w4as at bellsouth.net
Tue Jun 3 19:20:17 PDT 2008


Michael, I doubt a 2 meter SWR meter will give you any type of useful  
information for 440.  Many are rated for 1.8 Mhz - 148 Mhz or similar.

Before you blame the antenna, take a look at your coax, primarily the  
connectors.  Make sure the connectors and the coax don't twist if you  
attempt to move them.

You didn't mention what type of rig you are using.  Or how difficult  
it would be for you to get a close look at the antenna.  Since it's  
homebrew, whatever system you used to match it, might have moved.   
Consider testing it on the FM part of the band, and see if your rig  
complains.

If it doesn't, then that's your answer.  Your tuning method isn't  
working.  Or, try using a local 440 repeater and see if a local ham  
will loan you an SWR meter that will work on 440.

73 de W4AS
Sebastian

On Jun 3, 2008, at 8:33 PM, Michael Tondee wrote:

> 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
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