[TowerTalk] Tuning Antennas with the MFJ-259

[K7LXC at aol.com]

In a message dated 3/28/2009 12:01:54 P.M. Pacific Daylight Time,  
towertalk-request at contesting.com writes:

>  I am looking at getting an MFJ antenna analyzer and would  like to ask the 
group (because I am sure there are many users of  the
analyzer here) three things:

>  1. Can you tune an  antenna while it is not erected, like laying on a work 
table with this  analyzer, or do you have to have it
installed and in place first and can  you tune it with the coax hooked up or 
do you have to be at the  antenna.



Great question.  You're not really going to "tune" it (unless of course your 
antenna analyzer  measurements indicate you should). Your going to check it 
for resonance. You can  check any antenna for resonance. It might not resonate 
where you want but that's  another discussion.
 
        When you have a yagi on the  ground after assembly, by all means hook 
up your antenna analyzer and take a  look. Since it's close to the ground, an 
HF yagi will resonate somewhere below  where it's tuned for. That's added 
ground capacitance influencing the  antenna. A 40M antenna might resonate 
somewhere down at 6.7 or so. No big deal.  What you're REALLY looking for is that it 
LOOKS like an antenna. That is, that  it dips SOMEWHERE. If it does, it's a 
bouncing baby antenna. If not, start  checking everything; e.g. measurements, 
connections, manual, etc. 
 
        Once you see a dip, then  you can install the antenna. Using a 
tramline, you can run the antenna up  and take a measurement. Then you can lower it 
and make any adjustments to tune  it. Run it up and down as many times as you 
need and you're good to go. 
 
        Works every time.
 
Cheers,
Steve    K7LXC
TOWER TECH -
Professional tower services for hams
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