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Re: [TowerTalk] Beta match adjustment

Subject: Re: [TowerTalk] Beta match adjustment
Date: Mon, 19 Jul 2010 07:27:51 EDT
List-post: <">>
Rick, please clarify the 37 @-45 degrees info. What is that?
Gerald K5GW
In a message dated 7/18/2010 11:00:39 P.M. Central Daylight Time, writes:

Scott,  you need to shorten the driven element until the impedance is  
approximately 25 - j25 ohms (or 37 @-45 degrees)  without the beta  
match.  Then attach the beta match and adjust its length until the  
impedance is close to 50 ohm resistive.  I have seen some programs  
that would give you a good starting length for the beta match based 
on  the diameter and spacing of the beta rods but I don't have any on 
this  computer now.

Good luck, Rick, N6ND

NM8R writes:

Are  there any beta match experts onboard who could give me some guidance  
adjusting a beta match on a 40m beam?

I built a 40m 2 element  Yagi.  Physical detail on the antenna can be shared
if  pertinent.  It plays well, but I would like to utilize a DXE beta  match
to see if I could improve the match.

I have an antenna  analyzer thus can measure a variety of antenna 
At my frequency  of interest, R=Z @ 26 ohms, and an angle of 0 degrees.  
is  without the Beta in place.  Beta in place has yielded no  worthwhile
results, regardless of setting.

The antenna is on a tilt  over/crank down tower so I can access it at ground
level to work, but would  like to minimize the number of times my XYL has to
crank the tower up and  down.  (That was a joke.  She actually does help  

So how does one configure a beta match?

The info  that came with the beta match suggests experimenting with the 
and  driven element length to tune it at ground level, but the info with it
is  vague as to the process.  And, I can't uncover a correlation that  would
permit me to pre-tune it at ground level that translates to being  tuned 
raised on the tower at 65 feet.

I have searched the Tower  Talk archives and while I uncovered a lot of good
information, the key to  tuning the beta match still eludes me.

Many  thanks.

n6nd at n6nd dot com  

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