[AMRadio] new antenna and matchbox a bust.


w4rl at bellsouth.net w4rl at bellsouth.net
Mon Jan 29 13:23:27 EST 2007


Brett, my food for antenna thought.

Having 40 feet of balanced line to a center fed 100 footer may be a bit too much to ask of the tuner.
I am assuming the tuner is the Johnson Matchbox (250 watt?).   For 80 and 40 meters, I have found success using at least 125 feet fed at the center and at least 60 feet of balanced line.  The balanced line at the radio end is terminated to a 1:1 balum from which 10 feet of RG-13 goes to the unbalanced  output SO-239 on my RF Power Components "Maxi Tuner" of the Lew McCoy Ultimate Transmatch design.  The 10 foot length of coax allows me to pass throught the shack's wall with all my other antenna feedlines.  Recently I extended the antenna into a horizontal loop (rectangle) which measures 120 by 60 by 120 by 60.  It is still fed at the center of one 120 foot leg, and the other/opposite 120 foot leg is open at its center.  The antenna will tune 160 meters with ease, along with 80 and 40.  I did extend the feedline to a total length of 110 feet.   Of note, I live in a subdivision and have a lot size of approximately 90 by 140 feet.  Hope this information may be of some help to you with your situation.  

Good luck and I hope you get an antenna configured to suit you ham radio needs.

Regards,

Robert  WPE4FGR  W4RL  Pensacola Fl

 

> 
> -----Original Message-----
> From: amradio-bounces at mailman.qth.net
> [mailto:amradio-bounces at mailman.qth.net]On Behalf Of Brett gazdzinski
> Sent: Monday, January 29, 2007 9:19 AM
> To: 'Discussion of AM Radio in the Amateur Service'
> Subject: RE: [AMRadio] new antenna and matchbox a bust.
> 
> 
> 
> Today I put up about 50 feet each side, up about 35 feet,
> fed with 40 feet of open wire line.
> Coming into the house I used 2 RG214 runs, with the shields
> tied together at the ends, into the Johnson antenna tuner.
> 
> A worse working thing I ever put up.
> It seems to work real well on receive, but the lowest
> swr I was able to get on 80 or 40 was 3 to 1
> and even then it acted crazy.
> 
> I also tried connection both to the single wire
> terminal on the tuner, no go there, worse then ever.
> 
> I put my dummy load on the balanced antenna terminals
> and it would not tune to a low swr at all.
> 
> I wonder how things would work if I left the antenna
> at 100 feet and feed it with coax, and used the
> heathkit antenna tuner to tune to 80 and 40 meters?
> 
> Brett
> N2DTS
> 
> 
> 
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