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Author Topic: Folding back a dipole to adjust for higher f?  (Read 2392 times)
K5LXP
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Posts: 4475


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« Reply #15 on: August 04, 2013, 06:46:51 AM »

For locations where this is simply too long,
...
 designed my ZS6BKW with a detachable window line,

All the above responses taken into consideration, just make another doublet, say half as long and deploy it or the longer one as needed.  It's just wire.

Mark K5LXP
Albuquerque, NM

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K7RNO
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Posts: 279




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« Reply #16 on: August 04, 2013, 02:37:25 PM »

Should'a tried out the tree first—it all worked out just fine, in full length. At least on that tree.

When I tuned into the 20m band, I thought something was wrong, I couldn't hear ANYTHING, nothing at full volume. Then I tuned around, and there they were...

Never had that quiet experience before (because I never had such a good antenna). But then, I'm green behind my ham ears...

Thanks again to all!
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73,
aRNO
NAQCC #6870, SKCC #11131
AA5WG
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Posts: 496




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« Reply #17 on: August 04, 2013, 03:24:31 PM »

Hi to all,

An effective approach to multi-band operations is use a link antenna coupler combined with home brew ladder line (if needed balanced coax) and a center fed balanced antenna, one antenna for many bands.

This antenna system allows you to series feed and parallel feed (current feed and voltage feed) your antenna.  

If needed, this antenna system also allows you to add shunt or series reactance to your feed line (inductive/coil - or capacitive/ variable capacitor) effectively changing your antenna system electrical length.

Altering your antenna system electrical length provides a desired low impedance or high impedance point at the coupler feed line connection.    

No folded back wire is needed.  String up a random length balanced antenna and get on all the bands.  This is a resonant tuned antenna system.  

Incorporating the above "old timer" antenna system will provide high efficiency, much learning and years of enjoyment.

In the comfort of your radio shack (once you have your link antenna system up and running) you change bands by changing taps on the coil(s) and twisting a couple of knobs to preset know positions.  Done.

Chuck

  
« Last Edit: August 04, 2013, 04:13:28 PM by AA5WG » Logged
KB5UBI
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Posts: 97




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« Reply #18 on: August 04, 2013, 04:15:23 PM »

Hi to all,

An effective approach to multi-band operations is use a link antenna coupler combined with home brew ladder line and a balanced antenna, one antenna for many bands.

This antenna system allows you to series feed and parallel feed (current feed and voltage feed) your antenna.  

If needed, this antenna system also allows you to add shunt or series reactance to your feed line (inductive/coil - or capacitive/ variable capacitor) to change effectively your antenna system electrical length.

Altering your antenna system electrical length provides a desired low impedance or high impedance point at the coupler feed line connection.    

No folded back wire is needed.  String up a random length balanced antenna and get on all the bands.  This is a resonant antenna system.

Another words, once you have your link antenna system up and running you change bands by changing a couple of taps on the coil(s) and twist a couple of knobs to preset know positions.  Done.

Chuck

  

I have to agree. Put up as much wire as you can and use the tuner and / or feed line length for multiband use. Also be aware a folded back portion will act as a trap to any freq where it's a 1/4 WL. 
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