[Antennas] Baluns and tuners

Fri, 7 Jun 2002 11:57:56 -0700

> -----Original Message-----
> From: [email protected] [mailto:[email protected]]
> Sent: Thursday, June 06, 2002 5:00 PM
> To: 'Jan Reimers'
> Subject: RE: [Antennas] Baluns and tuners
> 
> 
> Jan,
> 100 watts you could forget the balun
Really!?!?  Then then feed line is going radiate!

> and it would work TV 
> twin lead will
> work 

Let's say I am transmitting on 17M into a 40M dipole, there will be high SWR
on the feedline.  Can 300 Ohm TV wire really handle this without significant
lossage?

> a 400 OHM feed line would take you to 1500 WATTS, and as for the
> turns on the balun mostly follow the directions you have diameter and
> number of turns. You can see how it works and adjust as needed to
> achieve the performance you want. REMEMBER ITS NOT ROCKET SCIENCE the
> old timers like my dad did a lot of trial and error.

That is a good point, perhaps I am being too finicky.  

Thanks
Jan
> 
> Randy
> AC7NJ
> 
> 
> -----Original Message-----
> From: [email protected]
> [mailto:[email protected]] On Behalf Of Jan Reimers
> Sent: Thursday, June 06, 2002 3:07 PM
> To: Antennas Email Group (E-mail)
> Subject: [Antennas] Baluns and tuners
> 
> 
> Thanks again to everyone who helped out with my balanced 
> tuner question.
> The
> Richard Measures article was very informative.
> 
> 	I have managed to build a simple Pi network tuner (unbalanced)
> with
> a roller inductor, and would like to use it to feed parallel 
> line going
> to
> some sort of wire antenna (I suppose I'll start with a 40M 
> dipole).  So
> I
> need a balun between the tuner and the feedline.  I have purchased a
> ferrite
> core for this purpose (man these traditional parts are hard to find!).
> I
> also have some 300 Ohm "radio shack special" flat line, but I 
> could also
> make a higher impedance parallel line with thicker wire and Plexiglas
> spreaders.  I plan to run max 100W but with high SWR between the tuner
> and
> antenna. I have never done any of this before so here are my novice
> level
> questions:
> 
> 1) Is the 300Ohm flat line suitable, or would I be much better off
> making my
> own (more manly) feedline?
> 2) Should I wind the balun in a 4:1 arrangement, or do I need 
> to closely
> match the resistance ratio of the antenna feed line and tuner output
> (even
> though the antenna Z will be jumping around depending on what 
> band I am
> on).
> The only reason I prefer 4:1 is that the ARRL antenna book tells me
> exactly
> how many turns to do for 4:1.
> 3) Once I wind the balun how do I know it works?  i.e. How do I know I
> have
> the right number of winds and that the current on the 
> feedline is really
> balanced.  (I am the proud owner of 1 voltmeter and 1 SWR meter, not
> much
> more!)
> 
> Thanks
> Jan (VA7JNR)
> - - - 
> 
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> Larry Wilson KE1HZ [email protected]
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