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Subject: [TowerTalk] Re: Returned mail: Host unknown (Name server: conesting.com: host not found)
From: K7GCO@aol.com (K7GCO@aol.com)
Date: Tue, 24 Jul 2001 19:18:10 EDT
I In a message dated 7/20/01 2:29:02 PM Pacific Daylight Time, 
 charlie.ocker@tellabs.com writes:
  << 
   Bill Coleman wrote:
   > How about mounting a balun outside, and bringing coax underground / into
   > the building?
   
   A balun work's best when it see's a pure resistance, or nearly so.  A
   balun at the end of a piece of coax, feeding a length of balanced line
   that feeds an antenna, will almost be guaranteed to see a reactive load.
   
   A better idea would be to place the balun at the input of a balanced
   tuner.  If there are difficulties in bringing in the balanced line to
   the tuner, then a small section of shielded balanced line can be
   employed.
   
   73,  Charlie  N9CO    (no expert on balanced lines, just my empirical
   observations)
    >>
  A random coax length and a short open wire line here adds up to a length 
 that can often increase (but not always) the reactive component on each 
band. 
  As I suggested a balanced 100 or 150 ohm coax "Needs No Balun", matches the 
 loop fairly close on the various bands, is very tolerant to SWRs above 2:1 
on 
 160,80&40M, presents low reactive Z's to the tuner with a loop cut for say 
 1.78 MHz on all band and a coax that is multiple of 91' 2" of .66 VF.  It 
 matches easily and quickly with the 2 knobs of a Match Box also modified for 
 160M.  I've been there and done that off an on now for about 50 years to be 
 fairly firm on my recommendation for the least problems. 
 
 I've had tuners at the antenna controlled with 2 selsyns and a stepping band 
 switch but on the LF's, it's a "total waste of time 2 ways and a serious 
 elevated housing problem".  Open wire line (of certain lengths) is so 
 forgivig with the proper tuner in the shack and knowledge how to use it, 
this 
 system is very practical indeed.  6M an up tuners and amplifiers at the 
 antenna is a good idea.   Keep it simple.
  
  If you can use open wire line the losses are even less and far cheaper than 
 coax.  One TTer has a full size 80M vertical 500' or more way fed with open 
 wire line, 2 low loss baluns, had a measured loss less than a dB as I 
 remember, it doesn't change and is easy to repair if needed.  I don't think 
 the coax exists with that low loss at any cost for that length.  Use 
 multiples of 137' for .98 VF and 123' for 450 ohm ladder .89 VF line for the 
 friendliest Z's the tuner will ever see on all bands.  ARRL keeps making the 
 serious mistake of recommending "open wire line of any length".  That has 
 done more to lower the popularity of open wire line and those who have 
 trouble adjusting the Match Box and/or other tuners than any other factor in 
 Ham Radio.  Running it on top of a wooden fence line is a great idea.  If 
you 
 don't have a wooden fence--put one in whether you need it or not.  Feedline 
 Security you know.  Or dress it up, use big poles and make it look like a 
 110V power line and it "will look natural" even to the neigbors.
  
  The "Cloud Warmer" label for the Horizontal Quad Loops is really not 
 accurate in one sence.  It infers the Clouds are "resistive."   Actually all 
 RF goes through clouds and with high angle it goes through 2 horizontal 
 layers.  With a low angle the RF goes through a long length of the Cloud 
 layer twice again which in miles can be much longer.  If clouds are 
resistive 
 the loss would be higher for the same thickness of them.  High angle is 
 optimum for most contacts on the LF's other than for DX and high angle is 
 open 24 hours a day year around where low angle skip isn't.  The RF after 
 using a small area under the antenna for a reflector which can be improved 
 with a small square radial system or chicken wire, will not touch ground 
 before it hits most of the receiving antenna first.  It's a very low loss 
 path all the way.  I call it the "Slam Dunk Antenna."  It often does better 
 than a dipole the same height for certain reasons that aren't entirely 
 obvious other than it's actually a 2 element beam with a quad DE already 
with 
 2 dB gain with a higher feedpoint Z.  It reaches out very well also.  The 
75M 
 loop I had 20' high with no radial system under it in SD fed with 137' of 
 open wire line would give a 20/9 report with 100W into Seattle no dipole 
 would.  This performance was hard to explain and I didn't really care--it 
 flat out worked great.  It worked great on 160M also.
 
 The only antenna I had in SD prior to '56 that worked on a par on 75M was a 
 top loaded 75M dipole 60' high with the feeders tied together.  W7IIP then 
 W8IIP was the first I heard using it from Bremerton,Wa and he had a great 
 signal 3-6 S units above its strength used as a horizontal as was similar 
 with my horizontal.  I'm anxious to add a ground system under horizontal 
 loops to see what it does for the signal at all distances and will have the 
 chance to do this for a show down side by side--one with and one without.
 
 Enjoy the mystery, use one and tell your own signal success stories.  If you 
 want DX put up a 4 Square or a "vertical in the middle of the loop," play 
the 
 various phasing games and share a dual radial system--it's been done before 
 and it works.  How about a horizontal loop suspended inbetween the tips of a 
 4 square?  It's worth a try in Eznec first.  To reduce coupling to the 4 
 Square tips whatever it might be, one could install the loop for the next 
 highr band.  There is a way to load a quad loop at 1/2 F and it will still 
 have great performance with a similar broadside pattern.  Be creative!  K7GCO
   

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