[TowerTalk] Wire Size for 800 meter longwire

[Barry]

Something else to think about...
In my (limited) experience, if a model changes dramatically for a 
small change in length, height, etc., there is probably something 
wrong with the model.
Barry, W2UP

On 13 Oct 2005 Joe Giacobello wrote:

> Jerry, I have not followed this thread very closely, but is the 
> reduction in gain with galvanized from resistive losses?
> 
> 73, Joe
> 
> K4SAV wrote:
> 
> >An update on the 800 meter long wire performance.
> >
> >Using 17 ga aluminum wire vs 0.5 inch galvanized cable I had first
> >assumed, decreases the gain by about 3.7 dB.
> >
> >The antenna pattern is very sensitive to the exact overall length.
> >Looking at it another way, it is sensitive to frequency change.  A
> >frequency change of 50 KHz changes what used to be a peak lobe into a
> > null (looking mostly at the pattern off the end of the wire).  For
> >example, off the end of the wire, at 1.8 Mhz and an elevation angle
> >of 10 degrees the gain may be -1 dB.  Move to 1.85 MHz and the gain
> >is -13 dB, same angle.
> >
> >The method of feeding the wire also effects the pattern.  I assumed
> >end fed with the shield dropping straight down into the salt water. 
> >This seems to produce the best pattern I could find.
> >
> >Implementing a vee beam with an 80 degree included angle seems to
> >reduce the pattern into something that is very scrambled and with
> >lower gain.
> >
> >I am normally unsure about simulator performance when wires are close
> >to the ground, but in this case since this is an almost perfect
> >ground, this seems to be within the guideline of the simulator.  The
> >simulator shows very little difference between using perfect ground
> >and salt water except between 0 and 3 degrees elevation.
> >
> >Jerry, K4SAV
> >
> >  
> >
> >> 
> >>
> >>    
> >>
> >
> >_______________________________________________
> >
> >See: http://www.mscomputer.com  for "Self Supporting Towers",
> >"Wireless Weather Stations", and lot's more.  Call Toll Free,
> >1-800-333-9041 with any questions and ask for Sherman, W2FLA.
> >
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> >
> >  
> >
> _______________________________________________
> 
> See: http://www.mscomputer.com  for "Self Supporting Towers",
> "Wireless Weather Stations", and lot's more.  Call Toll Free,
> 1-800-333-9041 with any questions and ask for Sherman, W2FLA.
> 
> _______________________________________________
> TowerTalk mailing list
> TowerTalk at contesting.com
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--
Barry Kutner, W2UP              Internet: w2up at mindspring.com
Newtown, PA                     Frankford Radio Club