Tacos Digest, Vol 123, Issue 4 -- NOT SURE WHAT THE SUBJECT SHOULD BE, , , BUT...

[Gerald Wolczanski]

What an interesting paper.

Digging around on the Internet, one would think that without BALUNS no
antenna would seem to work.  When these folks installed RF chokes on the
feedline, the chokes got warm (current flowing on outer shield), but
they saw no difference in the radiated field "when the transmitter power
was adjust to match the new impedance".

Here's an example of the pro-BALUN crowd:
http://www.w8ji.com/ground_plane_verticals.htm

When I became an avid SWL in the late 1950's, it seemed like every
European ham was running "100 watts and GP".  Perhaps ignorance was
bliss; maybe they NEEDED a BALUN, but the antennas worked fine without
them.

I've been pondering an elevated radial system for a 30 meter vertical.
I may give this a try.  There's also been talk about the need for
precise symmetry.  Les Moxon, G6XN, in his book "HF Antennas for all
Locations" makes the case that the 1/4 wave radial is the length to be
avoided!

In the case of "Beverage vs. Moxon", I'm going with Beverage, if only
for the name.  Burp.

Jerry
KI4IO




On Wed, 2013-05-15 at 00:03 -0400, Chip Fetrow wrote:
> In medium wave broadcasting, we use 120 equally spaced quarter wave  
> (or longer) buried radials.  BUT, should we?  Likely not.
> 
> Going below 120 radials on or under the ground is a move away from  
> radiation efficency.  Going to 60 would never be acceptable for  
> broadcasters... UNLESS...
> 
> They are elevated radials.  If you move the feed point of the vertical  
> radiator and the ground radials up at least 0.1 laymda, insulated from  
> ground, especially at the far ends, four to six radials are just fine.
> 
> Yea, it does require some telephone poles, but the radiation efficency  
> is as good as 120 in or on ground radials.
> 
> There are many published articles, but this one seems to be not only  
> good, but a very easy read.
> 
> http://www.commtechrf.com/documents/nab1995.pdf
> 
> Clarence M. Beverage, is a very sharp RF engineer, and yes, he is the  
> son...
> 
> --chip
> 
> On May 3, 2013, at 12:30 PM, tacos-request at amrad.org wrote:
> 
> > Message: 2
> > Date: Fri, 3 May 2013 12:30:16 -0400 (EDT)
> > From: rabruner at aol.com
> > To: tacos at amrad.org
> > Subject: Re: Tacos Digest, Vol 123, Issue 3 -- NOT SURE WHAT THE  
> > SUBJECT SHOULD BE,,, BUT...
> >
> > We are waiting for the electrician or someone very much like him to  
> > show up from the power company and put the meter in. After that. We  
> > should be bee-lining it to getting on the air and getting the work  
> > bench set up.
> >    I have three quarters of a mile of electric fence wire for  
> > putting in 60 1/4 wave radials for 80 meters. I would like to have  
> > used 14ga THHN insulated copper as in the past, but a radial field  
> > like that is almost 4000 feet of wire and at $70 per 500 feet it was  
> > out of the question. Galvanized steel doesn't have as a good  
> > electrical properties as copper, but it should last a minimum of 5  
> > to ten years by which time we can be moving on to something else. I  
> > have another quick fix on the way, a 50 foot Channel Master push up  
> > mast from which to float a several inverted vees. On 80 meters, that  
> > should put the radiation center almost high enough for regular  
> > dipole operation. If I get a little NVIS out of it, so much the  
> > better.
> 
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