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

[Chip Fetrow]

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.