[Antennas] 468/Freq in Mhz

[Billy Cox]

W4RNL's site is a good start, so are the others, especially those
who have gone in much more depth with their study of the subjects
at hand ... Cebik <now a SK> offers a good 1st pass review on 
many different topics, but he's not the final word.

He, for example did not do much as to real 4x phased arrays on the 
low bands ... so he's no expert of knowledge for real world experience. 
The others sources I provided are however, especially for radials/etc.

Cebik in fact suggests others ... including N6LF's work and ...

"8. The best sources for basic information on phased vertical 
arrays is The ARRL Antenna Book, Chapter 8, and Low Band 
DXing, Chapter 11."

http://www.cebik.com/content/fdim/fdim4.html

One needs to also keep in mind he modeled MANY ideas, but 
only built real world examples of very few. His insight as to what
and how to model antennas, and as well, what to watch out for 
as to errors is quite valuable.

Now back to radials ...

For example if the vertical is short <in degrees> then you may
be better off with more, and shorter radials, than with a few 0.25w.

 ... so if you have say a 40' vertical for 80m, then more shorter 
~ 40' radials from the same amount of copper wire on hand, 
than only a few longer ones.

... and with such shorter <in degrees> verticals, there is a need
for an ever better ground system to control system losses.

Using only a "few" elevated radials with less than 0.25w verticals
may surprise one as to what the REAL systems losses are ... 

Several have published studies on this, check QST and other
sources for their past texts.

The study by Brown, with 120 radials @ 0.4w is also interesting
to read as to the details of their results and why, especially as
to them running out of more copper wire to do more testing ....

K4ERO and others have published their studies, complete with 
the trade offs of how many radials and how long as one cite ...

ON4UN, N7CL, N6LF, W8JI ... all have spent quite a bit of their 
time and study on this topic to try and prevent the passing 
around of "ham lore" as to poor or inaccurate data.

Again, I suggest that study of the same might be quite useful
for you, especially some of the more recent published studies.

73 de Billy, AA4NU


-----Original Message-----
>From: cboone at earthlink.net
>Read Cebik's (W4RNL) papers on the subject....HIS is the definitive on radials..and I use his info to make my statements.
>
>Chris
>WB5ITT
>
>-----Original Message-----
>>From: Billy Cox <aa4nu at ix.netcom.com>
>>Sent: Aug 24, 2009 8:45 PM
>>To: "antennas at mailman.qth.net" <antennas at mailman.qth.net>
>>Subject: Re: [Antennas] 468/Freq in Mhz
>>
>>Chris,
>>
>>You might want to do some study on this topic of radials as your 
>>statement is not quite "spot on". 
>>
>>Depending on the vertical height, being 0.25w may or may not be of 
>>any importance, ditto as to always be 1/4 wave. 
>>
>>Same goes for saying 4x elevated is the same as 40x buried. Many
>>have done published studies as to how many, how long, and why.
>>
>>ON4UN's books and N6LF's website are good places to start.
>>
>>Lots of variables with verticals and ground systems to make any 
>>'this is always true' statements ...
>>
>>73 de Billy, AA4NU
>>
>>-----Original Message-----
>>>From: cboone at earthlink.net
>>>Radials can be insulated or not...as long as they are 1/4wave in 
>>>length or longer...Personally, I like elevated radials...you can get 
>>>away with 4 vs 10x as much buried and get the same results....
>>>
>>>Chris
>>>WB5ITT
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