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Re: Topband: radials

Subject: Re: Topband: radials
From: Jan Erik Holm <>
Date: Fri, 05 Nov 2010 07:39:07 +0100
List-post: <">>
I would shoot for 60 1/4 wl on the ground (like W3LPL says). This will
be "very close to" optimum and the losses in the near field will be well 
below 1 dB. Anything less is going to be "dB down".

Measuring SWR or Z or bandwidth is not a way at all to measure how
efficient the antenna is. The only way to find out is to measure the
radiated field strength.

Good reading is what N6LF writes,

Also what K2AV writes on this reflector is good reading.

I can tell you a true story, this is no science and no measurements
was done to confirm anything. When I first got on 160 back in the
1980´ties I did put up a 110ft top loaded radiator. Then I started
to put out radials....I put out 10...went inside and made QSO´s and
got 559 569 reports most of the time....went outside and put out
some to the shack and made QSO´s...etc etc etc. It was
not until I came up to 70-80 radials I started to get 599 reports
and started to "get a feel" that the antenna was kicking. At that
point I was only using 100W but power level is not important in
this case.
Now after this I went all silly and crazy and nuts, I did put out
even more radials and didn´t stop until I had 250 radials, then I
was very tired. This was over 20 years ago and during this time
I have had a number of different vertical radiators above this ground
screen and everything seems to radiate very well. Now I´m old and
even more tired and do not have the same interest so I would not
do it again (I think!), but you never know when you go nuts.

On 2010-11-04 16:22, Brendan Minish wrote:
> Under my 1/4 wave Inverted L (~18M vertical section) I have a mix of
> buried radials and radials lying on the grass (for the winter months
> only)
> In total there are around 20 radials with lengths of between 1/8 and 1/4
> wavelength long.
> the ground here is very good, in the winter the field is saturated
> nearly all the time and the system seems to play well.
> The far field ground is the same type of soil and the Irish weather
> keeps it well saturated all winter..
> With all the radials out the feed point impedance at resonance is around
> 25 Ohms but it's hard to say how much of this is due to the proximity to
> the tower and other antennas.
> I have the opportunity to roll out a couple of rolls of chicken wire on
> top of the radials, however there is significant work involved and I'll
> have to get it back up again in the string. Am I likely to be able to
> improve things further or would my efforts be better spent getting more
> radials out ?
> Any suggestions on how to make some quantifiable measurements as I
> change things?
UR RST IS ... ... ..9 QSB QSB - hw? BK

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