TopBand: verticals

[T. A. Russell]

N4KG  comments interspersed in text.


On Thu, 14 Aug 1997 15:45:49 +0100 Peter Chadwick
<Peter.Chadwick@gpsemi.com> writes:
>Greg asks: 
>
>>Maybe I've missed something, but I don't understand why everyone is 
>>so keen to achieve an exact resonance.  What is so difficult about 
>>tuning out the reactive part?
>
>History says an antenna must be resonant. 

LORD   NO!

One of my favorite antennas is a  simple 20M (halfwave) dipole
which I use primarily on the WARC bands but is tunable from 10 to 30 M
(using ladderline feeders) and a Johnson 250 W (AM full carrier) tuner
which
handles 1KW  CW/SSB with no arcing or melting.  In my early days on the 
WARC bands, I convinced an African station to work me on 12 and 17M  
using his 15M co-ax fed dipole.  He was so excited he asked if I thought 
it would work on 30M.  It did, and he stayed for a full hour, handing out
the
first 30M contacts ever from his country. 

Bottom line: an antenna need  NOT be resonant to radiate.   de Tom N4KG
(Transmission line losses are reasonably low for SWR below 3:1 on the
high bands, higher on the low bands).

I've never seen a reason for
>it either, but there are experts around who claim that if an 80m 
>dipole
>is more than 10KHz off resonance, it won't work - or at least won't 
>work
>DX.
>

I tune my 80M antennas for CW and use a tuner (MN-2000) on SSB.
With 310 countries on 80M, I would say that they work.  de  N4KG

>It's also been claimed by the same experts that lowest SWR is always
>achieved at resonance for any antenna. 

Not necessarily.  Look at the impedances on a Smith Chart.  de  N4KG

I trust generalisations less 
>and
>less as I get older
>
>73
>
>Peter G3RZP
>
>--

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