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. 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.
>
>It's also been claimed by the same experts that lowest SWR is always
>achieved at resonance for any antenna. I trust generalisations less
>and
>less as I get older
>
>73
>
>Peter G3RZP
ANYTHING can be made to radiate Peter; it all depends upon ones
definition of efficiency.
On 160M just about anything from roughly 1/8 wave to 3/8 wave electrical
height will be a credible performer if the user pays sufficient attention
to the ground system.
On topband, half wave and 5/8 wave radiators are generally not very
effective for DX. There have been numerous postings here and also studies
explaining the "popular" elevation angles for 160M DX. The concensus is
that roughly 20 to 45 degrees will cover "most" requirements.
There will always be the exceptions. One of my best QSO's was busting the
huge pileup on one call to work 3Y5X on Bouvet with an inverted V at 55'
apex and the ends at ground level. I had just moved to this QTH and that
was all the antenna I could get up at the time.
Conversely, I worked 3Y0PI, VK0IR, etc with equal ease with the verticals
in later years. You go figure it out!
73....Carl KM1H
>
>--
>FAQ on WWW: http://www.contesting.com/topband.html
>Submissions: topband@contesting.com
>Administrative requests: topband-REQUEST@contesting.com
>Problems: owner-topband@contesting.com
>
--
FAQ on WWW: http://www.contesting.com/topband.html
Submissions: topband@contesting.com
Administrative requests: topband-REQUEST@contesting.com
Problems: owner-topband@contesting.com
|