At 09:48 AM 10/5/2005, Peter wrote:
>Hi there,
>
>does somebody knows a good link to a webpage,
>for some info's how to build a rotary dipole for 30m.
>Using alu. tubes,with traps and total lenght around the 30feet perhaps.
>
What about adapting one of the many "shorty forty" designs? Basically, a
loading coil in the middle, with the taps chosen to get the right impedance.
For reference, a 10 meter long copper wire, 1mm in diameter, suspended 30
meters above soil with 5 mS/m conductivity, and epsilon=13, has a feedpoint
impedance of about 27-527j ohms.. In the classic shorty forty scheme,
you'd have a air core autotransformer to do the matching. The X doesn't
change all that fast:
at 10.0 MHz, 26.4 -548j
at 10.3 MHz, 27.7 -506j
>Kind regards,Peter ON7BJ.
>_______________________________________________
>
>See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless
>Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with
>any questions and ask for Sherman, W2FLA.
>
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_______________________________________________
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather
Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
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