At 09:11 AM 1/31/98 -0500, you wrote:
>
>If I understand correctly, to attenuate a 20 meter harmonic in the ten
>meter band, the 20 meter antenna line has a T-connector in it and off of
>that t-connector is a 1/2 wavewlength (at 20 meters) open stub........
>
Jim, if you want to attenuate the 20 meter harmonic in the 10 meter
band, you use a SHORTED 20-meter quarter wave (aprox. 11' 8" of .66 vf
line) connected to the t-connector. On 20 meters that line is an
OPEN CIRCUIT in parallel with the feedline but it is a SHORT CIRCUIT
for the second harmonic energy (the 28.x MHz stuff). Similarly, to
attenuate the 2nd, and 4th harmonic energy from 40 meters one would
use a piece of line aprox 23' 6" (.66 vf).
73,
... Joe Subich, W8IK ex-AD8I
<w8ik@ibm.net>
"Hindsight is an exact science."
--
FAQ on WWW: http://www.contesting.com/towertalkfaq.html
Submissions: towertalk@contesting.com
Administrative requests: towertalk-REQUEST@contesting.com
Problems: owner-towertalk@contesting.com
Search: http://www.contesting.com/km9p/search
|