On 10/20/2011 5:28 PM, Sal wrote:
wrote in message
. fr...
HI,

I picked up two coils that could be a trap for the CWA-840 COMET antenna.
(They have two stickers "CL-840").
The manual of the CWA-840 says : 40/80m dipole.

I found amazing that there isn't any capacitor in // of these coils...
These coils measure 76uH.
Could someone tell me how they works ?
In the manual of the CWA-840, each leg of the 7MHz section, is
11.1meters in lenght , wich, it seems to me, that it is rather longer
that 1/4 wave. (10.1m).
Why ?

Thanks a lot for your answers

CWA-840:

-----[ ]-------------ooo--//--
2.3m coil 11.1m balun


All coils are self-resonant at some frequency. Wind it right and off you
go!

"Sal"



Good point, Sal. I hope the OP has a GDO to tell him the self-resonant
frequency. If not, there are other ways.

John, KD5YI

http://www.w8ji.com/traps.htm

"W5DXP" wrote in message
...

http://www.w8ji.com/traps.htm
-
Cool!