[TowerTalk] Insulator Placement Clarification

[Jim Brown]

jeremy-ca said:

>They will decouple similarly as when used over coax or small ones
>over transistor leads.

Which is not very much decoupling at HF. I agree with Jim Lux that 
ferrites in this application are a complete waste of money. 

Ferrite chokes are VERY useful as "egg insulators" in transmission 
lines, but again, at HF you need a WOUND choke, not a few beads, to 
be effective. 

See http://audiosystemsgroup.com/RFI-Ham.pdf

As to the application to LPDA or multiband antennas -- what matters 
is the wavelength of the transmit frequency. The key is to make the 
smallest segment of the guy wire a relatively small fraction of a 
wavelength at the highest transmit frequency. I'd go with Frank's 
advice of a quarter wave being the maximum length, and consider 
going even shorter very close to the antenna. 

73,

Jim Brown K9YC