The 100,000 ohm resistor is there to dissipate static charge before it builds
up a charge, ie it is continuously bleeding the voltage, never allowing it to
get to the pucnch through ratings of the diodes and coils. Of course, there
is a time constant, which is easily calculated. (See ARRL Handbook).
Other circuit elements can modify that, but the real protection is that
static, which is a build up effect on insulated objects, (antenna), cannot
build up if it is grounded in any way.
Of course the best method is a DC grounded antenna, but that entails
capacitive coupling, or gamma match,etc. Also, not common for dipoles.
The loop mentioned has the added advantage that it is a magnetic antenna, and
thus more immune to electrical field interference that might be objectionable
on a dipole or vertical.
73, Stuart K5KVH
--
FAQ on WWW: http://www.contesting.com/tentecfaq.htm
Submissions: tentec@contesting.com
Administrative requests: tentec-REQUEST@contesting.com
Problems: owner-tentec@contesting.com
Search: http://www.contesting.com/km9p/search.htm
|