[30m] Screwdriver antenna problem

[Brian Kassel]

Jason and Gang:

    It is important to consider that it is quite possible for the ohm 
meter  probe to pierce the oxidation on aluminum so that one thinks that 
he is measuring the conductivity of the aluminum piece, but in reality, 
the connection is actually high resistance.  There is nothing wrong with 
using aluminum  conductors as radials if one has them available.   There 
are lots of ways to make good, low resistance connections to copper or 
other materials used for radials.  In some of my mobile and portable set 
ups I use copper tape to which is soldered other conductors.  Also, 
please remember that the impedance at the base of the screwdriver 
antenna, or any other short antenna,  is extremely low.  It is 
imperative that a good, low  resistance (measured in milli-ohms) 
connection be made at this point.  Generally this means big conductors, 
and robust soldering.  MANY hams make this mistake in their mobile 
antenna set ups.  Old RG-8 coax braid works well to which to solder the 
radials.  Thing BIG wires!  Away from the base, thin wire can be used 
for the radials themselves.  As others have pointed out, the screw drive 
antenna is really only half of the total antenna.  Why spend hundreds of 
dollars on the first half, and none, or comparatively little,  on the 
second half? ;)

Brian K7RE