[30m] Screwdriver antenna problem

[Karl Larsen]

Jason Hsu, AA0II wrote:
> I apologize for yesterday's no-show.  I have an antenna problem that I
> STILL haven't been able to diagnose.  And I have a dirty little secret:
> I'm the most incompetent antenna installer to ever earn a license.
> Other people can work the world with double digit SWR, a dummy load, or
> a piece of scrap metal lying around.  On the other hand, I can't radiate
> anything unless everything about the antenna is just perfect.  (Well, at
> least I didn't shoot my hunting partner.)
>
> I'm using a DK3 Screwdriver antenna in the backyard.  When I adjust the
> coil for minimum SWR (as shown by my antenna analyzer), I transmit and
> find that the SWR is extremely high.  I switch back to the antenna
> analyzer and find that the SWR has gone back up to 4 or more.  What's
> more, the SWR shows no minimum when I tune through the frequencies.  In
> fact, disconnecting the antenna from the coax doesn't seem to change the
> SWR in this case.  When I bring the antenna analyzer outside and connect
> it directly to the antenna (bypassing all of the coax, the ICE surge
> suppressor, and the balun), I still find the same behavior but at a
> higher SWR (presumably because of the elimination of coax losses).
>
>   
    The dirty little secret is Jason, you have no ground under the 
antenna. That vertical is a 1/4 wave and it requires a good ground 
system. Your ground system is your coax :-)
> The problem doesn't come up when I connect the antenna-end of the coax
> to a dummy load.  So it has to be the antenna.
    Nope. You have no ground. I suggest you run 4 wires about 32 feet 
long from the ground side of your coax connector on the antenna. Then 
try it again. I bet it works a lot better.
>   I tried using alcohol
> wipes to clean the parts of the antenna where the wires leading to the
> balun are attached.  I checked the connection between the upper whip and
> the lower mast unit and couldn't find a problem.
>
> HELP!  What could my problem possibly be?
>
>   
    See above.

> Jason Hsu, AA0II
>
> ______________________________________________________________
> 30m mailing list
> Home: http://mailman.qth.net/mailman/listinfo/30m
> Help: http://mailman.qth.net/mmmain.htm
> Post: mailto:30m at mailman.qth.net
>
>
>