[Mobile-Portable] Texas bug catcher

[D C *Mac* Macdonald]

When you are already down 12 dB or much more from a full-sized
antenna on 75m, losing another 3-6 dB is not a good idea.
 
To resonate the system over a wider range, use a motor driven
(or manual) roller inductor in series with the bug-catcher right
before the feed point.  Losses of signal with this method will
be minimal.  Set taps on the bug-catcher coil to make resonance
at the highest frequency you will be using then add the amount
of series inductance needed to drop reflected power to minimum.

Use a shunt capacitor (across the feedpoint to ground) to get
SWR down to nearly zilch.  Try 1000, 750, or 470 pFd for 75m.
Try 470, 270, or 200 pFd for 40m.  There used to be some "boxes"
available with switched capacitors for this purpose.  Swan made
one and I think MFJ may have made one recently.
 
It all worked like gangbusters for me for over 20 years.
 
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
~ 73 - Mac, K2GKK/5 ~
~ (Since 30 Nov 53) ~
~ Oklahoma City, OK ~
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~











> Date: Tue, 6 Jul 2010 00:20:44 -0400
> From: whitaker at pa.net
> To: mobile-portable at mailman.qth.net
> Subject: Re: [Mobile-Portable] Texas bug catcher
> 
> de WB2CPN
> Seems like you could improve on the Bandwidth a bit
> if you could lower the "Q" somewhat without messing
> up the tuning. Maybe use resistance wire in the top
> hat or coil. Nobody would notice if you lost 3 or 6 dB
> unless you are trying to work me and my under ground
> antenna.
> 73 Clete