I recently bought a Little Tarheel "screwdriver" antenna and attached
it to the custom front bumper of my one ton dually Dodge via an unused
tab there for off road driving lights I did not install. The bumper and
monolithic brush gards etc weigh, including the 12,000 lb Warn winch,
500 lbs. The installation method has the base of the antenna attached to
the hole in the light mounting tab and provides a SO-239 style socket to
accept a cable with a PL-259 male connector. More easily weatherproofed
than other approaches commonly employed.
I connected my Comet antenna analyzer to the end of the coax in the cab,
set it for 14.3320 MHz, and ran the manual control while watching the
meter. Near the VSWR minimum the VSWR reading changed quickly making it
a bit of a challenge to stop at the minimum but with a little practice
and perseverance it wasn't too hard. At or very close to the VSWR
minimum the impedance was 52 ohms and the VSWR was less than 1.1:1
So what does this mean? Did I tune the antenna, flatten the coax, match
the impedance, adjust something, calibrate something else, or just
observe a totally random event whose "nice" readings were coincidental,
a lucky accident meaning nothing?
I did purchase an automatic antenna tuner called a Turbo Tuner 2. It has
no switchable inductors or capacitors. It just drives the coil in the
base of the antenna past the VSWR null noting the time it takes to go to
the same VSWR on one side of the null to a similar value on the other
side and backs up one half that. Pretty simple. Makes some simplifying
assumptions which are easy targets for the cognoscenti hereabouts if
they can tear themselves away from the hot debate re angles dancing on a
head of a pin.
It isn't just me, there are hoards of other deluded users who thing this
system works well. What remains for me to note is how well it works.
Have I created a dummy load with an attached stainless steel whip?
I have a longer whip, as of yet not tried, that is too tall to use
mobile but should do well parked. Yeah, yeah, I know, no tower involved
but does dovetail with the current chatter re antenna couplers, those
antenna to rig devices known by many names.
Patrick NJ5G
Patrick Greenlee wrote:
Hey, Dude! Don't forget Swan and Atlas... Herb wasn't exactly a bozo
nor surrounded by bozos.
On 5/3/2014 11:10 PM, Roger (K8RI) on TT wrote:
On 5/3/2014 11:20 AM, David Jordan wrote:
Common use since no code licenses or since most of the Navy radio
ops, Collins and Drake tech have passed- on. ;-/
Sent from Dave's iPhone4 ;-)
Common use long before that. Line tuner and antenna tuner were in
commomn use nack in the 60s and 70
On May 3, 2014, at 9:51 AM, Jim Lux <jimlux@earthlink.net> wrote:
On 5/3/14, 5:56 AM, Marsh Stewart wrote:
Someone posted the following on the subject of antenna tuners:
"They aren't
adjusting the resonance of the antenna, so what are they tuning?"
When I adjust the capacitance and inductance of my "antenna tuner" my
antenna does not change length or height, and the length of the
feedline
does not change. Could it be because it is not really an "antenna
tuner" but
is actually an impedance matching network?
It does make the antenna appear to be resonant at R=50 whle L & C are
equal
73
Roger (K8RI)
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