[TowerTalk] "Antenna Tuner"

[Patrick Greenlee]

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 at 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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