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Old July 1st 05, 12:26 PM
Kevin & Natalia
 
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Default Antenna Tuner for 20m Dipole - Build

Hi All,

I have just built a 20m dipole as a temp antenna for home.
I will be driving it with a TS-830 transceiver, which uses valves in the
final stage.
I know that I can only use it close to the cut frequency, but want to build
a small tuner to allow me to go off the cut slightly.
I only want the tuner to be used on 20m, so I do not need any coil tapings
for switching bands, so maybe a couple of caps will do the job.

Look forward to any replies.

Regards

Kevin, ZL1KFM.


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Old July 1st 05, 12:44 PM
Jim
 
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Kevin,
Since the 830s uses valves (tubes on this end) no tuner is necessary.
Simply adjust plate and load or tune and load if moving more than 50
Khz.
I never required a tuner with my TS-820S.
Regards,
Jim, K4SQR

Kevin & Natalia wrote:
Hi All,

I have just built a 20m dipole as a temp antenna for home.
I will be driving it with a TS-830 transceiver, which uses valves in the
final stage.
I know that I can only use it close to the cut frequency, but want to build
a small tuner to allow me to go off the cut slightly.
I only want the tuner to be used on 20m, so I do not need any coil tapings
for switching bands, so maybe a couple of caps will do the job.

Look forward to any replies.

Regards

Kevin, ZL1KFM.


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Old July 1st 05, 02:20 PM
Cecil Moore
 
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Kevin & Natalia wrote:
Hi All,

I have just built a 20m dipole as a temp antenna for home.
I will be driving it with a TS-830 transceiver, which uses valves in the
final stage.
I know that I can only use it close to the cut frequency, but want to build
a small tuner to allow me to go off the cut slightly.
I only want the tuner to be used on 20m, so I do not need any coil tapings
for switching bands, so maybe a couple of caps will do the job.

Look forward to any replies. Regards Kevin, ZL1KFM.


Hi Kevin, feed it with 450 ohm ladder-line. Make the ladder-line
length an integer number of 1/2 wavelengths. Then you can tune
your antenna system to resonance without a tuner by adding one
foot of ladder-line for lower frequency operation and subtracting
one foot for higher frequency operation. Varying the length of
the ladder-line by 0, 1, or 2 feet should cover the entire 20m
band. My resonant frequencies are 0' = 14.34 MHz; 1' = 14.2 MHz;
2' = 14.1 MHz. Of course, it doesn't have to be in one foot
increments. 35 cm increments might be better. :-)
--
73, Cecil http://www.qsl.net/w5dxp


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Old July 1st 05, 02:35 PM
Dale Parfitt
 
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"Kevin & Natalia" wrote in message
...
Hi All,

I have just built a 20m dipole as a temp antenna for home.
I will be driving it with a TS-830 transceiver, which uses valves in the
final stage.
I know that I can only use it close to the cut frequency, but want to

build
a small tuner to allow me to go off the cut slightly.
I only want the tuner to be used on 20m, so I do not need any coil tapings
for switching bands, so maybe a couple of caps will do the job.

Look forward to any replies.

Regards

Kevin, ZL1KFM.

Hi Kevin,

The 830 already has a tuner built into it- the Pi network output circuit.
When you go through the tune/load procedure you are marching the 830's
output to the load. To put another tuner on the output would be redundant.

Dale W4OP


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Old July 1st 05, 03:08 PM
Dan Richardson
 
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On Fri, 1 Jul 2005 22:26:27 +1200, "Kevin & Natalia"
wrote:

Hi All,

I have just built a 20m dipole as a temp antenna for home.
I will be driving it with a TS-830 transceiver, which uses valves in the
final stage.
I know that I can only use it close to the cut frequency, but want to build
a small tuner to allow me to go off the cut slightly.
I only want the tuner to be used on 20m, so I do not need any coil tapings
for switching bands, so maybe a couple of caps will do the job.

Look forward to any replies.

Regards

Kevin, ZL1KFM.


The pi-network tuning range of the TS-850 (I had owned one at one
time) is capable of tuning the entire 20-meter band on your setup.
Don't worry about it.

73,
Danny, K6MHE


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Old July 4th 05, 12:10 AM
Old Ed
 
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"Cecil Moore" wrote in message
...
Kevin & Natalia wrote:
Hi All,

I have just built a 20m dipole as a temp antenna for home.
I will be driving it with a TS-830 transceiver, which uses
valves in the final stage.
I know that I can only use it close to the cut frequency, but
want to build a small tuner to allow me to go off the cut slightly.
I only want the tuner to be used on 20m, so I do not need any
coil tapings for switching bands, so maybe a couple of caps will
do the job.


Look forward to any replies. Regards Kevin, ZL1KFM.


Hi Kevin, feed it with 450 ohm ladder-line. Make the ladder-line
length an integer number of 1/2 wavelengths. Then you can tune
your antenna system to resonance without a tuner by adding one
foot of ladder-line for lower frequency operation and subtracting
one foot for higher frequency operation. Varying the length of
the ladder-line by 0, 1, or 2 feet should cover the entire 20m
band. My resonant frequencies are 0' = 14.34 MHz; 1' = 14.2 MHz;
2' = 14.1 MHz. Of course, it doesn't have to be in one foot
increments. 35 cm increments might be better. :-)
--
73, Cecil http://www.qsl.net/w5dxp

Hi Cecil,

I know you like to tout ladder-line/tuned feeder as the solution for
everything from SHF to ingrown toenails... but don't you think you're
a bit over the top this time? Kevin should be able to get full-band
SWR under 1.5 using convenient coax feed, with no worries about
fussy window line, and no tuner of ANY kind, including tuned-feeder.
And you suggest he deliberately create a 5:1 or so SWR at the antenna
by using a mismatched feedline, just so he can have the joy of building
and using a tuned feeder??? Sheesh! Horses for courses, Cecil.

73, Ed


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Old July 4th 05, 01:09 AM
Dan Richardson
 
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On Sun, 03 Jul 2005 22:10:08 GMT, "Old Ed"
wrote:

I know you like to tout ladder-line/tuned feeder as the solution for
everything from SHF to ingrown toenails...


My thoughts exactly, but more eloquently stated. G

Danny, K6MHE

email: k6mheatarrldotnet
http://users.adelphia.net/~k6mhe/
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Old July 4th 05, 01:37 AM
Cecil Moore
 
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Old Ed wrote:
And you suggest he deliberately create a 5:1 or so SWR at the antenna
by using a mismatched feedline, just so he can have the joy of building
and using a tuned feeder??? Sheesh! Horses for courses, Cecil.


I'm not familiar with the TS-830 so I assumed he had a real problem.
It's a sub-set of the same problem I solved with my 20m rotatable
dipole. I provided the same solution I presently use and with it he
gets the added bonus of 20m-10m operation. BTW, 13 cent/ft 450 ohm
ladder-line with a 9:1 SWR is a lot less lossy than 13 cent/ft coax
with an SWR of 1:1. He gets all band operation above 14 MHz and greater
efficiency for half the price. Why is that over the top? :-)
--
73, Cecil http://www.qsl.net/w5dxp


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Old July 4th 05, 02:25 AM
Cecil Moore
 
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Dan Richardson wrote:

wrote:
I know you like to tout ladder-line/tuned feeder as the solution for
everything from SHF to ingrown toenails...


My thoughts exactly, but more eloquently stated. G


I had no idea what a TS-830 was. I was just trying to be
helpful. And that's exactly the solution I use with my
SGC-500.
--
73, Cecil http://www.qsl.net/w5dxp


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