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.

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.

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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"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

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

How about just a couple of relays? If you have some 300 ohm or 450 ohm
feedline available, I can give you a simple solution. E-mail me at


"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.

"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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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/

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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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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"Cecil Moore" wrote in message
...
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

Hi again, Cecil...

I think the "problem" here is that you tend to superimpose your
priorities over those of the original questioner:

"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..."

Multiband operation, while desirable in my book, was not
something Kevin asked for. He also did not say he wanted
the cheapest possible feedline.

As to loss, if Kevin needs as much as 100 feet of feedline, and
wants to use a conveniently small cable like RG-8X, he can
expect to lose 1.5 dB or so. That might be a dB or so worse
than window line--if the latter is in a favorable environment.
Kevin would need mighty sharp ears to tell the difference.

73, Ed


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Hi All,

Thanks for all the information, there was plenty to think about, and decide
to do.

Just for the record, I wanted a simple dipole, using coax, as it is easier
to work with in my home, no windows near to run ladder-line.
I do agree that ladder-line would of made it work better across other bands
with a tuner, but I just wanted something on 20m.
The rig, TS-830S, being tube finals, from the information will allow me to
tune off the cut frequency with tuning the tubes. So I will be able to move
across the band without too much problem.

I have the dipole cut and ready to go up, was going to do it today, however
the rain came down, and washed that idea away, have to wait for the weekend
now.

Again thanks to all.

Kevin, ZL1KFM.

"Old Ed" wrote in message
nk.net...
"Cecil Moore" wrote in message
...
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

Hi again, Cecil...

I think the "problem" here is that you tend to superimpose your
priorities over those of the original questioner:

"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..."

Multiband operation, while desirable in my book, was not
something Kevin asked for. He also did not say he wanted
the cheapest possible feedline.

As to loss, if Kevin needs as much as 100 feet of feedline, and
wants to use a conveniently small cable like RG-8X, he can
expect to lose 1.5 dB or so. That might be a dB or so worse
than window line--if the latter is in a favorable environment.
Kevin would need mighty sharp ears to tell the difference.

73, Ed


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