On 18/05/15 06:57, Helmut Wabnig wrote:
On Sun, 17 May 2015 14:43:19 -0500, FBMBoomer
wrote:

On 5/17/2015 6:53 AM, Helmut Wabnig wrote:
hello,
I am a newcomer in amateur radio shortwave and so far
have built a dipole antenna with ladder line.

Not a G5RV, not a ZEPP, not a DOUBLE ZEPP, not a DOUBLETT,
but a dipole, a non-resonant antenna, if you know what I mean.

Unfortunately the antenna feedpoint is 25 meters away.
Now I am searching for a remote automatic tuner
for balanced feed line, aka hen's ladder, and coax input.

Presently I am using a BG-430 military Generalstab radio tuner.
http://www.radiomuseum.org/r/zellweg...em_se_430.html
It is the lower right foto, the thing in the center with the 4 black
feet. Works only 80 and 40 meters.
In more detail:
http://www.radiomuseum.org/r/zellweg...geraet_ag.html
Look at the schematic, upper part.
The input coax connects to the "balun" transformer,
and two variometer coils connect to the antenna output.

I have not been able to find anything useable on the market.
SGC tuners are ruled out, they are strictly for long wires
and nothing else. They make their money with the UN and other
mobile militaries, amateurs are not existent for them.
Amateurs use dipoles and ladder lines.
No, you can't use an SGC on a dipole.
If you do, you are wasting your money.

What rermains are MFJ and LDG coax tuners in combination
with a 1:4 balanced transformer. Thus the 25 m coax line would see
a fine SWR and no losses due to reflections. The coax from the tuner
output to the balun input make very short to avoid reflection losses.
Very high voltages will oscillate there!

What I like less is the balun at the high end, would prefer
a symmetric tuner with a balun at the coax input and balanced
symmetric output, like the Zellweger tuner does.
The MFJ-974HB is also a fine thing.
Really symmetrical at the tuning circuits, but manual.

100 Watt are fine, 400 Watt are better. (Maximum in Austria)
Can you help me, please?
OE8UWW



Helmut,

All of these replies are right on the mark. There is nothing wrong with
SGC tuners, even for your use. I personally have not heard of problems
with any tuners currently on the market except for perhaps some limited
range tuners built-in to transceivers.

Save yourself future update problems. Buy a 1500 watt tuner if you are
allowed 1500 watts where you live. Most hams in my part of the
Midwestern US use amplifiers.

BTW, I share the responders concern here about your criticism on SGC
tuners. It was unfounded. I personally own and use a very old Ten Tec
229. It has worked perfectly for decades. Again, read the current QST
article about feeding dipoles. It is eye opening. As a youngster might
say "600 ohm ladder line rules" :-)

Thanks for the answers, but I have an absolute abhorrence against
grounding the left side of my dipole, as the SGC recommends.
Again: ground from the transceiver, ground is on the outside of the
coax, ground is at the frame of the SGC, and they recommend to connect
the left dipole half to that ground frame.
Alternatively the other side of the dipole:-)

Of course it will work.
A rusty nine inch nail will work.
Anything that conducts electricity will work.
But it is a shame.

Therefore I am searching for an automatic tuner with symmetric output.
Additionally I would prefer to have the balun at the coax input side,
not at the high voltage output balanced side.
Am not sure if that is justified, though.
It just looks better to me,
but the losses may be equal here and there.
Still thinking about that.
Does it matter or not?


w.

=========================

Helmut , have a look at : http://www.palstar.com/en/tuners/

They have both manual and auto tuners , Perhaps a bit pricey but very
well constructed.
The local radio club here in the north of Scotland have a manual tuner
from them (my personal preference) working very smoothly .
The club bought it second hand ; still delighted with it after 5 years.

Frank , GM0CSZ / KN6WH in IO87AT