I've used balanced line systems and tuners and baluns for years. In general the 135 ft center fed wire with your choice of balanced line, I use the vinyl covered 450 line from The Wireman, will work quite well.    I bring the line from the feed point of the antenna all the way to the operating position where it terminated into the 1:1 current balun.  Balanced line of this type is not near as difficult to use as many will allude.   Just use common sense.  Be sure to use lightning protection on the line before it enters the house.

Regarding baluns, keep in mind that one is not "matching the line" i.e. 450 ohms but the overall load Z.   Hence the better choice is the 1:1 current balun and not the 4:1 as many seem to believe.    Also, understand that the design and rating of baluns is based on a matched operating condition on both sides of the balun.  The 135 ft center fed wire with balanced feed is in most cases far from matched.  Thus the balun should be rated for much higher power than one would ever expect to run.  In my case, for legal limit power, my balun is rated at 10KW.    I do use BALUN DESIGNS products for my applications.  Be sure you select a balun which is designed to be used with a tuner as the voltage / current ratings will be different than those for matched applications.


What is a matched application for a balun?.  A good example is a folded dipole made of and fed with balanced line.  Typically the folded dipole Z is about 300 ohms regardless of line impedance. However, due to reasonable proximity to the earth, the impedance is more like 200 to 250 ohms.   Hence a 4:1 balun is the ideal choice providing an unbalanced feed to the transmitter of about 50 ohms.

Here is a good source for real world applications and performance of baluns. http://www.dj0ip.de/balun-stuff/

73

Bob, K4TAX


On 2/12/2018 9:29 AM, David Bunte wrote:
Alan -

I am pleased with results I have gotten with units from BALUN DESIGNS.
Their 1161 & 1171 models are possible choices. I know some folks would
rather spend less and build their own, but if that is not your preference,
then look at these models.

Best of luck.

73 de Dave - K9FN

On Mon, Feb 12, 2018 at 10:20 AM, Alan Lambert <a...@thelamberts.com> wrote:

MORE Info

As is I can work 80-10.  Some bands are better then others but I can
work them all with an SWR in the 1:1  to 1.3:1  range.    The fed line
is 450 window. The dipole is center fed.

On Mon, Feb 12, 2018 at 9:26 AM, Alan Lambert <a...@thelamberts.com>
wrote:
I could use a little advice

My present setup is;
KX3 > KPA100 (w/ ATU)  >   MFJ Balanced line tuner  >  ladder line fed
80m Inv 'V'

I run this with the ATU disabled and then manually tune.  Obviously
this is time consuming and makes band switching a pain so I am
considering removing the MFJ from the chain and start using the ATU.
Also I plan to add a KPA/KAT500 in the near future and my MJF tops out
at 300w so I has to go anway.


The questions are...

1) Should I do it? or will I see a significant performance decrease?

2) If I do  -  How should I make the ladder to coax conversion? I
think I need a "tuner balun"?

73
Alan
KN4BBC
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to dpbu...@gmail.com

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to rmcg...@blomand.net



______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com

Reply via email to