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-   Antenna (https://www.radiobanter.com/antenna/)
-   -   6:1 balun (https://www.radiobanter.com/antenna/226105-6-1-balun.html)

Ralph Mowery July 25th 16 07:45 PM
6:1 balun
 
In article , says...



I don't understand. The antenna is 300 ohms from 80 to 10 meters? This
boggles the mind.

No, the antenna is not 300 ohms from 80 to 10 meters, but it is
somewhere around that for most of the ham bands from 80 to 10 meters.

The main thing for me is to get it below a SWR of 3:1 or so over the ham
bands. Many of the OCF antennas will not do 5 MHz, 10 MHz, or 21 MHz
with a low swr. That is ok with me as I don't work 10 and have a
triband beam that covers 21 MHz. If I really want to work the few
frequencies at 5 MHz I can always use my manual tuner and just take a
hit on the losses which probably are not too much at that frequency and
feeding the antenna with 100 feet of some rg 8 type coax.

The antenna I put together for field had a very low swr (below 2:1) on
most bands but 15 meters where it was about 5:1. That was at 25 or so
feet. The same length antenna at 50 to 60 feet at my house and the swr
is much higher. That is the reason to go from a 4:1 to a 6:1.

When it cools off some I will put the now completed balun on the antenna
and see what it does.




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Ralph Mowery July 25th 16 09:55 PM
6:1 balun
 
In article ,
says...

In article t,
Ralph Mowery wrote:

Yes, I want a 6:1 balun. It is for an off center fed antenna that is up
around 50 to 60 feet. To be used from 80 to 10 meters. I have had one
up for a number of years and used a 4:1 bought balun that is suspose to
be good for 5 KW. It heats up and the SWR goes up after several minutes
of SSB usage with about 1200 watts. Works fine at 600 watts. My
research seems to incicate that at that height a 6:1 is a beter match.

Since the feedpoint impedance of an OCF is a function of the feedpoint
location (how far off-center it is), could you reduce the impedance
towards 200 ohms and use a 4:1 balun by simply moving the feedpoint
some distance towards the center?

While that sounds like a good idea, it also shifts the frequencies where
the SWR is low, especially when trying to get it to work with low swr
over most of the ham bands below 30 MHz.

I could lower it to about 25 feet and use the 4:1 but I want it as high
as I can get it which is about 50 to 60 feet now.
Mostly flat as it is suported on the ends and near the middle around the
same heigth.

Part of the heigth is so I can use the Carolina Windom idea of using a
voltage balun and dropping from the feed point about 20 feet. and
putting in an in line choke. I don't know if it will work as they
say,but suspose to give some vertical radiation along with the
horizontal.



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