[TowerTalk] Re: TH7 Balun

[John Schaffner Jr. - K8LN]

Short story......My BN-86 on my TH7 needed replaced....Why not build my own,
so I did.  50 beads on teflon coax. On the antenna, the balun showed the swr
close to the chart, but too high on the bottom cw edge.  I checked the balun
into a dummy load and it looked great.  I even used the old BN-86 box to
mount my bead balun, I knew the leads were the right lenght.

W H Y??????  before the BN-86 failed the swr was 1.7 on 20     1.8 on 15
1.6 on 10 .......on the bottom of the band

With my bead balun
20 meters 2.0 to 1
15 meters  2.3 to 1
10  meters 1.7 to 1     The swr did drop quickly on all bands as I went up
in frequency, but to high for me.

Replaced my balun with the BN-4000 and the swr lowered,  the antenna works
now as before.


I believe the design on the TH7 requires the BN-86 or 4000 to perform.
Alittle costly, $88.00 for the 4000, but it works here.

GL
John
K8LN


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