[QCWA] Baluns Part 8 (Mark McGilvray)

[Jeffrey D Angus]

On 8/18/2012 11:44 AM, Mark wrote:
> I have use 300 ohm ladder line 50ft length into
> a W9INN BALUN BOX MODEL MFJ-912 with a 6ft
> RG-213 Coax and it works great.
>
> 73
> Mark/k5mrk
 From MFJ "Giant 2-core 4:1 balun wound with Teflon wire
connects to high voltage ceramic feed-thru insulators."

Without taking one apart, I am fairly certain that they MFJ
balun you mention is a 4:1 choke type. Because this is a
4:1 transformation, this introduces a built in 1.5: mismatch
regardless of what ever else is going on with the antenna
(load).

That it works "great" is a testament to the ability of the
tuner to deal with not only the load presented by the
antenna, but the additional transformation of the 6 foot
section of mismatched coax.

Jeff-1.0
wa6fwi