Topband: Warning MFJ 269 (and maybe 259) manuals (distance to fault)

[Tom Rauch]

> The DTF method described in the manual does not always
work well as it
> tells you to switch to the next lowest band rather than
finding the
> lowest X for the next lowest Z, which could be in the same
"band". At
> first I got very unrealistic values until I tried to
simply find the
> next lowest Z rather than the next lowest Z in the next
lowest band as
> you mentioned. In any case, I thought the results were
impressive. Now
> 2500 ft.....I don't even have space in my backyard for
that even when
> it's coiled up. :)

Within the last two years or so MFJ must have revised the
MFJ-269 manual and changed what was a correct procedure to
an incorrect procedure for checking distance to fault! That
makes me leery of the entire edited manual of course.

The 269 manual on the MFJ web site as of this moment is OK
(at least as far as the distance to fault working), the
original manual was correct, but the one KR1ST e-mailed me
is totally messed up!

To measure distance to fault or length of stubs the correct
procedure is to tune for minimum R on the meter while
watching for X to be as low as possible. You then push  the
gate button to enter that frequency. You can then tune UP or
DOWN from that spot to the very next frequency where the
impedance meter reading is minimum watching X to go to zero
or the lowest possible reading. You then push the GATE
button again.

You DON'T go to the next band and look around for a dip, you
go to the NEXT DIP UP OR DOWN in frequency from the initial
dip frequency.

I'm not sure if this problem is only in this analyzer manual
or all of them, but since it can mess people up when working
with antennas I think it is worth calling attention to.

73 Tom