[CQ-Contest] Correctly measuring coaxial phasing lines with an MFJ 269

[Bob Shohet KQ2M]

Help!

It has been a few years since I have had to measure/cut a phasing line with the MFJ269
and I can't find my earlier notes.

I know the formula for length of one half-wavelength is 492/freq. x Vf.
I have a 170' piece of Buryflex Foam 50 ohm Coax

Questions:

In order to find the Vf I believe that I need to do the following:

1) Connect one end (through a PL259) of the coiled coax into
the MFJ269 and short the other end.
:
2) Measure for lowest Resistance and X (Impedance).

Following this procedure, I get the following minimum values 
of R of 12 and X = 0 at  

11.54 mhz
13.89 mhz
16.19 mhz
18.54 mhz  

Then dividing 170 by 6 (half wavelengths) and then dividing by (492/13.89), gives me a 
Vf of 0.800 close to what it should be.  Same result if I divide 170 by 7 and then divide by 
(492/16.19).  

I note that the dips occur about every 2.33 mhz and 6 x that = 13.98 mhz.

Is this correct?  Please advise,  Tnx & 73

Bob

Bob Shohet, KQ2M

kq2m at kq2m.com

www.rlsfinancialgroup.com



Bob Shohet, KQ2M