[TowerTalk] Why the inconsistent line impedance

[K8RI]

On the page I've included two traces.
The top trace contains a coax to the AV640 with a second trace where a 6 
turn choke on 5 2.4" 31 mix cores are mounted about 4 feet below the 
AV640 feed point.  The second image shows the green trace where the line 
runs through the AT5K bypass line. The line to the AV640 consists of 
about 60 feet of LMR600, an N-type male, and adapter and a UHF PL259 on 
the end of about 100 feet of LMR 400 with the same choke mounted below 
the feed point.  You can see the three connectors as a slight dip in the 
impedance line.

http://www.rogerhalstead.com/ham_files/TDR1.htm

Can anyone tell me why the impedance is a sloping or irregular line 
where all the single band antennas have a very straight trace with the 
only blips and dips being connectors, the amp bypass, and the tuner bypass?

These appear to be indicative of a change in tuning on 6-meters and 10 
meters.

73

Roger (K8RI)