[TowerTalk] Idea for the 259B ?

[Curtis, David B]

Well, actually, if you wanted to unplug the antenna end of the feedline
momentarily and do a TDR measurement, you could easily find out length*VF by
looking for the reflection of the open circuit.  You would also need to (and
should be able to) calculate the feedline loss at the same time. (A real
feedline with loss is a spiral on the Smith chart, not a circle which
represents lossless feedline.)

Sounds like SMOP to me.  (SMOP == Small Matter Of Programming...)

73, Dave N6NZ

-----Original Message-----
From: Jim Reid [mailto:kh7m@hsa-kauai.net]
Sent: Tuesday, May 23, 2000 4:34 PM
To: W8JI@contesting.com; towertalk@contesting.com
Subject: [TowerTalk] Idea for the 259B ?



It has been wondered: 

Could  the next iteration of the MFJ-259 (maybe the
 MFJ-269 ?)  be designed to read the ACTUAL impedance
 at the antenna terminals, not just at the shack end of the
 feedline?  In other words, add a chip programmed to do the
 Smith chart calcs and display the result.  I bet it will be
 coming soon.

But maybe the actual feedline length would also have to be
known,  probably could not be a random unknown.  And the
259B  could not be used to determine the length,  as the line
would be terminated in who knows what Z,  hi.

Well,  it was a thought.

73,  Jim,  KH7M



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