Dear Reg & Group:
You are correct. The value found on the blackboard is wrong. I was
too hasty. When sitting down, the answer becomes clear. Perhaps at my
age my brain needs to be seated in order to work correctly.
You hypothesis on what we did wrong may well be on point. No way to
know.
Thank you also for your suggestions about the use of your computer
programs.

I apologize for being too hasty and not following the advice I
continually give my students: check your work.

73 Mac N8TT
--
J. Mc Laughlin - Michigan USA
Home:

"Reg Edwards" wrote in message
...
"J. McLaughlin" wrote -
Dear Reg:
Lab equipment was not used. The lab was just a convenient
gathering
place with a blackboard. (No cigarettes in our lab or anywhere
inside
buildings.)
I suspect that we made an arithmetic error. Need to revisit
what we
did - much too late at night right now.
Thanks for the poke. 73 Mac N8TT
===================================

Mac, you didn't make an arithmetical error. I think you used the wrong
value
of terminating reactance Xt. Just a Sherlock Holmes deduction. ;o)

The value of terminating reactance which gives greatest possible
magitutude
of reflection coefficient is equal to the magnitude of Zo which is
equal to
|Zo| = Sqrt( Sqr( Ro) + Sqr( Xo) ).

As you have already deduced, maximum value occurs when the angle of Zo
is
equal to -45 degrees at which Ro = -Xo.

You incorrectly set the terminating inductive reactance XL equal
to -Xo
whereas XL should have been Sqrt( 2 ) times greater.

Now if XL is incorrectly made -Xo then the reflection coefficient
calculates
to Sqrt( 5). Which is where your 5 comes from.

Somewhere in these threads I made the exactly same error myself in a
non-calculating context where it was not likely to be noticed. The
pair of
errors, yours and mine, were probably just coincidental.

I do hope I have not just introduced another. ;o)

You appear to be in an educational establishment. There are two
programs
available from the website below which you may find useful. Download
in a
few seconds and run immediately programs COAXPAIR and RJELINE3. They
have
been written according to classical transmission line formulae,
generally
accurate to all figures displayed and may be used to check other work
which
uses only engineering approximations. There are others also of
educational
value.
----
=======================
Regards from Reg, G4FGQ
For Free Radio Design Software
go to http://www.g4fgq.com
=======================