Yes, post the pics, instructions, etc, please. Or email to
jocjoatmindspringdotcom, if you prefer. Many thanks.


John



"Jerry Martes" wrote in message
...
Ian

This line is showing a reflection of 1/10th of the incident voltage. I
am not inclined to refine the mismatch inherent with this construction at
this time. I dont require this line to be a "lab standard". I might try
to minimize the reflection later.
I tapered the line from 2 inch OD down to BNC in only about 3 1/2
inches.
And, I made no attempt to account for the teflon discs used to hold the
center conductor in the center of the line.
I dont even have enough stuff to evaluate the adapters from N to BNC. I
assume the reflection at 137 MHZ is acceptable to me. I sure cant do
anything about adapters from N to BNC anyway.

The slotted line does provide a flat voltage at the probe for all points
along the slot when it is terminated with the BNC 50 ohm load. Nothing I
have here is quality test equipment.
I'm impressed with the fact that I was able to measure load impedances
pretty accurately when they are outside the 1.5 to 1. VSWR circle.

It impresses me that a slotted line can be so easily constructed with
"Home Depot" stuff and still give alot of information on load impedance..

Jerry



"Ian White, G3SEK" wrote in message
...
Jerry Martes wrote:
Is there anyone interested in seeing pictures of a home made VHF
slotted
line?? I bought some copper pipe at Home Depot and built a 50 ohm
line
that seems to work very well.

Definitely! (I'm always a sucker for VHF test equipment.)

H-P used to make one of these, in the form of a very deep trough-line
with massively braced side castings. There was also a 'lite' copy in the
old ARRL VHF Handbook.

If you can minimize the residual SWR (the variation in probe readings
along the line when terminated in a precision 50R load) and other
sources of variability, then you'll be able to make highly accurate
vector impedance measurements at VHF.


--
73 from Ian G3SEK 'In Practice' columnist for RadCom (RSGB)
http://www.ifwtech.co.uk/g3sek