On Mon, 10 May 2004 06:22:29 GMT, "Jerry Martes"
wrote:

[Richard's good stuff snipped]

You can lead 'em to water, but you can't make 'em drink.

|
| I'm pretty sure I'll try to make it coax instead of "slab" like HP does
|it. I saw some 2 inch copper pipe at Home Depot today. They sell it in 5
|foot lengths for about $22.00. I'm OK with using only 1/2 wavelength for
|the slotted coax. I thought I might be able to 'get away with' using my
|scope for detecting the line voltages. I am wide open for learning that my
|approach has extremely difficult to solve problems. It all seems fairly
|easy right now.
| I was hoping to get a response from someone who either had built a line or
|knew of a publication on the pitfalls associated with making a slotted line.

Wes

Maybe I missed your point. I am trying to learn how to build a slotted
line for impedance measurements at 137 MHz. It would be real helpfull to me
to see how someone has built one at home. I'd sure appreciate hearing about
how you did it or what you know about how I could build one here in my
garage.
In fact, I'd like to know more about why a person (HAM type) would use the
slab line configuration in preferance to coaxial.

Jerry

"Wes Stewart" wrote in message
...
On Mon, 10 May 2004 06:22:29 GMT, "Jerry Martes"
wrote:

[Richard's good stuff snipped]

You can lead 'em to water, but you can't make 'em drink.

|
| I'm pretty sure I'll try to make it coax instead of "slab" like HP does
|it. I saw some 2 inch copper pipe at Home Depot today. They sell it in
5
|foot lengths for about $22.00. I'm OK with using only 1/2 wavelength for
|the slotted coax. I thought I might be able to 'get away with' using my
|scope for detecting the line voltages. I am wide open for learning that
my
|approach has extremely difficult to solve problems. It all seems fairly
|easy right now.
| I was hoping to get a response from someone who either had built a line
or
|knew of a publication on the pitfalls associated with making a slotted
line.

Jerry Martes wrote:
In fact, I'd like to know more about why a
person (HAM type) would use the slab line
configuration in preference to coaxial....

One advantage of slab line is that when you
drop something like a set screw into the
line, it falls right on through. (Been there,
done that).

I've used the HP slab-line instrument and
obtained very good, repeatable results with
it.

Others have commented that the big advantage
is ease of fabrication, and I have to agree.
Cutting a slot in a water pipe seems like a
lot of trouble for minimum gain.

Another alternative might be a trough line.
This is a slab line with bottom side closed
off. The advantage this would provide is a
means of supporting the center conductor
by means of a longitudinal, dielectric strip
between it and the bottom plate of the line.
A long piece of Teflon fiberglass would be
ideal for this. The line dimensions would
have to be adjusted to maintain a 50-ohm Zo.

Anyway, it's an interesting project. Good
luck with it.

Jim, K7JEB
Glendale, AZ