dykesc wrote in
:
On Jun 4, 4:33*pm, Owen Duffy wrote:
I have thought about this in the past, mainly the prospect of a relay
switched autotuner that reported a calculated load Z based on the
found matching solution, but I concluded that it was not likely to be
of reasonable accuracy over the tuner range.
Probably would be as accurate as any other gear we can afford Owen.
I doubt it. Again it relates to the loss characterisation of the
components. If you could do that, the device could also calculate its own
efficiency... now that would be a feature that would kill the market!!!
I'm going to suggest that MFJ make that a feature on an auto tuner. I
See above.
....
There is at least one instrument for the
ham market that purports to make such measurements at normal
transmitter power. IIRC, R&S used make a commercial product, but it
wouldn't have come cheap.
I looked on the R&S site. The only thing I found was a "Field Fox"
analyzer selling for $7,599.00. It is the cat's meow, but guess I'll
have to stick with my 259B.
http://www.telepostinc.com/ for a ham instrument (LP-100).
There is at least one other low level antenna analyser that
represents that it is less affected by interference than the '259B.
Which one Owen.
http://w5big.com/ AIM4170.
The operative word in my statement was "represents". As to whether it is
actually better, and whether it is adequate, you will need to depend on
owners. The badging of the instrument as AS doesn't add value for me.
Problem is that many of the people using these things see them as a magic
bullet and don't actually understand transmission line fundamentals,
which questions their opinion of the performance of the instrument.
That has become very obvious to me.
We haven't dispensed with the need for a good reflectometer in capable
hands, or is it just that we haven't dispensed with the need for capable
hands?
BTW, for referring measurements at one place to another, TLLC at
http://www.vk1od.net/calc/tl/tllc.php may be of interest. It would be a
challenge to incorporate those calcs in a small 8 bit microcontroller,
their capacity and performance on logs, hyperbolic cosines, etc is the
issue. Probably why most of the tools that do this, use a client on a PC
to do the calcs and presentation.
Owen