Dear Roy:
Very interesting!
It just did not occur to me to test. Now that the EMC book I have
been helping with is finally being printed (over ten years in the
crafting) I shall put an appraisal of the AEA on our list of activities.
It occurs to me that almost all of my use of the instrument has been
below about 10 MHz. At those frequencies, my suspicions probably were
not tripped by a discrepancy of half a degree (or smaller).
I did buy the instrument after at least one change of hands.
Thank you very much for the heads-up. I am shaking my head in
wonder that that property I never thought to check.
Warm regards, Mac N8TT
--
J. Mc Laughlin - Michigan USA
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"Roy Lewallen" wrote in message
...
A very capable engineering colleage of mine mentioned some time ago
that
an AEA he had purchased worked very well except for one thing -- the
reference point appeared to be inside the instrument. He said it was
as
though there were another length of line (about 5 cm as I recall)
inside. For example, measurement of a short circuit would indicate the
amount of positive reactance you'd expect from such a line. This might
not be too important for general purpose HF use, but would be a
problem
with some measurements, especially at high frequencies. It could be
removed by mathematical adjustment of the measurement results, of
course.

I mentioned this problem to the AEA folks at Dayton, not long after it
changed hands, and they might have fixed it. Do you see this
phenomenon?

I saw a similar thing when I spent a few minutes playing with the very
first model of Autek. I don't see this with my MFJ.

Again, the problem might have been fixed, but it's something to look
for, particularly on an older used unit.

Roy Lewallen, W7EL