On Mar. 9, Ed Hare, W1RFI, said:
"Alas, to my knowledge, no one doing testing looks at more than a sample of
one. The ARRL Lab ends up spending about 20-30 test hours on a major rig
and it really isn't possible to do complete testing on more than one. We do
sometimes look at a few other samples, from staff equipment to one borrowed
for a few hours from a local dealer. If we find anything interesting, it is
put up in the expanded test result reports. In the ones I have looked at, I
have seen significant variation in things like dynamic range and the like."
To underscore Ed's point, I just came across the January '92 QST review of
the Ten-Tec Argonaut II/Delta II transceivers. The ARRL lab found IP3 of
the Argonaut to be -11 dbM while the Delta II IP3 tested at +2 dbM. Other
indices showed considerable variations as well. The reviewer, Dave Newkirk,
noted that the receiver portions of the two rigs were identical. He went on
to say: "The receiver variations we found . . . reflect sample-to-sample
variations in a single radio product."
It was a coincidence that ARRL had two radios with identical receivers to
go over since, as Ed states, ARRL usually tests only one sample. So the
variations noted by Dave Newkirk would have gone unreported otherwise.
Were the significant sample-to-sample variations found by ARRL in 1992
limited only to Ten-Tec radios of that vintage, or to just that one
manufacturer? I go back to my recent experience vis a vis an FT-920 I had
vs the new Argonaut V during a CW contest and have to wonder how many
radios we buy actually attain the performance measurements in ARRL's tests
or the manufacturer's claimed specs? It looks as though the chances of our
getting a particular rig that meets those measures are uncertain at best.
Of course, reducing the uncertainty means tighter quality control which
translates into increased production costs. So, as buyers in a small market
we really cannot expect that, I guess.
73,
John, W3ULS
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