[TenTec] Sample-to-Sample Variations

[John Rippey]

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