[ICOM] Sherwood Engineering test numbers

[Jan Robbins]

Hi John, et. al.,

There is NO MORE RELIABLE set of third-party measures of receiver 
performance ANYWHERE in the world  than Rob's.  Whether you, in your 
particular environment and set of needs, care about what he says, is 
entirerly your business; there are many good reasons for buying this 
radio or that (I own a 706MKIIG; it has a terrible receiver).  But NO 
ONE, including ARRL labs, comes close to his validity and reliability 
(if terms like "validity" and "reliability" are confusing, look 'em up 
before you comment on somebody's systematic measurements; they are 
well-known in the trade, one of the reasons why  no expert in 
receiver/.transceiver performance I have ever heard of does not check 
Rob's facts first). 

Many of us who've been involved with receiver performance and comparison 
for years (in my case nearly 50) START with Rob's figures.  Unless you 
can show us someone else who has BETTER methods of measurement AND more 
experience (Rob has 30+ years of it, over many more receivers than 
anyone else, as well as no vested interests in his comparisons), AND 
more systematically gathered data  that is in any way contradictory to 
his ( NO ONE, so far as I know, has ever been able to contradict his 
reesults with equal valid/reliable measures), we will take Rob's data 
anytime, and anybody else has to convince us otherwise--and not by 
"personal experience" comments about some particular radio.

I have had many of the radios Rob measures here in my shack, and have 
been fortunate enough to be able to run A/B tests on them.  In NO CASE 
did Rob rate a radio better than my comparisons showed (Icom 7800 with 
3khz roofing filter wins hands down).  But that was nothing more than my 
"personal experience."  A lifetime of training and research in 
statistical design, measurement, and anlysis convinced me long before I 
was able to make those in-shack comparisons that Rob was "the guy" in 
estimating (and comparing) receiver performance.

I aplogize for being so vehement.  I have spent my life in statistical 
data and analysis, and have been a ham since I was 15 (I'm now 63). No 
one knows receiver performance better than Rob Sherwood.

Vy 73 to all!   Happy Fall (at least it is here in Iowa!).  Jan N0JR


John Geiger wrote:

>How much stock does everyone place in the Sherwood
>Engineering receiver test numbers (www.sherweng.com)? 
>While I admit that the 2khz spacing is a much more
>useful measurement than the 20khz the ARRL has used
>for a long time, and I believe that Rob Sherwood knows
>what he is talking about when he tests receivers, I
>have a hard time believing some of his numbers.
>
>For example, he measures the 2khz IMD DR for the Icom
>706MKIIG at 74db. This places it right in line with
>the PROII and PROIII at 75db, and better than the
>756PRO (71db), FT1000D (69db), FT1000mp MK V (69db),
>and the Icom 746 (70db).  Now I have owned many of
>these radios, and I did not find the 706MKIIG to have
>that good of a receiver, definitely not better than
>the 756PRO or the Yaesu FT1000 series.  It overloaded
>pretty bad under contest conditions.  What am I
>missing in his measurements, that makes the 706MKIIG
>look so much better than these other radios?
>
>73s John W5TD 
>
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