[R-390] Ray's Receiver Article

[Perry Sandeen]

Wrote>  Let's look at this logically. (AKA "the duck" test).  Mounting soapbox.

Wrote: Ooh, I decided to not get on my soapbox here anymore. Too many times I saw
obvious-to-everyone-else-parodies and offered simple physical measurements that prove them wrong,
and I got raked over the coals.<snip>

Sorry you got raked over the coals.  Regarding the coal-rakers someone on the list should have
"called ‘em out."  The list rules state that this isn’t a forum for a few bright smart-asses to
jerk anothers chain. 

Forgive me if I’m dumber that Forrest Gump after a frontal lobotomy.   I don’t "get" any math
parodies or parodies within parodies.  I fixed things, not design them so something may be going
on far over my head.  In fact, when some of these "parodies" were going on there seemed to be some
very less-than-courteous exchanges.  Tom, if you or someone on the list can lead me by the hand
step by step I certainly would appreciate that. 

What I did see was rather harsh comments to a respected ham author who wrote a rational, skilled,
tested article.  

Wrote: For some strange reason I never saw the original post that inspired all these posts. "Ray"
or "Roy" or ???<sniped>

The article was never posted on the reflector.  It was one I requested from members on the list. 
The title is "The R390A Receiver: A Milestone in HF Communications" by Ray W. Osterwald.  It was
published in Electric Radio magazine.  The published date isn’t on the copy I have.

The sensitivity numbers question came  up in: Part Three: "The Competition-Grade" R390a.  After
extensive tube, component substitutions and circuitry modifications.  Ray believes he has
measured: A) A MDS value of <-150 DBM which he qualifies as reaching his test equipment leakage
values.  B) 10 dB S/N ratio: .022 uV (parameters not stated).  C) AM sensitivity: .1uV at 4 Kc
I.F. bandwidth.  D) Single-tone blocking dynamic range: 123.5 dB.  E) Two-tone spurious-free
dynamic range: 101 dB at 20 Kc. Signal spacing and 85 dB at 10 Kc spacing. "Dynamic range
measurements are also limited by equipment leakage, so the numbers are probably conservative".

Some have posted that according to laws of physics that the 10 dB S/N ratio of .022 uV is not
possible.  I sure don’t know.

What I do know after re-reading the article several times is that Ray spent an enormous amount of
time, effort and expense to create a better radio AND was kind enough to write it and share it
with us.  After editing  the list chronologically for five years I’ve found that very few make
contributions at Ray’s level. 

Even if some of his numbers are off, why should he be crucified?  Which of us made a perfect
receiver?  Belly up to the bar fellows.  I’ll loan a stock R390a to be modified by anyone who can
prove on paper that he can do better than Ray.                 

We also must concede that his modified radio is miles ahead in performance than the stock R390a. 
Whether one wants to do that with their radio(s) is a personal choice. Regards, Perrier

PS.  On my next I’ll let you know how I really feel.


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