On May 27, 7:13 pm, "Michael A. Terrell"
wrote:
labtech_one wrote:

Everything made, no matter how hard we try will have small differences, no 2
resistors will have
exactly the same value, thats why they have a rating like 20%, 10%, 5%
tolerance they are within,
say 10% of the rated resistance ( a 100 ohm resistor may be 90 ohms or
110 ). With that in mind,
and the number of resistors in a radio, there can be 1,000's or millions of
combination. And every
component in the radio is the same way ( capacitors, transistors, wire,
coils, diodes, etc )

So no 2 radios will EVER be exactly alike, they will be ( like their
components) within 20% or 10%
of a rated 'projected' radio design. More expensive radios use closer
tolerence components so they
will have much closer performance, but cheap-o's using 20% tolerence parts,
you may be lucky if they
are even similar

The old 50%, 20% and 10% are obsolete tolerances.

Since almost everything made today uses surface mount, 5% is the worst
tolerance you'll see. 1% is common, .1% and .01% are seeing more use in
critical circuits. We were using 1% resistors and capacitors in 95% of
the locations, and 1% capacitors in critical RF, IF and Video circuits.
(Audio was treated as narrow band video).

In fact, the 1% resistors were cheaper in 2000 than the 5% they
replaced.

--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida- Hide quoted text -

- Show quoted text -

Again I would like to thank everyone for their reply to the question.
So it seems, that very cheap identical radios have a good chance of
having variations in performance, because of cheap, low quality
components. Components can vary greatly in quality just by chance. One
cheap inexpensive radio might be a relatively great performer, and a
second of the same radio might be very poor in performance. Luck of
the draw.
And very expensive, very complicated radios (like the ICOM
R9000) might also have some minor differences in performance between
two or more of them, because of their complexity. As Bob stated, " I
believe Rob Sherwood once said that the Icom R9000 was so complex,
that most samples he saw had at least some minor issue or other. "
And radios somewhere in the middle in price and complexity
would have on the whole less variation, and perform much more the
same.
All under identical testing conditions of course.

Thanks again everyone, but as before, if anyone has more to add
to this thread, feel free,

Cato