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


"Cato" wrote in message
oups.com...

Here's a question that I have often wondered about....

Let's say you have two of the same radio model... two Sony
7600GRs, two Kaito KA1102s, Eton E5s, Icoms, Kenwoods, etc. or
whatever...

How likely is it that they will both have the very same
sensitivity, selectivity, scanning sensitivity, (both stopping on the
same stations during a scan etc.) etc.??

Or will one of the two always be a bit better then the other? Both
a bit different??

Cato

On May 20, 10:50 am, "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

"Cato" wrote in message

oups.com...





Here's a question that I have often wondered about....

Let's say you have two of the same radio model... two Sony
7600GRs, two Kaito KA1102s, Eton E5s, Icoms, Kenwoods, etc. or
whatever...

How likely is it that they will both have the very same
sensitivity, selectivity, scanning sensitivity, (both stopping on the
same stations during a scan etc.) etc.??

Or will one of the two always be a bit better then the other? Both
a bit different??

Cato- Hide quoted text -

- Show quoted text -

Greetings: I certainly appreciate everyones opinion on my question
about the similarity or difference in reception of two radios of the
same manufacturer and model number.
It appears from the reply so far, that if one was to sit down
with any two such radios, and did a side by side comparison, it should
come as no surprise if there are small differences in reception
sensitivity, selectivity etc., and we should just accept that fact and
live with it.
But in most cases, as price and quality of components go up,
variations in reception between two radios of the same manufacturer
and model number should become less.
If any one else has any comments on this topic, I will certainly
be interested in reading them.

Regards, Cato

Cato wrote:

Greetings: I certainly appreciate everyones opinion on my question
about the similarity or difference in reception of two radios of the
same manufacturer and model number.
It appears from the reply so far, that if one was to sit down
with any two such radios, and did a side by side comparison, it should
come as no surprise if there are small differences in reception
sensitivity, selectivity etc., and we should just accept that fact and
live with it.
But in most cases, as price and quality of components go up,
variations in reception between two radios of the same manufacturer
and model number should become less.
If any one else has any comments on this topic, I will certainly
be interested in reading them.

Regards, Cato


Even if the radio are the same, or nearly so, another challenge is how to
make the measurements accurately. If you are scanning the band to see what
one picks up vs. another, unless the radios are on the same antenna, and
scanning frequencies at exactly the same time there will be observed
differences. This is just because any fading of any signal being revived
can affect the results. In comparing radios for real world results, you
will have trouble because the real world is constantly changing.

If you use lab equipment to make the measurements then you have a much
better chance at seeing differences in radios. At least your measurements
will be more consistent. However, then you would need to relate the lab
measurements to real world application.

I wouldn't be overly concerned about componenet tolerances. A good designer
would understand the component variations and either specify proper
components or design the circuit so that it is not that sensitive to
component variations. On many circuits the variations of components are not
that critical. (A few are, but many are not.) So generic comments about
component variation are not important. What is important is looking at
those component values that really do matter.

Alignment can matter significantly, especially in front end circuits. I've
seen lots of performance variation in AM radios because the tracking
between antenna, RF, and oscillator tuning was bad. If you look at the
circuits in many modern radios, you'll find designs that also minimize the
need for critical alignment.

craigm

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

KE4ODD wrote:

Are you near I-75?


About 10 miles or so. You can Email me for more info.


--
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

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

Yep,all depends on how they were tuned at the factory.You will probally
never find two same same cars tuned exactly alike either.
cuhulin

KE4ODD,I am bout half a mile North (of course South is always bestest)
of I-20 in the West side of Jackson,Mississippi.If you arrrr comin
thisaway,,,, bring wimmins with you,,,,,,
cuhulin
.................................................. .............
Weep no morrrre,,,,, my Ladddyyy,,,, ohhhhhh,,, weeppppp no morrrrre
forrrrr meeeee,,,,,,
.................................................. ............

In article ,
says...
KE4ODD wrote:

Are you near I-75?


About 10 miles or so. You can Email me for more info.





I'm closer than that. About 4.

BDK

Well,y'all get together and have a good time then.
All Hands on Deck movie is on Radio tb now
cuhulin