Sort of like fuel gages/sending units in cars,they can be off by quite a
bit.
cuhulin

In article .com,
"john" wrote:

Telamon wrote:
In article ,
BDK wrote:

In article m,
says...

David wrote:
On Fri, 05 Jan 2007 02:17:32 GMT, Telamon
wrote:

In article .com,
"john" wrote:


An exception would be radios that have a signal strength meter in
dBm,
which is an absolute scale.

Millivolts?

actually the palstar and the drake scales are in Decibels, while the
kenwoods scale is in Db at the top and millivolts at the bottom. also
before anyone asks my rf gain is fully clockwise on both the drake and
kenwood. the palstar doesn't have a rf gain control.



You can't even be sure identical radios will have the same S-Meter
readings, in most cases. The reading is pretty meaningless, except to
compare antennas, or if a preselector is used, to adjust for max
reading.

Nonsense.

--
Telamon
Ventura, California

so a stronger s-meter reading on one radio indicates the more sensitive
radio? in this case the kenwood?

It could. Like I posted earlier the readings would be comparable if the
radio has an absolute scale such as dBm instead of a relative scale.

--
Telamon
Ventura, California

How do you figure that this is nonsense? Typically, SWL radios would have
their S-Meter calibrated at 14MHz, so that S9 would equal 50uV. You are
correct when you mention S-Meters that are calibrated in dBm as being
absolute, as long as the system in in calibration for gain distribution,
etc. Receivers that have this function do provide for setting up the gain
distribution.
Now, the mystery continues.................what exactly do you mean by the
following statement?

"The RF gain control just sets maximum sensitivity of the radio and does
not change the gain of the radio so by turning all the way down you are
at the radios published maximum sensitivity. As you turn it up you are
desensitizing the radio."

The above statement, in quotes, is a new one to me. Could be showing my
young 54 year old age. The RF gain control only sets the maximum sensitivity
of the radio when it is controlling the bias to the RF stage in addition to
the I.F. stages, and this usually isn't the case, except for some of the
older tubed equipment.
Most RF gain controls USUALLY only set the gain of the I.F. stage. This has
nothing to do with the sensitivity of the system, if we are talking about
noise figure (I realize that you didn't mention that, so I won't put words
in you mouth on this one).
When you turn up the RF gain control, you don't desense the radio, but you
do give the AGC loop more gain. Maybe this is what you meant.

Pete

No.

"john" wrote in message
oups.com...

Telamon wrote:
In article ,
BDK wrote:

In article m,
says...

David wrote:
On Fri, 05 Jan 2007 02:17:32 GMT, Telamon
wrote:

In article
s.com,
"john" wrote:


An exception would be radios that have a signal strength meter in
dBm,
which is an absolute scale.

Millivolts?

actually the palstar and the drake scales are in Decibels, while the
kenwoods scale is in Db at the top and millivolts at the bottom. also
before anyone asks my rf gain is fully clockwise on both the drake
and
kenwood. the palstar doesn't have a rf gain control.



You can't even be sure identical radios will have the same S-Meter
readings, in most cases. The reading is pretty meaningless, except to
compare antennas, or if a preselector is used, to adjust for max
reading.

Nonsense.

--
Telamon
Ventura, California

so a stronger s-meter reading on one radio indicates the more sensitive
radio? in this case the kenwood?

"Telamon" wrote in message
...
In article .com,
"john" wrote:

Telamon wrote:
In article ,
BDK wrote:

In article m,
says...

David wrote:
On Fri, 05 Jan 2007 02:17:32 GMT, Telamon
wrote:

In article
s.com,
"john" wrote:


An exception would be radios that have a signal strength meter
in
dBm,
which is an absolute scale.

Millivolts?

actually the palstar and the drake scales are in Decibels, while
the
kenwoods scale is in Db at the top and millivolts at the bottom.
also
before anyone asks my rf gain is fully clockwise on both the drake
and
kenwood. the palstar doesn't have a rf gain control.



You can't even be sure identical radios will have the same S-Meter
readings, in most cases. The reading is pretty meaningless, except to
compare antennas, or if a preselector is used, to adjust for max
reading.

Nonsense.

--
Telamon
Ventura, California

so a stronger s-meter reading on one radio indicates the more sensitive
radio? in this case the kenwood?

It could. Like I posted earlier the readings would be comparable if the
radio has an absolute scale such as dBm instead of a relative scale.

--
Telamon
Ventura, California

If the radio has a meter that is calibrated in dBm, it should have identical
readings with another radio that has a meter calibrated in this manner.
But.....................it is possible that one of the radios can hear weak
signals better. Most of the radios that have an S-Meter calibrated in dBm
are millitary radios that are built to a certain spec. True, there may be
some differences in perceived signal quality, but generally, you can take a
Rockwell HF-2050, HF-8000 series, a Harris RF-590, Racal 6790, a WJ 8718,
and they will all sound very similar. The design spec is going to call for a
certain amount of gain, overload rejection etc. If the receiver doesn't meet
these specs, the manufacturer can lose the contract.

Pete

On Fri, 5 Jan 2007 10:51:03 +0000 (UTC), (Geoffrey
S. Mendelson) wrote:

Pete KE9OA wrote:

When you turn up the RF gain control, you don't desense the radio, but you
do give the AGC loop more gain. Maybe this is what you meant.

Wouldn't that make it an IF GAIN control?

A while back I read a review by the ARRL of a transciver and they brought up
an interesting point. Modern receivers have enough gain to "hear" the
normal background noise, so beyond that it really does not matter.

In my environment the noise is so high that almost anything can hear it,
my R-5000 often hears S9 level background noise on 40m and nearby SW
bands. (5-10mHz).

Geoff.
The RF gain control can be very handy for reducing noise to the point
where SSB voice comms sound extremely HiFi.

S-UNIT DISCUSSIONS AT URL:

http://www.ac6v.com/sunit.htm

CL

In article .com,
says...

Telamon wrote:
In article ,
BDK wrote:

In article m,
says...

David wrote:
On Fri, 05 Jan 2007 02:17:32 GMT, Telamon
wrote:

In article .com,
"john" wrote:


An exception would be radios that have a signal strength meter in dBm,
which is an absolute scale.

Millivolts?

actually the palstar and the drake scales are in Decibels, while the
kenwoods scale is in Db at the top and millivolts at the bottom. also
before anyone asks my rf gain is fully clockwise on both the drake and
kenwood. the palstar doesn't have a rf gain control.



You can't even be sure identical radios will have the same S-Meter
readings, in most cases. The reading is pretty meaningless, except to
compare antennas, or if a preselector is used, to adjust for max
reading.

Nonsense.

--
Telamon
Ventura, California

so a stronger s-meter reading on one radio indicates the more sensitive
radio? in this case the kenwood?



Now THAT would be nonsense.

Even supposedly identical receivers have differing S-Meter readings. You
can set the meter level to whatever you want. They supposedly are
normally calibrated to something like S-9 = 50 Microvolts. Supposedly.
But like any other adjustment, it can be off.

BDK

In article telamon_spamshield-2557A0.23063004012007
@newsclstr03.news.prodigy.net,
lid says...
In article .com,
"john" wrote:

Telamon wrote:
In article ,
BDK wrote:

In article m,
says...

David wrote:
On Fri, 05 Jan 2007 02:17:32 GMT, Telamon
wrote:

In article .com,
"john" wrote:


An exception would be radios that have a signal strength meter in
dBm,
which is an absolute scale.

Millivolts?

actually the palstar and the drake scales are in Decibels, while the
kenwoods scale is in Db at the top and millivolts at the bottom. also
before anyone asks my rf gain is fully clockwise on both the drake and
kenwood. the palstar doesn't have a rf gain control.



You can't even be sure identical radios will have the same S-Meter
readings, in most cases. The reading is pretty meaningless, except to
compare antennas, or if a preselector is used, to adjust for max
reading.

Nonsense.

--
Telamon
Ventura, California

so a stronger s-meter reading on one radio indicates the more sensitive
radio? in this case the kenwood?

It could. Like I posted earlier the readings would be comparable if the
radio has an absolute scale such as dBm instead of a relative scale.



And most SW and ham radios don't.

BDK

In article telamon_spamshield-F6523C.20501704012007
@newsclstr02.news.prodigy.com,
lid says...
In article ,
BDK wrote:

In article m,
says...

David wrote:
On Fri, 05 Jan 2007 02:17:32 GMT, Telamon
wrote:

In article .com,
"john" wrote:


An exception would be radios that have a signal strength meter in dBm,
which is an absolute scale.

Millivolts?

actually the palstar and the drake scales are in Decibels, while the
kenwoods scale is in Db at the top and millivolts at the bottom. also
before anyone asks my rf gain is fully clockwise on both the drake and
kenwood. the palstar doesn't have a rf gain control.



You can't even be sure identical radios will have the same S-Meter
readings, in most cases. The reading is pretty meaningless, except to
compare antennas, or if a preselector is used, to adjust for max
reading.

Nonsense.



Wanna bet? In most cases, side by side, identical models have different
meter readings. Usually it's slight, but sometimes it's huge. My JRC
NRD-515 has a "tight" meter. SSB audio can be clearly heard with the
meter at the left peg. Another 515 I had here for interconnect repair
was just as sensitive as mine, but the same signal would read S-2 or 3.
Same thing has happened with Kenwood R5000's, R2000's, and JRC NRD-525s.
(The first ones had a "spastic" S-Meter, later ones were cured of this)

In "pro" radios it might be true, but in hobby receivers, it's not true
that S-meters have any real correlation with signal strength in
comparing one radio to another.

BDK