Is there a standard RF input level per "S" Unit?

If so, please post the location. Thanks.

"Avery Fineman" wrote in message
...
Is there a standard RF input level per "S" Unit?

If so, please post the location. Thanks.


There is no "standard". You will often see it mentioned as 6 db of power
per S-unit. At one time 50 microvolts into the receiver was S-9 and you
went down 6 db of power per S-unit from there. I doubt that any receiver
will follow that so called "standard".

The rule voor 50µV = S9 does still exists, this is voor HF, @50 Ohm input
impedance at receiver.
"They" (radioamateurs) use another rule for VHF.
It's in the software MultiCalc, Google will find the adres, it's for free.
Official or not, if everyone use this rule then it is a standard for me.
Greetings Bas.


"Avery Fineman" schreef in bericht
...
Is there a standard RF input level per "S" Unit?

If so, please post the location. Thanks.

I find that most of them seem to sort of follow the rule that 4uV is S9, 3dB
down is each S-Point, that's for VHF/UHF.

Sam

"bviel" wrote in message
...
The rule voor 50µV = S9 does still exists, this is voor HF, @50 Ohm input
impedance at receiver.
"They" (radioamateurs) use another rule for VHF.
It's in the software MultiCalc, Google will find the adres, it's for free.
Official or not, if everyone use this rule then it is a standard for me.
Greetings Bas.


"Avery Fineman" schreef in bericht
...
Is there a standard RF input level per "S" Unit?

If so, please post the location. Thanks.






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On Fri, 26 Nov 2004 05:56:42 +0100, "bviel" wrote:

The rule voor 50µV = S9 does still exists, this is voor HF, @50 Ohm input
impedance at receiver.
"They" (radioamateurs) use another rule for VHF.
It's in the software MultiCalc, Google will find the adres, it's for free.
Official or not, if everyone use this rule then it is a standard for me.
Greetings Bas.


"Avery Fineman" schreef in bericht
...
Is there a standard RF input level per "S" Unit?

If so, please post the location. Thanks.




On HF there is no need for an S-meter standard because it seems to be
the rule to give report 59. If you don't you soon have a bad
reputation of giving wrong reports

I installed an MC3356 log detector and calibrated it for S9 = 50uV.
For about 15 years there has never been any signal of S9+30dB, most
reports should be around 539....579, but again you logging problems,
because everybody expect 599 and some log programs don't include the
reports, they are supposed to be 599

73
Jan-Martin
LA8AK (ex-G5BFV)
---
J. M. Noeding, LA8AK, N-4623 Kristiansand
http://home.online.no/~la8ak/c.htm

On HF there is no need for an S-meter standard because it seems to be
the rule to give report 59. If you don't you soon have a bad
reputation of giving wrong reports

A signal doesn't have to be S9 to be heard 5 by 9.
I would usually tell the guy on the other end what
the S meter read, and also how readable he was.
When the band is quiet QRN wise, I could honestly
give a 59 report to someone hardly moving the meter.
OTOH with heavy QRM+QRN someone could be pumping
30db over and still be a rough copy.

"Ken Scharf" wrote in message
...
On HF there is no need for an S-meter standard because it seems to be
the rule to give report 59. If you don't you soon have a bad
reputation of giving wrong reports

A signal doesn't have to be S9 to be heard 5 by 9.
I would usually tell the guy on the other end what
the S meter read, and also how readable he was.
When the band is quiet QRN wise, I could honestly
give a 59 report to someone hardly moving the meter.
OTOH with heavy QRM+QRN someone could be pumping
30db over and still be a rough copy.

Then you are still passing out wrong signal reports. The first one would be
something like 5 x 2 or 5 x 3 and the second one would be 2 x 9 or 3 x 9.

The first number is how well you can understand what is being said and the
second is how strong the signal is.

Ralph Mowery wrote:
"Ken Scharf" wrote in message
...

On HF there is no need for an S-meter standard because it seems to be
the rule to give report 59. If you don't you soon have a bad
reputation of giving wrong reports


A signal doesn't have to be S9 to be heard 5 by 9.
I would usually tell the guy on the other end what
the S meter read, and also how readable he was.
When the band is quiet QRN wise, I could honestly
give a 59 report to someone hardly moving the meter.
OTOH with heavy QRM+QRN someone could be pumping
30db over and still be a rough copy.


Then you are still passing out wrong signal reports. The first one would be
something like 5 x 2 or 5 x 3 and the second one would be 2 x 9 or 3 x 9.

The first number is how well you can understand what is being said and the
second is how strong the signal is.


If you mean the actual strenth of the signal in uv at the antenna,
then you are correct. If you mean the strength of the signal in your
EARS that's another story. One is an actual measurement, the other
is subjective. (How would you measure signal strength if you
were using a receiver without an s meter, such as an old SW3?)

Avery Fineman wrote:
Is there a standard RF input level per "S" Unit?

If so, please post the location. Thanks.

There is an IARU recommendation, which originated in Region1
(Europe/Africa) and I believe has been adopted by IARU world-wide.

The Region 1 recommendation is:
http://www.algonet.se/~k-jarl/ssa/IARU/smeter.html
Google should also bring up the full technical paper behind this, and
probably the current IARU recommendation. ISTR there's something on the
ARRL website too.

The 1990 Region 1 recommendation simply states that:

STANDARDISATION OF S-METER READINGS
1. One S-unit corresponds to a signal level difference of 6 dB,

2. On the bands below 30 MHz a meter deviation of S-9 corresponds to an
available power of -73 dBm from a continuous wave signal generator
connected to the receiver input terminals,

3. On the bands above 144 MHz this available power shall be -93 dBm,

4. The metering system shall be based on quasi-peak detection with an
attack time of 10 msec +/- 2 msec and a decay time constant of at least
500 msec.


IARU functions very much like an
Entmoot...only...not...quite...so...hoom...hasty. In 2004, they are just
starting to think about the gap between 30MHz and 144MHz:
http://home.hccnet.nl/a.dogterom/Vie...4_19_Chair.rtf


But all the other comments about S-meters are true as well: that no
S-meter actually conforms to this recommendation; that it makes no
practical difference; and that hardly anyone cares.

There's a very good web page with lots of practical measurements, at:
http://www.seed-solutions.com/gregor...rimentation/SM
eterBlues.htm


--
73 from Ian G3SEK 'In Practice' columnist for RadCom (RSGB)
http://www.ifwtech.co.uk/g3sek

In article , "Ian White, G3SEK"
writes:

Is there a standard RF input level per "S" Unit?

If so, please post the location. Thanks.

There is an IARU recommendation, which originated in Region1
(Europe/Africa) and I believe has been adopted by IARU world-wide.

Thanks, Ian, and thanks to all others responding. A plus to Reg
Edwards for mentioning the U.S. military receiver specs which
I was hunting around for but could not find. :-(

Reason for asking is that I'm going to make a meter scale for a
little receiver a-building, using (nobody blanch, please) MS
Paint from a scanner (accurate 1:1) digitization of the removed
meter scale plate. I've done that with a normal-expanded scale
meter on a 120 W variable autotransformer box used on the
bench. MS Paint will do color in 256-color mode for a better
appearance. An inkjet printout on heavy photo paper stock
results in a fine-grain scale sturdy enough to replace the stock
plate in a little 2 1/2" microammeter.

Note: That works only on the old-style meters with removeable
scale plates (screw mounting type). Newer snap-together plastic
case types aren't recommended for that.

That method started on wondering how accurate an ordinary
scanner was...solved by scanning a 6-inch metal scale, printing
it, then comparing the real scale to the printout. By eyeball it
was dead-on! :-) I've done that for drill guides on PC board
stock used for both circuit boards and small enclosures since
and find it very time-economical. Machine shop accurate it isn't
but then my home shop drill locations were never that accurate
using scribe marks on "dye-chem" blue lacquer painted on
aluminum. :-) [rubber cement holds the paper printout on the
work, removes easily afterwards]