[Elecraft] S-Meter Calibration

Mon Feb 11 14:17:02 2002

Ron's is an excellent point.  Signal reports, at least according to the
RS(T) system, were probably never intended to be made according to an
S-meter.

It brings out a pet peeve... Here is the "official" definition of RS
reports:

Readability

1--Unreadable
2--Barely readable, occasional words distinguishable.
3--Readable with considerable difficulty.
4--Readable with practically no difficulty.
5--Perfectly readable.

Signal Strength

1--Faint signals, barely perceptible.
2--Very weak signals.
3--Weak signals.
4--Fair signals.
5--Fairly good signals.
6--Good signals.
7--Moderately strong signals.
8--Strong signals.
9--Extremely strong signals.

...and here is how it seems most hams interpret it, with tongue in cheek:

Readability

1--(not used)
2--(not used)
3--(not used; could be taken as an insult)
4--Barely readable.  Do not use if other station has given you a "good"
report.
5--Perfectly readable, or readable with considerable difficulty.
Use "5" if signal is unreadable due to interference, since that's not his
fault.

Signal Strength

1--(not used)
2--(not used)
3--(not used)
4--(not used)
5--(not used; could be taken as an insult)
6--Faint to very weak signals.
7--Weak signals.
8--Fair signals.
9--Good to strong signals, or signals of any strength in contests or DX
pileups.

On phone, be sure to indicate how many dB the S-meter swings above the "9"
mark, and whether the meter is "Scotch" (S) or "Very Scotch" (VS).

If readability or signal strength varies, always use the highest numbers.
Increase both numbers somewhat if other station reports 599.
Be sure to say "thanks" for "FB" reports such as 589 or 599.

-----Original Message-----
From: Ron D' Eau Claire <[email protected]>
To: [email protected] <[email protected]>
Date: Monday, February 11, 2002 1:18 PM
Subject: RE: [Elecraft] S-Meter Calibration

>Jonathan, K1RFD, wrote:
>
>> Incidentally, there is the widespread belief that one S-unit
>> equals 6 db.  I
>> understand that this is now the exception rather than the rule, and most
>> S-meters now run 4 db or less per S-unit.
>>
>> After all, the higher the S-meter reads, the better the receiver,
>> right?  :>
>
>
>I believe the 6 dB/S-unit came from some of the receiver manufacturers of
>the 50's or thereabouts. A manufacturer needs something to have the
assembly
>line set things to and that seems to have been what many or most of them
>settled upon. Even then, many (most?) receivers had widely varying
>sensitivity over the HF range so the 'calibration' was only good on the
>frequency the factory used.
>
>Ever since before I went to school, 3 dB was used as the "minimum
>discernable change in a signal level by ear in a typical radio
>communications environment with some background noise and fading due to
>propagation". So it seemed to make some sense to define an S-unit as twice
>that level or something that would be obviously noticed under most
>conditions.
>
>Given that the RST system defines "S" as the signal strength on a 1-9 scale
>as measured by the operator's ear, I calibrated my K2 S-Meter with absolute
>accuracy. I tuned in a signal that I judged to be "S-9" and adjusted the
>meter to indicate S-9. A few other checks and adjustments on signals at S-5
>and S-3 completed the calibration. If I ever want to check the calibration
>on the K2 to see if the S-Meter is still accurate, all I have to do is tune
>in a signal and see if the meter agrees with my ears. If not, the S-meter
>needs re-calibrating <G>.
>
>Ron AC7AC
>K2 # 1289
>
>
>
>_______________________________________________
>Elecraft mailing list: [email protected]
>You must be a list member to post to the list.
>Postings must be plain text (no HTML or attachments).
>See: http://mailman.qth.net/mailman/listinfo/elecraft
>Elecraft Web Page: http://www.elecraft.com
>