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MY S METER IS BIGGER THAN YOUR S METER

Never get too pedantic about S Meter readings. These must be the most talked about topic on the air. True to say the figures "over nine" lend importance to a report and the graphic use of red in some designs make the listener feel something really special - even somehow dangerous, possibly harmful to the set - is going on, but they are for the most part only a guide. Have fun with them by all means but please do not hold them up as gospel.

Only in a few classic designs has the law on which the S Meter scale is based been fully interpreted. Even then the antenna has to be an EXACT match to the input impedance of the set with no compromises. Radio hams exchanging signal reports should realise that to be of any value, the two operating stations must be identical from the ground up. Quite literally, as soil conductivity around an antenna is a vital part of its characteristics. Having said all that, what kind of voltages exist at the antenna socket?

S Meter reading

Antenna PD

SINPO

Perceived Strength

S9+60dB

50 millivolts 

5

Acutely strong

S9+50dB

16 millivolts 

5

Acutely strong

S9+40dB

5 millivolts 

5

Extremely strong

S9+30dB

1.6 millivolts 

4

Extremely strong

S9+20dB

500 microvolts 

4

Extremely strong

S9+10dB

160 microvolts 

3

Extremely strong

S9

50 microvolts 

3

Very strong

S8

25 microvolts 

3

Strong signals

S7

12 microvolts 

2

Moderately strong

S6

6 microvolts 

2

Good signals

S5

3 microvolts 

2

Fairly good signals

S4

1.5 microvolts 

2

Fair signals

S3

0.8 microvolts 

1

Weak signals, DX

S2

0.4 microvolts

1

Very weak signals, rare DX!

S1

0.2 microvolts 

 

Barely usable signals 

Where the signal is acutely strong, report the level but listen on the attenuator. With signals this strong, there is no need for the real performance of a communications receiver so avoid overload distortion with a prod at the ATTN button.

The SINPO levels are my invention. They are "marks out of five" for Signal strength, Interference, Noise level, Propagation path and an Overall rating.

Your scribe only reports "fair", "good" or "excellent" since the modern radio memory system is the station log and whatever is held in there has to have some entertainment value.

However the hobby seems to demand lots of numbers, so here are a few more in a marks-out-of-five rating for readability;

R Readability
R5 Perfectly readable
R4

Readable with little difficulty

R3 Readable with considerable difficulty

R2

Barely readable, occasional words audible

R1

Unreadable

So, a "five and nine" report is an excellent signal, something like a "one and two" isn't worth staying up for. We do enjoy hearing reports of ones and twos on 80m, the chap going on to say, "but I don't care what the meter says - I'll give you a five and eight because I heard every word!"

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