Well .. seems like the picture shows 48 dB makes S-9, or 5 1/3 dB per S
Unit..... which as I seem to remember back when learning this stuff, that 5
point something dB was accepted as the S Unit, even though it could -- and
would -- vary between manufactures.
Eventually, along about the 70s, became accepted as doubling your output
power would increase an S Meter reading by 1/2 S Unit, or 3dB. Finding a
receiver with an anywhere near linear meter was difficult, and was usually
said to just use the meter readings as a reference, not a scientific fact.
----- Original Message -----
From: "Guy Olinger, K2AV" <firstname.lastname@example.org>
To: "TowerTalk" <email@example.com>
Sent: Tuesday, August 06, 2002 12:07 AM
Subject: [Towertalk] S units have been 6 db for a long time
> Have a look at the meter (carrier level indicator) on this photo of an
> excellent condition pre-WW2 RME 69.
> Calibration is 0-72 db in six db steps, with a lower scale clearly in
> S units, going 1-9 every six dbs.
> The photo is good enough that you can read the "RADIO MFG ENGINEERS"
> and the PEORIA, ILLINOIS, U.S.A. in the meter face fine print.
> I think the RME 69 is mid thirties. This is back when you had to read
> the manual to see what the knobs did. Notice the complete lack of
> stamped lettering around the knobs.
> So the IDEA of an S unit being 6 db is quite a bit older than some
> have put forward. Whether this one is any better than modern receivers
> at displaying real signal levels is anyone's guess.
> I'm intrigued as to what process was used to create the dial
> calibration for the main tuning. Photo offset of a hand-drawn master?
> This is part of an EBay auction at
> I watch the ads for the occasional excellent photos of these old
> pieces of equipment.
> 73, Guy.
> Self Supporting Towers, Wireless Weather Stations, see web site:
> Call 888-333-9041 to place your order, mention you saw this ad and take an
additional 5 percent off
> any weather station price.
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