Posted by
Earl W Cunningham on
Apr 19, 2005; 4:45am
URL: http://elecraft.85.s1.nabble.com/XG1-Report-tp377307p377309.html
Ron, AC7AC wrote:
"Someone I was chatting with recently said he had tested the S-meters of
several receivers and found that 1 S-unit can equal anything from 3 dB to
more than 6 dB. I had always assumed the target was 6 dB/S-unit.
Apparently not so."
==========
Years ago, there were two "standards" for S-meters.
1) The Collins standard was 100 uV = S9 and each S-unit was 8 dB.
2) The Hallicrafters standard was 50 uV = S9 and each S-unit was 6 dB.
Manufacturers naturally adopted the Hallicrafters standard because the
Collins standard resulted in a stingier S-meter (higher S-meter readings
= better receiver, right? - No!!!!)
It is rare, with the new transceivers currently on the market to find one
that strictly adheres to the "standard". Virtually every tranceiver
today uses the 50 uV = S9 criterion, but the change per S-unit is much
less than 6 dB. This results in a substantial signal such as 1 uV (which
should read S3.5 on an accurate S-meter).not even budging the S-meter on
most receivers today.
In dB above S9, the S-meters most transceivers today seem to be fairly
accurate.
If all manufacturers complied with the "standard" to the letter, S-meter
readings would be more meaningful. As it is now, they are useful only
for reference readings such as when someone does an A/B check on his
antennas with you.
BTW, the values I posted originally were with the receiver preamp turned
off in all cases.
73, de Earl, K6SE
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