Posted by
VR2BrettGraham on
Jan 22, 2011; 2:27am
URL: http://elecraft.85.s1.nabble.com/Fw-K3-K144XV-P3-Signal-Strength-Readings-tp5937006p5950027.html
A lonely G3UCK said, seemingly talking to himself:
> No comments from Elecraft or elsewhere on my posting below, so perhaps my
> conclusions are wrong or maybe I'm just expecting results too quickly.
> Any
> views anyone?
I have wondered about this IARU R1 Recommendation about S-meters. In
order to comply, it means transverters have to be 20 dB hotter on the
output for the same input signal level, as the transverter is usually
used with a radio where S9 is -73 dBm & not -93 dBm.
Or all radios have some means to make the S-meter seem 20 dB "hotter"
when used with a transverter. I am not aware of any that do. None that
I have do this, so I guess transverters are that way.
For radios that straddle R1's -73/-93 dBm S9 boundary, we should also
see signs of compliance with the Recommendation. A quick check of one
such reasonably current product from one of The Big Three I own that I
do not recall acting like it complies with the Recommendation shows that
indeed, it does not. It is has one of these new-fangled "light bulb"
S-meters, where S1 is set to light up at different levels on 70cm, 2m,
6m, 10/20m & 80m (total spread between them: 9 dB). S9 is set to 31,
31, 28, 25 & 22 dB above S1 on those bands, respectively. From S9 to
S9+60 is 60 dB.
The narrative for this Recommendation, found at
http://iaru-r1.org/index.php?option=com_remository&Itemid=173&func=download&id=178&chk=b8ce4681621e009741d6eabdce8eef20&no_html=1"At the IARU Region 1 Conference in Hungary 1978 the need for a
harmonised standard for the "S-meter
scale" was expressed and a proposal was accepted for publication in
society journals. The essential
recommendation was 1 S-point is 6 dB . At the Brighton Conference in
1981 the recommendation was
formally adopted as a standard for amateur radio equipment manufacturers.
At the 1990 Torremolinos conference an amendment was adopted which
reconfirmed the -93 dBm
reference level for frequencies above 144 MHz, but no statement was
issued for the bands between 30
and 144 MHz.
Although not explicitly stated the implication of the recommendation is
that on VHF and higher frequencies
the S-meter will deviate on the thermal noise only ( S2 in 3 kHz
bandwidth, S3 in 12 kHz bandwidth).
Although the recommendation is not too complex it seems to be rather
difficult to implement by
commercial manufacturers."
A good Recommendation would make sense on its own - not need a narrative
& perhaps not one that says what this one does. A good Recommendation
would be followed & might also be something that we could look back at &
see why it was we are told things should be done that way. This was
just a quick look, but my impression is that if S-meters are to work
this way, it should be like an IARU bandplan & apply to just R1.
73, ex-VR2BG/p.
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