On Tue, 30 Jan 2001 23:36:06 +0000, Stewart Bryant
<[email protected]> wrote:
Why do the manufacturers still bother with S units.
Why don't receivers just measure dBuV or dBm at the antenna?
While it certainly would be nice to have a dependable dB scale on the
meter, I do not see the point of calibrating the scale to some antenna
terminal reference level on LF. On UHF/microwave, dbuV or dBm scales
make some sence, since these values could be related to the internal
noise temperature of the receiver.
In order to give some usable information (e.g. in the report
exchange), the reported value should be derived from the actual field
strength [V/m] or power density [W/m²] around the receiving antenna.
If this is not possible, I do not see much advantage of promoting dBuV
over S-units, provided that the S unit scale is linear (e.g. 6 dB / S-
unit).
Paul OH3LWR
73
Strewart
Dick Rollema wrote:
To All from PA0SE Walter, DJ2LF, wrote: But nevertheless -
what about S9 on LF is 500uV? I would prefer to stick to S9
is 50µV over 50 ohms (or better S9 means -73dBm, to make it
independent of receiver input impedance) and one S-point
is 6dB. These are values recommended by IARU and therefore
can be considered as a "standard" that has been accepted
internationally (except by the receiver manufacturers). I
don't think IARU has stated a lower frequency limit, only
that it should be used below 30MHz. Using a new "standard"
for LF would add to the confusion which is already big
enough. If it is nevertheless felt that S9 is 500µV would be
better for LF then this should be made a proposal to be
presented at the next IARU conferences in the three
regions. 73, Dick, PA0SE
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