> > It's amazing, but I really think most of our s meters are
> miscalibrated and the strongest signals tend to be more
> like s9+20 and not s9+40 as our meters tend
> to read. Anyway, I find it extremely rare when the 40 db range is
> not enough for the close in stuff.
I haven't seen an S-meter yet that tracks below S-8 or conforms to
any standard, although many or most are OK above S-9. I have
heard some new software based S-meters are OK.
I would never depend on an unverified S meter for estimating signal
levels, nor does signal level range at one location hold for other
locations.
Living out here on an island near mid-Pacific, I know I have
NEVER rcvd a signal of a strength of 9 + 40 dB on the amateur
bands. From some of the other islands, from 120 to 350 miles
away, from stations running full 1500 watts, more like 9 + 15 or
maybe even on occasion, +20 dB; from the rest of the world, not a
chance.
This is a common argument from people on PSK, who want the
entire world to run 5 watts so all stations have similar or equal
levels to keep them inside the limits of the soundcard-filtered
system, which has a dynamic range of 50 dB or so.
In the real world, it doesn't work. Propagation and station
differences cause a much greater difference in signal levels even if
everyone runs the same power. Someone comes along with a good
antenna and location and good propagation, and everyone screams
"high power".
As I said before, I typically have a noise floor of -110dBm or so on
a winter night on 160. At sunrise and sunset times when the band
is still open, noise floor (250Hz BW) might be as low as -130dBm.
W4ZV and N4UK (about 400 miles away) are at times about -
30dBm.
W8LRL in WVA is readable here running about 30-50 microwatts,
his MFJ-259B antenna analyzer actually just booms in. Assuming
he runs 1500 watts, that would be in the 70 to 80dB level difference
between my noise floor and his signal.
I see similar situations on 80 and 40, with very strong single-hop
signals and a very low noise floor.
Not only that, the problem we actually face with receivers is the
**accumulated power** of ALL the signals within the roofing filters,
not just the level of each individual signal.
Many others who live in rural locations and operate low bands have
similar situations, and certainly many of us don't even recognize
overload.
73, Tom W8JI
W8JI@contesting.com
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