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Old August 20th 06, 12:54 AM posted to rec.radio.shortwave
Somebody Somewhere Somebody Somewhere is offline
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First recorded activity by RadioBanter: Jul 2006
Posts: 89
Default Icom R75 receiver, Signal Strength Meter


Telamon wrote:
In article ,
"Guy Atkins" wrote:

"Telamon" wrote in message
...

Again a digital version of an analog function has no additional inherent
value over analog but it could. An example here would be a low and peak
temporary hold display. Normal would be green, max would be red and blue
min signal colors. The red and blue would last a second or two so the
green level indication could respond quickly to enhance the display.


I like the SDR-1000's digital meter (in dBm), as the averaging function
(rate) can be adjusted to the user's liking, or turned off. The peak hold
and normal display colors (in gradient color hues) can be changed, too, for
best visibility. There is also a really cool "analog" representation of an
s-meter as an option, that displays in true s-units and incorporates the
peak hold feature. The "needle" changes color briefly at the peak reading.
It's a high-resolution and realistic representation of an S-meter, and
floats in a separate window so you can place it on the Windows desktop
wherever you like. Finally, because the SDR-1000 is user-calibrated with a
Elecraft XG-1 or other signal meter, the digital meter and the "analog"
s-meter are highly accurate across their range. My SDR-1000 blog entry from
April 13th shows this S-meter in its prior form, before it was changed to a
"floating" window.


Analog or digital dBm is certainly more useful that s units.

You can program any kind of display you like on the computer supported
radios.

I would not want the averaging on at all preferring that the display
update as fast as possible so that the rate of signal fluctuation can
be seen in real time. The drawback is that with rapidly changing signal
you would have a tough time seeing the min and max and that is where
the min and max hold for a second or two with the different colors
would display. I've seen this type of display on audio VU metering and
I think it would be good for signal strength indicator.

--
Telamon
Ventura, California


The JRC NRD-545's S meter can show a signal's "max peak" reading, where
the highest reading signal "bar" remains lit for a second or two after
the signal strength starts to fall. Meanwhile, the actual strength of
the signal can still be seen at any given moment, as the S-meter
continues to function as usual. It's just that the one bar showing the
peak reading remains lit. I really liked that feature of the 545 (I now
have a Ten-Tec RX340).

I never understood the DBm scale, which my RX340 has in addition to the
usual S unit scale.
Can one of you radio eggheads explain exactly what "DBm" measures? I
think it means decibels per meter, but that still tells me nothing. Is
it "meter" as in wavelength?