Dave,
When working with S-meter readings I like to use the built-in Signal
Generator on the PowerSDR, Setup window, Tests tab. I set the Receive
Mode to Tone and Scale to 0.000010 which gives -110 dBm on my RX1
Meter. This gives a nice steady receive level. Make sure the tone (on
the slider) puts the signal within the filter passband.
I then go to the CAT Control tab and click the Test button which brings
up the CAT Command Tester window. Typing zzsm0; as the Command input
gives a response of ZZSM0062; (for the -110 dBm set level). 62/2-140 =
-109.
Signal Generator Scale = 0.000003 gives -120 dBm on my RX1 Meter. This
gives a response of ZZSM0040; .
Don't know why you are getting ZZSM0106; for -119 dBm. Sorry can't be
of any more help.
Bill - K7UOP
On 12/20/2012 10:18 AM, Dave Watson wrote:
Bill/Bob,
ZZSM is not working for me yet... :-(
For example:
When I read ZZSM0 through the serial port with a PowerSDR S-Meter reading of
~1, I get ZZSM0106. The S-Meter on PowerSDR reads -119 dBm. If I use the
formula 'dBm = (ZZSM/2)-140' I get (106/2)-140 which equates to -87 dBm.
That is a difference of 32 dBm.
Any suggestions are appreciated...
Dave (W4DJW)
-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of Bill K7UOP
Sent: Wednesday, February 02, 2011 5:42 PM
To: 'Bob Tracy'; 'FlexEdge'
Subject: Re: [FlexEdge] CAT S-Meter readings
Thanks Bob, good info.
I take it DttSP is a class internal to PowerSDR.
The main thing I get is the scaling: sm = ((int)num+140)*2;
So for me, num = sm/2-140 (for num in dBm). Ahh yes, the output of my
program now looks better.
Thanks, Bill - K7UOP
-----Original Message-----
From: Bob Tracy [mailto:[email protected]]
Sent: Wednesday, February 02, 2011 3:10 PM
To: 'Bill K7UOP'; 'FlexEdge'
Subject: RE: [FlexEdge] CAT S-Meter readings
Bill,
The way it is calculated depends on the radio model, here's the code from
ZZSM:
We first get the raw signal strength from DttSP
num = DttSP.CalculateRXMeter(0, 0, DttSP.MeterType.SIGNAL_STRENGTH);
Then we plug in the calibration offsets (this is where it varies by radio
model, F5K code shown)
num = num +
console.MultiMeterCalOffset +
Display.RX1PreampOffset +
console.RX1FilterSizeCalOffset +
console.RX1PathOffset +
console.RX1XVTRGainOffset;
if (console.RX1Loop)
num = num + console.LoopGain;
Finally, we scale the results and return a fixed length string
num = Math.Max(-140, num);
num = Math.Min(-10, num);
sm = ((int)num+140)*2;
return sm.ToString().PadLeft(3,'0');
Hope this helps,
BobT, K5KDN
-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of Bill K7UOP
Sent: Wednesday, February 02, 2011 3:38 PM
To: FlexEdge
Subject: [FlexEdge] CAT S-Meter readings
The CAT Command Dictionary says:
ZZSM P1 P2 P2 P2;
P2 = 000 to 260
Each increment of ZZSM is approximately 0.5 dBm.
To get to actual dBm I've tried dBm = P2 / 2 - 130 but it doesn't quite
jive with what I'm seeing on the Flex 5k s-meter. Is there an offset?
What is the conversion from P2 to dBm?
de Bill - K7UOP
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_______________________________________________
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[email protected]
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This is the FlexRadio Systems e-mail Reflector called FlexEdge. It is used
for posting topics related to SDR software development and experimentalist
who are using beta versions of the software.
_______________________________________________
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[email protected]
http://mail.flex-radio.biz/mailman/listinfo/flexedge_flex-radio.biz
This is the FlexRadio Systems e-mail Reflector called FlexEdge. It is used for
posting topics related to SDR software innovation and other technical SDR
topics.
