Thanks for the quick reply Bob,
After reading your post I wondered why we would get such different results. I never shutdown the Flex5000A so it could have easily been running since I did the upgrade to 2.5.3. In addition I run a SoftRock40 and a Hermes SDR radio on the same computer at the same time on different bands. They never get shut off either. Using VspMgr on each, it is easy to mistake which port is connected to the software I'm developing. So, after shutting down and restarting all of them, I retested and the PowerSDR 2.5.3 connected to the Flex5000A is getting the same results you have. It's the Hermes running OpenHPSDR that has the discrepancy. I'll have to repost this to their reflector to see if they changed the algorithm. The 3rd party software I'm developing is an SDR scanner I started back in May. I didn't have time to fine tune the S-Meter until the holidays with some use it or lose it vacation time. With this software the user specifies when to pause scanning based on the S-Meter level. It's important the scanner knows when the signal strength reached the user specified maximum threshold. Here is a YouTube video of what I have so far. http://youtu.be/td72wVn5XGg 73 Dave (W4DJW) From: Bob Tracy [mailto:[email protected]] Sent: Thursday, December 20, 2012 1:40 PM To: Dave Watson Subject: Re: [FlexEdge] CAT S-Meter readings Dave, I'm not real sure just what to say. I checked my system, using 2 meters so I could get a low S meter reading, and found the ZZSM command to track the PowerSDR meter withing a couple of dBm. Just to make sure, I went to HRD and watched the S meter on the HRD console, it was tracking very closely with the PowerSDR meter. There is a little latency when travelling over the serial port so they probably never will be identical unless you are on a fixed-level signal. I don't see any error of the magnitude you are describing. What third party program are you using? Bob On Thu, Dec 20, 2012 at 11:18 AM, Dave Watson <[email protected]> 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 _______________________________________________ Flexedge mailing list [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 development and experimentalist who are using beta versions of the software. _______________________________________________ Flexedge mailing list [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 development and experimentalist who are using beta versions of the software. _______________________________________________ Flexedge mailing list [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.
