Re: [Flexradio] Preamp issue - Results
At 01:15 PM 3/4/2007, Mark Mumaw wrote: I get about -130dBm when I use this method. Is this what was is expected??? Converting that to an receiver noise figure: 500 Hz = 27 dBHz so -130-27 = -157 dBm/Hz, compared to a kTB thermal noise floor of -174 dBm/Hz, about 17 dB NF, which is pretty typical for a HF receiver. You could also check what noise floor you get with the SDR1000 disconnected and the input to the A/D shorted. The difference is the noise added by the SDR1000 (which is probably quite small). For the SDR1000, the noise floor would be set by a combination of things.. The preamp, if you have it on. The noise in the instrumentation amps after the QSD. Reciprocal mixing from phase noise on the LO. Mark NU6X Jim, W6RMK ___ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com/ FlexRadio Knowledge Base: http://kb.flex-radio.com/
Re: [Flexradio] Preamp issue - Results
I get about -130dBm when I use this method. Is this what was is expected??? Mark NU6X This is just not possible with the way we do calibration. Something else is amiss. After calibration against a known source, BOTH of your radios should read -90 dBm if you present -90 dBm at the antenna terminals. That is because the calibration process removes all of the system differences at the calibration frequency. NOW, you can have a higher NOISE FLOOR than Joe. That is entirely possible. Calibrate your radio so that BOTH OF YOU read the exact same meter readings given the same source (and the peak on the display shows up at the same level on the display). Set your filter to 500 Hz. Read the METER in Signal Avg setting. TURN THE TONE OFF. The meter reading will be of the average cumulative noise power in the 500 Hz filter. THIS IS the definition of MDS as measured in the ARRL labs. It is mathematically equivalent to what they do. Good luck, Bob N4HY ___ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com/ FlexRadio Knowledge Base: http://kb.flex-radio.com/
Re: [Flexradio] Preamp issue - Results
Mark Mumaw wrote: I get about -130dBm when I use this method. Is this what was is expected??? Exactly what mine gets. Mark NU6X Bob N4HY -- AMSAT Director and VP Engineering. Member: ARRL, AMSAT-DL, TAPR, Packrats, NJQRP, QRP ARCI, QCWA, FRC. ARRL SDR WG Chair Taking fun as simply fun and earnestness in earnest shows how thoroughly thou none of the two discernest. - Piet Hine ___ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com/ FlexRadio Knowledge Base: http://kb.flex-radio.com/
Re: [Flexradio] Preamp issue - Results
Dana, it looks to me that you may have a problem with the filter switches either on the BPF or the RFE boards. Due to bit errors and/or unreliable connections wrong filter(s) get selected. That has happened to me. 73, Ahti OH2RZ On 03/03/07, N1OFZ [EMAIL PROTECTED] wrote: When we calibrated with the XG1 both radios (SDR-1000s) showed the received signal at S9 after calibration. The 10 dBm difference was on a signal we tuned to on the air. I think it was on 20m. I have not yet had a chance to get the radio back on the air at my home to compare to the Yaesu. Hopefully this afternoon when the kiddie and XYL take a nap! Thanks, Dana N1OFZ ___ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com/ FlexRadio Knowledge Base: http://kb.flex-radio.com/ ___ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com/ FlexRadio Knowledge Base: http://kb.flex-radio.com/
Re: [Flexradio] Preamp issue - Results
Hi all, I spent some time last night pouring over the ECO's and determining which ones were done to my radio. I did end up taking off the BPF board to get a better look at the RFE. Also during this process I reviewed the block diagrams that Peter sent (thanks!). Today with the help of Joe (AB1DO) I was able to test my radio against his radio. When we hooked up the XG1 my radio was showing the XG1's signal at about S3. It was also quite a bit off frequency and suffered from some serious image issues. After a few runs at calibrating it and tweaking it back on frequency we ran it against Joe's SDR. The result were that the calibrating (with a good signal source) seems to help significantly. My radio still seems to be about 10 dBm down from his but I believe it to be because his radio has the newer preamp (ECO025). We listened to a signal that was showing around -90 dBm on my radio vs. his which was showing about -80 dBm. I guess the lesson learned is that if you own a SDR-1000 you best get a XG1 or similar signal source. Maybe future Flex Radio models can incorporate a similar circuit? Unfortunately, I had to go back to work but I'm looking forward to getting it hooked back up in the shack tonight. Thank everyone who responded with suggestions and comments. And a big thanks to Joe for making time today to help me sort out the problems. It's great to have a local fellow Flexer! '73 Dana N1OFZ ___ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com/ FlexRadio Knowledge Base: http://kb.flex-radio.com/
Re: [Flexradio] Preamp issue - Results
Dana, The question of sensitivity still remains as far as I can tell. Can you borrow an attenuator and bring the XG1 down to the noise floor on both yours and Joe's radio. The 10 dbm difference may be a calibration issue rather than a sensitivity issue unless you can still hear signals on your Yaesu that you cannot hear on your SDR. 73 Tom W0IVJ N1OFZ wrote: Hi all, I spent some time last night pouring over the ECO's and determining which ones were done to my radio. I did end up taking off the BPF board to get a better look at the RFE. Also during this process I reviewed the block diagrams that Peter sent (thanks!). Today with the help of Joe (AB1DO) I was able to test my radio against his radio. When we hooked up the XG1 my radio was showing the XG1's signal at about S3. It was also quite a bit off frequency and suffered from some serious image issues. After a few runs at calibrating it and tweaking it back on frequency we ran it against Joe's SDR. The result were that the calibrating (with a good signal source) seems to help significantly. My radio still seems to be about 10 dBm down from his but I believe it to be because his radio has the newer preamp (ECO025). We listened to a signal that was showing around -90 dBm on my radio vs. his which was showing about -80 dBm. I guess the lesson learned is that if you own a SDR-1000 you best get a XG1 or similar signal source. Maybe future Flex Radio models can incorporate a similar circuit? Unfortunately, I had to go back to work but I'm looking forward to getting it hooked back up in the shack tonight. Thank everyone who responded with suggestions and comments. And a big thanks to Joe for making time today to help me sort out the problems. It's great to have a local fellow Flexer! '73 Dana N1OFZ ___ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com/ FlexRadio Knowledge Base: http://kb.flex-radio.com/ ___ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com/ FlexRadio Knowledge Base: http://kb.flex-radio.com/
Re: [Flexradio] Preamp issue - Results
Hi Dana, Are you saying that, with the same signal input (from a test generator, for example), your radio, after calibration, shows roughly a 10 dB difference in its s-meter reading compared to the other radio? My experience with several Flex radios is that, if they're both calibrated with the same signal source, they'll both have the same s-meter reading (irrespective of whether the preamp IC is the new one or the old one). For example, if I calibrate with a -50 dBm source, the final result will be an s-meter that reads -50 dBm when I drive my radio with that source, and it does not depend upon the preamp IC that's been installed. If both your radio and Joe's radio were calibrated using the same signal source (your XG1, for example) then I'd expect you both to have the exact same reading for it (and for any other signals, too). The fact that you don't implies that the calibration of one of the radios might be incorrect. Of course, there might be other issues, too. - Jeff, K6JCA --- N1OFZ [EMAIL PROTECTED] wrote: Hi all, I spent some time last night pouring over the ECO's and determining which ones were done to my radio. I did end up taking off the BPF board to get a better look at the RFE. Also during this process I reviewed the block diagrams that Peter sent (thanks!). Today with the help of Joe (AB1DO) I was able to test my radio against his radio. When we hooked up the XG1 my radio was showing the XG1's signal at about S3. It was also quite a bit off frequency and suffered from some serious image issues. After a few runs at calibrating it and tweaking it back on frequency we ran it against Joe's SDR. The result were that the calibrating (with a good signal source) seems to help significantly. My radio still seems to be about 10 dBm down from his but I believe it to be because his radio has the newer preamp (ECO025). We listened to a signal that was showing around -90 dBm on my radio vs. his which was showing about -80 dBm. I guess the lesson learned is that if you own a SDR-1000 you best get a XG1 or similar signal source. Maybe future Flex Radio models can incorporate a similar circuit? Unfortunately, I had to go back to work but I'm looking forward to getting it hooked back up in the shack tonight. Thank everyone who responded with suggestions and comments. And a big thanks to Joe for making time today to help me sort out the problems. It's great to have a local fellow Flexer! '73 Dana N1OFZ ___ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com/ FlexRadio Knowledge Base: http://kb.flex-radio.com/ ___ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com/ FlexRadio Knowledge Base: http://kb.flex-radio.com/
Re: [Flexradio] Preamp issue - Results
are both s-meters calibrated to the same point? for example 50uv for s9? I had to adjust my Kenwood to the same S9 50uv I believe and they read almost the same all the time. I didnt see that mentioned anywhere, but if I missed it sorry I am missing some emails for some reason ignore me if it was mentioned. Stan AH6JR On Friday 02 March 2007 10:24 am, Jeff Anderson wrote: Hi Dana, Are you saying that, with the same signal input (from a test generator, for example), your radio, after calibration, shows roughly a 10 dB difference in its s-meter reading compared to the other radio? My experience with several Flex radios is that, if they're both calibrated with the same signal source, they'll both have the same s-meter reading (irrespective of whether the preamp IC is the new one or the old one). For example, if I calibrate with a -50 dBm source, the final result will be an s-meter that reads -50 dBm when I drive my radio with that source, and it does not depend upon the preamp IC that's been installed. If both your radio and Joe's radio were calibrated using the same signal source (your XG1, for example) then I'd expect you both to have the exact same reading for it (and for any other signals, too). The fact that you don't implies that the calibration of one of the radios might be incorrect. Of course, there might be other issues, too. - Jeff, K6JCA --- N1OFZ [EMAIL PROTECTED] wrote: Hi all, I spent some time last night pouring over the ECO's and determining which ones were done to my radio. I did end up taking off the BPF board to get a better look at the RFE. Also during this process I reviewed the block diagrams that Peter sent (thanks!). Today with the help of Joe (AB1DO) I was able to test my radio against his radio. When we hooked up the XG1 my radio was showing the XG1's signal at about S3. It was also quite a bit off frequency and suffered from some serious image issues. After a few runs at calibrating it and tweaking it back on frequency we ran it against Joe's SDR. The result were that the calibrating (with a good signal source) seems to help significantly. My radio still seems to be about 10 dBm down from his but I believe it to be because his radio has the newer preamp (ECO025). We listened to a signal that was showing around -90 dBm on my radio vs. his which was showing about -80 dBm. I guess the lesson learned is that if you own a SDR-1000 you best get a XG1 or similar signal source. Maybe future Flex Radio models can incorporate a similar circuit? Unfortunately, I had to go back to work but I'm looking forward to getting it hooked back up in the shack tonight. Thank everyone who responded with suggestions and comments. And a big thanks to Joe for making time today to help me sort out the problems. It's great to have a local fellow Flexer! '73 Dana N1OFZ ___ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com/ FlexRadio Knowledge Base: http://kb.flex-radio.com/ ___ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com/ FlexRadio Knowledge Base: http://kb.flex-radio.com/ ___ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com/ FlexRadio Knowledge Base: http://kb.flex-radio.com/
