ZIP files showing Linrad noiseblanker on HF

Early in the morning 7/3/2003 I found that pulse-type noise on 20 meters was totally obliterating the SSB signals I was trying to listen to on my SDR-1000. This pulse noise appears and disappears and is out of my control. I could copy no stations thru the noise with the SDR-1000. I decided to see what Linrad would do with the noise, and I made some wave files of the results. The files are of a very STRONG VK station that came thru the noise on Linrad. Other stations did not. On the SDR-1000, I couldn't copy the station though I could hear him down in the noise. I made the wave files from Linrad, and then went back to the SDR-1000 to make some wave files there. It took me a while to do this,as I had the Linrad HF receiver disassembled as I had taken it to W2SZ/1 to try as a microwave IF, and I had to send the sound to another computer to make wave files of the SDR-1000, and by the time I did all that the noise was less intense and intermittent. Initially it had raised the noise floor on both the SDR-1000 and Linrad by 20-30 dB. I made some wave files with the SDR-1000 anyway, and then went back to Linrad to make one last file showing how benign and intermittent the noise had become. It is now gone and so I can't make any more files at the moment.

Conditions:

Same R7 Vertical for both receivers

No external preamp

Frequency 14.180 MHz

SDR-1000 on +40 dB

Linrad receiver using TAK893 mixer to RX2500

Linrad run with smart blanker only, dumb blanker only, both on; all conditions eliminated noise entirely

I did NOT adjust Linrad noise blanker properly for the strong VK signal. Thus there is minor distortion which does NOT affect copy. This distortion would not be present had I set the thresholds for the Linrad noiseblankers properly.

linnbsav1.zip is Linrad with the noise blankers on at the beginning of the file . At the middle of the file I turned the noise blankers off briefly so you could hear the noise. Note that with the blankers on you can hear both the strong VK and the weaker stateside station with whom he is QSOing.

linnoisav2.zip is Linrad with the noise blankers off. I should have recorded for a longer span so you could see that the weaker station was totally obliterated.

linnoisav3.zip is Linrad with the noise blankers off; this was recorded after the SDR files, to show how benign and intermittent the noise had become by the time I figured out how to record the SDR-1000 audio. I believe that this is a relatively weak VE that the VK was working.

sdr1000n742003.zip is the SDR1000. This is the VK station, who is actually a K1 on vacation down there. The noise had gotten somewhat better at this point.

sdrn2.zip is the SDR1000 again, same station.

Here are some additional files that I recorded using the SDR-1000, Linrad, and the Elecraft K2 on 20 meters the next day when there was no pulse noise.

Conditions:

Same R7 Vertical for all 3 receivers

No external preamp

Frequency 14.23x MHz for SSB

SDR-1000 on +40 dB

Linrad receiver using TAK893 mixer to RX2500

K2 operating with KDSP2 off for SSB

k2b.zip is a fairly strong SSB station heard on the K2

sdrb.zipis part of the same SSB QSO heard on the SDR-1000. The stations in QSO were of comparable signal characteristics

linradb.zip is part of the same SSB QSO heard on Linrad

k2.zip is again SSB QSO heard on the K2

sdr1000a.zip is again the SSB QSO heard on the SDR-1000

linrada.zip is the same SSB QSO heard on Linrad

Here are some files that I recorded using the SDR-1000 and Linrad on 20 meters on 7-12-03 UTC when there was again pulse noise.

Conditions:

Same R7 Vertical for all receivers

No external preamp

Frequency 14.26x MHz for SSB

SDR-1000 on +26 dB

Linrad receiver using TAK893 mixer to RX2500

sdr712a.zip is an SSB station heard on the SDR-1000

sdr712b.zip is another SSB station heard on the SDR-1000

linrad712a.zip is an SSB station heard on Linrad with dumb NB on

linrad712b.zip is the same SSB station heard on Linrad with NB off

linrad712c.zip is again the same SSB QSO heard on Linrad with dumb NB on

linrad712d.zip is the same SSB QSO heard on Linrad with NB off

linrad712e.zip is another SSB QSO heard on Linrad with both dumb and smart NB on

linrad712f.zip is the same SSB QSO heard on Linrad with NB off

Here are some wave files of the NCDXF/IARU cw beacons on 14.100 MHz. Each file covers a full 3 minute cycle of the beacons.

Conditions:

Same R7 Vertical for all receivers

SDR-1000 hardware was used as the input for Linrad. The I/Q output of the SDR-1000 hardware was fed to the Linrad software receiver rather than to the SDR-1000 software receiver for the Linrad experiments.

The SDR-1000 hardware was also used as the hardware for the SDR-1000 recordings, which were made using the SDRConsole Software.

k2beac.zip is the wave file of the beacons as received by the K2. K2 parameters: preamp on; K2DSP on; 100 Hz CW DSP filter on; Noise Reduction on, parameters: Beta, 89 & decay, 71; Noise Blanker 1 on; Analog filter 100 Hz.

k2nodspnonb.zip is the K2 with DSP and noise blanker turned off

sdrbeac.zip is the wave file of the beacons as received by the SDR-1000 hardware and software

linsdrbeacsdnbon.zip is a wave file of Linrad receiving the beacons with both smart and dumb noise blankers turned on. Filter is set to 150 Hz and AFC is off.

linsdrsdnbon100hzbeac.zip is a wave file with Linrad using a 100 Hz filter, with both noiseblankers on and AFC off.

linsdrsdnbonafconbeac.zip is a file made with Linrad using 60 Hz filter with the noise blankers and AFC on.

linsdrnboff75hz.zip is a wave file recorded with Linrad using 75 Hz filter with the noise blanker turned off and AFC turned off.

linbeac713a.zip is a wave file made using the SDR-1000 as front end for Linrad, after calibrating Linrad for the SDR-1000 using a PTS500 for spur reduction calibration and a Tektronix PG 508 pulse generator for pulse calibration. The file was recorded when there was no pulse noise present, so noise blankers were turned off. A 90 KHz filter was used on Linrad, no exp, no coherent processing. The sdr-1000 set at 14.095 MHz, 40 dB preamp setting. I/Q output from the SDR-1000 was fed into a Delta44 soundcard sampling at 96KHz for Linrad processing. Linrad center frequency listed as 144.086 produced proper frequency calibration. Linrad then shows the 144.100 beacon at 14.099.758 MHz. The recording started at 10:03:11 am EDT 7-13-03. 3 minute recording duration.

linbeac713b same parameters, Recording started at 10:06:33. Not placed on website due to space restrictions.

linbeac713c same parameters, Recording started at 10:10:15. 5 minute recording. Not placed on website due to space restrictions.

linbeac713sa "S" file started at 10:16:09. 73.5 MB. Not placed on website due to space restrictions.

linbeac713a.gif is a gif file of Linrad screen taken at 10:20:00

linbeac713sdroff.gif is a gif file of Linrad screen taken shortly after sdr-1000 turned off [power removed from it], to show difference in waterfall display with and without input from SDR-1000.

lin713noi.zip was started at 22:27:08 on 7-13-03. The SDR-1000 was set to 'SPEC' mode and the vfo set to 14.090 and locked. Linrad center frequency was set to 144.090 [really 14.090 MHz], and the beacons show up at 14.099.175 MHz. 3 minute recording duration. THere was about 10 dB of pulse noise during this recording, which was made with both smart and dumb noise blankers turned on.

lin713noioff.zip was started at 22:31:18 on 7-13-03. Parameters were as for the file lin713noi.zip. 3 minute recording duration. THere was again about 10 dB of pulse noise during this recording, which was made with both smart and dumb noise blankers turned off.

linbeac713sb "S" file recorded while 10 dB pulse noise present. 7.2 MB zipped. available by request

linbeac713sc "S" file recorded while 10 dB pulse noise present. 9.5 MB zipped. available by request

lin713noi2.gif shows Linrad screen. At the bottom of the waterfall display the noise blankers are off, and at the top of the waterfall both noiseblankers are turned on

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