End-fed presented RF to shack SignaLink resetting.CF7CDB. Special call 150 anniver-sary of Canada.CF2QR. WHAT HAPPEND WITH THE 10 METER?NOTHING SO TO MAKE.CE4KCA. ICOM 7300 50 watts + Windom anten-na.9H1CG. My favouritebut LP with the poor propagation is no longer LICENCE 17-06-2014.9A6TT. Rig is IC-7600 (100W) and ANTis Dipole.7N2UQC. Thank you for your great copy my QRP signal.7L4IOU. Really bad conditions only few open-ings many stations with nice signal but endless cq test and neverhear with care for a qrp or low power stations anyway nice trySEE NEXT YEAR.4M6CQ. A lot ofBig Gun stations went over my QRP 5 watts near or over myfrequency but I enjoyed the fight and I did my best as always.Best 72 and 73.4M5EN. It was my first CQWPX RTTY contest and I really enjoyed it very much. 11ġ2 Test of a Sound Blaster X-Fi Surround 5.1 Pro on a PMSDR SDR-receiver Test setup overview: Audio galvanic isolator HP8640B Signal generator USB PC USB Line In Line out 12ġ3 Test results Test conditions: - Input device:sound Blaster X-Fi Surround 5.1 Pro, Line input volume is set to maximum - PC: HP XW4400 Workstation, WinXP SP3 - Software: HDSDR V2.DX QRMFT950 80W Antena FD4, BIM20-15M.3Z9K. 8ġ0 Modification results Also the result after the modification to increase the filtering for the ADC internal quiescent reference voltage are noticeable: The center noise peak was reduced by 10dB! Before modification: After modification: 10ġ1 Test of a Sound Blaster X-Fi Surround 5.1 Pro on a PMSDR SDR-receiver Test setup: Sound Blaster X-Fi Surround 5.1 Pro Audio galvanic isolator (RF-SYSTEM) PMSDRreceiver To avoid ground loops between sound interface and receiver, i suggest to use a audio galvanic isolator between the sound interface and receiver I/Q-output. ) 7Ĩ 4) Add a polarized capacitor (100 uf/ 6,3V) across C40: + - ADC C40 () Note: This additional capacitor improve the filtering for the ADC internal quiescent reference voltage, to reduce the noise at very low frequencies. However, this does not seem to be a problem in this case. Noise&spures level improvement modification (and improvement of Power Supply Rejection Ratio) (Important note: Any disassembly and/or modify of the unit will void the warranty!) Disassemble the unit: 5 1) Remove the pin's to get the 4 screws.Ħ 2) Remove carefully the top cover with the knob: DAC ADC 6ħ 3) Add a polarized capacitor (1000 uf/ 6,3V) across C100: + - ADC DAC C100 Note: Yes, i know that a huge capacitor (1000 uf) cause a high current peak at power on. High dynamic range ADC's needs a clean, low noise power supply. After some tries, i have found the origin of the spures: The power for the internal analog section (VA) of the ADC. So i tried to find a solution to reduce these spures. 4ĥ The spures (up to 9 db above the noise floor) are probably caused by noise on the USB power supply line and can be vary from PC to PC. The lowest noise level is about -126,5dB at 20kHz 3Ĥ Tests The second test was the noise performance at very low frequencies near to 0Hz, another important feature for SDR applications: Test conditions: - All analog inputs are unplugged, line input volume is set to maximum - PC: HP XW4400 Workstation, WinXP SP3 - Software: HDSDR V2.1, I/Q input mode, RBW=11,7Hz vertical scale: 1dB/div from -100dB to -129dB - sampling rate 96kHz / 24bit The center peak level around 0 Hz are about -109 db, maybe due a low filter capacitor for the ADC internal quiescent reference voltage. 2ģ Tests The first test after the installation was the noise performance, one of most important feature of a soundcard for SDR applications: Test conditions: - All analog inputs are unplugged, line input volume is set to maximum - PC: HP XW4400 Workstation, WinXP SP3 - Software: HDSDR V2.1, left input mode, RBW=11,7Hz vertical scale: 1dB/div from -131dB to -114dB - sampling rate 96kHz / 24bit Many spures spaced by 1 khz, maybe from the USB power supply line. (Note: the upper sampling rate limit of the ADC (CS5345) and a DAC (CS4361) are 192kHz) For a SDR (Software Defined Radio) application, a quality 24 bit soundcard running at 96kHz or more is recommended, but this will not always mean to spending many money. SB1095) have a ADC (Cirrus Logic CS5345) and a DAC (Cirrus Logic CS4361) which have a dynamic range of 104 db and work with a sampling rate up to 96kHz/24bit. Furthermore, this card (in my case: Model no. 1Ģ Easy to install, the bus-powered USB 2.0 Sound Blaster X-Fi Surround 5.1 Pro does not require an extra power adapter. This card are provided with drivers for WinXP, Vista and Win7. 1 Using the Creative Sound Blaster X-Fi Surround 5.1 Pro USB sound interface as baseband sampler for QSD based SDR receivers Martin Pernter, IW3AUT Updated The Creative Sound Blaster X-Fi Surroud 5.1 Pro is a external sound interface for PC with a USB2.0 High speed interface.
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