RADIXON WR-G35DDC EXCALIBUR ULTRA User Manual Download Page 116 | Manualshive

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WiNRADiO G35DDC HF Receiver

116

Appendix C – Dealing with Interference

Electromagnetic Interference (EMI)

is what prevents us from receiving a

clear signal, even when the receiver should be sensitive enough to receive it.
There are many types of interference you can experience with radio receivers,
emanating from both natural and man-made sources.

Natural interference is produced by atmospheric phenomena such as storms
and sun activity.

Not so surprisingly, man-made interference is often worse. Sources include
electric motors, power lines, passing cars, electrical welding equipment,
fluorescent lights, domestic appliances, computer networks, etc. Receiving
antennas should always be as far away from sources of electromagnetic
interference as possible.

One significant source of man-made electromagnetic interference is the
personal computer, and the video monitor in particular. Since the

WiNRADiO

Excalibur Ultra

receiver requires a personal computer to operate, this creates

a potential paradox. The receiver itself is designed to be substantially immune
to computer-generated interference. However, any receiver needs to be
connected to an antenna, and antennas can’t discriminate between useful
signals and interference. The interference from your computer can either
radiate directly to the antenna, or it can be conducted to it along the outer
conductor of the lead-in cable. Even in professional radio receiving stations, a
lot of care and effort is always needed, if this type of self-interference is to be
avoided.

Some computers are worse than others in terms of generated electromagnetic
interference. The specifics of a computer-based software-defined receiver
require a careful consideration with respect to computer-generated noise. Over
the past decade or so, computers have become considerably quieter in terms
of radiated radio frequency interference (RFI). Replacing CRT monitors with
modern LCD types has substantially contributed to this, as have strict FCC
and CE requirements with respect to allowable levels of RFI for consumer
products.

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Summary of Contents for WR-G35DDC EXCALIBUR ULTRA

Page 1: ...WiNRADiO by RADIXON WR G35DDC EXCALIBUR ULTRA TM Software Defined HF Receiver User s Guide Ver 1 10 ...

Page 2: ...ny form or by any means without the written permission of the publisher Trademarks WiNRADiO G3 G313 G31DDC G33DDC G35DDC G39DDC Excalibur Excalibur Pro Excalibur Ultra and Excelsior are trademarks of WiNRADiO Communications All other brand and product names are trademarks of their respective owners Patents WiNRADiO technology is protected by US Pat No 6 289 207 and other pending US and internation...

Page 3: ... the computer and peripherals must be shielded and grounded Operation with non certified peripherals may result in interference to radio and TV reception Modifications Any changes or modifications to the WiNRADiO receiver not expressly approved in this book could void the user s authority to operate this equipment Limitation of Liability and Remedies The information published in this book has been...

Page 4: ...ra 19 Resizing the Application Window 23 Drop Down Menu Controls 23 Tuning the Excalibur Ultra 25 Manual Frequency Entry 25 Tuning Knob 27 Keyboard Tuning 27 Multiple Receiver Operation 28 Point and Click Tuning 29 Dragging the Passband 29 IF Shift and Passband Tuning 31 Frequency Stepping 33 Frequency Display Offset 34 Receiver Selection 35 Mode Selection 36 AMS Mode 37 ISB and DSB Modes 38 DRM M...

Page 5: ...05 Date and Time Display 105 Appendix A SDR and DDC Primer 106 Appendix B Troubleshooting 113 Appendix C Dealing with Interference 116 Appendix D Demodulator Spectrum Width 118 Appendix E Waterfall Spectrum Palettes 119 Appendix F Recording File Formats 120 Appendix G G35DDCi PCIe Card Connections 123 Appendix H Compliance Declarations 125 Please don t forget to register as a WiNRADiO user to rece...

Page 6: ...WiNRADiO Excalibur Ultra will take you right to the leading edge of what is possible with today s technology As the name Excalibur suggests a magical sword synonymous with power and bravery this is not just a receiver it is a powerful radio communications instrument in a class of its own We have crafted it with meticulous workmanship utmost care attention to detail and dedication to excellence to ...

Page 7: ...sktop PC requiring no additional desk space no interface wiring and no power supply it relies on power supplied by the PC The receiver can be ordered with various hardware options such as external reference input or output coherent clock input and digital synchronization interface for coherent applications The antenna input is an SMA type connector with 50 ohm impedance An SMA to BNC adapter is su...

Page 8: ... MB separate drive with min 160 Mbits s data throughput for recording playback 1 2 TB Sound card Any standard Windows supported sound card Interface PCI e x1 slot OS Windows XP Vista 7 8 The CPU speed directly influences the maximum selectivity and DDC bandwidth that can be achieved with this receiver The receiver is still usable on slower computers including dual core CPU computers but with a tra...

Page 9: ...e power cord Remove the computer case Choose an empty PCI Express slot as far as possible from the power supply and from other cards First touch the computer metalwork with your hand to drain any static charge then carefully insert the card into the vacant slot and push down until it is firmly seated Screw the metal bracket at the end of the card to the computer case This must be done to provide p...

Page 10: ... the chapter Connecting the Antenna Long wire baluns WiNRADiO also manufactures long wire antenna impedance transformers often referred to as long wire baluns The pictured WR LWA 0130 adapter can be used to match the impedance of a long wire HF antenna to the 50 ohm input impedance of the Excalibur Ultra receiver as well as provide a convenient grounding point This usually results in a significant...

Page 11: ...e sound card is only used for the demodulated audio output On Windows 7 the audio volume can be adjusted using the WR G35DDC volume slider inside the Applications section and the master volume inside the Device section Both controls need to be unmuted Click on the speaker icon and then click on the Mixer link to bring up the sound card control panel different Windows versions may use a different m...

Page 12: ...later Common mode choke The WINRADiO WR CMC 30 common mode choke provides a means of reducing or eliminating common mode noise from an antenna feedline resulting in a considerable increase of the received signal quality Common mode noise is generated by computers light dimmers and other electric or electronic appliances Such noise can be a problem especially in the lower portions of HF spectrum wh...

Page 13: ... particular when you are using long wire antennas In some cases signal reception may be significantly enhanced with improved grounding Unfortunately results are not always predictable due to variations in individual installations so some trial and error experiments may be required in the search for ultimate performance With long wire antennas good grounding is absolutely essential If you don t app...

Page 14: ... receiver In order to make a connection to the coaxial cable a number of options exist These include WiNRADiO antenna accessories such as the WR CMC 30 Common Mode Choke see www winradio com cmc30 or the WR LWA 0130 Long Wire Adapter sometimes referred to as a long wire balun see www winradio com lwa which along with their other intended purpose also provide a convenient ground connection stud tha...

Page 15: ...diately obvious and which would be a shame to miss Start the WiNRADiO Excalibur Ultra receiver application by double clicking on the program icon The receiver s virtual control panel will appear The control panel has some basic elements similar to conventional shortwave receivers and many new ones as well For example you will note the wideband spectrum analyzer at the bottom that shows the real ti...

Page 16: ...ne on the right is the Demodulator spectrum scope You can adjust the receiver s selectivity bandwidth for optimum reception using the row of numbered buttons at the bottom of the Tuning tab the leftmost tab located just under the AM mode selection button The numbers on the buttons represent the bandwidth in kHz To adjust the bandwidth continuously use the DEM BW control located at the top of the d...

Page 17: ...p and down arrow keys on the PC keyboard The Alt Shift and Ctrl keys can be used to a similar effect as with the tuning knob to modify the frequency increment step If your mouse has a wheel as we would recommend you can also use this you might find it somewhat similar to using the tuning knob of a conventional receiver And again the Alt Shift and Ctrl keys when used together with the mouse wheel m...

Page 18: ...C bandwidth DDC BW All standard HF signals can be demodulated with 20 kHz DDC bandwidth without a decrease in the demodulation quality Wider DDC bandwidths affect display and recording while increasing the CPU load considerably Avoiding Front End Overload If the S meter shows the words ADC CLP the analog to digital converter ADC is overloaded i e clipping the signal In such case use the Attenuator...

Page 19: ...or contains a bank of user configurable filters that can be used to filter out strong frequencies in the vicinity of the received signal and so reduce overloading and intermodulation distortion The signal then passes through a low noise and low distortion two stage amplifier whose first stage can be enabled or disabled by the user When enabled this adds approximately 10 dB of amplification making ...

Page 20: ...e DDC is in fact a functional equivalent of the mixer local oscillator and filter but rather than outputting an analog intermediate frequency signal its output is in a digital form This digitally down converted signal then arrives in the computer via the PCI Express interface where it is filtered and demodulated entirely in software using purely computational digital signal processing methods ther...

Page 21: ... within the current DDC spectrum these will be described in greater detail in a later chapter Tuning the Excalibur Ultra The spectrum scope at top right shows the spectrum as seen and acted upon by the currently selected virtual receiver This spectrum represents the output of the final decimation process and is available for final filtering and demodulation As a convenient short hand we will refer...

Page 22: ...n both the DDC and demodulator spectrum This is equivalent to the IF Shift function of conventional receivers Clicking on any of the three spectrum scopes will cause the receiver to tune to the corresponding frequency As the WiNRADiO Excalibur Ultra consists of three receivers in one this does have some ramifications which will be explained in a greater detail in the following chapters If you are ...

Page 23: ...e internal boundaries separating the three spectrum scopes Below is an example of how the application window can be resized This was achieved by first dragging the right hand edge of the application panel to extend the panel horizontally then making more room for the DDC spectrum at the expense of the demodulator spectrum by dragging the vertical line separating them to the right and finally by ve...

Page 24: ... it double clicking will select it and also close the list If you don t have a mouse wheel for example using a laptop with a touch pad instead of a mouse you can also use the keyboard up down cursor keys to navigate inside the list There is also another difference with this control On a long list you can click and drag the list and the mouse cursor wraps from the top to the bottom of the screen an...

Page 25: ...MHz or h for Hz after entering the digits The tuned frequency will be then displayed in those units Any invalid keystrokes are ignored The same principle of changing the displayed frequency units is applied anywhere in the Excalibur Ultra application where frequency is to be entered if you prefer to display or enter the frequency in different units simply terminate the entry with h for Hz k for kH...

Page 26: ... band descriptions can be overridden with a call sign or a user defined description of a particular frequency stored in memory This overrides the band description for that particular tuned frequency only It is also possible to change the naming and frequency allocations for entire frequency bands This can be done by editing the file called bands csv in the program installation folder usually C Pro...

Page 27: ...ouse button As the knob rotates the frequency will change in 1 kHz steps Holding the mouse button down will accelerate the tuning The step size can be changed to 100 Hz 10 Hz or 1 Hz by pressing the Alt Shift or Ctrl keys respectively while clicking the tuning knob with mouse button The tuning knob can also be conveniently rotated using a wheel of a wheel equipped mouse or any other standard Windo...

Page 28: ... as well as keep the other receivers tuned to their existing frequencies the software will dump disable one or both of the other two receivers giving priority to the currently selected one except if one of the other receivers is currently recording or its frequency is locked by the user In such case the new frequency will not be accepted and the recording or lock indicators inside the other receiv...

Page 29: ... tune the currently selected receiver to the corresponding frequency Also when clicking on the spectrum the Shift or Ctrl keys can be held down which will round the tuned frequency to the nearest kHz or 100 Hz respectively However there are some ramifications depending on which one of the three spectrum scopes you click Clicking inside the Wideband spectrum scope at the bottom of the application w...

Page 30: ...nge of the tuned frequency As with point and click tuning there are again some differences in behavior depending on which particular spectrum window the highlighted passband is being dragged in Firstly the wideband spectrum Dragging the grey area in the wideband spectrum will relocate the DDC passband to a new frequency However this movement will be disallowed if ...

Page 31: ...ator spectrum will result in continuously changing the filter bandwidth This function is not available in the DDC spectrum so as to prevent unwanted dragging of the entire passband when the shaded area becomes too narrow with larger DDC bandwidths For LSB mode dragging the right hand edge of the greyed out filter passband results in tuning dragging the left hand edge results in adjusting the filte...

Page 32: ...or example in order to avoid interference from an adjacent channel If you do this and you are for example tuned to an AM station using the AMS mode or an SSB station using the USB or LSB modes then moving away from the exact carrier frequency will result in a whistle being heard its pitch being directly proportional to the IF shift displacement This is because while you have changed the tuned freq...

Page 33: ... Tuning tab all the function tabs will be described in more detail in one of the following chapters The buttons marked 5 9 and 10 select the stepping size They correspond to the stepping size in kHz For example 5 kHz station spacing is typically used on short waves 10 kHz spacing separates medium wave stations in North America while 9 kHz spacing is used on medium waves elsewhere in the world The ...

Page 34: ...d frequency rather than having to manually transpose the displayed frequency to the down converter s input signal For this purpose there is an option to add a user defined offset to the displayed frequency This option is called Display offset and is located under the Options top menu bar As usual you can enter the display offset in Hz kHz or MHz by terminating the entered value with either h k or ...

Page 35: ... each receiver is displayed inside their associated tabs If the frequency of one of the other receivers does not fit into the current DDC bandwidth that receiver becomes disabled and the frequency in the tab turns red to indicate the disabled condition The position of all three virtual receivers is shown inside the DDC spectrum with the currently selected receiver highlighted If a receiver is tune...

Page 36: ...uttons are located at top right of the receiver control panel The individual buttons correspond to the following modes AM Amplitude Modulation AMS Amplitude Modulation Synchronous Demodulation LSB Lower Side Band USB Upper Side Band CW Continuous Wave Morse Code FM Frequency Modulation ISB Independent Side Bands DSB Dual Side Bands DRM Digital Radio Mondiale HF Digital Radio FSK Frequency Shift Ke...

Page 37: ...or minus 1 5 kHz default value from the actual signal frequency to enable easy tuning by pointing and clicking near the peak in the DDC spectrum or dragging the filter passband area in the demodulator spectrum Once locked to a signal the capture range automatically reduces Sync lock range to plus or minus 50 Hz default value from the signal frequency The reason for such reduction is to avoid kidna...

Page 38: ...nal select LSB on one and USB on the other and record the signals separately In the DSB dual sideband mode both side bands carry the same information but the carrier is either entirely or partially suppressed The controls and operation are similar to the AMS mode DRM Mode The DRM mode is a new broadcasting system designed to introduce digital broadcasting to medium and short waves This is achieved...

Page 39: ...the SNR value A DRM signal is capable of carrying four independent services i e four different streams of audio and text The four service selection buttons are used to select the particular service if a choice is available The Excalibur Ultra s DRM decoder can also decode multimedia content which is audiovisual information that may be broadcast by some DRM stations If such multimedia content is de...

Page 40: ... frequency readout of the main receiver display correspond to the published frequency allocation tables the tone frequency must be different The FSK tone frequency is traditionally set to 1 9 kHz due to the typical characteristics of modems relying on transmitters operating in a suppressed carrier mode However any offset may be used and the values are automatically saved UDM Mode The UDM User Defi...

Page 41: ...of the receiver s operation Tuning Tab The Tuning tab contains controls for Passband tuning BW presets demodulator spectrum Centering AFC Automatic Frequency Control and Stepping buttons For the AMS ISB and DSB modes it also contains lower or upper sideband selection and for the UDM mode there is also a mode selection Passband tuning The passband tuning control duplicates the function of dragging ...

Page 42: ...dths change depending on the selected mode offering an optimum choice of typical values applicable to that mode To change the demodulator bandwidth continuously you can use the DEM BW control located above the demodulator spectrum scope There are two ways you can use this control Either click on the box and highlight all digits then type the bandwidth directly into the edit box you can terminate t...

Page 43: ... the other adjusts the filter bandwidth The tuning edge is highlighted for easy orientation The same applies to AMS ISB and DSB modes if only one sideband is selected Frequency Stepping Another facility available under the tuning tab is Frequency stepping The buttons marked 5 9 and 10 select the stepping size They correspond to the stepping size in kHz The 5 kHz station spacing is typically used o...

Page 44: ...s spectrum and you would like to see this station relocated to the center of the demodulator spectrum AFC Automatic Frequency Control The AFC button when engaged forces the receiver to automatically adjust its tuning to follow the frequency drift of the received transmission Band Selection In the AMS ISB and DSB modes the tuning tab also includes Band selection controls These make it possible to c...

Page 45: ...he audio filter is a bandpass filter with continuously adjustable lower and upper cut off frequencies When the audio filter is enabled its low and high cut off frequencies can be adjusted using the Low and High controls The De em control is used to adjust de emphasis relating to the filter s slope from the highest frequency to the lowest which is particularly important for FM signals a typical de ...

Page 46: ... inside the Audio spectrum accessible by pressing the Audio button The filter can be also adjusted graphically by dragging either edge of the audio filter passband Clicking the RF button while the audio spectrum is displayed will return the spectrum scope to the default spectrum mode ...

Page 47: ...s it possible to disable the audio output It is faster and more practical to use than setting the volume to zero with the added benefit of not changing the set volume level To use the mute control simply click on this button Click again to release Audio Mixer The WiNRADiO Excalibur Ultra includes an audio mixer which makes it possible to combine audio outputs from the three virtual receivers in va...

Page 48: ...nly RX3 will be heard because it is currently selected and not connected to mixer Mix on Left on Right off Mix on Left off Right on Mix off RX1 Audio will come out for RX1 and RX2 only RX1 from left channel and RX2 from right channel Mix on Left on Right off Mix on Left off Right on Mix on Left off Right off RX3 Audio will come out for RX1 and RX2 only RX1 from the left and RX2 from the right chan...

Page 49: ...nd analog domains reducing distortion and improving signal quality For more information about the VSC please refer to the webpage www winradio com vsc The VSC control buttons become available once the VSC is installed Engaging the VSC button connects the selected receiver to the virtual sound card Using the IF button you can select the entire contents of the demodulator spectrum to the VSC the Aud...

Page 50: ...elated to the memory facilities of the Excalibur Ultra There are three types of memories User memory making it possible to store and recall arbitrary frequencies and group them together in a tree like structure HFCC memory useful for identification of stations according to the HFCC database EIBI memory that serves to identify stations according to the EIBI database You can select between these mem...

Page 51: ...rs and a hotkey To store a frequency into memory the receiver must first be tuned to that frequency Next click on the Store button A Store frequency window will pop up At the top of the window is the Callsign edit box That s where you would store a callsign or a name of the station whose frequency you are storing The next line contains a Description where you can type your comments regarding the s...

Page 52: ...y Hotkey For quick tuning to your favorite stations you can also assign a Hotkey function keys F2 to F12 to up to eleven different frequencies If you then press this hotkey the associated frequency will be instantly recalled Hotkeys which are already assigned will be shown in the drop down list preceded with an asterisk However you can overwrite the previous assignment with a new one if you wish R...

Page 53: ... and the frequency will be tuned Then close the window Editing Memory To change the settings for a particular frequency click on the Edit button or select Edit from the right click menu A window will open showing the current settings All settings can be edited After the entry has been edited click on OK ...

Page 54: ...from memory To delete all frequencies in a particular folder click on the Delete button at bottom left under the folders You will be asked to confirm that you want to clear all the frequencies in the folder Viewing User Memory To see the entire user memory structure you can use either the Recall button or the equivalent function Show user memory under the Memory top bar menu The User memory window...

Page 55: ...ntly selected group as displayed under the memory tab Memory Stepping Memory stepping makes it possible to step through frequencies stored in the current user memory file To step through groups or the individual memory frequencies use the left or right arrow buttons located under the memory tab next to Group or Item drop down list controls When the receiver is tuned to a frequency that is almost e...

Page 56: ...Memory File When the WiNRADiO Excalibur Ultra receiver application starts up the most recently used memory file will be opened automatically To open a different memory file select Load user memory from the File menu A dialog box will pop up allowing you to choose a memory file to load HFCC and EIBI The WiNRADiO Excalibur Ultra makes it possible to use two special frequency databases HFCC and EIBI ...

Page 57: ...ould be opened and its contents saved as HFCC TXT This file should replace the existing file of the same name in the My Documents Winradio G35DDC folder The EIBI list can be found at www eibispace de The data file is named EIBI TXT and it should simply be downloaded and saved to the My Documents Winradio G35DDC folder If either the HFCC or EIBI table is selected then whenever a frequency is tuned ...

Page 58: ... table Notch The Notch tab contains controls dedicated to the Notch filter function There are two notch filters that can be operated simultaneously The notch filter is a band stop filter which can be used to minimize the effects of interference falling inside or near a received station s spectrum Each filter is activated by pressing the associated Enable button The center frequency and the width c...

Page 59: ...ch filter stopband to the center of the demodulator filter passband This can be useful in situations when the notch filter is hidden beyond the currently visible demodulator spectrum limits in particular when the spectrum is zoomed in The following picture shows a signal with a strong interference in the passband the large peak right of center at the cursor position In the resulting audio typicall...

Page 60: ...e specified threshold the squelch will mute the receiver Noise squelch determines the level of noise in the received demodulated audio above which the squelch will mute the receiver This is particularly useful for the FM mode where there is a considerable level of noise in the absence of a useful signal The current Noise content value is shown next to the corresponding control Voice squelch determ...

Page 61: ...l Then tune to an occupied frequency where there is a useful signal and note the noise content value again Then set the noise threshold somewhere between these extreme values Note that the noise squelch is particularly effective in the FM mode and its values also depend on the demodulator bandwidth setting The adjustment procedure for the voice squelch is similar Tune to an unoccupied channel firs...

Page 62: ...he medium position For most practical applications the medium setting is recommended Slow setting would be used especially with Morse code CW mode while fast AGC speed might be appropriate for very noisy signals where noise bursts might temporarily desensitize the receiver if a slower AGC was employed While the timing of the slow medium or fast speed settings is fixed the remaining three settings ...

Page 63: ...ransmissions where the transmitter is switched on intermittently In such cases if the maximum gain was not limited the AGC might tend to increase the maximum gain too much which could result in unpleasant noise bursts between transmissions By limiting the maximum gain such noise bursts can be reduced or eliminated Manual Gain The Manual gain mode can be enabled using the Manual button which is mut...

Page 64: ...rom atmospheric effects and man made interference There are two types of noise blankers available one using the Short Time DDC Averaging method and another one using the ADC Input Threshold method The Short Time DDC Averaging method is based on comparing the instantaneous signal level at the DDC output demodulator input to a short time exponential average If the instantaneous level exceeds the sho...

Page 65: ...00 corresponds to the entire input range of the ADC Pause The Pause facility makes it possible to temporarily stop the audio and resume it at any time a useful function if one needs to get away from the receiver for a while This is a rather unique feature specific to the Excalibur Ultra the world s first in professional HF receivers While the receiver is pausing the entire incoming down converted ...

Page 66: ...tically removed from the buffer to make room for the incoming signal so that simultaneous buffering and playback can run for unlimited time effectively making it possible to listen to the signal with an adjustable delay In pause mode the Progress bar is greyed out and only shows the increasing amount of data in the buffer In resume mode the Progress bar becomes enabled making it possible for the u...

Page 67: ...ectrum is a subset of the DDC spectrum making it possible to inspect the signal with the highest resolution The demodulator filter bandwidth adjustable using the DEM BW control is the bandwidth of the last filter and the actual demodulated signal The demodulator spectrum width is the lesser value of 64 kHz and the DDC bandwidth The relationship between the selected DDC bandwidth and the width of t...

Page 68: ...trum scope includes Zoom buttons located at their respective tool panels Use the two zoom buttons to zoom in and out of the spectrum this is a useful feature for observing frequency peaks in close detail for example where stations are very close to one another When the spectrum window is zoomed you can use the bottom slider to conveniently navigate to a portion of the spectrum that you wish to ins...

Page 69: ...ccuracy of the various point and click operations inside the displayed spectra will be limited by the width of the displayed spectrum remember that the width of any of the spectrum scope windows is adjustable and can be extended over two or more monitors and the respective RBW limit of the particular spectrum scope The demodulator spectrum scope offers the best accuracy Spectrum Averaging The AVG ...

Page 70: ...an optical baseline It defines the lowest signal level value which should correspond to the darkest palette color i e black All signal levels below this baseline value will be drawn in this color also The palette gravity can be used to highlight a given signal level of special interest with additional contrasting colors If for example the palette gravity has been selected at 80 dBm then the monito...

Page 71: ...ble for users to create their own color palettes For details please see Appendix E Waterfall Spectrum Palettes Spectrum Markers This facility exists in the wideband DDC and audio spectrum scopes making it possible to mark frequencies of interest set reference points and calculate differential frequencies ...

Page 72: ...unctions become available Set marker reference this will set this particular marker as a reference from which frequency differences will be calculated and displayed for the other markers The reference marker will be marked with an R next to its displayed frequency The differential value with respect to the reference marker will be displayed next to the other markers Did you know The WiNRADiO AX 17...

Page 73: ...ted Tune to marker at xx xxx MHz this will tune the receiver to the marker frequency Clear all markers this function removes all markers from the spectrum Baseline Level The wideband spectrum scope makes it possible to adjust the baseline level using the Min Level control This adjusts the minimum displayed signal strength level and serves to maximize the useful display space in situations where th...

Page 74: ...ilable in this display mode When the Audio filter is enabled using the Filter button under the Audio tab its passband will be shown as a gray area superimposed over the audio spectrum The low and high cut off frequencies of the filter can be graphically adjusted by dragging the left and right edges of the displayed passband The input audio signal to the filter is shown in a darker color while the ...

Page 75: ... the demodulator spectrum mode Recording Functions At the top of DDC and demodulator spectrum scopes there are special Recorder buttons that serve to reveal their respective recording facilities Pressing this button will reduce the height of the spectrum scope at the bottom and utilize the extra space for the recorder controls ...

Page 76: ...d create separate audio files of three different stations The DDC spectrum recorder can be very useful in situations where there the DDC spectrum is to be searched for interesting stations or even when just one interesting signal is of some significance and needs to be analyzed A weak or interference obscured signal can thus be re received many times with different demodulator filter bandwidths no...

Page 77: ... and from zero to 30 seconds for audio recordings The Insert FDT button serves to insert the current local time and the currently tuned frequency into the file name with DDC files this will be the current center frequency of the DDC bandwidth As a result the file name may for example look like this rec 12 345678MHz_11 07 04_15 34 57 ddc for DDC files or rec 12 345678MHz_11 07 04_15 34 57 wav for a...

Page 78: ...d then incremented each time a new file is created For example the file name may look like this rec 001 wav When recording audio files the recording depends on the squelch condition If the receiver is squelched the recording will pause until the squelched condition is cleared When selecting the file name extensions you will be also offered WiNRADiO proprietary rxw for DDC recordings or wwv for aud...

Page 79: ... disappears this needs to be done manually If sensitivity appears poor please first ensure that the attenuator is disabled Preamplifier The Preamp button engages a low noise preamplifier which adds approx 10 dB of amplification to the front end and so increases sensitivity Please note that the actions of both the attenuator and preamplifier are compensated for by the S meter This means that the S ...

Page 80: ...is engaged its passband is indicated by a greyed out area visible in the spectrum S meter The WiNRADiO Excalibur Ultra receiver is equipped with a very sensitive and selective Signal Strength Meter S meter which makes it possible to measure peak or RMS signal level in dBm µV or S units within the demodulator filter passband The measurement units are selected by appropriately marked buttons at the ...

Page 81: ...dwidth gray shaded area in the demodulator spectrum display Please note that the actions of both the attenuator and preamplifier are compensated for by the S meter This means that the S meter always displays the true value of the signal strength at the antenna input within the available measurement range If the range is exceeded either Overrange or Underrange indicators are displayed in the S mete...

Page 82: ...are all saved as images using the standard BMP format Memory Export and Import The Save user memory as and Load user memory functions can save or load the user memory in the CSV format comma separated values making it possible to export frequencies in this commonly used format as well as import frequencies from third party sources Each line of CSV file contains the following information in this pa...

Page 83: ...file type in the respective window for example Did you know The comma separated values CSV file format is a very common human readable computer data format where numbers and text are stored in a plain text form Lines represent rows of a table and commas separate individual fields in the rows This format is actually quite old and pre dates personal computers by more than a decade a Fortran compiler...

Page 84: ...number of user settings making it possible to customize the receiver s look and behaviour adjust its numerous operational parameters activate various test and measurement displays calibrate the receiver as well as restore factory defaults for user definable parameters ...

Page 85: ...and normally intended for operation to 32 MHz Thanks to a high speed analog to digital converter the Excalibur Ultra is able to extend the maximum usable frequency to nearly 50 MHz The receiver s sensitivity starts declining at approximately 45 MHz due to the action of the anti aliasing filter ...

Page 86: ...tly DDC wide view In this spectrum viewing mode the bottom RF spectrum scope is replaced by the DDC spectrum while the demodulator spectrum is displayed above in full panel width This arrangement is more practical when working with the maximum DDC bandwidth where the DDC spectrum is basically identical to the HF band Disabling the DDC wide view mode brings the default spectrum displays placement b...

Page 87: ...load which will depend on this setting It may not be advisable to select a value resulting in more than say 30 CPU load as the computer may then become sluggish Should the computer become sluggish or even freeze as a result of this adjustment please reduce the demodulator filter length to a lower value Note also that the CPU load can be lowered while keeping selectivity high by reducing the DDC ba...

Page 88: ... used with the receiver Enter the required offset value in the Display offset edit box click OK and this value will be added to the displayed frequency Time The time information displayed in the top menu bar can be either the local time as provided by the PC or UTC Co ordinated Universal Time This can be selected by the user using this option It is also possible to select 12 or 24 hour time displa...

Page 89: ...ually impaired radio operators as a preferred alternative to a graphical user interface All shortcuts can be user defined If there is a conflict in the definition table the same keystrokes are specified for more than one function this will be highlighted in red The Default button restores the factory defaults and the Enable button can be used to enable or disable all shortcuts VSC Set up The Virtu...

Page 90: ...ze can be adjusted to control latency while the buffers count should be set to an optimum value to avoid drop outs in data due to unequal sampling rates between the applications Audio Buffering The audio signal resulting from the receiver filtering and demodulation process is sent to Windows multimedia output device i e in most cases the PC sound card Prior to this the audio data are buffered in o...

Page 91: ... the receiver will capture the signal and lock to synchronization If you are tuning to a new signal this Tune capture range is initially quite wide within 1 5 kHz factory default value from the actual signal frequency to enable easy tuning by pointing and clicking near the peak in the DDC spectrum or dragging the filter passband area in the demodulator spectrum You can adjust the Tune capture rang...

Page 92: ...increased possibility of losing sync due to a nearby strong signal When the signal is locked in synchronization this is indicated using a lock symbol located in the top left corner of the frequency display Audio Output The audio output function makes it possible to allocate each of the three virtual receivers to different audio devices available on your computer This may be handy in special applic...

Page 93: ...um wave stations in North America while 9 kHz spacing is used on medium waves elsewhere in the world Show Measurements The Test and Measurement functions of the Excalibur Ultra receiver make it possible to indicate the ADC input level in percentage of the entire ADC range Frequency error of the received signal assuming the receiver is tuned to the correct frequency AM modulation depth for AM modul...

Page 94: ...r the maximum SINAD Then gradually keep reducing the generator output level to the point when SINAD drops to 10 dB The receiver sensitivity is then equal to the generator level at this point Measuring AM sensitivity using SINAD rather than the conventionally used S N N is quite appropriate as SINAD also includes distortion which is as much an impediment to intelligible reception as noise and there...

Page 95: ...ile inviting the possibility of audio drop outs or distortion Both these controls are available under Options Show Waterfall Timestamps Invoking this option makes the waterfall spectrum display show time stamps making it possible to relate spectrum events to absolute time Calibration Since the Excalibur Ultra uses an accurate and stable temperature compensated crystal oscillator with 0 5 ppm parts...

Page 96: ...ce software defined narrow band receiver with superior quality crystal filters and a significant reserve in sensitivity and so able to provide a better signal to noise ratio than the Excalibur Ultra on very weak signals When the G313 receiver is connected selecting the Hand off receiver option under the Options top menu bar allows the Excalibur Ultra to pass the tuned frequency mode and bandwidth ...

Page 97: ...ged If the dark blue of the default skin does not suit there are more to choose from to suit the user s personal preference Restore factory defaults If you get lost by too much experimenting help is always at hand The Restore factory defaults function resets all the variables to the factory default values ...

Page 98: ...n Memory contains the following facilities Show user memory makes it possible to show and edit the entire memory structure while Memory search range serves to adjust the scope of search inside both the user memory and HFCC and EIBI databases Only stations within the specified frequency interval from the currently tuned frequency will be included in the search ...

Page 99: ...es and times When Show task list is selected the Task list is shown You can add new recording tasks by pressing the Add button at bottom left This opens the Add task window Did you know Not all calendars were synchronised with the Sun or the phases of the Moon Some ancient Egyptian calendars were synchronized to the motion of Venus ...

Page 100: ...WiNRADiO G35DDC HF Receiver 100 ...

Page 101: ...ither run a special purpose plug in an external application program or make a recording The last option Record selected by default is the one that is most commonly used The file name edit box allows to chose the recorded file name and the actual recording file format for more Information about recording formats please refer to Appendix F If the recording action is selected you can then select whet...

Page 102: ...hese last two functions serve for convenience and duplicate the Add and Edit buttons By default the recorded audio files are saved in the My Documents WiNRADiO G35DDC folder but you can change this using the function Recording directory in the scheduler top bar menu You will be presented with a file browser making it possible to select a folder where any audio files recorded by the scheduler will ...

Page 103: ...to log signal strength on up to three frequencies at the same time These are specified by simply tuning one or more of the three virtual receivers RX1 to RX3 to the desired frequencies A simple dialog box makes it then possible to specify the file path and name into which the logging will be made in the CSV format and the logging period ...

Page 104: ...p bar menu is Plugins Like many WiNRADiO products the Excalibur Ultra has the capability to integrate with WiNRADiO s XRS Extensible Radio Specification plug ins that can extend the receiver s capability in many respects These can include various general purpose enhancements related to particular user interface functions as well as additional demodulators and other signal processing facilities It ...

Page 105: ...ormerly called GMT Greenwich Mean Time which is the standard time used around the world This is provided because most shortwave stations announce their broadcast times in UTC Both time modes derive their information from the PC clock The time difference is determined by a setting in your Windows Control Panel Date and Time setting Time Zone tab Did you know Coordinated Universal Time is abbreviate...

Page 106: ...ts tuned circuits and various amplifiers mixers and oscillators Following the final down conversion the resulting signal is applied to a demodulator and then to the audio output circuits These receivers depend only on hardware for their performance and functionality In the currently prevailing nomenclature of the SDR industry they are formally referred to as SDR Tier Zero receivers meaning that th...

Page 107: ... additional cost Radio receivers that implement such software control yet still retain most of their other functionality defined by hardware are often classified as SDR Tier One or Software Controlled Radio Second Generation SDR The second generation SDR receivers bring the radio computer integration a step further by including an analog to digital converter ADC into the essential functionality of...

Page 108: ... same input a software routine will always produce the same result not depending in variations and aging of components such as diodes resistors and capacitors Another advantage of this concept is in the ability to present the IF signal in a real time spectrum display Being able to see a signal and its neighborhood in addition to merely hear it has brought about a major paradigm change and increase...

Page 109: ...minate hardware based heterodyne processes and introduce the concept of digital down conversion where the local oscillator and a mixer can be replaced with a single software reconfigurable hardware component Modern ADCs can achieve a sampling rate of 100 MHz and beyond The Nyquist theorem says that the maximum frequency that can be sampled needs to be smaller than half of the sampling rate see www...

Page 110: ...One of the great practical limitations of SDR receivers is the ability to send the data produced by the device into the computer There are a number of transport mechanisms such as Firewire Ethernet and USB However none are perfect and as a compromise between user convenience and flexibility USB 2 0 remains the favored interface of choice USB 2 0 has a design limit of 480 Mbit s although this is re...

Page 111: ...interfaced disk drives it is important to remember that If the external hard drive is USB interfaced and connected via a USB hub shared with the Excalibur Ultra the total USB data transfer speed has to be shared thus reducing the performance of both devices So far we have discussed the clever digital bits of SDRs but we should not ignore the RF issues associated with direct sampling such as the ef...

Page 112: ...e close to 50 MHz With a signal input of less than 50 MHz all is well But above 50 MHz an image or alias signal will appear in the spectrum below 50 MHz For example if a signal at 85 MHz is present due to the aliasing effect this would appear on 15 MHz and potentially mask a wanted signal there In the Excalibur Ultra this effect is significantly reduced by the use of a high quality low pass filter...

Page 113: ... a peak but there is no sound coming from the speaker please check the following The Mute button under the Audio tab is disengaged and the volume is set to a medium level say 15 AGC under the Gain tab is enabled and set to medium speed The squelch is disabled the Enable button under the Squelch tab is disengaged The sound card output is properly connected to speakers or headphones and both the Wav...

Page 114: ...he maximum level under the Audio tab try to adjust the Wave and Master volume also in the sound card control panel or on the amplified speakers you are using Make sure that AGC under the Gain tab is enabled Try to adjust the Gain parameter under the Audio tab excessive audio gain can cause distortion I can hear the audio and tune the receiver but the software is very sluggish sometimes it may even...

Page 115: ... outdoor antenna is preferable Watch for ground loop problems for details see the chapter Connecting the Antenna Reception is obscured with a buzzing interference Check for the sources of interference in your surroundings it could be fluorescent lights a lamp dimmer or other household appliances Your PC could be the culprit Unless you are able to suppress the interference at the source the only so...

Page 116: ...uires a personal computer to operate this creates a potential paradox The receiver itself is designed to be substantially immune to computer generated interference However any receiver needs to be connected to an antenna and antennas can t discriminate between useful signals and interference The interference from your computer can either radiate directly to the antenna or it can be conducted to it...

Page 117: ...pical but curable problem with PC controlled receivers A most effective remedy is the WiNRADiO WR CMC 30 Common Mode Choke see www winradio com cmc30 which is well proven to cure most common mode interference problems In extreme cases two or more chokes can be used placed strategically along the antenna lead where suitable grounding points exist Long wire antennas while most commonly used also app...

Page 118: ...4 100 64 125 64 160 64 200 64 250 64 320 64 400 64 500 64 640 64 800 64 1000 64 1250 64 1600 64 2000 64 2500 64 3200 64 4000 64 5000 64 6400 64 8000 64 10000 64 12500 64 16000 64 20000 64 25000 64 32000 64 The demodulator spectrum width is important to keep in mind when the VSC is used with the IF output The width of the exported spectrum of the VSC IF output equals to that of the demodulator spec...

Page 119: ...he waterfall the bottom line corresponds to the minimum signal strength min_SS Each line contains a set of decimal RGB values separated by spaces 0 0 0 represents black 255 255 255 is white The incoming signal strength values are mapped to this color space as follows If the attenuator is off the minimum signal level is 150 dBm the maximum level is 0 dBm If the attenuator is on the attenuation valu...

Page 120: ...en replaying an RXW recording the recorder panel shows the original time of the played back signal and the DDC spectrum scope shows the original DDC frequency If Waterfall timestamps option is enabled the DDC waterfall also shows the original time in its vertical axis All DDC files are stereo as they are stored in the I Q form and 32 bit except for 3 2 MHz and wider DDC bandwidth which are 16 bit ...

Page 121: ... players such as the WiNRADiO WAARP The following standard naming conventions apply to files created by the DDC and audio recorders If the Insert FDT button is pressed a file with a name such as rec 12 345678MHz_11 07 04_15 34 57 ddc is created The center frequency of the DDC spectrum together with the current local time are saved as a part of the file name to be able to position the spectrum accu...

Page 122: ...e will be automatically closed and named rec 12 345678MHz 001 001 ddc where the sign denotes these split sections and recording will automatically continue into a file named rec 12 345678MHz 001 002 ddc If you manually stop and restart the recording it will continue to a file named rec 12 345678MHz 002 ddc etc ...

Page 123: ...al inputs that may or may not be installed depending on the customer requirement At the rear of the card there is a standard 6 pin connector for auxiliary power as well as and optionally an SMA connector for coherent clock input The Auxiliary Power connector is useful if more than one card is installed in the computer and there is not enough power provided by the PCI Express bus ...

Page 124: ...ock source At the component side of the card there is an optional Digital synchronization interface connector which is needed together with aforementioned Coherent clock input to synchronize multiple receivers in coherent multichannel applications For more detailed technical information about these connections please refer to the particular product s technical specifications ...

Page 125: ...erference that may cause undesired operation We have determined and warrant that the above described device has been shown to comply with the requirements of the FCC Part 15 by having a device tested at an accredited testing laboratory Each unit marked is identical to the device as tested Compliance assumes no unauthorized changes will be made to the equipment and it will be maintained and operate...

Page 126: ...ed of separately from the municipal waste stream via designated collection facilities appointed by the government or by the local authorities 3 The correct disposal of your old appliance will help prevent potential negative consequences for the environment and the human health 4 For more detailed information about the disposal of your old appliance please consult your city office waste disposal se...

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Page 128: ...WiNRADiO C O M M U N I C A T I O N S w w w w i n r a d i o c o m ...

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