Ja, det er let at gå til, det mester drejer sig om software, selve den elektriske del er rimelig overskuelig. Man kan for få hundrede kroner lave en radio der er som en der kostede adskellige tusinde for år tilbage. F.aks. kan man købe en af de moderne digitale TV modtager dongler til en halvtredser, så kan man modtage hele VHF og UHF området ved hjælp af den og en computer.
Søg lidt på SDR på nettet og så finder du masser af artikler om emnet, på youtube er der også masser.
Nej egentligt ikke, men jeg har altid været interesseret i kortbølgelytning og har en fin sony SW100 som jeg førhen brugte en del i udlandet til at høre bl.a. DR kortbølge samt BBC mv.
Selv om jeg ikke har lyttet til kortbølge i nogle år interesseret det mig stadig, og når det så kombineres med computer er det yderligere et plus.
hvor der ofte findes modtagere til SDR. Bl.a. fra EDR's horsensafd. har de haft et project med SDR kaldt LIMA, der oprindeligt stammer fra Tyskland som byggesæt.
De fleste DVB-T/S/C(2) dimser (USB, tv-modtagerbokse, TV, harddiskoptagere, media-centre, HTPC...) ...
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Mange frit tilgængelige internet-fjernstyrede radiomodtager er baseret på SDR - prøv dem via kilderne og links!:
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A Brief Discussion of Some Software DSP Solutions I've tried:
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Citat: "... DSP is an acronym for "Digital Signal Processing". Anytime an analog signal is converted to digital form and processed in some way, that is DSP. The use of DSP techniques in amateur radio is exploding, both in terms of its use in commercial transceivers and receivers, and in terms of homebrew hardware and software construction projects available to and undertaken by hams ... I have found that Linrad does an absolutely superb job of allowing me to hear the desired weak signal hidden in the midst of the all the noise and clutter present at my QTH. It does this better than any other receiving system I have ever tried. ... [PS: Nu kan man også få musearm af at være radioamatør...:] By clicking with the mouse cursor at any point on the waterfall ... IT IS POINT AND CLICK RECEIVING!!! ... If you want a different filter bandwidth or shape factor, you just take the mouse over to the baseband display, and drag the filter curve wider or narrower, and the filter adjusts graphically. THIS REALLY WORKS!! ..."
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Teknisk:
Se:
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SDR anvendes typisk sammen med:
Zero-IF receiver:
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Andre relaterede eller ens termer (kært barn har mange navne?):
Quadrature Sampling Detector QSD (Dan Tayloe N7VE): Tayloe Detector IQ based tranceiver Dirodyne
Til sender: quadrature-sampling exciter (QSE)
God (tysk): Quadrature Sampling Detector - ein moderner Geradeausempfänger [retmodtager]:
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IQ-kanalerne laves noget i denne stil:
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I/Q In-phase/Quadrature component:
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Citat: "...The component that is in phase with the original carrier is referred to as the in-phase component. The other component, which is always 90° (\begin{matrix} \frac{\pi}{2} \end{matrix} radians) out of phase, is referred to as the quadrature component..."
IQ-signalbehandling er faktisk en gammel metode som også anvendes ved analog (og digital) SSB-(de)modulation:
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Citat: "... To generate an SSB signal with this method, two versions of the original signal are generated which are mutually 90° out of phase. Each one of these signals is then mixed with carrier waves that are also 90° out of phase with each other. By either adding or subtracting the resulting signals, a lower or upper sideband signal results. ..."
Det er vistnok denne metode YU1LM anvender:
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Citat: "... In Weaver's method, the band of interest is first translated to be centered at zero, conceptually by modulating a complex exponential exp(j?t) with frequency in the middle of the voiceband, but implemented by a quadrature pair of sine and cosine modulators at that frequency (e.g. 2 kHz). This complex signal or pair of real signals is then lowpass filtered to remove the undesired sideband that is not centered at zero. Then, the single-sideband complex signal centered at zero is upconverted to a real signal, by another pair of quadrature mixers, to the desired center frequency. ..."
ZERO-IF AND NEAR-ZERO-IF QUADRATURE RECEIVERS FOR SDR:
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Citat: "... Zero Intermediate Frequency (ZIF) and Near Zero Intermediate frequency (NZIF) quadrature receivers are more sensitive to circuitry mismatch, which causes I-Q imbalance that may be frequency dependent over the signal bandwidth. ..."
I Softrock anvendes 74HC4052 og andre CMOS baserede digitalt styrede kontakter som I/Q-mikser:
SM 5 BSZ - I/Q mixer for direct conversion radio (Sept 28 2001):
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Citat: "... The simple HCMOS mixer in fig 1. produces a second order spur at -50dB when the level is adjusted for a standard low noise op-amp to degrade the dynamic range by less than 3dB. ... Fig 1. A quadrature nixer [mixer] using 74HC4052. The control inputs are fed from a synchronous counter that divides a local oscillator by four. As a result the switch loops through all four positions during a period of 4 local oscillator cycles, see fig. 2. For each switch position only one connection is made between the antenna and either output. This way the make before break operation of the switch will not cause shortcircuits across the coil as would be the case using 74HC4053 as in an older design. The dynamic range of the 74HC4052 design is superior to that of the 74HC4053 design. ..."
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Ældre:
RX-350 HF DSP RECEIVER (der findes en bedre udgave idag med DRM (Digital Radio Mondiale) MF-udgang):
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"... The built-in 34 bandwidth filters from 300 Hz to 8 kHz are instantly selectable by turning a knob. All filters are independent of mode - use any available filter in any receive mode. ... Momentary 'SWEEP' function shows band activity in 8 selectable coverage rates. Find the signals without even being on frequency! Simply tune to a desired frequency, select one of 8 SWEEP ranges, and press the SWEEP button. Signals will be shown on the bar graph on opposite sides of the starting frequency. A cursor will appear and allow you to tune RX-350 to any signal visible on the screen. Easy! ... RX-350 HF DSP Receiver $1199.00 ... SPECTRUM SWEEP DISPLAY 8 widths from 240 Hz to 2.4 MHz, with tuning cursor and selectable Autosweep function. ..."
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Her er en fiks og færdig SDR/DSP baseret HF-transceiver:
Ten-Tec is pleased to announce the successor to the original ORION transceiver: ORION II:
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Pris - sølle 3995$...av. Og så kan man ikke engang se SSTV, fjernsyn eller Doom II på farveskærmen. Det er simpelthen anakronistisk at de har sat et antikt drejespoleinstrument på forsiden hvor farveskærmen også er...
Opgradering? = ny firmware!
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Det flyder også med selv-byg SDR:
SoftRock-40:
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Citat: "... The SoftRock-40 is a small, low-cost, good performing 40-meter "software defined radio" receiver that plugs into a computer USB port and delivers I-Q audio signals to the computer's sound card. It was designed by Tony Parks, KB9YIG and Bill Tracey, KD5TFD as an "SDR sampler project" for hams everywhere to easily try out software defined radio. ..."
og deriviater:
November 2008 Informationen zum SoftRock RXTXv6.3 XTALL:
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PowerSDRv1.12.0 SoftRock RxTx Si570 Setup.msi:
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PowerSDR Software For Software Defined Radio I.F. Stage Use
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Euro SOFTROCK-RXTX ?87:
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Essex:
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Softrock RxTx:
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SoftRock V7.0:
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A small, low-cost "Software Defined Radio" receiver kit for 40-meters, used with powerful software on the PC for multi-mode operation:
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For radioamatører (ældre):
W7PUA DSP-10 2 Meter. [SDR] Software Defined Transceiver. Surface-Mount Kit:
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The DSP-10 is an amateur-radio, software-defined 2-meter transceiver that can be built at home. It operates on SSB, FM and CW modes. Features are tailored to operation with weak signals on VHF, UHF and Microwave frequencies. DSP-10 All-Mode 2m:
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DSP-10 Weak-Signal Update.
2-Meter EME [Earth-Moon-Earth] QSO with Single Yagis and 150 Watts:
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W7PUA DSP-10 2 Meter Software Defined Transceiver Surface-Mount Kit
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We're creating an open source Software Defined Radio. We're designing the s/w and h/w to enable experimentation with the latest digital wireless protocols:
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RadioRaft 3.21 Multimode Radio Data Decoder Software for decoding
12 ARQ modes, 10 FEC modes, 3 packet modes and many others ...
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openQRP:
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Software Defined Radio:
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SDR forum 2.0:
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Software Defined Radio "Blueberry SDR":
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Building and Using the WB6DHW
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This software can demodulate DRM, AM, FM, SSB, CW from 12 kHz IF signal:
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issue 365, May 2007, Elektor: Software Defined Radio With USB interface:
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A Software Defined Radio for the Masses, Part 4:
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DIGITAL IF: The VITA (49) Radio Transport (VRT) Providing Interoperability for Software Defined Radios:
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jansky eme:
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MFSK means Multi - Frequency Shift Keying
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849,00 ?
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VIP Perseus hovedside:
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$1100
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Penelope:
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Mail-lister:
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Citat: "... Additionally, all A/D conversions are performed internally in the FLEX-5000 so a sound card is not required. There are two additional versions of the FLEX-5000 (models C and D) that provide higher levels of integration. ... The FLEX-5000C? model has a built in Intel Core2 Duo processor and comes with the Microsoft Windows XP operating system, wireless keyboard and mouse. The FLEX-5000D? includes everything above and adds a 9" LCD display with touch screen, 300 Watt PA and a large tuning knob. ..."
The FlexRadio FLEX-5000A? High Performance Software Defined Radio at its Best!
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Citat: "... Top Performing Narrow-Spaced Two-Tone 3rd Order IMD Dynamic Range at 2 KHz - (Not 20 KHz Like Everyone Else Advertises). An Incredible 105 dB on 14 MHz. ... Industry Leading Narrow Spaced 3rd Order Intercept Point: +33 dBm at 2 KHz Tone Spacing. ... No Sound Card Required! No longer do you have to worry about interfacing a sound card to your PC. The FLEX-5000 has integrated the A/D and D/A processing hardware built inside the radio. A high quality 192 KHz 24-bit DACs with exceptional performance numbers provides the spectral samples for the DSP to process. The integrated converters also eliminate audio cabling requirements between the transceiver and PC. ... True Full Duplex Operation for Simultaneous Transmit and Receive ... True Diversity Receiving with the Second Independent Receiver ... By locking both receivers to the same frequency you can produce "stereo diversity" which allows your brain to more easily sort the signal from the noise. ... Single 1394 FireWire Connection to your Computer ... Transverter Ready - Full Duplex 28 MHz IF The FLEX-5000's incredible receiver is perfect for weak signal VHF+ and WSJT operation as a 28 MHz IF for interfacing to external transverters. The FLEX-5000 will turn your VHF-UHF-microwave setup into the highest performance station around. Full duplex operation opens the door for satellite communications as well. ... No External Calibration Equipment Required ..."
FLEX-5000 Block Diagram This PDF file is the block diagram of the FLEX-5000 full duplex /triplex architecture:
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Fundet via:
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MAX2023 High-Dynamic-Range, Direct Up-/Downconversion 1500MHz to 2300MHz Quadrature Mod/Demod. Highest Linearity, Lowest Noise 1.5GHz to 2.3GHz ZIF Modulator/Demodulator Enables Zero-IF Direct-Conversion Architectures for DCS/PCS EDGE BTS Transmitters:
Jeg lytter til audio i hovedtelefon gennem en FM transmitter i audio stikket på min Macbook når jeg ser TV (over LAN fra en Elgato EyeTV Netstream DTT):
FM signalet modtages med en ældre (analog) Sony FM Walkman:
Fin lydstyrke. Jeg er nød til at skrue ned selvom jeg har dårlig hørelse.
Jeg har så anskaffet en Ennovia DAB+/FM Bærbar Radio modtager, model EN-DAB51
Det er vel nok en SDR? Medens lydstyrken på DAB/DAB+ er fin når det er radio, så er lydstyrken på FM radio (analog) meget dårlig/lav.
Er det mon fordi en SDR ikke "oversætter" det analoge signal godt nok?
Findes der så en (digital?) transmitter, der vil virke bedre med DAB+/FM modtageren end min nuværende (Belkin) FM transmitter?
Den specifikke SDR - nok ja. Især hvis A/D-konvereteren ikke omsætter til nok bits - og den digitale signalbehandling ikke foregår med nok bits og dermed laver grovere afrundninger.
Generelt om SDR - nok nej. Men SDR er selvfølgelig ikke garanti for god lydkvalitet.
Den eneste kvindelige elektronik-geek jeg er stødt på og som accepterer et rodet skrivebord og hjemmelavede antenner. ;-) Og hun ved hvad hun snakker om og er rimelig pædagogisk:
Software Defined Radio VLOG Part 1:
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(Her præsenteres også et ægte gitterdykmeter med elektronrør:) Software Defined Radio Vlog - Part 2:
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Software Defined Radio Vlog - Part 3:
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Software Defined Radio Vlog Part 4 - Frequency Scanning:
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Software Defined Radio Vlog Part 5 - Baseband Capture and Audio Out:
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Software Defined Radio Vlog Part 6 - VGA and 256 Point FFT:
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Software Defined Radio Vlog Part 7 - AM Demodulation and Floating Point:
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Jeri Ellsworth:
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Jeri Ellsworth youtube:
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F.eks. lav dine egne transistorer:
Semiconductor:
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Homebrew NMOS Transistor Step by Step - So Easy Even Jeri Can Do It:
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Make a Point Contact Transistor at home:
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OA81 og OA90 kan f.eks. også anvendes.
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Sep 01, 2004, Listening to FM Radio in Software, Step by Step:
Citat: "... However, if one looks at many reports of the FlexRadio software defined radio, it is clear that FlexRadio have never succeeded in getting a decent FM demodulator. The performance of those never seems to live up to the hype. ... But to add a DSP and A/D just for demodulation is pricey compared a simple analog pll demodulator. ..."
Better FM demodulator:
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Citat: "... You will not outdo a standard analogue PLL with low phase noise in the VCO in a hurry.Why go digital when there is a perfectly cheap analogue solution? ..."
Grov sammenligning:
Generelt bruger SDR mere strøm end analoge AM og FM radioer.
I "manualen" til DAB+/FM radioen - der har indbygget batteri, der oplades gennem et USB kabel - oplyses 22 timer for FM og 8 timer for DAB+ med note om, at de 8 timer DAB+ kan variere med signalstyrken.
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