D STAR Wikipedia. ICOM IC 9. 1AD handheld transceiver with the D STAR UT 1. D STAR Digital Smart Technologies for Amateur Radio is a digital voice and data protocol specification for amateur radio. The system was developed in the late 1. Im spending a month or so improving the speech quality of a couple of Codec 2 modes. I have two aims Make the 700 bits codec sound better, to improve speech. Ham. net Article Say Yes To DStar K9RUF encourages people to learn more eHam. Web site dedicated to ham radio amateur radio. Q. What is the frequency range A. MHz, although straw poll tests on preproduction units indicate that units can be stretched down to 51. MHz or so. Codec 2 is an open source speech codec designed for communications quality speech between 7 bits. The main application is low bandwidth HFVHF digital. DSTAR Digital Smart Technologies for Amateur Radio is a digital voice and data protocol specification for amateur radio. The system was developed in the late 1990s. Japan Amateur Radio League and uses minimum shift keying in its packet based standard. There are other digital modes that have been adapted for use by amateurs, but D STAR was the first that was designed specifically for amateur radio. Several advantages of using digital voice modes are that it uses less bandwidth than older analog voice modes such as amplitude modulation and frequency modulation. The quality of the data received is also better than an analog signal at the same signal strength, as long as the signal is above a minimum threshold and as long as there is no multipath propagation. D STAR compatible radios are available for HF, VHF, UHF, and microwave amateur radio bands. In addition to the over the air protocol, D STAR also provides specifications for network connectivity, enabling D STAR radios to be connected to the Internet or other networks, allowing streams of voice or packet data to be routed via amateur radio. D STAR compatible radios are manufactured by Icom, Kenwood, and Flex. Radio Systems. 1HistoryeditIn 1. The process was funded by a ministry of the Japanese government, then called the Ministry of Posts and Telecommunications, and administered by the Japan Amateur Radio League. In 2. 00. 1, D STAR was published as the result of the research. In September 2. Icom named Matt Yellen, KB7. TSE now K7. DN, to lead its US D STAR development program. Starting in April 2. Icom began releasing new D STAR optional hardware. The first to be released commercially, was a 2 meter mobile unit designated IC 2. H. Icom followed up with 2 meter and 4. MHz handheld transceivers the next year. However, the yet to be released UT 1. D STAR mode. Eventually, the card became available and once installed into the radios, it provided D STAR connectivity. The June 2. 00. 5 edition of the ARRLs QST magazine reviewed the Icom IC V8. JARL released some changes to the existing D STAR standard in late 2. Icom, aware that the changes were coming, delayed the release of their hardware in anticipation of the changes. D-Star+%E2%80%93+What+is+it+Method+of+moving+voice+packets+encoded+by+the+AMBE+vocoder%2C+locally%2C+regionally%2C+or+globally..jpg' alt='Ambe Codec Software For Windows' title='Ambe Codec Software For Windows' />It has been suggested that List of opensource codecs be merged into this article. Discuss. The following is a list of compression formats and related codecs. Developer and manufacturer of lowbitrate, voice compression software and hardware solutions for use in consumer, commercial, and military communications. Ambe Codec Software' title='Ambe Codec Software' />The Icom ID 1 1. GHz mobile radio was released in late 2. DummyRepeaterDV3000-2.jpg' alt='Ambe Codec Software' title='Ambe Codec Software' />The ID 1 was the first and only D STAR radio that provides digital data DD mode operation. In this mode, data can be transferred at 1. RJ 4. 5 Ethernet jack on the radios. The first D STAR satellite. Ambe Codec SoftwaresIssuu is a digital publishing platform that makes it simple to publish magazines, catalogs, newspapers, books, and more online. Easily share your publications and get. DSTAR System 1 Technical Requirements for the Wireless System 1. Voice Communication 1. General Terms 1 Communication Method. S5su-7gZo/WcfMPKcCkfI/AAAAAAAACAs/bWqpOewY-ywoJJI6U4Xjf2gQgwwUGbfRwCLcBGAs/s1600/RX%2BGroup%2Blist.JPG' alt='Ambe Codec Software To Purchase' title='Ambe Codec Software To Purchase' />QSO occurred between Michael, N3. UC, FM 1. 8 in Haymarket, Virginia and Robin, AA4. RC, EM 7. 3 in Atlanta, Georgia while working AMSATs AO 2. Miniaturized satellite in 2. The two experienced minor difficulty with doppler shift during the QSO. As of late 2. 00. D STAR users talking through D STAR repeaters with Internet connectivity via the G2 Gateway. There are approximately 5. G2 enabled repeaters now active. Note, these numbers do not include users with D STAR capabilities that are not within range of a repeater, or working through D STAR repeaters that do not have Internet connectivity. The first D STAR capable microsatellite was launched in early 2. OUFTI 1 is a Cube. Sat built by Belgian students at the University of Lige and I. S. I. L Haute cole de la Province de Lige. The name is an acronym for Orbital Utility For Telecommunication Innovation. The goal of the project is to develop expertise in various aspects of satellite design and operation. The satellite weighs just 1 kilogram and utilize a UHF uplink and a VHF downlink. In 2. Flex. Radio Systems added D STAR support to their line of HF transceivers and receivers via a software upgrade. D STAR support requires the addition of the Thumb. DV device8 from NW Digital Radio. Technical detailseditThe system today is capable of linking repeaters together locally and through the Internet utilizing callsigns for routing of traffic. Servers are linked via TCPIP utilizing proprietary gateway software, available from Icom. This allows amateur radio operators to talk to any other amateurs participating in a particular gateway trust environment. The current master gateway in the United States is operated by the K5. TIT group in Texas, who were the first to install a D STAR repeater system in the U. S. 1. 0D STAR transfers both voice and data via digital encoding over the 2 m VHF, 7. UHF, and 2. 3 cm 1. GHz amateur radio bands. There is also an interlinking radio system for creating links between systems in a local area on 1. GHz, which is valuable to allow emergency communications oriented networks to continue to link in the event of internet access failure or overload. Within the D STAR Digital Voice protocol standards DV, voice audio is encoded as a 3. AMBE encoding, with 1. FEC, leaving 1. 20. DV mode. On air bit rates for DV mode are 4. In addition to digital voice mode DV, a Digital Data DD mode can be sent at 1. A higher rate data protocol, currently believed to be much like ATM, is used in the 1. GHz link radios for site to site links. Radios providing DV data service within the low speed voice protocol variant typically use an RS 2. USB connection for low speed data 1. Icom ID 1 2. 3 cm band radio offers a standard Ethernet connection for high speed 1. Gateway servereditThe current gateway control software rs rp. G2, more commonly called Gateway 2. Though most Linux distributions should be suitable, the recommended configuration uses Cent. OS Linux 5. 1 with the latest updates, typically running kernel 2. BIND 9. 2. 1 or later. The CPU should be 2. GHz or faster and the memory should at least be 5. MB or greater. There should be two network interface cards and at least 1. GB free of hard drive space which includes the OS install. Finally for middleware, Apache 2. Tomcat 5. 5. 2. 0, modjk. Open. SSL 0. 9. 8d, Java SE 5. SQL 8. 2. 3 are utilized, but these can be different as updates occur. Along with the open source tools, the Icom proprietary dsipsvd or D STAR IP Service Daemon and a variety of crontab entries utilize a mixture of the local Postgre. SQL and BIND servers to look up callsigns and pcname fields stored in BIND which are mapped to individual 1. During installation, the Gateway 2. Web based open source tools from source for standardization purposes, while utilizing some of the packages of the host Linux system, thus making Cent. OS 5. 1 the common way to deploy a system, to keep incompatibilities from occurring in both package versions and configuration. Additionally, gateways operating on the U. S. trust server are asked during initial setup to install DStar. Monitor which is an add on tool that allows the overall system administrators to see the status of each Gateways local clock and other processes and PIDs needed for normal system operation, and also sends traffic and other data to servers operated under the domain name of dstarusers. By this means a complete tracking of user behaviour is technically possible. Installation of this software also includes Java. APRSd, a Java based APRS interface which is utilized on Gateway 2. IcomD STAR GPS tracking system called DPRS to the more widely known and utilized amateur radio APRS system. 2005 Audi A6 Mmi Software Update. Over the past 3. 0 years, HF radio noise in urban areas has steadily increased. S6 S9 noise levels are common, which makes it hard to listen to the signals we want to receive. Ive been wondering if we can attenuate this noise using knowledge of the properties of the noise, and some clever DSP. Even 6d. B would be useful, thats like the transmitting station increasing their power by a factor of 4. Ive just spent 2 months working on a 4d. B improvement in my Free. DV work. So this week Ive been messing about with pen and paper and a few simulations, exploring the problem of man made noise on HF radio. PWM Noise. One source of noise is switching power supplies, which have short, high current pulses flowing through them at a rate of a few hundred k. Hz. A series of short impulses in the time domain produces a series of spectral lines i. Hz switcher produces tones at 2. Hz, 4. 00k. Hz, 6. Hz etc. These tones are the birdies we hear as we tune our HF radios. The shorter the pulses are, the higher in frequency they will extend. Short pulses lead to efficient switch mode power supplies, which is useful for energy efficiency, and especially desirable for high power devices like electric car chargers and solar panel inverters. So the trend is shorter switching times, higher currents and therefore more HF noise. The power supplies adjust the PWM pulse width back and forth as they adjust to varying conditions, which introduces a noise component. This is similar to phase noise in oscillators, and causes a continuous noise floor to appear in addition to the tones. World Of Warcraft Collection Epub Reader. The birdies we can tune around, but the noise floor sets a limit on urban HF operations. The Octave script impulsenoise. Here is a plot of some PWM impulse samples top, and the HF spectrum. Ive injected a wanted signal at 1. MHz for comparison. Given a switcher frequency of 2. Hz, with 0. 1. V impulse amplitude, the noise floor is 9. BV down, or about 1. V. This is S5 S6 level noise, assuming 0. V impulse amplitude induced onto our antenna by local switcher noise, e. TV. These numbers seem reasonable and match what we hear in our receivers. Single Pulses. Single, isolated pulses are an easier problem. Examples are lightning or man made sources that produce pulses at a rate slower than the bandwidth of the signal we are interested in. A single impulse produces a flat spectrum, so the noise at frequency f Hz is almost the same as the noise at frequency fdelta Hz, where delta is small. This means you can use the noise at frequencies next to the one you are interested in to estimate and remove the noise in your frequency of interest. Here is an impulse that lasts two samples, the magnitude spectrum changes slowly, although the phase changes quickly due to the time offset of the impulse. Turns out that if the impulse position is known, and most of the energy is confined to that impulse, we can make a reasonable estimate of the noise at one frequency, from the noise at adjacent frequencies. Below we estimate the phase and magnitude green cross of frequency bin Hk1 nearby blue cross from bin Hk. Ive actually plotted Hk 1, Hk, and Hk1 for comparison. The error in the estimation is 4. B down, so thats a lot of noise removed. Unfortunately this gets harder when there are multiple impulses in the same time window, and I cant work out how to remove noise is this case. However this idea might be useful for some classes of impulse noise. Noise Blanker. Another idea I tried was blanking out the impulses, buy opening and closing a switch so that the impulses are not allowed into the receiver. This works OK when we have a wideband signal, but falls over when just a bandpass version is available. In the bandpass version the pulse is smeared over time and we are no longer able to gate it out. There will also be problems dealing with multiple PWM signals, that have different timing and frequency. I havent looked at samples of the RF received from any real world switcher signals yet. I anticipate the magnitude and phase of the switcher signal will be all over the place, due to some torturous transfer function between the switcher and the terminals of my receiver. Plus various other signals will be present. Possibly there is a wide spectrum short noise pulses that we can work with. However Id much rather deal with narrow bandpass signals consisting of just our wanted signal plus the switcher noise floor. Next Steps. I might get back to my Free. DV work now, and leave this work on the back burner. I do feel Im getting my head around the problem, and developing a bag of tricks that will be useful when other pieces fall into place. The urban noise appears to be localised, e. This suggests its coupled into the HF antenna by some local effect like induction. So another approach is to estimate the noise using a separate receiver that just picks up the local noise, through a sense antenna that is inefficient for long distance HF signals. The local noise sequence could then be subtracted from the HF signal. I am aware of analog boxes that do this, using a magnitude and phase network to match the differences in signals received by the sense and HF antennas. However a DSP approach will allow a more complex relationship like an impulse response that extends for several microseconds between the two antenna signals, and allow automatic adjustment. The noise spectrum can change quickly, as PWM is modulated and multiple devices turn on and off in the neighborhood. However the relationship between the two antennas will change slowly if they are fixed in space. This problem reminds me of echo cancellation, something I have played with before. Given radio hardware is now very cheap 2. SDR dongles, multiple receivers could also be used. So my gut feel remains that HF urban noise can be reduced to some extent e. B suppression using DSP. If those nasty PWM switchers are inducing RF voltages into our antennas, we can work out a way to subtract those voltages.