You can run Free. DV using a free GUI application for Windows, Linux and OSX that allows any SSB radio to be used for low bit rate digital voice. Alternatively you can buy a SM1. Free. DV adaptor that allows you to run Free. DV on any HF radio without a PC or sound card.

If you are a hardware or software developer, you can integrate Free. DV into your project using the LGPL licensed Free. DV API. Speech is compressed down to 7.

63 useful links about Electronic circuit design and misc. In general, the LRIT and HRIT signals are not strong. There is not much room for a non-optimal setup. You need a good low noise figure LNA, a filter if you have.

Introduction FreeDV is a Digital Voice mode for HF radio. You can run FreeDV using a free GUI application for Windows, Linux and OSX that allows any SSB radio to be.

Hz wide signal comprised of 1. QPSK carriers which is sent to the Mic input of a SSB radio.

Software Defined Radio, SDR, Kurzwelle, Röhrenaudion, NF Sinus Generator, Wienbrücke, LC Tester, Kapazität Meßgerät, Induktivität Meßgerät, HF Meßkopf. In electronics and telecommunications, modulation is the process of varying one or more properties of a periodic waveform, called the carrier signal, with a.

The signal is received by an SSB radio, then demodulated and decoded by Free. DV. Free. DV 7. 00. C is approaching SSB in it's low SNR performance. At high SNRs Free. DV 1. 60. 0 sounds like FM, with no annoying analog HF radio noise.

Free. DV was built by an international team of Radio Amateurs working together on coding, design, user interface and testing. Free. DV is open source software, released under the GNU Public License version 2. The modems and Codec 2 speech codec used in Free. DV are also open source. News July 2. 01. 7Ver 1. Free. DV GUI program - improved Hamlib support, removed unused features and simplified dialogs, up to date OSX support, more documentation.

February 1. 6 2. 01. Ver 1. 2 of Free. DV GUI program with 7. C - speech quality close to Free.

DV 1. 60. 0 with greatly improved low SNR performance October 1. Ver 1. 1. 0 of Free. DV Quick Start Guide QSG released. September 2. 5 2. Ver 1. 1 of Free.

DV GUI program with voice keyer. August 2. 5 2. 01. Ver 1. 0. 0 ? How would you feel if one or two companies owned the patents for SSB, then forced you to use their technology, made it illegal to experiment with or even understand the technology, and insisted you stay locked to it for the next 1.

That's exactly what was happening with digital voice. But now, hams are in control of their technology again! Free. DV is unique as it uses 1. Open Source Software, including the speech codec. No secrets, nothing proprietary! Free. DV represents a path for 2. Amateur Radio where Hams are free to experiment and innovate, rather than a future locked into a single manufacturers closed technology.

Demo Video. Watch this video of a Free. DV QSO. Here is what you need: A SSB receiver or transceiver. Free. DV software, download links are below. The same cables and hardware that you use for other digital modes that are based on PC programs will work with Free.

DV, but you will need a second sound interface for the microphone and speaker connections to the Free. DV program. A USB headset of the sort used by gamers is all you need for the second sound interface. Configuring Your Radio.

Turn off as much processing as possible. In general noise blankers, DSP band limit filtering and narrow bandpass filters are more likely to hurt than help, while compression, DSP noise or carrier elimination, and voice processing are definitely wrong for Digital modes. Free. DV's HF modem does its own DSP, and in general this is true for other digital programs as well. You can see the received effect of different settings in the S/N (signal to noise ratio) display of Free. DV. A higher S/N is better. Drive your transmitter to an average power of about 2.

PEP power. There is a 8- 1. B peak- to- average power ratio in our HF modem.

Over- driving will reduce the received S/N. More is not better for DV! Download. Source Code. Documentation. Several guides are available Who can I Talk Too? USA 1. 4. 2. 36 MHz USB Anytime Casual QSOs. Netherlands 3. 7. MHz in USB Every Sunday 1.

UTC Net. Australia VK5 7. MHz Every Sunday 1. AM Local WIA Broadcast is WIA Broadcast and call back. Australia VK3 7. 1. MHz Anytime Free. DV beacon. Australia VK3 1. MHz Every day at 3 and 4pm AET Casual QSOs.

UK 3. 6. 43. MHz LSB Sundays mornings at 0. RSGB broadcast by Matt G6. WPJ Support. Please post your questions to the . Richard Shaw KF5. OIM maintains the Cmake build system, Windows and Fedora packaging.

Walter, K5. WH is leading Windows testing in the USA. As development continues, many people are helping whom we have not credited on this web site, but we appreciate all of their work. History. In 2. 01. Free. DV was coded from scratch by David Witten (GUI, architecture) and David Rowe (Codec 2, modem implementation, integration).

The Free. DV design and user interface is based on FDMDV, which was developed by Francesco Lanza, HB9. TLK. Francesco received advice on modem design from Peter Martinez G3.

PLX, who has also advised David on the FDMDV modem used in Free. DV. Mel Whitten, K0. PFX has contributed greatly to the design, testing and promotion of several Digital Voice systems, including FDMDV.

This practical experience has led to the current design – a fast sync, no FEC, low latency system that gives a “SSB” type feel for operators. Mel and a team of alpha testers (Gerry, N4.

DVR; Jim, K3. DCC; Rick, WA6. NUT; Tony, K2. MO) provided feedback on usability and design of Free. DV. Bruce Perens has been a thought leader on open source, patent free voice codecs for Amateur Radio.

He has inspired, promoted and encouraged the development of Codec 2 and Free. DV. Links. Google Digital.

Voice group. FDMDV Digital Voice Resource Page. Codec 2 Voice Codec. FDMDV Modem. Why Open Source Digital Voice Is Important. Free. DV Specification. Notes for users of Tigertronics rig interfaces.

K7. VE's Free. DV QSO Finder. David Rowe interviewed about CODEC2. Ham. Radio. Now. tv Episode 8. Bruce Parens and Mel Whitten interview at Dayton Hamvention 2. FAQ. Q1: Is there any way to save the screen settings when you drag the tabs to multiple windows on the main screen? Try converting your wave file to that format. It works fine with Fldigi, and other programs.

For example you may have changed the default serial rate on your radio. Carefully check the serial parameters on your radio match those used by Free. DV in the PTT Dialog.

Adding Free. DV To Your Hardware Product or Software Project. If you are a hardware or software developer, you can integrate Free.

DV into your project using the LGPL licensed Free. DV API. No license fees are required to use Free. DV. Including it in your project is a simple as compiling a library of C code. Free. DV does not require an operating system, it runs happily .

It does require a hardware Floating Point Unit (FPU). The Free. DV stack is gcc compilable C software that runs in about 1% of the CPU resources on a modern PC. Free. DV 1. 60. 0 has even been ported to a . C and basic C++ skills (but not DSP).

See TODO list at bottom of freedv- dev README. Porting DSP code from GNU Octave (Matlab) to C. You need basic Octave, C, and basic DSP skills.

Take a look at codec. You need embedded C development skills on Linux (but not DSP). Similar to Arduino without the IDE. Tasks like building User Interface (UI) features.

How did it compare to Free. DV? Free. DV represents an open and free future for digital voice over Ham Radio. You can help by donating via Pay. Pal (which also allows credit card donations): The Free. Asme Viii Pressure Vessel Design Software on this page. DV developers have donated 1. Your donation will reduce the out of pocket costs of the developers for hardware, travel, and Free. DV promotion at Ham events.

Buying a SM1. 00. Free. DV adaptor allows you to run Free. DV on any HF radio without a PC or sound card. This supports David Rowe, the primary developer of Free.

Circuit Design - Software: Circuit Design. Spice. - Analog circuit simulation program for the typical circuit designer. Commercial version for windows. From schematic to Gerber files for PCB vendors. The program have additional plugins to calculate another kinds of coils. Easy to learn and easy to use, Design.

Spark PCB is free and can you can download Design. Spark from this site. Elsie is an uncommon commercial- grade lumped- element (. For the first time, designing circuit boards is simple for the beginner and efficient for the professional. Particularly good in valve amplifier design, for aiding the design of transmission line resonators.

Inductance calculations accuracy is around 1%. Also, coils with maximum Q for given inductance, resonant RF chokes, PI and T resistive attenuators calculations are provided. Skin effects, radiation losses and other minor side effects are not accounted in maksimum Q factor coils calculations. Program assumes using copper (Cu) enameled or silver (Ag) plated wire. Program is writen bilingual in English and Serbian by YU1. AW. . It uses exactly the same unique and robust algorithm as NL5 Circuit Simulator.

Simple and intuitive interface, fewer components and models, no fancy and powerful features that are only useful for specialized applications. RF, Microwave & Antennas. Offer calculators for Resistors, capacitors, inductors, power supplies, filters, attenuators and antennas. You can enter either discrete components or transmission lines, see the results on screen and/or generate Postscript output. Component values can be changed numerically or using scrollbars.

The resulting scales will typically be nicer- looking than those found on many commercial meters. NFM implements the method of Agilent application notes AN 5. AN 5. 7- 2 for noise figure measurement, but with the addition of an adjustable attenuator after the noise source and between the DUT and instrument. A great tool for students, amateurs, as well as for experienced engineers. Design and modeling of magnetic components such as inductors, planar transformers and integrated magnetics used in power- electronics applications.