HamSphere
Encyclopedia
HamSphere is a software Amateur Radio
simulator that allows licensed radio amateurs and unlicensed enthusiasts to communicate with one another using a simulated ionosphere
. It was designed by Kelly Lindman, a radio amateur with callsign 5B4AIT.
The system allows realistic worldwide connections between amateur radio operators as well as radio enthusiasts. In general it is similar to other VoIP applications (such as Skype
), but with the unique addition of characteristics such as channel selection by tuning, modulation, noise effects and shortwave propagation simulation.
Before using the system it is necessary for a radio amateur's callsign to be validated. The HamSphere system relies on different amateur online callbooks for verification before his or her callsign is added to the list of validated users.
The system may be used without a verified radio amateur license and has a callsign generator providing unique unofficial HamSphere callsigns. The unlicensed user is required to pass a small exam before getting access to the system.
The software is written to run on Microsoft Windows, Apple or Linux using Java. There is another edition of the software running on Apple mobile devices (iPhone, iPod touch, and iPad), and is available as beta on request.
model and pre recorded signal envelope. Multipath propagation is achieved by inducing multiple simulated electromagnetic paths digitally thus producing signal fading
and audio distortion.
mixing the local oscillator
signal with the received signal, very similar to Software-defined radio
. The digital artifact
of the decoded audio signal is later filtered with a 17-order FIR filter with a bandwidth of 2.8 kHz.
Amateur radio
Amateur radio is the use of designated radio frequency spectrum for purposes of private recreation, non-commercial exchange of messages, wireless experimentation, self-training, and emergency communication...
simulator that allows licensed radio amateurs and unlicensed enthusiasts to communicate with one another using a simulated ionosphere
Ionosphere
The ionosphere is a part of the upper atmosphere, comprising portions of the mesosphere, thermosphere and exosphere, distinguished because it is ionized by solar radiation. It plays an important part in atmospheric electricity and forms the inner edge of the magnetosphere...
. It was designed by Kelly Lindman, a radio amateur with callsign 5B4AIT.
The system allows realistic worldwide connections between amateur radio operators as well as radio enthusiasts. In general it is similar to other VoIP applications (such as Skype
Skype
Skype is a software application that allows users to make voice and video calls and chat over the Internet. Calls to other users within the Skype service are free, while calls to both traditional landline telephones and mobile phones can be made for a fee using a debit-based user account system...
), but with the unique addition of characteristics such as channel selection by tuning, modulation, noise effects and shortwave propagation simulation.
Before using the system it is necessary for a radio amateur's callsign to be validated. The HamSphere system relies on different amateur online callbooks for verification before his or her callsign is added to the list of validated users.
The system may be used without a verified radio amateur license and has a callsign generator providing unique unofficial HamSphere callsigns. The unlicensed user is required to pass a small exam before getting access to the system.
The software is written to run on Microsoft Windows, Apple or Linux using Java. There is another edition of the software running on Apple mobile devices (iPhone, iPod touch, and iPad), and is available as beta on request.
Uses
Operators using the HamSphere software can operate it in two modes:- Simulation mode. This is the unique feature of HamSphere allowing the user to maintain connections under natural realistic conditions. Signals may vary and interference is present giving the user the impression that he or she is using a real shortwave transceiverTransceiverA transceiver is a device comprising both a transmitter and a receiver which are combined and share common circuitry or a single housing. When no circuitry is common between transmit and receive functions, the device is a transmitter-receiver. The term originated in the early 1920s...
. - Simulation off mode. This mode entails connection to other operators with the reliability of VoIP (noise-free) while maintaining the other typical charateristics of radio communication.
Operating modes
The HamSphere software has two modulation types:- Double-sideband suppressed-carrier transmissionDouble-sideband suppressed-carrier transmissionDouble-sideband suppressed-carrier transmission : transmission in which frequencies produced by amplitude modulation are symmetrically spaced above and below the carrier frequency and the carrier level is reduced to the lowest practical level, ideally completely suppressed.In the double-sideband...
or DSB is the default mode of operation where the operator uses speech audio/phone. - Continuous waveContinuous waveA continuous wave or continuous waveform is an electromagnetic wave of constant amplitude and frequency; and in mathematical analysis, of infinite duration. Continuous wave is also the name given to an early method of radio transmission, in which a carrier wave is switched on and off...
or CW where the operator utilizes a built-in Morse CodeMorse codeMorse code is a method of transmitting textual information as a series of on-off tones, lights, or clicks that can be directly understood by a skilled listener or observer without special equipment...
keyer.
Propagation model
The mathematical algorithm for the wave propagation is based on a stochasticStochastic
Stochastic refers to systems whose behaviour is intrinsically non-deterministic. A stochastic process is one whose behavior is non-deterministic, in that a system's subsequent state is determined both by the process's predictable actions and by a random element. However, according to M. Kac and E...
model and pre recorded signal envelope. Multipath propagation is achieved by inducing multiple simulated electromagnetic paths digitally thus producing signal fading
Fading
In wireless communications, fading is deviation of the attenuation that a carrier-modulated telecommunication signal experiences over certain propagation media. The fading may vary with time, geographical position and/or radio frequency, and is often modelled as a random process. A fading channel...
and audio distortion.
Detector and Filters
Signals are received and converted into audible form by using a product detectorProduct detector
A product detector is a type of demodulator used for AM and SSB signals. Rather than converting the envelope of the signal into the decoded waveform like an envelope detector, the product detector takes the product of the modulated signal and a local oscillator, hence the name...
mixing the local oscillator
Local oscillator
A local oscillator is an electronic device used to generate a signal normally for the purpose of converting a signal of interest to a different frequency using a mixer. This process of frequency conversion, also referred to as heterodyning, produces the sum and difference frequencies of the...
signal with the received signal, very similar to Software-defined radio
Software-defined radio
A software-defined radio system, or SDR, is a radio communication system where components that have been typically implemented in hardware are instead implemented by means of software on a personal computer or embedded computing devices...
. The digital artifact
Digital artifact
A digital artifact is any undesired alteration in data introduced in a digital process by an involved technique and/or technology.-Possible causes:...
of the decoded audio signal is later filtered with a 17-order FIR filter with a bandwidth of 2.8 kHz.
See also
- EchoLinkEcholinkEchoLink is a free computer-based Amateur Radio system that allows radio amateurs to communicate with other amateur radio operators using Voice over IP technology on the Internet for at least part of the path between them...
- eQSOEQSOeQSO is a client–server software program designed by amateur radio enthusiasts for linking amateur radio frequency gateways and repeaters via the internet by using a Voice over IP protocol...
- Internet Radio Linking ProjectInternet Radio Linking ProjectThe Internet Radio Linking Project, also called IRLP, is a project that links amateur radio stations around the world by using Voice over IP . Each gateway consists of a dedicated computer running custom software that is connected to both a radio and the Internet. This arrangement forms what is...
- Radio over IP
- Wide-Coverage Internet Repeater Enhancement SystemWide-Coverage Internet Repeater Enhancement SystemWide-coverage Internet Repeater Enhancement System is a standard created by Yaesu designed to link compatible amateur radio repeaters over Voice over IP, allowing any home stations using those repeaters to communicate with each other over VoIP....