Most fascinating to listen to are the stereo audio streams, which can become quite active during geomagnetic storms. Oct 24, 2008 a soundcardbased saq vlf receiver johan sm6lkm has made available software to allow you to receive vlf transmissions, such as those by saq, using your pc soundcard. Natural radio is a specialty involving signals of natural origin within the very low frequency spectrum and below. Computer software is available for monitoring and data logging. Inspire vlf 3 receiver the inspire vlf 3 is the third version of the popular receiver used by students and others to observe natural radio and other low frequency emissions. It features a 14 bit 80 mss analogtodigital converter, a highperformance fpgabased digital downconverter and a highspeed 480 mbits usb2. A simple peace of software combined with a wire antenna connected to the soundcards input is enough to pick up vlf signals. Receiving saq and other vlf stations ernest neijenhuis. Recently amateur radio hobbyist de8msh wrote in to let us know about how he was able to receive vlf very low frequency signals using a very rare refcom fc vlf upconverter and his direct sampling modified rtlsdr. You can hear sferics, tweeks, whistlers and other vlf radio sounds at any time of the day, but the hours around dawn and dusk are generally best. The main category is weak signal operating mode that is about weak signal operations. A software toolkit for vlf timestamped reception, signal processing, storage and. Great for checking your system is working correctly by listening for alpha beacons, gbz and other. It is connected between the antenna and a shortwave radio receiver.
This is because vlf radio waves commonly reflect off a layer of charged particles electrons in the ionosphere redirecting the signal back toward the surface of the earth. Based on bench experiments, i discovered that putting the vlf receiver in close proximity to the gps board and embedded pc a modified alix 2d3 injected all sorts of digital hash into the receiver. About a pc as vlf receiver the resource is currently listed in in 2 categories. Due to its limited bandwidth, audio voice transmission is. This band has the unique characteristic of having a portion fall within the audio frequency range of our ears. Inspire vlf3 receiver the inspire vlf3 is the third version of the popular receiver used by students and others to observe natural radio and other low frequency emissions. Web controlled receivers, online receivers to listen to hf and vhf radio spectrum category is a curation of 36 web resources on, your remote smeter, globaltuners. Electronicsvlfreception with the pc wikibooks, open. Our customers include professional communications radio users in government, industry, military, security, surveillance and spectrum monitoring organizations, as well as many radio and computer enthusiasts. Nov 04, 2016 in earlier days for reception of vlf signals you either had to buy or to build an appropriate receiver or converter. His antenna is the pa0rdt mini whip which requires 12v of power that is delivered directly by the refcom fcvlf.
The receiver provides enough power output to drive our serial port interface. Lowcost software defined radio compatible with many sdr software packages. The saqrx program is believed to be totally harmless, i have never heard of. For vlf receivers, the new communications system should be interoperable with all legacy. The inspire vlf 3 receiver is designed to receive radio waves in the 010 khz range. Although its primary application was intended to be on highdensity longhaul microwave systems the 6041 slm may be employed on any communications equipment requiring. Rycom 6041 selective level meter voltmeter vlf receiver makes measurements of both level and frequency on frequency division multiplex fdm equipment baseband signals. Saq aka grimeton radio station is a heritage vlf transmitter in sweden that transmits cw at 17.
Recently amateur radio hobbyist de8msh wrote in to let us know about how he was able to receive vlf very low frequency signals using a very rare refcom fcvlf upconverter and his direct sampling modified rtlsdr. Electronicsvlfreception with the pc wikibooks, open books. Using a pc sound card to receive vlf radio signals youtube. Then you need some spectrum analysis software, to record and view the radio signals from the antenna. Between 0 and 14mhz, in transmission and reception, it works. Inspire vlf3 radio receiver kit since 1989, the inspire project, inc. Great for checking your system is working correctly by listening for alpha beacons, gbz and other vlf msk signals. If you are more interested in the reception of vlf natural radio which is a broadband audio application, there is another document for you. The pc is used to convert the vlf signal into a souncard runs at 44100 hz nominal sample rate frequency is converted down to an audio frequency of 650hz or similar.
Vlflfmf bands upconverter for sdr and analogue radios. See also the live vlf natural radio page for updates. Now this is what the circuit looks like without the upgrades and modifications. Few of these receivers are based on a systems approach and none include all. Please see notes at the bottom of this sheet before contacting me about this unit. Very low frequency vlf detector circuit homemade circuit. If all instructions and notes are followed, there should be. This most interesting software program, has even a special setting for use of the analysis tool, as a soft rx for vlf use. Saqrx is a soundcardbased usb upper sideband receiver covering 022 khz and the filter bandwidth is selectable in three steps, 300, and 2400 hz. This link is listed in our web site directory since wednesday jan 16 20, and till today a pc as vlf receiver has been followed for a total of 756 times. Fixing up a receiver is easy enough, we linked to the original saqrx vlf receiver and the extended version in our previous coverage. Build your own vlf receiver the information here is most helpful to a person with a knowledge of electronic circuitry and fundamentals. Grimeton radio saq is the last transmitter in the world preserved that generates vlf radio frequencies with an alternating current generator alternator, i.
While the concept of sdr is not new, the rapidly evolving capabilities of digital electronics. Most vlf receivers of this type are operated at full gain. There are now dozens of software defined radio packages that support the ultra cheap rtlsdr. When paired with free sdr software running on a pc, it can serve as a beginners ham radio receiver or as a. The vlf receiver is also compatible with the popular radio skypipe data logging software, but extra components will be required. A complete vlf receiver implemented in software on a pc. On this page we will attempt to list, categorize and provide a brief overview of each software program. Many vlf receivers have been developed over the years and some are available in kit form or already built. Perseus is a software defined vlf lfmfhf receiver based on an outstanding direct sampling digital architecture. Sm6lkms brilliant little vlf receiver implemented entirely in software and available free via the internet.
The band is also known as the myriameter band or myriameter wave as the wavelengths range from one to ten myriameters an obsolete metric unit equal to 10 kilometers. The signal from the antenna usually a loop antenna is filtered out to limit the signals to the frequencies of interest in the vlf and lowerlf frequency range. Streaming audio from the vlf receivers listed above are quite reliable. The closeup of the vlf receiver below shows a 363k resistor and 750 pf capacitor from the antenna fahnstock clip to the gate of the j201 jfet or any type suitable for low voltage application. Sferics from lightning as much as 2000 to 3000 kilometers away can be detected by the vlf receiver even though an event that far away is occurring well over the visual horizon. Example of using this method to receive vlf signals from russia and. This article describes how to use your pc as a receiver for narrowband signals in the vlf radio spectrum. The vlf receiver has a tuning range of about 12 khz to 35 khz, requires a supply of 15 volts dc at 35ma, and provides output signals at 0 2.
I found that moving the receiver at least 10 feet from the alix and gps and including a little extra power filtering eliminated that problem. Inspire vlf 3 radio receiver kit since 1989, the inspire project, inc. Saqrx is a soundcard based usb upper sideband receiver covering 022 khz. The small sdr hardware pictured above is an entrylevel unit. Designed for vlf radio signal processing, it also has applications for meteor forward scatter, seismographic and natural radioactivity recording, elf and magnetometers, radio astronomy, bat detection, amateur radio, and other projects which require precision timestamps preserved through signal capture, storage, and postprocessing. This list is a synthesis of several sources and may contain obsolete or. A 47 megohm resistor connects the gate to the source and ground and also the microphone cables shield and the drain simply connects to the. The polar response of the completed receiver was plotted with the equipment mounted on a large protractor as shown below. Wolf dl4yhf, the creator of spectrum lab, has june 15th 2001, updated his latest release v1.
The vlf receiver very low frequency receiver is a software defined radio sdr, which makes it possible to receive radio frequencies between 0 hz 96. Winradio communications manufacture radio communications equipment for a very wide range of applications. Products winradio communications the future of radio. Very low frequency or vlf is the itu designation for radio frequencies rf in the range of 330 khz, corresponding to wavelengths from 100 to 10 km, respectively. Were talking about radio waves, like the amfm signals you get, just at an even lower frequency. This receiver is very flexible in setup and has the controls and enhancements necessary to make recordings that can be properly logged for further study. Fixing up a receiver is easy enough, we linked to the original saqrx vlf. Aug 24, 2017 in particular, the air force is seeking white papers from industry and academia on whether there have been useful advancements in four aspects of vlf technology. He builds a simple receiver as a working example and a highpowered transmitter that can put out over 2600 watts. Unesco world heritage site grimeton radio saq grimeton radio saq is the last transmitter in the world preserved that generates vlf radio frequencies with an alternating current generator alternator, i. Mar 19, 2019 this is the vlf receiver circuit that ive upgraded and modified it senses ac fields lightening and even receives ship and aircraft radio too. Softwaredefined radio sdr is a radio communication system where components that have been traditionally implemented in hardware e.
Very low frequency and extremely low frequency radio isnt practiced very much. Here is a list of vlf transmitters suitable for sid monitoring. This was originally produced to allow people to receive saq on 17. The vlf receiver can be used for radio astronomy in the detection of solar flares and other events in space, and for monitoring lightning activity. Fixed receiver installations portable receivers software defined radios vlf receiver kit. Elf vlf stands for extremely low frequency and very low frequency, and refers to the range 300 hz to 30 khz. His antenna is the pa0rdt mini whip which requires 12v of power that is delivered directly by the refcom fc vlf. It is called a software defined radio or sdr for short. Designed for vlf radio signal processing, it also has applications for meteor. We categorize the programs into general purpose software, single purpose software, research software and software compatible with audio piping.
A sdr receiver can be as simple as this rtlbased sdr. The inspire vlf3 receiver is designed to receive radio waves in the 010 khz range. Most radio receivers require complex frequency conversion to change and then demodulate the radio signal into an audio signal which is passed on to the amplifier stage to drive the speaker or headphones. Local tilt and ellipticity of vlf broadcasts are measured and resolved into inphase and quadrature components of vlf response. Vlf receivers, vlf antennas, vlf propagation and waveform modes, and modifying legacy software. For this task you have a selection of several programs. Vr2hf online yaesu ft817 pop online yaesu ft817 transceiver receive only over the net using r. Asias first online receiver, first online ft817, and worlds first fullfeatured online receiver operates just like a desktop radio including audio encoding time of less than 1 second. On our planet, the most potent source of elf vlf waves is lightning, so a lot of what we do comes down to studying lightning and its. If all instructions and notes are followed, there should be no problem with it whatsoever.
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