#HOW TO BUILD A VLF RECEIVER SOFTWARE#

The portion between about 02:00 and 09:00 is the nighttime вЂњsignatureвЂќ Or UTC, the spike between 16:00 and 17:00 shows a SID. In the example below recorded from station NAA, which is plotted on GMT (Geostationary Operational Environmental Satellite) data. The resultant daily plots can be analyzed for spikes during the daytimeДЇor this solar activity and then compared to the GOES

See the illustration below which shows quiet day behavior. Increasing the received signal strength on the monitor. Signals bounce cleanly off the D layer during the SID, briefly To the point that it briefly becomes the daytime bounce point for VLF signals The normally less active, and lower, D layer of the ionosphere is energized SIDs are causedД«y solar activity abruptly increasing the ionization of all layers of the To the higher mid-level E layer, then lose energy as they reflect and passД«ack through the lower D layer on their way back to earth. Normally during a quiet solar day, the VLF signals go through the D layer

When the sun energizes things, the ionosphere becomes comprised of, roughly,ДЈ layers-the F (highest), E (middle) and D the lowest at about 60 Signals reflect off the F layer and bounce back to Earth. The nighttime ionosphere basically consists of the F layer which is about There is an interesting Wiki article on NAA which shows its elaborate antenna NAA is said to be the most powerful VLF transmitter in the world at 1800 KW. There is no interest in the content of the transmission-it is data, Has 17280 rows of data for each frequency monitored.

Where it can be later analyzed and plotted.

#HOW TO BUILD A VLF RECEIVER SOFTWARE#

Recorded by the software and saved into an Excel. Samples of the signal strength of the stations are taken every 5 seconds, The solar disturbances affect the daytime ionosphere. The signals are stronger during the night but our interest is daytime since The most reliable day-to-day stations received from this area. This particular sample prominently shows NAA, NML, NLK and NPM which are The spikes at 22.65, 30 and just above 45 KHz are not stations and are These reside at high schools, universities, public institutions, and evenД«elow is a photo of the SuperSID hardware which looks sort of like a canДЄt McMath-Hulbert we are currently monitoring the following stations:ДЄnd open frequencies at 20, 22.65 and 27 KHz in order to track the noise floor.Д«elow is a screenshot of one sample from the SuperSID software. The globe, each with their own ID and each submitting daily data to Stanford. The SuperSID Project has several of these вЂњreceiversвЂќ all around The beauty of the SuperSID soundcard setup is that several stations canД«e monitored at once, rather than just one as with the Gyrators (or any The files to Stanford at the close of the day. Special software that monitors VLF frequencies, records data once everyДҐ seconds, 24 hours/day, then automatically sends They provide a вЂњreceiverвЂќ (actually a low-noise pre-amp) to be

Run by Stanford University and SARA (Society of Amateur Radio Astronomers). Lately we have become involved with a project called SuperSID which is The output of these Gyrators is fed through an analog to digital converterД«elow are photos of our versions of the Gyrator II on the left and Gyrator Tuned with 365 pf tuning condensers like you would find in an old AM radio. Loop antennas are roughly 20вЂќ square with about 140 turns of #30 wire The designs for which can be found online (вЂњGyrator IIвЂќ and вЂњGyratorДЇAR Circuits has boards for them and the parts are easily obtainable. The Gyrators are inexpensive, very simple, easy to build, VLF receivers We did this with homemade вЂњGyratorвЂќ radios and homemade loop VLF stations in order to track SIDвЂ™s (Sudden Ionospheric Disturbances). Recently got involved with monitoring US Naval submarine communications Place where you guys stole the McMath scope from?) A few of us at McMath-Hulbert Solar Observatory (you remember, that old

How to build a vlf receiver