Sudden Ionospheric Disturbances Supplement

Click image to enlarge.

The chart above was made by Al McWilliams, A-94, using an ADR2000A A/D converter. This converter has many advantages over the converter designed by former Solar Division Chairman Joseph Lawrence that many of us use to record SES on a computer. Although Lawrence's converter does a fine job and is adequate for making the monthly SID report and can produce Rustrak format strip chart recordings using the Piclogger plotting software it nevertheless falls far short of what can be done with the ADR2000A using software Al has written for it to produce the chart above. Most important is it can produce the chart above in real time and display it on the monitor. This gives it the same advantage people like about the Rustrak strip chart recorders, which is you can see the trace being made in real time. If you are nearby you can often see the beginning of the SES as it starts to rise and follow its development through maximum and decay in real time. The ADR2000A shows the same thing on the monitor. But there is an even greater advantage: You can use the computer for other purposes such as answering email and the ADR2000A continues making your SES chart without interruption. When you are finished with whatever you were using the computer for, just click on an icon and there is your SES recording again in real time with the part it made while you used the computer right there as if you hadn't used the computer at all.

As you can see from the above, the good news is you don't need a separate dedicated computer to make uninterrupted continuous 24-hour SES recordings. The bad news is the ADR2000A costs $265 (but still less than the cost of a new Rustrak strip-chart recorder). This is a lot of money but Al's software to run the ADR2000A is free and he continues to improve it. Then too there are all those many advantages plus additional nice things it can do described below. You will have to decide for yourself if you would want to spend the extra money, most of which is balanced out by not needing a separate dedicated computer. Below are excerpts from letters from Al McWilliams that give more details how his software works:

.............. I am recording 25.2 kHz using a 4 x 8 feet loop antenna located in the basement of my home. Here is a recording of 25.2 kHz using the basement loop, ADR2000A, and my own software. The signal comes in very strong even with the loop in the basement. The basement loop is part of a preamp circuit whose output goes to the Gyrator 11 receiver. Only the loop is in the basement - all other stuff in the den including the preamp. I have all gains turned down to minimum. Still, the output of the Gyrator 11 is 6 volts DC so I have an additional pot between the Gyrator 11 and ADR2000A to further attenuate the signal. The ADR2000 has a range from -5 volts to + 5 volts and has +/- 15 volts overload protection built in ............... This is a real-time-display chart which still continues while I write email. The text box at top shows the point number, the local DST time, the date, and then the voltage and time separated by a "@" symbol. This text box updates every  time a reading is made (every 2 seconds in this case). Note the inverted SESs. I edited out the bottom half of the chart where negative voltages would be displayed. The data are recorded in a file which later can also be converted to DAT form if a Rustrak type graph is desired. Each data line is the same as shown in the text box above (a little too much info but I can easily change that) The label at top is entered automatically. Again, the times are off UT by one hour (yet to be fixed). The program allows one to save the current chart to Desktop at any time without stopping the program. The labeled time is central daylight savings time. I fixed the vertical time lines bug. The time width of the chart depends on how many points and time between points which one selects when starting the program. So the whole width could be, say, only one hour or 50 hours. The above chart will have 36000 points at 2 seconds per point which is 72000 seconds or 20 hours. The program will then stop and leave a data file on desktop as well as a picture on desktop. If one stops the program at any time the data file and picture are auto stored to desktop....... Here is a snapshot of my ADR2000A running program which shows 25.2 maintenance. I used Wincopy which allows one to copy any portion of one's computer screen and save it. Here I saved the entire top half of the ADR2000A program display while it was running. In the usual manner (mouse drag) one can move the graph to any part of one's screen while it is running. So the running real time graph can be moved almost entirely off screen while it is running in real time. Again, subtract 1 hour from the time numbers on the graph to get UT (so that 25.2 went down at 12 UT, for example). The automatically saved graph does not include the top portion (the parts in dark orange) which only display while the program is running. The fine print at the top of the graph depicts when the program was started (12:41:15 AM central daylight savings time), etc. and this entire fine print line is saved as a part of the graph. When the program ends it will have recorded 80,000 data points (this number was entered as an answer to a prompt when the program was started) and the 80,000th point will plot on the extreme right hand side of the graph ...........As stated earlier all the ADs are listed at site http://www.ontrak.net/ together with prices and ordering information. The ADR7700 has only one analog input channel but 16 bit resolution. The ADR2000A has eight analog input channels and 12 bit resolution. The ADR112 has two analog input channels and also 12 bit resolution but presumably can only take from 0 to +5V input so would not be the best for magnetometers. The ADR112 costs $129, the ADR2000A costs $265 and the ADR7700 costs $225. All come with a computer cable. A power adapter for ADR112 and ADR 2000A can be ordered for $12.95 (or one can get one at Radio Shack). I am not sure how the ADR7700 is powered. I feel pretty sure that all of Ontrak's ADs can be programmed using Visual Basic and will work with my program with at most minor modifications.

The ADR2000A has other features which the ADR112 and ADR7700 do not have (such as two 12 bit analog outputs, one 16 bit event counter, and 8 digital 1/0 lines). Experimenters may want to use some of these additional features sometime. I should emphasize that my software is not general but includes only what I want to do with the ADR2000A at the present time. My next improvement will be to include more than one input channel. These boards will be most useful to those who are somewhat familiar with programming and who can therefore include features of their own interest at any time. There is not one single simple program which will run all possibilities for all features!!! (I believe that the ADR112 would be a minimal good replacement for the Lawrence system even though the ADR112 has only two analog input channels. The Lawrence software will not run it however. New software would have to be written using Visual Basic).

Best wishes, Al

The above excerpts from Al's letters are in response to questions I asked. Hopefully they will answer some of the questions you might wish to ask. If not you can email Al at amcwill417@email.msn.com (amcwiII417) for more information and his free software.

Below are two SES charts for the first and second of May made by Werner Scharlach A-9, in Tucson, Arizona recording NAA in Cutler, Maine on 24kHz. Below that are SES charts made by Jerry Winkler, A-50, in Houston Texas.

Jerry's multiplexed charts below made on 2, 5, 6, 13, 19 and 20 May record the signal from NAA in Cutler, Maine transmitting on 24 kHz and the 25.2 kHz signal from the new station in La Moure, North Dakota. Jerry's 25.2 signal is scattered by lightning on some days. His 5 May chart shows the gradual build up of thunder storms that day very well. 25.2 kHz is also the signal recorded by Al McWilliams to make his chart on the first page of this SID supplement. Al lives in St. Cloud Minnesota and is much closer to North Dakota so his SESs are inverted The signal is stronger there and thunder storms fewer, so his chart does not show lightning scattering the recording points.

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