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Radio Astronomy
Radio Astronomy Silver Level
Approved: MARCH 15, 2015 #2-S
Steve Boerner
sboerner@charter.net
Astronomical Society of Eastern Missouri (ASEM)
Silver Level
The Silver level is intended to take the radio astronomer to a higher level of experience in the Radio Spectrum. In addition to the Bronze level requirements, the applicant must observe a second type of radio source in the radio spectrum using a different instrument than you used previously. You may do this in combination with the Bronze level by submitting observing reports for the two different types of radio sources using the two different types of instruments, one of which, you must have personally built/assembled.
To receive the Silver Level Award, you must be a member of the Astronomical League, either as a club member or as a member at large.
Completion of two sets of different observations outlined in the five categories [1 )Space weather, 2) the Sun, 3) Jupiter, 4) Meteors, and 5) Galactic Radio Sources], using at least two different instruments will earn the Silver certificate and pin.
Observing Space Weather
Sudden Ionospheric Disturbance (SID) Monitor – When energy from the Sun hits the ionosphere electrons are stripped away from their nuclei, creating the ionized region in the upper atmosphere. During periods of intense solar activity – solar flare, solar storm, or coronal mass ejection – the ionosphere reacts and we can detect changes in very low frequency (VLF) transmissions from Earth. SID can detect these changes providing the opportunity to monitor what we call space weather. The data can then be submitted to the Stanford Solar Center.
Requirements: Observations of the solar wind must include at least three (3) incidents which are at least 24 hours apart. For each observation you should include a screen capture (or video) of your chart recording of the event. Include the date and time of the event, and location (latitude and longitude) of the instrument. Include still images with written explanation of set-up/equipment used, or video with audio explaining the set-up of the equipment you used for the observation. You may also print out paper copies (except for video) of these to submit if you so choose.
Hardware and Software (more pictures are below):
SuperSID (SSID) Pre-Amp with Software
https://squareup.com/market/society-of-amateur-radio-astronomers/supersid-pre-amp $58 including shipping
VLF Loop antenna
31 turns of insulated 20 gauge dog fence wire on a 48" square frame (500' wire)
Computer with an external USB HF SoundCard as directed in the SuperSID manual (96000 bps)
Prudent Way PWI-USB-A71 USB2 Sound Adapter
I ended up getting two of the Sound Adapters...one worked, the other didn't.
Purchasing the pre-assembled SuperSID monitor and software seemed an easier option than assembling essentially the same thing described in Andrews' book How to Build Your Own Radio Telescope or various receivers on the AAVSO web site. One deciding factor is the other solutions require tuning the antenna to a particular frequency. This requires hardware that is costly. The SuperSID solution does not need a tuned antenna and can monitor up to six beacons at a time. Additionally, support in the way of the Yahoo Group Super_SID with over 300 members helped make the decision. https://groups.yahoo.com/neo/groups/Super_SID/conversations/messages
NOTE: Yahoo Groups are now gone and have been replaced by Groups.io...https://groups.io/g/supersid
The SuperSID requires a 96000 bps sound card to log the data. Finding an external USB sound card that could do the task was one of the hardest part of the project. The Lord's from SuperSID were very helpful getting the right external USB sound card working and getting it ready to collect data. If you encounter difficulties getting your SuperSID working I suggest you post to SuperSID Groups.io. It isn't easy to get the USB sound dongle operating at 96k.
How it all works:
Very low frequency or VLF is the designation for radio frequencies (RF) in the range of 3 kHz to 30 kHz and wavelengths from 10 to 100 kilometers. These very long wavelengths mean that traditional shortwave antennas like dipoles or verticals can't be used because they'd be so big. Instead the magnetic component of VLF signals are detected by loop antennas in the range of 1-2 meters with 20-100 turns of wire. These very low frequency waves can diffract around large obstacles and so are not blocked by mountain ranges, and can propagate as a ground wave following the curvature of the Earth. The VLF can also penetrate seawater to a depth of at least 10 to 40 meters (30 to 130 feet), depending on the frequency employed and the salinity of the water, so they are used to communicate with submarines. As a result various governments have established VLF beacons for military communications. Most SID detection methods make use of a loop that is tuned with capacitors to maximize the signal at the frequency of a particular VHF beacon (see here for a list of beacons). The SuperSID is slightly different in that it monitors multiple beacons and doesn't used a tuned antenna making the process a bit easier. The SuperSID's configuration file contains the number of beacons to be monitored and their particular frequencies.
The normal practice is to point the loop antenna in the direction of a convenient VLF beacon from the list. The signal is monitored 24/7, passed to a pre-amp, then to a computer's 24 bit sound card. With no variation in the Earth's atmosphere the beacon's signal strength remains fairly constant. Variations in the atmosphere can cause the signal strength to vary widely. To look for these variations the signal is monitored periodically and the results are plotted and/or saved. The SuperSID takes a reading of the level of the configured beacons every five seconds, stores it in memory, and writes it as a CSV file for each beacon at the end of the day (6 pm). The CSV file can be plotted from the SuperSID software or read with a spreadsheet. The one downside of the SuperSID version of the software i used is that the results can only be seen at the end of the day. The events are not seen in real time. Apparently a beta version solves that problem, but I was unable to get it running.
During the day the radiation from the sun affects a region of the atmosphere called the ionosphere causing three new layers (D, E, & F) to form daily. Radio waves of various frequencies can bounce or scatter off these layers. During the night the sun no longer causes the ionization above a particular location on the Earth and the layers disappear. Monitoring the signal strength of a distant VLF beacon with a "quiet" sun over a 24 hour period produces a graph as seen on the left...higher at night, falling at sunrise as the ionization starts for form the new layers, rising slightly during the day as the sun moves towards the zenith, dropping slightly as the afternoon goes on, and climbing steeply with the setting of the sun/onset of night and the end of solar caused ionization.
During periods of intense solar activity – solar flares, solar storms, or coronal mass ejections – the ionosphere reacts and we can detect changes in very low frequency (VLF) transmissions from Earth. SID can detect these changes providing the opportunity to monitor what we call space weather. These changes generally increase the signal strength for a period during the day and that's what this program is after.
Searching for a "Good" Location:
The SuperSID Monitor is very sensitive to VLF noise and my house is apparently full of it. It took a few weeks of trial and error to find a noise free location. One real killer was our microwave.
The three beacons that I monitored are easily seen between 20-30kHz
NAA frequency = 24000 Hz (Cutler, MI)*
NLK frequency = 24800 Hz (Jim Creek, WA)
NML frequency = 25200 Hz (LaMour, ND)
*NAA consistently produced the best results, probably because of the fixed East/West position of the antenna cause by it's location nailed to the wall. My other choice was the North/South wall but it would require more coax.
I believe the first peak between 20-30k is noise from the computer itself.
After three weeks of frustration I realized that I needed to run the SuperSID monitor at a location far away from any electrical interference. The only possibility I could see was in our club's observatory 20 miles away in Broemmelsiek Park. I got permission and headed out to the park with my oldest tower computer running Windows XP, antenna and tools.
Home Office
It is a second floor location and what I originally thought might be a good location. It is 35 feet away from the kitchen and microwave, two stories above the electric box and furnace in the basement, and other that the computer itself what I though might be free from interference. While monitoring from this location I tried four different computers including two laptops on chargers and battery. While changing computers helped a bit, using the microwave in the kitchen literally killed the daily output graphs (see below).
Moving the SuperSID monitor to other locations in the house including the basement produces similar results.
If inside the house wasn't going to work I thought I might try outside. The graph looks better, but still too much noise and it still picked up the microwave.
As I said, the microwave pretty much kills the output and I couldn't find a place or a way to eliminate it (other than stop using it). The software autoscales the results...the signal from the microwave is a mountain and everything else is the flatlands.
Broemmelsiek Park Observatory
After three weeks of frustration I realized that I needed to run the SuperSID monitor at a location far away from any electrical interference. The only possibility I could see was in our club's observatory 20 miles away in Broemmelsiek Park. I got permission and headed out to the park with my oldest tower computer running Windows XP, antenna and tools.
I nailed the 4 foot square loop antenna to the inside of the west wall, routed the coax over the door and set the computer up in a headless configuration that could be accessed over the observatory's wireless network via VNC. There is an electric panel for the nine pads in the observatory ten feet away on the east wall but I hoped that it wouldn't interfere particularly during the day. The observatory is not on the Internet and the only way I could access the collected data is to make the 25 minute drive. I set everything up and made the VNC connection to get things running. I quickly saw that the noise levels were much lower (see screen shot to the left). I vowed not to touch anything for a week.
During the intervening week I worried about the computer in extreme conditions of an unheated observatory with nightly temperatures sometimes in the single digits. When I returned a bit more that a week later all was well with the computer and daily data. I did manage to capture some events and I've included them below.
Miscellaneous Pictures of the Working Setup
Exterior view of the west side of Broemmelsiek Observatory with roll off roof. The antenna is nailed to the right of the open door on the inside wall.
The tower computer was located on the floor to the left of the open door since the only 24/7 power is located there.
A six inch snowstorm was forecast for later in the day.
The 10+ year old tower computer used to monitor the SuperSID. If you look carefully you can see duct tape sealing openings to keep mice out. The SuperSID unit is on top of the tower.
The coax to the antenna runs up the wall on the left and over the top of the open door.
The wood structure above the tower is a built in desk. It gets very wet when snow melts. The tower is located on a dry spot.
T
he SuperSID monitor on top of the tower. One cable comes from the antenna (BNC connector), a second supplies power via USB, and the third takes the amplified signal to the 24 bit sound card.
The four foot square antenna is nailed to the west wall of the observatory around the white board. The 1x2s are easy to see in the picture but the yellow insulation isn't.
An out of focus picture of the antenna detail by the door.
Detail of the upper right corner of the antenna. You can see where the coax comes off the antenna and runs across the top of the door.
You can see the rail and rollers for the roof at the top of the picture.
A picture of the VNC window from the tower on my laptop.
To get data from the tower I'd plug a thumb drive into the only unused USB port on the computer. The unused port was down at floor level and required a bit of crawling around. Once the thumb drive was plugged in I'd make the VNC connection to the tower from my laptop and copy the week's files to the drive.
Two Prudent Way PWI-USB-A71 USB2 Sound Adapters
The one with the text doesn't support 24 bit while the unlabeled one on top does.
Monitoring Data:
Location used for all observations: Brommelsiek Park
http://www.asemonline.org/broemmelsiek-park-astronomy-site
Bortle Sky: orange
Longitude: 90.815o W
Latitude: 38.723o N
Elevation: 644 ft
I started recording data on 2/13/2015 and let the monitor run for a month. During that time I captured only a few events.
The solar flare classifications come from http://sid.stanford.edu
SuperSID Monitor Graph of NAA
2/13/2015 First full day running in the observatory at Broemmelsiek. The graph shows the expected shape of morning rise and evening fall so things are working well.
2/15/2015 Possible event: observed at 7:22 a.m. CST Not mentioned on http://sid.stanford.edu/database-browser/ so probably not an event. Future "possibles" will not be displayed unless sid.sanford.edu displays similar results.
2/18/2015 Beacon down for service. This happened weekly.
2/19/2015 An unexplained dip in the middle of the day at 12:08 p.m. Other receivers on the sid.sanford.edu site also showed the dip. Other dips occurred during the month but are not reported.
3/5/2015 #1: (see below for solar flare classification information)
An M1.2 event started at 18:11 GMT and reached a maximum at 18:18 GMT.
NAA frequency = 24000 Hz (Cutler, MI)
After almost a month and a half getting the first real "hit" was most positive.
3/11/2015 #2: (see below for solar flare classification information)
An X2.1 event started at 16:30 GMT and reached a maximum at 16:36 GMT.
An M1.0 event started at 19:05 GMT and reached a maximum at 19:09 GMT.
A C7.8 event started at 22:27 GMT and reached a maximum at 22:31 GMT.
NAA frequency = 24000 Hz (Cutler, MI)
3/12/2015 #3: (see below for solar flare classification information)
An M4.2 event started at 14:21 GMT and reached a maximum at 14:24 GMT.An M2.7 event started at 22:03 GMT and reached a maximum at 22:06 GMT.NAA frequency = 24000 Hz (Cutler, MI)
Solar Flare Classification Scale:
Within a class there is a linear scale from 1 to 9.n (apart from X), so an X2 flare is twice as powerful as an X1 flare, and is four times more powerful than an M5 flare. X class flares up to at least X28 have been recorded.
Interesting future projects include:
to see if I can get reasonable data using an SDR and upconverter. The beacon peaks are there in SDRSharp, but noise currently limits the quality of the data.
to see if a Raspberry Pi running with a solar charger can be used to collect data with the SuperSID monito
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