Radio Astronomy
Radio Meteors

The Astronomical League's Radio Astronomy Observing Program --  Radio Meteors

Approved:  January 21, 2015  #3-B
Click here to go to the Silver Level

Steve Boerner

sboerner@charter.net

Astronomical Society of Eastern Missouri (ASEM)

Bronze Level

The Bronze level is intended to introduce Radio Astronomy with a minimum of cost and equipment.

Requirements:  The applicant(s) must build/ assemble one Radio receiver/ antenna device and observe one of the radio sources listed  [1 )Space weather, 2) the Sun, 3) Jupiter, 4) Meteors, and 5) Galactic Radio Sources].  The device may be built by an individual or by a small group of no more than three persons, however all individuals must make their own observations.  You must submit all required documentation specified above for any observation to be considered.  You do not need to be a member of the Astronomical League to earn a RAOP Bronze certificate.

NOTE:  Following the above link to the Silver Level  (and Gold Level link you'll find there) will show you what I did to complete the four required activities to successfully complete the Radio Astronomy program.  I did not attempt to do 3) Jupiter.  If you wish to attempt the Jupiter activity you may wish to Google "Project Jove".  Another option is to see http://www.spaceacademy.net.au/spacelab/projects/jovrad/jovrad.htm .  This is an old page that does provide a BASIC program that can be used to find suggested times for likely Jovian decometric signals.   Finding the predicted times is actually the hardest part of the program since many of the old references are out of date.  Another suggestion is to use an SDR dongle running SDR# and Radio SkyPipe to detect the signals. If you scroll all the way down to the bottom of the page you'll find two attachments...Jovrad.txt (2018 suggested times) and "qbasic program to predict jupiter signals.exe.png" (the compiled BASIC program for predictions).  Google won't allow executable attachments thus the .png extension...just delete the .png.

Observing Meteors

Method Used to Detect Meteors:

An SDR (software defined radio) with a directional antenna is pointed towards a DTV transmitter that is beyond normal reception range.  Meteor ionization trails cause the radio waves to be scattered and the ones directed towards my antenna are received.  Software shows the echoes on screen and if powerful enough, a "ringing" sound is heard over the speakers.  Internet sources say the method is sensitive enough to detect meteors down to magnitude 7.  That's less than normal vision can detect from most locations.  The method also works through clouds and during daytime.  All things considered, pretty slick.

Hardware & Software:

• NooElec SDR (http://tinyurl.com/kncpcxa)  software defined radio--receives frequencies between 25-1700 MHz

• home made antenna -- a loop antenna cut for 66.31 MHz  length = 1005/66.31 = 15 feet 2 inches.

I used a loop rather than a dipole or Yagi because I needed to have the antenna indoors.  A Yaga would be almost 6 foot long with booms about 7 foot long.  A dipole would be 7 foot 1 inch loon.  The loop antenna was less that 4 foot on a side.

Computer running:

SDRSharp    (http://tinyurl.com/kkdd9l6),

VBCable      (http://tinyurl.com/nc5n7x4),

Argo       (http://tinyurl.com/m6m5qyk),

NCH Suite   (http://tinyurl.com/2rxxyr)

Hardware:

The SDR is tuned to the working frequency with SDRSharp and the bandwidth is set to 1500.  The SDR is set to USB mode with all automatic gain controls (AGC) turned off.   VBCable passes the radio signal to Argo for processing and display .   Argo is used because it gives a better picture of the event and allows the user to distinguish from airplane vs. meteor reflections.  Because of their speed, meteors will be vertical on the Argo screen while the much slower airplanes will be sloped diagonals.  The gain is set in SDRSharp  so the level in Argo is approximately half scale.  VBCable is used to bypass the microphone pickup of extraneous noise.  NCH Suite is used for video screen capture, video trimming, video editing, and conversion.  All software is free for non-commercial use.  

Various frequencies can be used.  Internet examples show meteor detection between 20 MHz to over 150 MHz.  Lower frequencies are reported to give better results including longer detection times and detecting fainter echoes.  Finding a workable frequency was the hardest part of the project.  You tune to a frequency that you normally can't pick up and hope to see it with a reflection.  There is no promise that it is really there or if it will be overwhelmed with noise as frequently occurs in the FM band.   I've selected the pilot carrier for WHBF Channel 4 from Rock Island, IL.   The antenna is located on the second story of my house in a north facing window.  Meteors scattering is displayed in Argo when I tune to 66,308,500 Hz in SDRSharp with my loop antenna pointed due north towards Rock Island, IL.  I tip my antenna up about 25 degrees. I tune 1 kHz down from the actual signal at 66.3095 MHz so the meteor scatter gives a tone that I can hear.  Tune 1 kHz below USB or 1kHz above LSB.  I may eventually try the audio and video carriers and stations too.   It is not unusual to see over 100 meteors per night although only about one in three are powerful enough to leave an audible trace.

See: http://www.roswellmeteor.com/Receiving%20Meteor%20Reflections%20Using%20DTV%20Transmitters.pdf for an explanation of the process.

Two good videos that show the process:

https://www.youtube.com/watch?v=wxWo-WlLwhA

https://www.youtube.com/watch?v=_WEV4kDL2UA

Other possible stations: (edited 8/7/2019 to reflect changes note Status column)

Call sign CH  Service City           State  ERPower        status      distance heading             tested

KOTA-TV 2 DT RAPID CITY  SD 18.2 kW     (gone)  932 miles 300 degrees   yes--good 

KNOP-TV 2 DT NORTH PLATTE NE 16.0 kW (gone)      645 miles 288 degrees   yes--good

KDLO-TV 3 DT FLORENCE    SD 14.4 kW  (OK)       705 miles 322 degrees

WHBF-TV 4 DT ROCK ISLAND IL 33.7 kW  (OK)       289 miles      0 degrees  <----  station used 

KSNB-TV 4 DT SUPERIOR    NE 23.5 kW  (OK)   470 miles 283 degrees

KNHL   5 DT HASTINGS    NE 45.0 kW     (gone)  525 miles 288 degrees

WMC-TV 5 DT MEMPHIS     TN 34.5 kW     (gone)   290 miles 174 degrees   yes--good

KCWX   5 DT FREDERICKSBURG  TX 23.7 kW      (OK)   907 miles 220 degrees

WOI-DT 5 DT AMES        IA 13.9 kW      (OK)   350 miles 326 degrees

Other Possible Stations: (none tested but opperational 8/2019)

Call Sign     CH City         State ERPower

WGGS-TV        2 GREENVILLE     SC 33.0 kW

WDPN-TV        2 WILMINGTON     DE 34.0 kW

WIWN           5 FOND DU LAC    WI 48.0 kW

WJSP-TV        5 COLUMBUS       GA     21.4 kW

WVUA           6 TUSCALOOSA     AL 26.0 kW

WRGB           6 SCHENECTADY    NY 30.2 kW

KBSD-DT        6 ENSIGN         KS 31.0 kW

KWNB-TV        6 HAYES CENTER   NE 45.0 kW

WPVI-TV        6 PHILADELPHIA   PA 56.0 kW

WRGB           6 SCHENECTADY    NY 60.0 kW

See:  https://www.fcc.gov/media/television/tv-query for a searchable database to find VHF-LO stations to use outside the Midwest.  Lower channels and greater power is better.

Note:  There are no VHF-LO channels in my area to interfere with this method.

VHF low-band (band I)  (frequencies in MHz) 

Channel  Lower edge  Video carrier     ATSC pilot  Audio carrier  Upper edge

    2         54         55.25         54.31         59.75             60

    3                60         61.25         60.31             65.75             66

    4         66         67.25         66.31 <---   71.75             72

                                        (Break in band plan)

    5         76         77.25         76.31         81.75             82

    6         82         83.25         82.31         87.75             88

Observations must include at least ten (10) events.   The applicant should submit a log including the date, time, and radio frequency at which each meteor was observed, as well as an audio or video recording of each event.

I've chosen to monitor the 2015 Quadrantid Meteor Shower the night of January 3-4, 2015.  I've submitted video files for the more powerful echoes in the days leading up to the event.  In addition, I have Argo screen captures from 8 pm until 8 am for the week surrounding the event.  

Nightly Captures: