• Below is the Tektronix MDO4104-6 spectrum analyzer display showing the Sun radio emissions from approximately 20.1 MHz to 24.0 MHz.
• The Sun radio emission is the white blueish horizontal line just above the bottom of the spectrogram from the fourth frequency division 20.1 MHz to the right edge at 24.0 MHz.
• The first set of strong signals from the left edge is the 17.5 MHz to 17.9 MHz broadcasting band.
• The second set of strong signals from the left edge is the 17 meter (18.068 MHz to 18.168 MHz) amateur radio band.
• Radio station WWV at 20.0 MHz is the red vertical line in the spectrogram just over one division left of center. WWV distance is 1,511 km with a bearing of 105.3 degrees.
• The strong set of signals just right of the center frequency is the 15 meter (21.0 MHz to 21.45 MHz) amateur radio band.

United States Frequency Allocations

Summary

The above spectrum trace shows the approximately 4 dB rise in nose level at 20.75 MHz center frequency for the strongest Sun radio emission signal acquired at 18:52:33 UT. Sun radio emissions are from approximately 20.1 MHz to 24.0 MHz and Sun was 26 degrees above the horizon when these radio emission occurred.

Tektronix MDO4104-6 spectrum analyzer.

• 17.5 MHz start frequency
• 20.75 MHz center frequency
• 24.0 MHz stop frequency
• 6.5 MHz frequency span
• 6.5 MHz capture bandwidth
• 100 Hz resolution bandwidth
• 650 kHz per horizontal division
• 5 dBm per vertical division
• ~7 seconds spectrum update rate
• Spectrogram bottom is the current spectrum trace shown at the bottom of the display.
• Spectrogram top is the oldest spectrum, approximately 30 minutes after the current spectrum trace at the bottom.

The below spectrum trace is before the solar burst at 18:52:26 UT.

Video

• Sun Radio Emissions Spectrogram with Tektronix MDO4104-6 on 2014-02-08
  • Notice the rapid onset and slower decay.
  • Compare the video with the Radio-SkyPipe II chart below.
  • Scroll through the video frame by frame to see each spectrum trace.

Observing Information

• OBS-Time: February 8, 2014, 1853 UT
• OBS-Location: Camas, WA USA, 16.6 miles East-North-East from the center of Portland, OR, USA

Spectrum Analyzer Equipment

• Tektronix MDO4104-6 Mixed Domain Oscilloscope 50 kHz to 6 GHz spectrum analyzer.
• Mini-Circuits 21.4 MHz coaxial bandpass filter 19.2 to 23.6 MHz.
  • Performance data
  • Performance curves
• Mini-Circuits ZFL-500LN+ Coaxial Low Noise Amplifier minimum 24 db gain, noise figure 2.9 dB typical, 0.1 to 500 MHz, flatness +/-0.5 dB total range, powered with 15 VDC.
  • Performance data
  • Performance curves
• Mini-Circuits 21.4 MHz coaxial bandpass filter 19.2 to 23.6 MHz.
  • Performance data
  • Performance curves
• Radiowavz 15-DP11 15M dipole antenna with 1:1 Balum
  • East - West orientation
  • 100 feet of RG6 quad shielded coax
  • Tuned to 20.1 MHz with RigExpert AA-54 HF antenna analyzer

Radio Equipment

• Icom IC-R75
  • 20.75MHz
  • LSB
  • AGC off
  • Preamp 2 on
• Behringer XENYX 302USB 5-Input Mixer with XENYX Mic Preamp and USB/Audio Interface
  • The HP laptop does not have a line input, only mic input.
  • XENYX 302USB works great taking the IC-R75 back recorder jack [REC] signal and digitizing it.
  • The XENYX 302USB has its own Line gain control.
  • The XENYX 302USB has its own headphone gain control.
    • I use a Y cable to run the XENYX 302USB to headphones which I use at night time and an external powered speaker when I am home alone. It was very impressive to hear this solar burst and watch it on Radio-SkyPipe II at the same time.
• MFJ Enterprises MFJ-1040C Preselector
• Radiowavz 15-DP11 15M dipole antenna with 1:1 Balum
  • East - West orientation
  • 100 feet of RG6 quad shielded coax
  • Tuned to 20.1 MHz with RigExpert AA-54 HF antenna analyzer

Software

• Radio-Sky Radio-SkyPipe II An Internet Enabled Strip Chart Recorder
• Radio-Sky Radio-Jupiter Pro 3 Sky map shows where Sun is in the antenna beam.
• Python 2.7.6 script running on a HP G70 Windows Vista laptop using socket server LAN cable without a router/hub to data log the Tektronix MDO4104-6 screen captures to a USB 16Gb memory stick plugged into the MDO4104-6.

Chart Analysis

• Sun burst is the large signal ending at 18:53:19 UT

• Zoom view
• Rapid onset and slower decay, burst looks like a shark fin.
• Multiple plateaus on trailing edge

Verifying Solar Burst

NOAA/ National Weather Service
National Centers for Environmental Prediction
Space Weather Prediction Center
Solar Event Reports (Edited Events)

• Solar burst began at 1850 UT and ended at 1853 UT
• Reporting observatory SAG: Sagamore Hill, MA, USA
• Event RSP: Sweep-frequency radio burst
• Frequency: 25 MHz to 180 MHz
• Particulars: type V burst of major intensity 2
  • Type V burst: Brief continuum burst.
  • 2 is significant intensity rating

:Product: 20140208events.txt 
:Created: 2014 Feb 09 2102 UT
:Date: 2014 02 08
# Prepared by the U.S. Dept. of Commerce, NOAA, Space Weather Prediction Center
# Please send comments and suggestions to SWPC.Webmaster@noaa.gov 
#
# Missing data: ////
# Updated every 30 minutes.
#                            Edited Events for 2014 Feb 08
#
#Event    Begin    Max       End  Obs  Q  Type  Loc/Frq   Particulars       Reg#
#-------------------------------------------------------------------------------
6070       1850   ////      1853  SAG  C   RSP  025-180   V/2 

NASA STEREO / WAVES

NASA STEREO / WAVES data

• Radio Astronomy, Observing the Sun (S5PRASunV04.pdf)
• The Radio-Sun by Jim Sky
• Australian Radio and Space Weather Services
  • Australian A Brief Introduction of Radiospectrogram Analysis
• A Brief Introduction of Radiospectrogram Analysis by David Darling
• CORONAL MASS EJECTIONS AND SOLAR RADIO EMISSIONS (PDF) by N. Gopalswamy
• NRAO Solar Radio Emission (PDF) by T. S. Bastian
• Solar radio emission processes (PDF) by Jeongwoo Lee
• Solar radio emission Chapter 11 (PDF) by W. R. Barron, E. W. Cliver, J. P. Cronin & D. A. Guidice
• Radio Monitoring Plots - Movies by R. Romagnan, M. Pick and S. Cnudde