Fry, Ghee

McTernan, Jesse

Rawlins, Linda

NASA Technical Reports Server

HamSCI Workshop | February 23-24, 2018 
NASA Marshall Space Flight Center
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Ghee Fry, WL7C
Jesse McTernan, KN4EZR
Linda Rawlins
NASA Marshall Space Flight Center, Huntsville, AL
Eclipse Radio Science at NASA
Marshall Space Flight Center
HamSCI Workshop | February 23-24, 2018
NJIT, Newark NJ 
https://ntrs.nasa.gov/search.jsp?R=20180001878 2019-08-30T13:06:31+00:00Z
HamSCI Workshop | February 23-24, 2018 
NASA Marshall Space Flight Center
2
The MSFC Eclipse Radio Science Team
Team:
Ghee Fry/WL7C Heliophysics/Space Weather
Linda Rawlins Retired NASA/Citizen Scientist
Jesse McTernan/KN4EZR Heliophysics/Electrical Engineering
Rob Suggs/KB5EZ, Space Environments/Meteoroids 
Linda Krause/K0DRK Heliophysics/Ionosphere/Space Weather 
Dennis Gallagher Heliophysics/Magnetospheres/Plasmaspheres
Mitzi Adams Heliophysics/Public Outreach
Tools:
- Ham Shack Rigs, Computers and Antennas
- Reverse Beacon Network
- Weak Signal Propagation Reporter Network
- Amateur Radio Community
HamSCI Workshop | February 23-24, 2018 
NASA Marshall Space Flight Center
3
Ionospheric Radio Wave Propagation
Lower frequencies (yellow), 
Higher (red) frequencies
Different take-off angles
http://www.swpc.noaa.gov/phenomena/ionosphere
Propagation (radio wave path)
Engaging students and citizen scientists
HamSCI Workshop | February 23-24, 2018 
NASA Marshall Space Flight Center
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Eclipse Effects on Signal Path
• Normal Summer Day: (ignoring a lot of electrodynamic processes, and no E-Region)
• D-Region absorbs 80M signals; 40M signals absorbed or signal strength decreases
• Eclipse Day:  Solar EUV, X-rays decrease into eclipse; recovers out of eclipse
• D-Region ionization reduced; ion-neutral recombination decreases electron density
• Radio wave absorption decreases; 80M signals pass through D-Region
• Erosion of lower F-Region raises ”reflection” height
• Over-the-Horizon (OTH) signal paths lengthen; propagation range increases
• Process reverses coming out of maximum eclipse
Left: Typical daytime signal paths.
Right: Signal paths during eclipse.
40M  path            80M ----
HamSCI Workshop | February 23-24, 2018 
NASA Marshall Space Flight Center
5
Station Locations
WL7C and K0DRK near Greatest Eclipse; NN4SA Northern Alabama
WL7C, Northern TN
K0DRK, Southern KY
NN4SA, Northern AL
NN4SA
WL7C
K0DRK
https://eclipse.gsfc.nasa.gov/eclipse.html / Google Map Data © 2018 Terms of Use
HamSCI Workshop | February 23-24, 2018 
NASA Marshall Space Flight Center
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WL7C Reverse Beacon Network Receiver/Skimmer
APSU Farm, Clarksville, TN (36.65N, 87.34W), Grid Square: EM66hn
South of eclipse centerline
RBN Skimmer in Cow Barn
HamSCI Workshop | February 23-24, 2018 
NASA Marshall Space Flight Center
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Eclipse Details at APSU Farm Site
https://eclipse.gsfc.nasa.gov/eclipse.html / Google Map Data © 2018 Terms of Use
HamSCI Workshop | February 23-24, 2018 
NASA Marshall Space Flight Center
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WL7C Reverse Beacon Network Skimmer
APSU Farm, Grid Square: EM66hn 
HamSCI Workshop | February 23-24, 2018 
NASA Marshall Space Flight Center
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Setting up WL7C at APSU
HamSCI Workshop | February 23-24, 2018 
NASA Marshall Space Flight Center
10
WL7C RBN Site and Antenna
82-foot DXE Alpha Delta fan dipole antenna for 80M, 40M, 20M, 10M
HamSCI Workshop | February 23-24, 2018 
NASA Marshall Space Flight Center
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K0DRK Reverse Beacon Network Transmitter
K0DRK Reverse Beacon Network Transmitter
North of Hopkinsville, KY  (37.04N, 87.30W)
Near eclipse centerline; Grid Square: EM67ia
80 watts feeding 10-80M Alpha Antenna
North of eclipse centerline
HamSCI Workshop | February 23-24, 2018 
NASA Marshall Space Flight Center
12
WL7C 40M Propagation Paths
Propagation paths of stations received by WL7C  August 21, 2017 between 1400-2000 UT. 
WL7C is at the apparent radiant point.
August 21, 2017: Day of Eclipse
HamSCI Workshop | February 23-24, 2018 
NASA Marshall Space Flight Center
13
WL7C Spots: GCD Distance vs Longitude
Size/darkness of spots means higher 
signal strength
HamSCI Workshop | February 23-24, 2018 
NASA Marshall Space Flight Center
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WL7C 40M (7.0 MHz): Contact Distance vs. Time
Day of Eclipse, August 21, 9:00-15:00 CDT
Colored lines represent spots from same station
HamSCI Workshop | February 23-24, 2018 
NASA Marshall Space Flight Center
15
WL7C Spots GCD Distance vs time
North
South
Day of Eclipse, August 21, 9:00-15:00 CDT
Colored lines represent spots from same station
HamSCI Workshop | February 23-24, 2018 
NASA Marshall Space Flight Center
16
NN4SA Weak Signal Propagation Reporter Transmitters 
Marshall Amateur Radio Club (MARC) Station
NASA Marshall Space Flight Center
Huntsville, AL (34.64N, 86.68W), 
Grid Square: EM64qp
Partial eclipse (96.5% obscuration)
5 watt transmitters on 80M and 40M
HamSCI Workshop | February 23-24, 2018 
NASA Marshall Space Flight Center
17
Weak Signal Propagation Reporter Map 8-21-17
Courtesy Robb Suggs, KB5EZ
NN4SA WSPR Propagation Paths – 80M band (3.5 MHz)
wsprnet.org  / Google Map Data © 2017 Terms of Use
Red pins represent 
stations receiving 
NN4SA
NN4SA at radiant in 
North Alabama
HamSCI Workshop | February 23-24, 2018 
NASA Marshall Space Flight Center
18
80M (3.5 MHz) Signal to Noise Ratio vs Time
Courtesy Robb Suggs, KB5EZ
Eclipse Day 
Next Day
NN4SA to AG0G Propagation
HamSCI Workshop | February 23-24, 2018 
NASA Marshall Space Flight Center
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NN4SA WSPR 40M Transmitter Reception
Rob Suggs - 40M HF Propagation and Eclipse 2017.jpg
Rob Suggs - 80M HF Propagation and Eclipse 2017.jpg
Reports of SNR on 40M by six WSPR stations showed enhancements of
signals during the eclipse (red lines), but not on the day after (green lines).
Figures indicates the range and azimuth from the NN4SA transmitter.
Figure courtesy Robb Suggs, KB5EZ
MSFC, Huntsville, AL (34.64N, 86.68W)
HamSCI Workshop | February 23-24, 2018 
NASA Marshall Space Flight Center
20
NN4SA WSPR 80M Transmitter Reception
Reports of SNR on 80M by six WSPR stations showed enhancements of
signals during the eclipse (red lines), but not on the day after (green lines).
Figures indicates the range and azimuth from the NN4SA transmitter.
Figure courtesy Robb Suggs, KB5EZ
MSFC, Huntsville, AL (34.64N, 86.68W)
HamSCI Workshop | February 23-24, 2018 
NASA Marshall Space Flight Center
21
Why Didn’t WL7C Hear K0DRK?
On the day of the eclipse, why didn’t WL7C hear K0DRK on 40M 
just 30 miles (53 km) away?
• Line of Sight?
• Terrain and Distance over the horizon
• Ground Wave?
• Distance, soil conductivity
• Near Vertical Ionospheric Skywave (NVIS)?
• foF2, was near 4.0 MHz +/- 0.5 MHz, 
• hmF2, height of F2 layer peak, ranging 196-244 km. 
• PIM says no
HamSCI Workshop | February 23-24, 2018 
NASA Marshall Space Flight Center
22
Parameterized Ionospheric Model (PIM)
40M Mid-Latitude Ray Traces
No NVIS?
Multi-Hop
Low angle long Path
7.0 MHz radio wave ray 
paths at different 
elevation (take-off) 
angles (E)
F = Frequency
E = elevation angle
foF2 3.5 - 4.5 MHz, 
hmF2 196-244 km. 
HamSCI Workshop | February 23-24, 2018 
NASA Marshall Space Flight Center
23
Conclusions and Lessons Learned
Conclusions
• 2017 total solar eclipse demonstrated that HF radio science 
can be done:
• On a shoestring budget
• By professional, citizen scientists, students and the amateur radio 
community
• Using grass roots crowd-sourced propagation spot aggregators (e.g., 
RBN, WSPR)
Lessons Learned
• Data quality can be impacted by the social nature of crowd-sourced 
observations: accuracy of location, timing, consistency
• Do the site survey BEFORE the eclipse !
• Radio Science is FUN !
HamSCI Workshop | February 23-24, 2018 
NASA Marshall Space Flight Center
24
Next Steps
• Improving ionospheric radio science capabilities:
• Install RBN CW Skimmer and WSPR receivers at MSFC/NSSTC
Upgrade SDR hardware, software, site location*
• Continue to engage Hams, students and citizen scientists
• Preparing for the next Big Eclipse opportunity
• Chile, 2019  (?)
• Mexico/USA 2024
  NASA/MSFC Postdoc Jesse McTernan/KN4EZR’s Talk for details
Thanks to ARRL, Virginia Tech and academic community, HamSCI, 
the Solar Eclipse QSO Party participants and especially the curators 
and volunteers of RBN and WSPRnet and other spot aggregator sites
HamSCI Workshop | February 23-24, 2018 
NASA Marshall Space Flight Center
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• Apollo 17 45th anniversary – 11-19 December 2017, beginning of event
• NASA founded 60th anniversary (act signed by President Eisenhower) – 29 July 1958
• ISS First Element Launch 20th anniversary – 20 November 1998
• ISS Node 1 Launch 20th anniversary – 4 December 1998
• 50th anniversary of Apollo 8 – launch 21 December 1968 
• Apollo 8 – splashdown 27 December 1968, end of event
https://nasaontheair.wordpress.com
NASA On The Air
QSL Card and Certificate


Eclipse Radio Science at NASA Marshall Space Flight Center

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