1. HF Applications in Emergency Communications Paul Cowley W0YR
Lessons From a COMMEX
HF Applications in Emergency Communications
Paul Cowley W0YR

2. Portions of this presentation are courtesy of Paul English – Chief US Army MARS
His presentation was given during Iowa’s Interoperability Exercise on 07 Sep 2017

3. Operation Stable Mercury 2017
Statewide communications interoperability exercise
Hosted by Iowa National Guard
ARRL Midwest Division newsletter: oct2017news.pdf
Field Radio Podcast (Episode 8): mercury-rising-with-paul-cowley-kb7vml/
Included HF training from NORAD-USNORTHCOM and US Army MARS

4. Logging Your Activities
Used to track significant events; use as a shift change briefing
Keep track of maintenance or equipment issues and resolution
Pass on outstanding issues, concerns, and upcoming events to the next shift
Track what personnel are on duty in case activities need to be researched
Becomes the official record of support provided during an incident
Numbers of personnel providing support
How you supported the incident = $$$$
If your support is not logged, IT DIDN’T HAPPEN!!

5. Voice Traffic Handling Tips
Speak sloooooowlllllyyyyyyy! (talk no faster than you can write!)
Speak clearly
Spell out difficult words phonetically
(ie: “NETCOM, I spell November Echo Tango Charlie Oscar Mike”)
Break up the message to allow receiver to ask for clarification
Speak slowly!
One final point… SPEAK SLOWLY and clearly

8. Characteristics of HF Frequencies
For long distances, use higher frequencies, 4-30 MHz;
4-10 MHz at night,
10-25 MHz during the day.
For very short distances (NVIS), use lower frequencies, 2-8 MHz;
2-3 MHz at night,
4 or 5 MHz during the morning and evening
5-6-7 MHz during the day

9. HF Propagation Information
Key HF Propagation Resources:
astStationList
tems/6/5
International Time Standard Stations
2.5 MHz
WWV
3.33 MHz
CHU
5.0 MHz
7.85 MHz
10.0 MHz
14.67 MHz
15.0 MHz
20.0 MHz

10. Obtaining Information by Listening
Time Station WWV
Time Station CHU
Fort Collins, Colorado
2.5, 5, 10, 15 and 20 MHz
Male voice announcement
Kauai, Hawaii
2.5, 5, 10, and 15 MHz
Female voice announcement
Ottawa, Canada
3.33, 7.85, and MHz
Time Stations transmit 24/7 and can be used to observe the propagation conditions to known locations.
Transceivers should have time station frequencies programmed into memory.
Time Station WWVH

11. Obtaining Information by Listening
General Rule(s) of Thumb:
Strongest signals at 15 or 20 MHz :
Use 6 or 7 MHz frequency for NVIS
Strongest signals at 10 and 15MHz:
Use 5 or 6 MHz frequency for NVIS
Strongest signals at 5 and 10 MHz:
Use 3 or 4 MHz frequency for NVIS
Strongest signals at 2.5 and 5 MHz:
Use 2 or 3 MHz frequency for NVIS
By monitoring signals from distant Time Stations, operating frequencies for short range (NVIS) communications can be determined.

12. What Exactly is This NVIS Stuff?
Propagation path, NOT an antenna type or mode of communication
“Fills in” distance between ground wave and first hop for low-angle DX communications
Typically covers the range between 50 miles and 600 miles; relatively free from fading
Works best with low antenna height
1/8 wavelength or less
Lower antennas = less received noise!
Does not require high power levels
25 Watts is usually sufficient due to shorter paths and reduced D-Layer attenuation
Utilizes any frequency below Critical Frequency (foF2) but above D-Layer attenuation/absorption frequency (LUF)
NVIS is not possible below LUF or above foF2
Generally needs frequencies in the range of 80/60/40 meters depending upon time of day

13. NVIS vs Lower-angle (DX) Propagation
“Traditional” low-angle Propagation – works well for DX communications
NVIS provides reliable regional communications at the expense of DX

14. Further Study - NVIS

15. Ionogram: Measuring the Ionosphere

16. Ionogram: Measuring the Ionosphere
Determining NVIS
Critical Frequency
F2 Layer
Height of signal refraction
F1 Layer
E Layer
Updates every 5 minutes
Determine freq’s for other distances

17. Ionogram: Measuring the Ionosphere
Same station… roughly the same time of day, but about two months apart
What would you expect for differences in propagation?

18. Ionogram: Measuring the Ionosphere

19. Ionogram: Measuring the Ionosphere

20. Ionogram: Measuring the Ionosphere

21. Measuring the Ionosphere
Compilation of all Ionosondes globally; updates hourly at 40 mins past the hour
For communications within ~300 km - The color at your location is the optimum frequency for F2 layer NVIS communication

22. Further Study - Ionograms

25. DoD Interoperability Exercise
DoD Communications Interoperability Exercise this weekend (4 Nov – 6 Nov 2017)
DoD will request county-by-county status reports via MARS organizations; MARS will interface with Amateur community
Primarily 60-meter event
High-power military broadcast on 60-meter Channel 1 ( kHz)
UTC Saturday / CDT Friday
Informational broadcast on 13,483.5 kHz
UTC Sunday / CST Sunday (remember the DST time change!)
Will likely request reports in the MARS ‘CNTY’ format
Format: FIPS CODE, REPORT TIME, POWER STATUS, WATER STATUS, SANITATION STATUS, MEDICAL FACILITY STATUS, COMMUNICATIONS STATUS, TRANSPORTATION STATUS, SOURCE, LOCATION
Example: 19169,051715,Y,Y,Y,Y,Y,Y,A,Ames

27. Lessons Learned
HF can fill a niche role in Iowa’s Emergency/Interoperable Communications plans
Largely statewide/regional in nature
NOT well-suited to local communications – that role is better left to VHF/UHF resources
60-meters is a unique and valuable RF resource
Need to program/modify radios in advance
Ideal frequency range for NVIS propagation paths
Secondary allocation, authorized for CW, Phone, Digital***
***Digital recommended PSK31, attended PACTOR III only
Handling voice traffic on HF requires patience and practice
There is a lot to learn about HF propagation
Practice is important!

28. Questions?