DPS-4D EI764 064 / 64.630750, -147.042904

Propagation for Snipers Net 3920 KHz 0200 UTC (Net Roster)

Receiver Audio Location - 64.6 / 147.4


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# Global Ionospheric Radio Observatory
# GIRO Tabulated Ionospheric Characteristics, Version 1.0 Revision B
# Generated by DIDBGetValues on 2017-09-11T07:56:03.429Z
# Location: GEO 64.66N 212.93E, URSI-Code EI764 EIELSON
# Instrument: Ionosonde, Model: DPS-4D
# Query for measurement intervals of time:
# 2017-09-11T02:00:00.000Z - 2017-09-11T02:30:00.000Z
# Data Selection:
# CS is Autoscaling Confidence Score (from 0 to 100, 999 if manual scaling, -1 if unknown)
# foF2 [MHz] - F2 layer critical frequency
#Time                     CS   foF2 QD





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Propagation Failure

Ionograms reveal no return signal reflections and recorded transmission were only of local ground wave stations


Hypothesized Conclusion

Failure of propagation due to Polar Cap Absorption manifesting as major D-Layer signal attenuation for central Alaska as shown on the below chart. 

D-Layer attenuation associated with reports by NOAA of Radio Blackout Activity

Radio blackouts reaching the R3 levels were observed over the past 24
hours. The largest was at Sep 10 2017 1606 UTC

Radio Blackout Forecast for Sep 11-Sep 13 2017

              Sep 11        Sep 12        Sep 13
R1-R2           80%           10%            1%
R3 or greater   50%            1%            1%

Rationale: The potential for R1-R3 (Minor-Strong) radio blackouts exists
on day one (Sep 11) from Region 2673. Probabilities are expected to drop
rapidly as the region moves further around the far-side of the Sun on
days two and three (Sep 12-13).



Area in RED defined as Polar Cap Absorption