[TangerineSDR] Bi-Weekly HamSCI Telecon This Thursday

[Dev Joshi]

Hi HamSCI,

This week is our bi-weekly HamSCI telecon on Thursday, Feb 04th at 2000z /
3 PM Eastern.

Here is the link:
https://scranton.zoom.us/j/286316405?pwd=QWdwMlFPbDlYeXg5ZDg1dmYzeFdCUT09

If you are asked for a password, it is “hamsci”.

Steve Cerwin WA5FRF,  will give us an update on his recent results from
analysing Doppler Frequency and Time of Flight Measurements .

Also, we are now accepting abstracts for the 2021 HamSCI workshop! Please
submit at http://hamsci.org/hamsci2021


Best,
Dev

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*Estimation of Ionospheric Layer Height Changes From Doppler Frequency and
Time of Flight Measurements on HF Skywave Signals*
 -- Steve Cerwin WA5FRF, Kristina Collins KD8OXT, Dev Joshi KC3PVE,
Nathaniel Frissell W2NAF

The HamSCI community has been studying apparent frequency shifts in the
reception of HF sky-wave signals from radio station WWV in Ft. Collins, CO.
WWV is a standard time and frequency station with atomic clock accuracy. If
the receiving station uses a GPS Disciplined Oscillator (GPSDO) for a
frequency reference, the atomic clock accuracy on both ends guarantees any
observed frequency shifts are attributable only to propagation effects
through the ionosphere. Causes for frequency shifts in the received signal
are recognized as complex and varied. A leading candidate is Doppler shift
resulting from dynamic changes in refraction layer height. These, in turn,
are caused by the diurnal transitions between night and day, passage of an
eclipse shadow, and ionospheric disturbances originating from solar flares
or X-ray events. For the case of changing refraction layer height, an
analysis of Doppler frequency and Time of Flight (TOF) data can estimate
the changes in skywave path length between the transmitter and receiver.
This data can be used in conjunction with an assumed geometric model and
propagation mode to infer the corresponding height profile over time. This
paper postulates one possible mechanism for observed frequency swings and
presents supporting experimental evidence. Comparisons between the
calculated height profile and data from ray trace programs and ionosonde
measurements are given.

----------------------------------------------
*Dev Joshi, Ph.D., *KC3PVE
Postdoctoral Research Associate
Department of Physics and Engineering
The University of Scranton
C: 617 775 9712
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