|Please explain the purpose of operation:
||The tests of the VIPIR HF Radar hardware intended for the Transportable Dynasonde System have been started using earlier approved by FCC Special Temporary Authorization (File Number 1895-EX-ST-2019). We have got the first light on the system and confirmed its ability to detect the ionospheric reflections. Operations proved to be non-disruptive for other users of the radio spectrum. At the same time, several problems with the radar hardware and firmware have been revealed, and we are working with the vendor to resolve the issues. The tests will continue until all the issues are resolved.
The standard Dynasonde sounding session is characterized by a pulse repetition interval of 5-10 ms and by the number of base frequencies from 500 to 600 in the frequency band 2–25 MHz. Base frequency is progressing steadily within each sounding session, so that only 8 pulses can occur at approximately the same frequencies. Pulses are grouped into a carefully designed pattern that facilitates echo detection and application of higher-level analysis routines. The 2 min interval between sounding sessions guarantees sufficient temporal resolution for sampling wave and other dynamic processes in the ionosphere. Pulse bandwidth of 30 kHz and raised cosine pulse envelope are specifically chosen to minimize possible Radio Frequency Interference (RFI) to other users of the spectrum. Effective Radiation Power of the system is only 10 W, and the duty factor 0.4-0.7%.
For the tests we will be using a version of the simple horizontal dipole G5RV ZS6BKW antenna optimized with 1:1 balun for low parasitic emissions. The antenna will be installed on the roof of the Engineering Center, 25 feet above the rooftop and 75 feet above the ground, with approximately West-East orientation.
The planned test operation will be strictly on a non-interference basis. The requested frequencies and operational transmission parameters are those permitted under Section 90.266 of the FCC rules: Long Distance Communications on Frequencies below 25 MHz. The permitted operational parameters are identified specifically in the FCCs Electronic Code of Federal Regulations, Title 47 (Telecommunication), Volume 1, Chapter 1, Part 2.106: Table of Frequency Allocations. The frequency bands requested are designed to avoid the Restricted Bands of Operation stipulations described in the Electronic Code of Federal Regulations, Title 47 (Telecommunications), Part 15 (Radio Frequency Devices), Subpart C (Intentional Radiators).
Dynasonde is a well-established low-RFI instrument. It has operated in many locations worldwide, without any RFI-related complaints. This includes the current multi-year Dynasonde operation at the NASA’s Wallops Island Flight Facility and previous Dynasonde operation in Boulder, CO on NOAA campus.