Here are a few page links for new projects I have been working on.
The image to the right is a weather satellite picture I received and processed from the Russian Meteor M N2 Satellite, sun glint on the sea is seen from this morning pass.
I have designed an HF low pass filter board that interfaces with Arduino or other 5V logic. Low Pass filters for 7MHz, 10MHz, 14MHz, 18MHz, 21MHz, 24MHz and 28MHz are selectable together with a spare on board relay for signal path switching. Check out the Filter here.
Digital modes have become by far the most popular operating method on the HF bands over the recent years. With the advent of FT8 operators can achieve world wide communication with relatively low power, typically <20W. A comphrehensive list of useful software is provided here.
QRSS is an extreme slow speed CW transmission mode. By slowing down the CW signal send rate the detected signal is decoded using Audio Spectrum Analyzer software instead of the traditional 'by ear' method. Slowing the CW dot and dash times to typically 3 second for a dot and 18 second for a dash increases the minimum required SNR ratio for detection considerably, typically 10dB (20dB with a dot length of ~ 10 seconds).
The transmitter used for QRSS is called an MEPT (Manned Experimental Propagation Transmitter). My design of an MEPT that sends QRSS as well as WSPR is documented here.
A Scalar Network Analyser based around an Arduino Nano, AD9850 DDS signal generator and a AD8307 Log Amp has been constructed and is detailed here.
Here is the link to my QRSS grabber. Running QRSSPIG on a Raspberyy PI3, using an RTL-SDR V3 dongle. It is located here.
