UTARC VHF High Speed CW Meteor Scatter

Screenshot of MS DSP v0.70 by 9A4GL The University of Texas Amateur Radio Club is now QRV on an exciting new operating mode: high speed CW! While Europeans have been active on HSCW meteor scatter for years, only recently have several North American stations become active on this mode. By sending Morse code at very high speeds (300wpm, 400wpm, 1000wpm!) even the very shortest meteor bursts on VHF frequencies can be long enough to carry an exchange of information. We use a computer and Creative Labs SoundBlaster 16 sound card to create the CW on transmit and buffer the audio on receive. Detection and decoding of the signal on receive is still accomplished by the human operator; the computer is used as a DSP filter to slow down the HSCW to a copyable speed.

17 November 1998: N5XU completes a second HSMS CW contact with NJ0M (EN34, Minnesota) in the first 11 minutes of the half hour sked that started at 0900 UTC. This was during the hours preceding the peak of the Leonids meteor shower. The speed was 4000lpm (800 words per minute), at 144.133MHz zero-beat. This is a new grid for the club on 144MHz.

• nj0m1.wav This ping from NJ0M contains both callsigns. This was a long burst.
• nj0m2.wav Rogers and report as received from NJ0M.

25 April 1998: N5XU completes first HSMS CW contact with W8WN (EM77, Kentucky) in the first 25 minutes of the one hour sked that started at 1400 UTC. The QSO was completed entirely with underdense pings, registering no better than 2 on the S-meter. The speed was 4000lpm (800 words per minute), at 144.133MHz zero-beat. This is a new grid and state for the club on 144MHz.

• w8wn1.wav This ping from W8WN contains both callsigns. It was received at 1401 UTC.
• w8wn2.wav Rogers and report as received from W8WN at 1422 UTC.

3 April 1998: N5XU completes first successful HSCW tests with K5IUA in EL29. K5IUA is within easy tropo range of our QTH in EM10dg, so testing the MS_DSP software was relatively painless. We need to make a few adjustments in our cabling, though, to make plugging in the receive audio cable easier and to make the PTT line actually work right. We are using MSDSP 0.7 and K5IUA was using MSDSP 0.51. Below are two audio files received over the air from K5IUA on 144.150 MHz.

• 2000lpm.wav Sent at 400 words per minute.
• 8000lpm.wav Sent at 1600 words per minute.