Stereo recording on 3 frequencies of part of W1AW's bulletin in 18 WPM CW (Morse code) which was broadcast in the evening from Newington Connecticut, made using the online remote shortwave SDR (Software defined radio) receiver of University of twente in Enschede Holland: http://websdr.ewi.utwente.nl:8901/ in USB mode. Information about W1AW's operation and operating schedule are at http://www.arrl.org/w1aw-operating-schedule The 20 meters (14046.5kHz) signal is heard on the right and is the highest tone, 40 meters (7046.7kHz) is monaural in the middle, and is the middle tone, 80 meters (3580.9kHz) is on the left and is the lowest tone. Together they make a major chord. I did that to better differentiate between the 3 and their different fading patterns and because it sounds cool. Occasional interference can be heard: some unknown digital noises on 80 meters, a carrier tuning up on 20 meters near the beginning, another one on 40 later on, and something that sounds like Amtor on 40 deedling in the background for a few seconds. Also heard are static crashes from lightning (mainly on 80 and 40) and the occasional pop on all freqs at once that I think are sdr glitches. I sinched the 3 recordings by ear by tuning all 3 instances of the receiver to Radio 4 at 198khz AM when the bulletin was finished, then reversing the files, finding a good mouth noise in all 3 to zero in on at extremely slow speed playback, which got me to the millisecond range, then testing 2 of the 3 recordings mixing with the third at different sub-millisecond start times to get it right on the nose, using first a echo frequency test (getting it as high as possible, and then testing that mixing start time by mixing the 2 in opposite channels to make sure they form a mono-sounding recording centered in the stereo field. Any time delay between frequencies should be just due to path differences and keying responsiveness in the individual transmitters in CT.
Tri-Freq JO32KF - websdr_recording_start_2017-05-31T00_22_52Z_14046.5kHz-7046.7kHz-3580.9kHz W1AW Bulletin.flac
聲道：2
類型：flac
bulletin、40-meters、receiver、static-crashes、lightning、headphones、stereo、20-meters、software-defined-receiver、hf、musical、shortwave、sdr、qsb、multi-band、morse-code、ionospheric、w1aw、amateur-radio、fading、cw、80-meters、radio、chord、multi-frequency、ham-radio、trans-atlantic
公告、40米、接收器、靜態崩潰、閃電、頭戴耳機、立體聲、20米、軟件定義的接收器、有限公司、音樂、短波、先生、QSB、多頻段、摩爾斯電碼、電離層、w1aw、業餘無線電、法定、CW、80米、無線電、弦、多頻、火腿無線電、跨大西洋
資料來源：freesound ( https://freesound.org )