Sometimes in the evenings I like to copy WLO broadcasting news and weather using RTTY and SITOR mode B the frequency is 8.475.225 LSB. I decided to use the K3's data mode and take advantage of the dual data filters.
I made this observation while using my Universal "M-8000 Communications Terminal" with the Butterfly filter installed. The Butterfly filter is a perfect filter for demodulating RTTY. It uses a combination of bandpass and notch to generate a coherent butterfly pattern. The M8000 is connected to an X/Y oscilloscope. I use the M8000 Decoder to copy RTTY and SITOR and it's connected to my K3's line out. The photos below were taken while I was copying 45/170 RTTY. When I copy WLO using LSB (the width control is set to 450Hz and with an I.F. offset of 2.25 I get a perfect butterfly pattern. When I switch to DATA mode using the dual filters the Butterfly pattern is distorted with non coherent phase shifts and in the noisy conditions the copy degrades. http://elecraft.365791.n2.nabble.com/file/n6756724/DSC01915.jpg http://elecraft.365791.n2.nabble.com/file/n6756724/DSC01917.jpg ----- Jack WA9FVP Willco Electronics -- View this message in context: http://elecraft.365791.n2.nabble.com/RTTY-FILter-tp6756724p6756724.html Sent from the Elecraft mailing list archive at Nabble.com. ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
