> -----Original Message----- > > My question concerns what pitch is easier to copy > when receiving fast cw when no qrm is present.
There has been research on the topic of sidetone and level. It concluded with 500 Hz and in some cases even lower tones to be favorable in noise free environments. This was published in Scandinavian Audiology, 1992, volume pages 255-60: Recognition of telegraphy signs at different listening levels and frequencies. by Montnemery P, Almqvist B, Harris S., Department of Audiology, University Hospital, Lund, Sweden. "The recognition of telegraphy masked by noise at 40 and 80 signs/min telegraphy speed was studied in 10 normal-hearing subjects at different sound pressure levels (25-85 dB SPL in steps of 5 dB) as well as at different test frequencies (2000, 1000, 800, 630, 500 and 250 Hz). The ability to recognize the signs varied with varying SPL. Recognition for most of the subjects was best at an SPL close to 70 dB. All subjects improved their recognition as the frequency was lowered to 500 Hz, some even at 250 Hz. These facts should be taken into consideration when training telegraphy operators as well as in the construction of radio receivers to permit listening at low frequencies. Furthermore, the critical ratio was calculated at the different test frequencies." 40 and 80 signs/minute should be 8 and 16 wpm. Peter Montnemery is SM7CMY and a K2 owner, but I am not sure that he is active on this list any longer. 73 Sverre LA3ZA http://www.qslnet.de/la3za/ _______________________________________________ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
