In March 2005, Rick KN6KB, the author of SCAMP, sent an update to the ARRL bandwidth committee; Rick posted this update to the SCAMP reflector, where it is available via
http://groups.yahoo.com/group/SCAMPprotocol/message/805 For those not participating in this reflector, here's an excerpt describing Rick's assessment of Busy Detection in SCAMP: <excerpt> The SCAMP clients and servers also incorporate an effective channel busy detector to significantly reduce QRM from either the careless operator or the hidden transmitter (3rd station not heard by the station manually initiating the connection but detected by the automated server). While there is and continues to be much comment from groups that would like to banish all automated (full or semi) transmissions these automated modes have proven to be a very useful and popular. These modes have also proven to serve best and be most efficient and reliable in times emergency when sufficient control operators are not always be available. The attached screen capture GIFs from the WL2K SCAMP server show that while not perfect the state of the art in automated busy detectors has improved considerably. The following GIFs were all made at fairly weak signals...Signals barely moving the S meter above the background noise. The SSB signal is about 1 S unit over the noise. Clear channel display (reference) Weak CW (about 1000 Hz on the display) PSK 31 signal at about 1000Hz with a weaker CW carrier below Pactor II signal near the bottom of the Pass band Pactor III signal showing mode transitions SSB voice at about 1 S unit over the noise There is no question that the integrated use of these types of busy detectors can substantially mitigate QRM from automated or semi automates stations even in difficult "hidden transmitter" scenarios. </excerpt> A month later, Rick posted another summary in http://groups.yahoo.com/group/SCAMPprotocol/message/1306 in which he said <excerpt> SCAMP is an experiment. Until SCAMP there was NO viable ARQ protocol soundcard mode. SCAMP has already proven that this is possible and that it can move messages with attachments error free with moderate S/N levels. It has also proven that automatic busy detectors are practical and can help solve QRM from the "hidden transmitter" problem. </excerpt> Thus software technology available for more than a year would if deployed dramatically reduce the QRM generated by semi-automatic stations. Rather than waste time debating the edge conditions under which busy frequency detection might be imperfect, we should recognize that it is already well above the bar and encourage its deployment. 73, Dave, AA6YQ ------------------------ Yahoo! Groups Sponsor --------------------~--> See what's inside the new Yahoo! Groups email. http://us.click.yahoo.com/2pRQfA/bOaOAA/yQLSAA/ELTolB/TM --------------------------------------------------------------------~-> Need a Digital mode QSO? Connect to Telnet://cluster.dynalias.org Other areas of interest: The MixW Reflector : http://groups.yahoo.com/group/themixwgroup/ DigiPol: http://groups.yahoo.com/group/Digipol (band plan policy discussion) Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/digitalradio/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
