Re: need some roofing filter advice?
Posted by
Bill W4ZV on
Jul 20, 2011; 10:22am
URL: http://elecraft.85.s1.nabble.com/need-some-roofing-filter-advice-tp6581353p6602111.html
Ed Muns, W0YK wrote
The K3 is entirely different. I've been operating SSB with a 1.5 kHz
bandwidth for three years now and it is perfectly intelligible. On prior
radios, though, I couldn't even get a 2.1 kHz filter to sound intelligible
enough to be useful. I think the difference is where the filter is located
relative to the signal.
The K3 is not actually different or it would be violating the laws of physics. To make ANY radio work using narrow bandwidths on SSB is simply a matter of optimizing the placement of the filter passband in the voice spectrum (as Ed states above). The FT-1000MP, K2, Orion and many others can be made to work with narrow filters. I first discovered this on an MP I used in the late 90s:
http://www.va3cr.net/va3cr2.net/markv/Troubleshooting/Filters.htm73, Bill