P.B. Christensen wrote: > > Since keying bandwidth is a function of the RF envelope shape, I'm not > sure > why anyone would want to narrow the K3 filter on CW transmit. >
Because most rigs have spurs and I wanted to make my signal as clean as possible. Typically these may be <80 dBc but still readable if the transmitter is using high power and the receiving station has good antennas (e.g. on 160m in particular). I often hear +/- 1 kHz -80 dBc spurs from FT1000 series rigs and of course the 2.4 kHz -60 dB spur from the Flex 5k (recently fixed thanks to W5ZN and others' persistence). If you look carefully at Figure 2 in ARRL's original K3 product review, you can see a few suspicious blips which I wanted to clean up. Unfortunately using 1 kHz to TX in the K3 caused other problems so I abandoned the idea. I'm not aware of any spur reports on the K3 since the VCO stiffener and KPA3 mods were implemented, so I agree there's probably no need now. http://www.elecraft.com/manual/ELECRAFT%20KSYN3%20Stiffener%20Mod%20Rev%20D.pdf http://www.elecraft.com/K3/mods/K3%20Technical%20Alert%201.pdf For any interested in assuring clean signals you should also consider the chirp mod (if applicable): http://www.elecraft.com/K3/mods/KSYN3%20DDS%20Gain%20Modification.pdf 73, Bill -- View this message in context: http://elecraft.365791.n2.nabble.com/Filters-and-Configuration-Questions-tp5891986p5892454.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
