-----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Larry Schimelpfenig Sent: Saturday, April 11, 2009 12:04 PM To: [email protected] Subject: [CQ-Contest] SOME THOUGHTS ON USING THE K3 ON SSB
What I'm about to relate here may very well be posted at other spots on the Inet, but I haven't had much luck in finding it, so this will hopefully be helpful to contesters using the Elecraft K3 on phone. I address two points. First is setting the crystal filter center frequency offset which greatly affects transmit audio quality. Second is use of the rear panel mike and audio in jacks in conjunction with sound card voice keying. We don't operate a lot of ssb from NR4M, but it's on the rise (don't blame Steve - a gun was held to his head). Somehow or other we decided to make an M/M effort in the ARRL SSB DX test. We spent hours trying to get good audio out of the K3. We were using a Heil headset with the HC-4 element. To make a long story short, while going through the menus I found FLx FRQ in the configuration menu. After reading about this menu item I played with it a little to see if it made a difference. Did it ever! The 5 pole crystal filters have a label on them specifying what the offset should be. Most are labled "-0.91". At some point we had done a master reset of the radio which set the offset at "0.0". When we set the offset to -0.89 as the filter in one of the K3s was labled, we received great audio reports. One of the contesting stations in MD was having transmit audio problems with the K3s there and they weren't sure that the 20M stack was working correctly as well. This morning four or five stations including the one with audio problems did some horse racing and got comparative audio reports from European stations. I told the station with problems about the filter offset. Interestingly enough they were using the eight pole ssb filters that should not have required offset according to the manual. On a whim, they tried the offset adjustment and found that made a difference. When we were done both of their K3s went from sounding terrible to being quite acceptable. Has anyone else using the eight pole ssb filter had to adjust the offset to get it to sound decent on transmit? In addition to a couple pair of Heil headsets with HC-4 elements, we have a couple of very comfortable headsets with hi fidelity mikes. We found that by adjusting the transmit audio equalizer, we could get pretty decent sounding audio from the hifi mike. The problem was that when we recorded the voice keyer messages on the computer and played them back through the radio there was one problem when using mike input and another when using line input. It appears that there is no transformer isolation on the mike input which resulted in hum and other extraneous noises. When running the audio into line in, it doesn't get pushed through the transmit audio equalizer. Ken K4ZW said he ended up using an extrernal isolation transformer and ran the sound card input into the rear mike jack. It would be nice if Elecraft could run the line in through the transmit audio equalizer when in the ssb mode! If there is detailed information regarding either of these subjects on the web, I'd appreciate knowing where! Otherwise, I hope it might be useful. 73 de Lar K7SV _______________________________________________ CQ-Contest mailing list [email protected] http://lists.contesting.com/mailman/listinfo/cq-contest ______________________________________________________________ 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
