Date: Thu, 30 Nov 2000 20:00:10 -0500 From: "Bob Lewis" Subject: Re: [Elecraft] PSK31 AF input Hi Charles, It was a 15K resistor in series. That series resistance forms a voltage divider with R14 (1K) in the SSB board which gives the correct input level from my sound card. On the receive side, it's 24K from the junction of R35 and R36 on the RF board (i.e. the AF OUT) to the sound card's mike input with a 620 ohm between the sound card's input and ground. +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ From: "Don Wilhelm" Subject: Re: [Elecraft] PSK31 AF input Charles and all, I am trying to also reduce the number of wires needed for PSK, and do not have the original posts either, but I can tell you what I have done so far - it works for me. 1) I created an extension of the jacks on my sound card so I can plug things into the sound card without going behind the computer. I used cables from Radio shack with molded stereo connectors and wired them to the jacks of a defunct sound card. One could also just use straight extension cables which are a stock RS item (be careful to use a shielded one for the MIC line - some of them are just 3 wires, no shield. 2) I made up an interface cable for the PTT line from the COM port - a simple one with a diode, resistor and 2N3904 - and brought the end of this cable to the operating position. 3) I then made a cable with an 8 pin MIC connector on one end, connected the PTT line, the Mic audio line (with a 24K series resistor and a 1K across the cable on the K2's Mic side - built them in the cable and covered with shrink wrap), and wired pin 5 of the MIC connector for the K2 audio out (my MIC configuration does not use pin 5). The non-K2 side of this cable has stereo plugs to mate with my sound card extension jacks and the PTT line. Now, I have yet to wire the audio out line in the K2 to pin 5 of my MIC connector, I am plugging into the headphone connector for the time being. My plan is to use a resistor of the same value as R35 and R36 on the RF board (the series resistors for the headphones), connect one end to the junction point of R35 and R36, and the other end to pin 5 of the MIC connector. I remember that someone mentioned the little computer jumpers which have a hole at the top are nice for soldering a wire onto, and I will try that, then plug one leg of the jumper on the header pin for pin 5 of the MIC connector. After I get the last step done, I will have just have to change the MIC plug to switch from PSK to SSB - some folks insist on using a switch box for FAST changes, but this works for me now - maybe a switch box later if I find I need it. 73, Don Wilhelm -Chapel Hill, NC W3FPR QRP-L # 485 K2 SN 0020 ++++++++++++++++++++++++ RE: Adjusting K2's Signal Power for PSK31 when changing frequencies........ --------- Date: Tue, 20 Nov 2001 09:33:55 +0000 From: "Julian, G4ILO" Subject: Re: [Elecraft] K2 as main station? I use a software approach for this, not hardware. I leave the Windows mixer output panel on the desktop so I can adjust the audio level with the mouse. To make it easily accessable, create a shortcut on the desktop containing the command "C:\WINDOWS\SNDVOL32.EXE /p" . - -- Julian, G4ILO. (RSGB, ARRL, K2 #392) Homepage: http://www.qsl.net/g4ilo "bob baxter" wrote: I haven't found that they change considerably from band to band -- maybe from 80m to 10m. However, I replaced the fixed resistor in my transmit interface with a pot and, when I change bands, it just takes a couple seconds to re-adjust the output to just extinguish the first ALC bar. Bob Baxter AA7EQ Bisbee, Az. +++++++++++++++++++++++++