Bill, I'm using a similar setup and I don't notice any issues. Though I've not used FSK441 before.
I have a MicroHam MK2R+ connected to the K3 and it also has built-in sound codecs with transformers. Works fine for AFSK and PSK. 73 Greg AB7R -----Original Message----- From: Bill W5WVO [mailto:[EMAIL PROTECTED] Sent: Sunday, March 02, 2008 6:28 PM To: Greg; Elecraft Reflector Subject: Re: [Elecraft] K3 Operating Tip: Setting up for PSK and other digitalmodes Nice summary, thanks Greg. I'll be using the K3 digitally for the WSJT modes on 6 meters, among others. Here's a question that occurred to me today: I am probably going to be using the SignaLink USB (built-in sound card / codex). This unit also has built-in 600-ohm isolation transformers -- as does the K3. Is there any problem presented by having two sets of transformers in the line? I worry that if the quality of both transformers isn't really good, the transformers could introduce nonlinear delay or amplitude characteristics, especially in modes like FSK441 which use a fairly wide range of audio frequencies. I'm sure the K3 transformers are the best, but I know nothing about the SignaLink -- and having two transformers in each line concerns me a little. Bill W5WVO Greg wrote: > Setting up your K3 for PSK (and other audio-based digital modes) > > The K3 is an outstanding platform for operating digital modes. It > already has dedicated direct FSK and PSK with your CW paddles. But > there is also an option to use Data-A mode to operate PSK or any > other audio based digital mode in conjunction with soundcard-based > digital mode software. > > It is usually best to use a second soundcard for your audio-base > digital modes. This way you will not be plagued with Windows sound > effects in your waterfall or in your transmitted signal. If you do > not have that option, you can always go into your Windows control > panel and open "Sounds and Audio devices." Select the Sounds tab and > set Sound Scheme to No Sounds. > > Here are the steps to setup for PSK using Data-A mode: > > 1. Set your soundcard volume to about 50%. > > 2. Connect soundcard output to the K3 LINE-IN. > > 3. Connect the soundcard input to the K3 LINE-OUT. > > 4. Set Menu item MIC SEL to LINE IN. The K3 will remember this MIC > SEL source next time you use digital modes. > > 5. Set mode to DATA. HOLD DATA MD to choose Data-A using the VFO B > knob. > > 6. Set power to ~20W (just something to start with). > > 7. Use the MIC control to set the drive level so that your output is > equal or just below what you dialed in (20W in this case). > Compression is locked at zero automatically when in Data mode and > cannot be adjusted. You should not see any ALC bars on the K3 > display (when set to CMP/ALC). When setup this way I get excellent > PSK31 results with TX IMD at ~ -26 dB to -32 dB - a very clean signal. > > FOR PTT > > You can use a separate line for PTT from a computer COM port to the > ACCY connector or the RCA PTT connection on the back of the K3. This > requires a simple circuit using a transistor and resistor between the > COM port and the K3. You can find this circuit on many ham radio > websites, including the AA5AU RTTY website (this will be a hyperlink > to http://www.aa5au.com/rttyinterface.html ). You can also use the > RS-232 serial connection if your software allows you to set it up > that way. Not all software allows you to do this. Some programs > will also allow PTT via CAT command. > > In the K3 CONFIG menu, set PTT-Key to either RTS - OFF or DTR - OFF. > Then in your software set PTT to either DTR or RTS as appropriate to > the same COM port the radio is connected to. > > > > ------------ > 73, > Greg - AB7R > Whidbey Island WA > > > > _______________________________________________ > Elecraft mailing list > Post to: [email protected] > You must be a subscriber to post to the list. > Subscriber Info (Addr. Change, sub, unsub etc.): > http://mailman.qth.net/mailman/listinfo/elecraft > > Help: http://mailman.qth.net/subscribers.htm > Elecraft web page: http://www.elecraft.com _______________________________________________ Elecraft mailing list Post to: [email protected] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
