K3: FSK or AFSK
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I'm trying to remember why I wanted a FSK-capable radio for RTTY. Before (the K3), I have used sound-card programs (MMTTY, WriteLog) - now I have the option. As I am a little short on serial ports, I initially set up the K3 using AFSK. Why should I switch?
Bill K6IFF |
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On 9/27/2010 4:30 PM, Bill Myers wrote:
> > I'm trying to remember why I wanted a FSK-capable radio for RTTY. Before > (the K3), I have used sound-card programs (MMTTY, WriteLog) - now I have the > option. As I am a little short on serial ports, I initially set up the K3 > using AFSK. Why should I switch? If I think of a reason Bill, I'll let you know. I managed 625 Q's in a sort of sporadic effort in the CQ WW RTTY this last weekend with N1MM, MMTTY, my laptop w/sound card, and two Radio Shack audio cables between Line[s] In and Line[s] Out on the laptop and K3. My AFSK A pitch is at 915 [I can hear that, I can't hear much higher than that, YMMV] which is also what I set in MMTTY, and that was the end of the set-up other than the levels which weren't at all hard. Be sure to turn off all the Windoze noises on your computer. I haven't really mastered dual-PB yet, or maybe I have and it's not a lot different than non-dual-PB. I do know that MMTTY was decoding stations [and I was working them] that I really couldn't hear, I could just see their faint trace on the WF. 73, Fred K6DGW - Northern California Contest Club - CU in the 2010 Cal QSO Party 2-3 Oct 2010 - www.cqp.org ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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In reply to this post by Bill Myers
Bill,
You have a successful setup, so why even consider switching. There is no difference between FSK and AFSK on the receiving end. The major difference on the transmitting end is that FSK is more tolerant of things like the mark frequency setting, but other than that, I cannot find any difference. Note: you still must select the mark frequency for proper receive decoding, but using FSK instead of AFSK removes that requirement from the transmit side only. 73, Don W3FPR On 9/27/2010 7:30 PM, Bill Myers wrote: > I'm trying to remember why I wanted a FSK-capable radio for RTTY. Before > (the K3), I have used sound-card programs (MMTTY, WriteLog) - now I have the > option. As I am a little short on serial ports, I initially set up the K3 > using AFSK. Why should I switch? > > Bill K6IFF > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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In reply to this post by Bill Myers
On 9/27/2010 4:30 PM, Bill Myers wrote:
> I'm trying to remember why I wanted a FSK-capable radio for RTTY. I've done thousands of RTTY Qs in contests, sometimes scoring fairly well, and I've NEVER used FSK. If you're using a radio that allows you to put the AFSK tones in the center of the radio's narrow passband IF, there's no good reason to bother with FSK. The K3 DOES allow that. So does the FT1000MP (I know because I did it with both radios). Some radios do NOT (some Icoms, I am told, and probably others). Some folks who don't know how to get audio cleanly from their computer to their radio manage to introduce hum, buzz, and distortion into the transmitted signal. But that is VERY easy to do properly, so that's not a good reason to do FSK either. If you DO have a problem with the computer interface, check out the tutorials on my website. http://audiosystemsgroup.com/publish.htm See especially the one on computer interfacing, and the chapter on Solving Problems in the Shack in the RFI tutorial. 73, Jim Brown K9YC ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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> On 9/27/2010 4:30 PM, Bill Myers wrote: >> I'm trying to remember why I wanted a FSK-capable radio for RTTY. > I've done thousands of RTTY Qs in contests, sometimes scoring fairly > well, and I've NEVER used FSK. If you're using a radio that allows you > to put the AFSK tones in the center of the radio's narrow passband IF, > there's no good reason to bother with FSK. The K3 DOES allow that. So > does the FT1000MP (I know because I did it with both radios). Some > radios do NOT (some Icoms, I am told, and probably others). Unfortunately, many transceivers (not the K3) do not allow optimum (narrow) receive filtering when operated in AFSK mode. The wide filters cause all kinds of AGC issues with strong adjacent signals. > Some folks who don't know how to get audio cleanly from their computer > to their radio manage to introduce hum, buzz, and distortion into the > transmitted signal. But that is VERY easy to do properly, so that's > not a good reason to do FSK either. Some folks still do not know how to set the K3 audio and power levels correctly (as indicated by regular questions about the matter here). FSK avoids that issue as well as improper shift due to the incorrect use of AFSK and NET in many software packages. 73, ... Joe, W4TV On 9/28/2010 2:06 AM, Jim Brown wrote: > On 9/27/2010 4:30 PM, Bill Myers wrote: >> I'm trying to remember why I wanted a FSK-capable radio for RTTY. > I've done thousands of RTTY Qs in contests, sometimes scoring fairly > well, and I've NEVER used FSK. If you're using a radio that allows you > to put the AFSK tones in the center of the radio's narrow passband IF, > there's no good reason to bother with FSK. The K3 DOES allow that. So > does the FT1000MP (I know because I did it with both radios). Some > radios do NOT (some Icoms, I am told, and probably others). > > Some folks who don't know how to get audio cleanly from their computer > to their radio manage to introduce hum, buzz, and distortion into the > transmitted signal. But that is VERY easy to do properly, so that's not > a good reason to do FSK either. > > If you DO have a problem with the computer interface, check out the > tutorials on my website. http://audiosystemsgroup.com/publish.htm See > especially the one on computer interfacing, and the chapter on Solving > Problems in the Shack in the RFI tutorial. > > 73, Jim Brown K9YC > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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Thanks to all - your help was conclusive. There is certainly no need to switch from AFSK. The filter issue was the reason my pre-K3 setups were not quite satisfactory!
So, I get to use that serial port for some other toy. That's a good thing! 73 Bill |
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