K3 psk D splater
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David,
I don't know what the max power would be before the internally generated PSK would produce too much IMD but I never use more than 50W. I thought you mentioned in your original post that you were running 25W and that would be fine. I have to wonder just how reliable is the receiving station. It could be you have a very strong signal at his place or, as someone else mentioned, he might have been running an agressive NB or similar. You may have trouble monitoring your signal locally so what I would do is get back on, make another QSO and see what the new partner has to say. I would be happy to sked with you if you think that would make the test easier. Send me an email off list if you would like to do that. GL and 73, Rick [hidden email] ______________________________________________________________ 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 vk4tux
Yes you are right Rick, let fix the OP's subject error listing.
RTTY FSK-D is the mode tried right ? Mark and shift, shift keying ascii ky keying from the k3 via K3 utility or Kcomm. I dont know how I let myself repeat the psk-d rubbish, but I am a very naughty boy. Adrian ... vk4tux |
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actually the OP, me was talking about PSK D at 31bps not RTTY FSK
D KComm will do both FSK and PSKD to the K3 On 5/30/2012 8:18 PM, vk4tux wrote: > Yes you are right Rick, let fix the OP's subject error listing. > RTTY FSK-D is the mode tried right ? Mark and shift, shift keying > ascii ky keying from the k3 via K3 utility or Kcomm. > I dont know how I let myself repeat the psk-d rubbish, but I am a very > naughty boy. > > Adrian ... vk4tux > > -- > View this message in context: http://elecraft.365791.n2.nabble.com/K3-psk-D-splater-tp7556767p7556824.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:[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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In reply to this post by vk4tux
I answered Adrian off list. The topic read PSK not FSK at the time. This
is what I had sent: -=-=-=-= PSK is not key shifting. That is FSK. PSK involves more than two unique tones, which means audio (phase) shifting; both on sending and receiving. It may be hidden in the -D modes, but audio is still en/decoded. The same is true for FSK (RTTY) decoding; the DSP detects the tones and durations to effect decoding. Ditto CW decoding. Only the K3 and a couple other radios can do this with no other software so most folks use a soundcard. I use a soundcard most of the time so I can watch the entire audio band for the station(s) I want to work. We're fortunate that we have the digital mode ability in the K3. I've only used it a few times, pretty cool feature. If the transmit audio and/or the receive signals are flawed, the transmission won't be properly decoded. If you can get a fine enough resolution on the P3, you can see the flaws, but most people use software which gathers the data from a soundcard. And properly setting those up appears to be more than some folks understand. Many soundcard folks overdrive their audio into their transmitter and others overdrive the soundcard from the receiver so the signals appear faulty (when it might just be the receiving station). If everyone (soundcard users) carefully set their levels, there would be fewer complaints. However, once a soundcard is properly set up, it's easy to see how many 'bad' signals are out there (quite a few). Others complain of folks running too much power, but that isn't a factor; signal cleanliness is the issue. I defy anyone to tell how much power is coming out of a clean station, be it 1/10 watt or legal limit. Signal strength isn't even a valid test because it could be band conditions, transmit and/or receive antennas or many other things. i.e. What's the difference from 100 watts into a dipole versus 10 watts into a 4 element beam? Answer: Not a darned thing except the beam focuses the energy. The inline signal strength is exactly the same. Most also have no clue how to notch out or otherwise remove LOUD signals (tripping an ALC response) so they can copy the weaker ones. The K3 makes this simple too; adjust the hi/lo cut, narrow the bandwidth or use the notch filter manually. Or do all three. Gee I like the K3; they thought of everything except the operator who understands how to USE what they've built. I'm getting there. ;o) -=-= So now all y'all know what he meant. Yes, it may be over simplified, but that's how I like it. ;o) Rick wa6nhc ----Original Message----- From: [hidden email] [mailto:[hidden email]] On Behalf Of vk4tux Sent: Wednesday, May 30, 2012 5:19 PM To: [hidden email] Subject: Re: [Elecraft] K3 fsk D splater Yes you are right Rick, let fix the OP's subject error listing. RTTY FSK-D is the mode tried right ? Mark and shift, shift keying ascii ky keying from the k3 via K3 utility or Kcomm. I dont know how I let myself repeat the psk-d rubbish, but I am a very naughty boy. Adrian ... vk4tux -- View this message in context: http://elecraft.365791.n2.nabble.com/K3-psk-D-splater-tp7556767p7556824.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:[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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On 5/30/2012 6:39 PM, Rick Bates wrote:
> I answered Adrian off list. Good response, Rick. I have two K3s and P3s for SO2R, so I can use one P3 to watch the RF output of the other radio. Transmitting AFSK RTTY or JT65 with about 30W out of the K3 driving the KPA500 to full power, IMD is at least -45dBC (that is, 45 dB below the carrier). I don't know enough about how PSK and FSK are generated within the K3 to be able to comment on what mechanisms or adjustments within the K3 might be generating IMD. As has been noted, it is well known that K3 IMD does rise when the power supply sags, but I haven't seen data on how much sag it takes for various levels of IMD. So yes, short beefy copper on DC power leads is a VERY good thing. 73, Jim 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 |
Re: K3 psk D splater
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In reply to this post by ve3dvy
Hello David,
If a PSK signal is generated in an early stage of a transmitter (or is fed into an input of a transmitter), then all of the transmitter's stages which follow should be "linear" to keep the signal clean. In the case of the basic type of PSK 31.25 signal consisting of a single tone, whose phase is changed by 180 degrees, the change of phase results in sidebands spaced 31.25 kHz each side of the main signal. If the transmitter's stages which follow are not adequately linear, then IMD products could create "splatter". In the case of solid state linear amplifiers, especially those using a "12 V" DC supply, to prevent poor linearity it is necessary to use a DC supply and interconnecting cables/ connectors which do not allow the supply voltage to "sag" with increasing current draw. I note that you said that there is almost a difference of one volt between 25W and 100W key down. 73, Geoff LX2AO On May 30, 2012 at 3:13 PM, David Moes VE3DVY wrote: > Question, What can cause splatter when using PSK-D I had the power > dialed to 25W so I certainly wasn.t running to much power, and just > to be sure that I was actually using PSK -d I had pulled the audio > line in/out from the K3. Am I missing something? ______________________________________________________________ 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 |
Re: K3 psk D splater
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Oooops :-( In my message to David Moes, I said:
> phase results in sidebands spaced > 31.25 kHz each side of the main signal. If the transmitter's stages which > follow are not adequately linear, then IMD products could create > "splatter". I meant 31.25 Hz not 31.25 kHz. 73, Geoff LX2AO ______________________________________________________________ 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 Geoffrey Mackenzie-Kennedy-3
Thanks Geoff
Understood. I have already shortened the leads quite a bit. and made a decent change in the voltage drop cant remember the difference. Last night I was also able to make some tests (before the lead length change) using the K3 into a dummy and the second reciever with a very short antenna and DIGIPAN My signal on PSK D looked great right up to full power. so I think I have everyting right and shouldn't have worried about what the other guy had said. The reason it had me going was that having worked PSK31 for many years using my old rig an then the K3 using DATA A I dont think Ive had any complaints for a long time. and on the first QSO I had with PSK-D someone complained. Murphy s law I guess. David Moes VE3DVY PS sorry that you are getting this twice Geoff initially I sent to wrong address I intended to post to the list On 5/31/2012 10:52 AM, Geoffrey Mackenzie-Kennedy wrote: > Hello David, > > If a PSK signal is generated in an early stage of a transmitter (or is > fed into an input of a transmitter), then all of the transmitter's > stages which follow should be "linear" to keep the signal clean. In > the case of the basic type of PSK 31.25 signal consisting of a single > tone, whose phase is changed by 180 degrees, the change of phase > results in sidebands spaced 31.25 kHz each side of the main signal. > If the transmitter's stages which follow are not adequately linear, > then IMD products could create "splatter". > > In the case of solid state linear amplifiers, especially those using a > "12 V" DC supply, to prevent poor linearity it is necessary to use a > DC supply and interconnecting cables/ connectors which do not allow > the supply voltage to "sag" with increasing current draw. I note that > you said that there is almost a difference of one volt between 25W and > 100W key down. > > 73, > > Geoff > LX2AO > > > On May 30, 2012 at 3:13 PM, David Moes VE3DVY wrote: > > >> Question, What can cause splatter when using PSK-D I had the power >> dialed to 25W so I certainly wasn.t running to much power, and just >> to be sure that I was actually using PSK -d I had pulled the audio >> line in/out from the K3. Am I missing something? > > ______________________________________________________________ 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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