K3 Harmonic Distortion
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Hi Everyone,
I'm re doing the thread as this time I have some concrete findings to share with you and wail be writing to Elecraft about this problem. My previous thread was about "ringing" in the audio but now it is harmonic distortion at three times the frequency. I went around M0GJH's house house with my K3 and put it side by side with his. I found the same distortion by listening on his radio too. A CW signal (as well as SSB) sounds a bit distorted and so we put the output into his PC which was running Ham Radio Deluxe DM780 with a waterfall display. Here you could quite clearly see that at 3 times any CW signal a signal was present and was beating with the fundamental causing distortion. The bandwidth was set to 1.5KHz and NR off. In fact with NR in there was no difference of the 3rd harmonic it was still there and very noticeable. Fundamental frequency received = 800Hz, Harmonic on waterfall display = 2400Hz. The RX EQ was set to flat. Mode used was CW. Line out from the back was used. Andrew M0GJH had mainly presumed that signals which sounded a bit "rough" were due to the station sending but in fact and it is my belief that there is a problem with the K3 be it in the audio section or DSP.... this I do not know as I don't have the knowledge. I hope there is a cure for this as it's frustrating listening to CW with this sort of distortion. Cheers, Berni G0IDA #1474 -- _______________________________________________ Elecraft mailing list Post to: [hidden email] 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 |
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Berni:
Have you looked at my measurements of K3 audio distortion at http://www.cliftonlaboratories.com/elecraft_k3_receive_audio.htm ? Indeed, there is odd order harmonic distortion, but that's commonly found in all receivers. The issue is how far down the distortion products are. A waterfall display can be quite misleading in this regard as it may mask the amplitude information. The odd order distortion seems to be generated in the audio stage(s), which is not unexpected. Jack K8ZOA Berni G0IDA wrote: > Hi Everyone, > > I'm re doing the thread as this time I have some concrete findings to > share with you and wail be writing to Elecraft about this problem. > > My previous thread was about "ringing" in the audio but now it is > harmonic distortion at three times the frequency. > > I went around M0GJH's house house with my K3 and put it side by side > with his. > I found the same distortion by listening on his radio too. > A CW signal (as well as SSB) sounds a bit distorted and so we put the > output into his PC which was running Ham Radio Deluxe DM780 with a > waterfall display. > > Here you could quite clearly see that at 3 times any CW signal a > signal was present and was beating with the fundamental causing > distortion. > The bandwidth was set to 1.5KHz and NR off. In fact with NR in there > was no difference of the 3rd harmonic it was still there and very > noticeable. > Fundamental frequency received = 800Hz, Harmonic on waterfall display > = 2400Hz. > The RX EQ was set to flat. > Mode used was CW. > Line out from the back was used. > > Andrew M0GJH had mainly presumed that signals which sounded a bit > "rough" were due to the station sending but in fact and it is my > belief that there is a problem with the K3 be it in the audio section > or DSP.... this I do not know as I don't have the knowledge. > > I hope there is a cure for this as it's frustrating listening to CW > with this sort of distortion. > > Cheers, > > Berni > G0IDA > #1474 > Elecraft mailing list Post to: [hidden email] 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 |
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In reply to this post by Berni G0IDA
I will also try two simultaneous signals and see if I can duplicate your
mixing observations. Jack K8ZOA Berni G0IDA wrote: > Hi Everyone, > > I'm re doing the thread as this time I have some concrete findings to > share with you and wail be writing to Elecraft about this problem. > > My previous thread was about "ringing" in the audio but now it is > harmonic distortion at three times the frequency. > > I went around M0GJH's house house with my K3 and put it side by side > with his. > I found the same distortion by listening on his radio too. > A CW signal (as well as SSB) sounds a bit distorted and so we put the > output into his PC which was running Ham Radio Deluxe DM780 with a > waterfall display. > > Here you could quite clearly see that at 3 times any CW signal a > signal was present and was beating with the fundamental causing > distortion. > The bandwidth was set to 1.5KHz and NR off. In fact with NR in there > was no difference of the 3rd harmonic it was still there and very > noticeable. > Fundamental frequency received = 800Hz, Harmonic on waterfall display > = 2400Hz. > The RX EQ was set to flat. > Mode used was CW. > Line out from the back was used. > > Andrew M0GJH had mainly presumed that signals which sounded a bit > "rough" were due to the station sending but in fact and it is my > belief that there is a problem with the K3 be it in the audio section > or DSP.... this I do not know as I don't have the knowledge. > > I hope there is a cure for this as it's frustrating listening to CW > with this sort of distortion. > > Cheers, > > Berni > G0IDA > #1474 > Elecraft mailing list Post to: [hidden email] 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 |
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In reply to this post by Berni G0IDA
On Mon, 01 Sep 2008 14:30:45 +0100, Berni G0IDA wrote:
>I hope there is a cure for this as it's frustrating listening to CW with >this sort of distortion. There are three things you should do. 1) Make sure that the AGC is on, and that the CONFIG AGC settings are at the defaults. 2) Reduce the LINEOUT GAIN (on the CONFIG menu) to a value less than about 4. This prevents distortion that could occur in the output transformer. 3) Adjust the input gain of your computer so that you have enough signal for the decoder to function, but not enough to cause distortion. This should correct any problems. 73, Jim K9YC _______________________________________________ Elecraft mailing list Post to: [hidden email] 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 |
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Jim
None of those things helps. I can reduce my LINE OUT gain to 1 and still see the 3rd harmonic easily on the waterfall. I've had many rigs and this is the first to do this. There was a thread about this not long ago. Do a nabble search on "ghost". There is also some distortion in the speaker output but I'm told that this is a separate amplifier. Steve Ellington [hidden email] ----- Original Message ----- From: "Jim Brown" <[hidden email]> To: <[hidden email]> Sent: Monday, September 01, 2008 12:05 PM Subject: Re: [Elecraft] K3 Harmonic Distortion > On Mon, 01 Sep 2008 14:30:45 +0100, Berni G0IDA wrote: > >>I hope there is a cure for this as it's frustrating listening to CW with >>this sort of distortion. > > There are three things you should do. > > 1) Make sure that the AGC is on, and that the CONFIG AGC settings are at > the > defaults. > > 2) Reduce the LINEOUT GAIN (on the CONFIG menu) to a value less than about > 4. > This prevents distortion that could occur in the output transformer. > > 3) Adjust the input gain of your computer so that you have enough signal > for > the decoder to function, but not enough to cause distortion. > > This should correct any problems. > > 73, > > Jim K9YC > > > _______________________________________________ > Elecraft mailing list > Post to: [hidden email] > 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 -------------------------------------------------------------------------------- No virus found in this incoming message. Checked by AVG - http://www.avg.com Version: 8.0.169 / Virus Database: 270.6.14/1645 - Release Date: 9/1/2008 7:19 AM _______________________________________________ Elecraft mailing list Post to: [hidden email] 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 |
RE: K3 Harmonic Distortion
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In reply to this post by Jim Brown-10
Jim is entirely correct although we will disagree a bit about the need to keep the line out as low as he suggests. My own measurements say the harmonic distortion is insignificant as long as the Line Out levels stay below .5V RMS. The headphone outputs are exceptionally clean as long as the audio amplifier level is kept below 2V peak (1.4V RMS) and the output impedance is not too low. In fact, noise in the audio amplifier (headphones) is 70 dB below the desired (CW at 500 Hz) signal +/- 250 Hz and 80 dB below the desired signal above that. All harmonics are down more than 60 dB as long as the headphone level is not at levels that could damage hearing (> 1.4V RMS). The headphone output in the K3 is cleaner than any amateur receiver I have seen and certainly better than the current crop from Ikensu or Yaecomwood. > -----Original Message----- > From: [hidden email] > [mailto:[hidden email]] On Behalf Of Jim Brown > Sent: Monday, September 01, 2008 12:06 PM > To: [hidden email] > Subject: Re: [Elecraft] K3 Harmonic Distortion > > > On Mon, 01 Sep 2008 14:30:45 +0100, Berni G0IDA wrote: > > >I hope there is a cure for this as it's frustrating listening to CW > >with this sort of distortion. > > There are three things you should do. > > 1) Make sure that the AGC is on, and that the CONFIG AGC > settings are at the defaults. > > 2) Reduce the LINEOUT GAIN (on the CONFIG menu) to a value > less than about 4. This prevents distortion that could occur > in the output transformer. > > 3) Adjust the input gain of your computer so that you have > enough signal for the decoder to function, but not enough > to cause distortion. > > This should correct any problems. > > 73, > > Jim K9YC > _______________________________________________ Elecraft mailing list Post to: [hidden email] 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 |
RE: K3 Harmonic Distortion
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In reply to this post by N4LQ-2
> None of those things helps. I can reduce my LINE OUT gain to > 1 and still see the 3rd harmonic easily on the waterfall. I've > had many rigs and this is the first to do this. Turn on the ACG and make sure the audio level from your Line Out does not exceed .7V RMS. As long as the AGC is on, I can turn my Line Out to 100 and not see any "ghost" except the 3rd harmonic on the waterfall in Digipan. An AF spectrum analyzer shows the 3rd Harmonic about -50 dB and others below that. If you insist on running with AGC off or low values of SGC SLP, TURN DOWN the RF gain to keep from overdriving the Line Out amp and transformers. Any reasonable soundcard should operate very happily with 200 to 500 mV RMS - well within the linear capability of the Line Out amp and transformers. > -----Original Message----- > From: [hidden email] > [mailto:[hidden email]] On Behalf Of n4lq > Sent: Monday, September 01, 2008 12:14 PM > To: Jim Brown; [hidden email] > Subject: Re: [Elecraft] K3 Harmonic Distortion > > > Jim > None of those things helps. I can reduce my LINE OUT gain to > 1 and still see > the 3rd harmonic easily on the waterfall. I've had many rigs > and this is the > first to do this. > There was a thread about this not long ago. Do a nabble > search on "ghost". > There is also some distortion in the speaker output but I'm > told that this > is a separate amplifier. > Steve Ellington > [hidden email] > ----- Original Message ----- > From: "Jim Brown" <[hidden email]> > To: <[hidden email]> > Sent: Monday, September 01, 2008 12:05 PM > Subject: Re: [Elecraft] K3 Harmonic Distortion > > > > On Mon, 01 Sep 2008 14:30:45 +0100, Berni G0IDA wrote: > > > >>I hope there is a cure for this as it's frustrating listening to CW > >>with this sort of distortion. > > > > There are three things you should do. > > > > 1) Make sure that the AGC is on, and that the CONFIG AGC > settings are > > at > > the > > defaults. > > > > 2) Reduce the LINEOUT GAIN (on the CONFIG menu) to a value > less than > > about > > 4. > > This prevents distortion that could occur in the output transformer. > > > > 3) Adjust the input gain of your computer so that you have enough > > signal > > for > > the decoder to function, but not enough to cause distortion. > > > > This should correct any problems. > > > > 73, > > > > Jim K9YC > > > > > > _______________________________________________ > > Elecraft mailing list > > Post to: [hidden email] > > 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 > > > -------------------------------------------------------------- > ------------------ > > > > No virus found in this incoming message. > Checked by AVG - http://www.avg.com > Version: 8.0.169 / Virus Database: 270.6.14/1645 - Release > Date: 9/1/2008 > 7:19 AM > > _______________________________________________ > Elecraft mailing list > Post to: [hidden email] > 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: [hidden email] 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 |
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In reply to this post by Joe Subich, W4TV-3
On Mon, 1 Sep 2008 12:38:31 -0400, Joe Subich, W4TV wrote:
>Jim is entirely correct although we will disagree a bit about >the need to keep the line out as low as he suggests. My own >measurements say the harmonic distortion is insignificant as >long as the Line Out levels stay below .5V RMS. Insignificant depends on the decoder, what you are decoding (PSK or RTTY), band conditions, and the operator. If a PSK operator is using the IF with a broadband setting and tries to work a signal that's really a harmonic, it won't work -- he'll be transmitting on a frequency displaced from the signal he thinks he's working (displaced by 2X the audio frequency of the actual signal if it's a third harmonic, 1X if it't the second harmonic). If it's a crowded RTTY contest, there can be lots of big signals creating that IM. Or the operator could be using a narrow roofing filter and those other signals are not there or heavily suppressed, so can't cause IM. >The headphone outputs are exceptionally clean as long as the >audio amplifier level is kept below 2V peak (1.4V RMS) and >the output impedance is not too low. In fact, noise in the >audio amplifier (headphones) is 70 dB below the desired (CW >at 500 Hz) signal +/- 250 Hz and 80 dB below the desired >signal above that. All harmonics are down more than 60 dB >as long as the headphone level is not at levels that could >damage hearing (> 1.4V RMS). YES! My measurements of the headphone output, taken at about 1 volt RMS, show harmonic distortion at about 0.02% and IM at less than 0.1%. That is VERY VERY good! 1VRMS is LOUD! >The headphone output in the K3 is cleaner than any amateur >receiver I have seen and certainly better than the current >crop from Ikensu or Yaecomwood. Yes. 73, Jim _______________________________________________ Elecraft mailing list Post to: [hidden email] 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 |
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In reply to this post by Jim Brown-10
Thanks everyone for the replies.
I just would like to put this thread back onto its tracks..... The problem is with CW (although SSB does suffer too) and the main problem is that I can hear the 3rd harmonic which when mixed with the fundamental makes a rough note on CW especially when tuning away going up in frequency. I only used the waterfall program to confirm and to see at which harmonic it occurred and line levels, AGC, PC cards etc...etc... have no baring on this as I'm not measuring anything, just confirming that it is there. I compared 2 K3s and both had the same effect. I'm using a Hiel headset to listen to CW it is also noticeable on the main speaker but less so due to its design. When confirming on the waterfall and indeed with my ears the rig is at default setting & no amount of tweaking helps. Even with 1KHz of filtering a 3rd harmonic is present. K9YC: 1) Yes 2) Line level is irrelevant as I'm just confirming that it is there and at which harmonic so as to give feedback to the reflector. 3) as above. N4LQ: I agree with you, nothing seems to help and I've never had this with the FT1000MP or my recent Mk v. W4TV: I envy the K3 you have.... as there is 3rd product distortion and never had this on any other rig... could there be a "bad batch" or K3s? Just like to re-iterate that the thread is not about how to set up your PC/LINE OUT or IN not to get distortion, it is about 3rd harmonic distortion present on the headphone socket and speaker with or without default settings! Jim: PSK + RTTY might have its own problems & its not part of my discussion, I'm trying to concentrate this thread on just one mode CW where this problem is significant as at times it is unpleasant to listen to. SSB also has this unpleasant distortion. There is one option a friend suggested.... wait until I get older and the hearing drops off in frequency.... at the moment it seems the only option..hi..hi..hi.. 73s Berni G0IDA Jim Brown wrote: > On Mon, 01 Sep 2008 14:30:45 +0100, Berni G0IDA wrote: > > >> I hope there is a cure for this as it's frustrating listening to CW with >> this sort of distortion. >> > > There are three things you should do. > > 1) Make sure that the AGC is on, and that the CONFIG AGC settings are at the > defaults. > > 2) Reduce the LINEOUT GAIN (on the CONFIG menu) to a value less than about 4. > This prevents distortion that could occur in the output transformer. > > 3) Adjust the input gain of your computer so that you have enough signal for > the decoder to function, but not enough to cause distortion. > > This should correct any problems. > > 73, > > Jim K9YC > > > _______________________________________________ > Elecraft mailing list > Post to: [hidden email] > 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: [hidden email] 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 |
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I've made a number of measurements on the K3's audio output a few days
ago in CW mode and again today, this time with two close spaced signals inside the SSB filter as well as a single tone. Yes, there are 3rd and other odd-order harmonics and, to a lesser degree, even order harmonics. However, these harmonics are down between 45 and 50 dB from the desired signal in most instances. That's quite a bit of odd order harmonic suppression, well under 1% THD. I can see intermodulation products and in-band artifacts with the AGC on and quite strong signal levels. These are also quite a bit down from the two tones, but certainly differ from the same signal levels applied to a receiver with analog detection stages. I cannot hear an objectionable beat note or rough audio, but I'm afraid that I fall into the category of being old enough to not have great high frequency hearing. I'll put some of the audio spectrum analyzer captures up on my web site later today or tomorrow. Jack K8ZOA Berni G0IDA wrote: > Thanks everyone for the replies. > > I just would like to put this thread back onto its tracks..... The > problem is with CW (although SSB does suffer too) and the main problem > is that I can hear the 3rd harmonic which when mixed with the > fundamental makes a rough note on CW especially when tuning away going > up in frequency. > > I only used the waterfall program to confirm and to see at which > harmonic it occurred and line levels, AGC, PC cards etc...etc... have > no baring on this as I'm not measuring anything, just confirming that > it is there. > > I compared 2 K3s and both had the same effect. > > I'm using a Hiel headset to listen to CW it is also noticeable on the > main speaker but less so due to its design. > > When confirming on the waterfall and indeed with my ears the rig is at > default setting & no amount of tweaking helps. Even with 1KHz of > filtering a 3rd harmonic is present. > > K9YC: > 1) Yes > 2) Line level is irrelevant as I'm just confirming that it is there > and at which harmonic so as to give feedback to the reflector. > 3) as above. > > N4LQ: > I agree with you, nothing seems to help and I've never had this with > the FT1000MP or my recent Mk v. > > W4TV: > I envy the K3 you have.... as there is 3rd product distortion and > never had this on any other rig... could there be a "bad batch" or K3s? > Just like to re-iterate that the thread is not about how to set up > your PC/LINE OUT or IN not to get distortion, it is about 3rd harmonic > distortion present on the headphone socket and speaker with or without > default settings! > > Jim: > PSK + RTTY might have its own problems & its not part of my > discussion, I'm trying to concentrate this thread on just one mode CW > where this problem is significant as at times it is unpleasant to > listen to. SSB also has this unpleasant distortion. > > There is one option a friend suggested.... wait until I get older and > the hearing drops off in frequency.... at the moment it seems the only > option..hi..hi..hi.. > > 73s > > Berni > G0IDA > > > > > Jim Brown wrote: >> On Mon, 01 Sep 2008 14:30:45 +0100, Berni G0IDA wrote: >> >> >>> I hope there is a cure for this as it's frustrating listening to CW >>> with this sort of distortion. >>> >> >> There are three things you should do. >> 1) Make sure that the AGC is on, and that the CONFIG AGC settings are >> at the defaults. >> 2) Reduce the LINEOUT GAIN (on the CONFIG menu) to a value less than >> about 4. This prevents distortion that could occur in the output >> transformer. >> >> 3) Adjust the input gain of your computer so that you have enough >> signal for the decoder to function, but not enough to cause distortion. >> >> This should correct any problems. >> >> 73, >> >> Jim K9YC >> >> >> _______________________________________________ >> Elecraft mailing list >> Post to: [hidden email] >> 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: [hidden email] 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 |
Re: K3 Harmonic Distortion
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In reply to this post by Berni G0IDA
Berni G0IDA wrote:
> I just would like to put this thread back onto its tracks..... The > problem is with CW (although SSB does suffer too) and the main problem > is that I can hear the 3rd harmonic which when mixed with the > fundamental makes a rough note on CW especially when tuning away going > up in frequency. Combining third and fundamental, at AF, should not produce a rough note. It should produce a string-like tone rather than the flute-like done from just the fundamental. If you are getting any low frequency beat, it means the signals are not harmonically related. (I think you would need an awful lot of third harmonic to shift much from flute to string.) -- David Woolley "The Elecraft list is a forum for the discussion of topics related to Elecraft products and more general topics related ham radio" List Guidelines <http://www.elecraft.com/elecraft_list_guidelines.htm> _______________________________________________ Elecraft mailing list Post to: [hidden email] 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 |
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In reply to this post by Jack Smith-6
I think it was me who used the term "ghost" signals when referring to the harmonically related CW traces I could see on the CW Skimmer display. I probably would have been completely unaware of it if I had never tried this program. It was only obvious as I was listening to CW with a narrow filter and the "ghost" traces were appearing in the part of the waterfall that you would be expect to be dark because it was outside of the passband. I would agree with the suggestion that the harmonics are at a low level relative to the main signal because they are masked by band noise when you open the filter up. I don't think there is much risk of calling someone on the third harmonic by mistake. I don't know what the voltage level of the line output is but the traces disappear if you turn the level down to 2, which unfortunately is too low for most sound card programs.
I don't know if those same harmonics are present on the speaker or headphone outputs, as distinct from the computer audio feed. I can only say that I find the K3 audio exceptionally pleasant to listen to. I much prefer it to the K2, or the FT-817, which are the only other radios I have. The only other radio I have had that sounded as clean and low-distortion as the K3 was an IC-756PRO that I had many years ago. If the harmonics are down by the kind of amounts that others have measured then the distortion figure is still within the specification for what after all is not meant to be an audiophile quality hi-fi output stage.
Julian, G4ILO. K2 #392 K3 #222 KX3 #110
* G4ILO's Shack - http://www.g4ilo.com * KComm - http://www.g4ilo.com/kcomm.html * KTune - http://www.g4ilo.com/ktune.html |
RE: K3 Harmonic Distortion
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In reply to this post by Jim Brown-10
Jim, > Insignificant depends on the decoder, what you are decoding (PSK > or RTTY), band conditions, and the operator. If a PSK operator is > using the IF with a broadband setting and tries to work a signal > that's really a harmonic, it won't work -- he'll be transmitting > on a frequency displaced from the signal he thinks he's working > (displaced by 2X the audio frequency of the actual signal if it's > a third harmonic, 1X if it't the second harmonic). If it's a > crowded RTTY contest, there can be lots of big signals creating > that IM. Or the operator could be using a narrow roofing filter > and those other signals are not there or heavily suppressed, so > can't cause IM. It would be a sorry situation if an operator can't tell the difference between a desired signal and an audio harmonic down 50 dB. K3_Line_out.jpg shows the line out spectrum of my K3 at 1 KHz, Data_A, 2.8 KHz 1st IF filter and 4 KHz filter. The third harmonic is -62 dB and the fifth harmonic is - 80 dB. See: www.microHAM-USA.com/Downloads/K3_Line_Out.jpg. A typical waterfall does not show the spurious signals at the soundcard input (noise on the cables) which is well below the "band noise" - typically around -60 dBu. 73, ... Joe, W4TV > -----Original Message----- > From: [hidden email] > [mailto:[hidden email]] On Behalf Of Jim Brown > Sent: Monday, September 01, 2008 1:33 PM > To: [hidden email] > Subject: RE: [Elecraft] K3 Harmonic Distortion > > > On Mon, 1 Sep 2008 12:38:31 -0400, Joe Subich, W4TV wrote: > > >Jim is entirely correct although we will disagree a bit about > >the need to keep the line out as low as he suggests. My own > >measurements say the harmonic distortion is insignificant as > >long as the Line Out levels stay below .5V RMS. > > Insignificant depends on the decoder, what you are decoding (PSK > or RTTY), band conditions, and the operator. If a PSK operator is > using the IF with a broadband setting and tries to work a signal > that's really a harmonic, it won't work -- he'll be transmitting > on a frequency displaced from the signal he thinks he's working > (displaced by 2X the audio frequency of the actual signal if it's > a third harmonic, 1X if it't the second harmonic). If it's a > crowded RTTY contest, there can be lots of big signals creating > that IM. Or the operator could be using a narrow roofing filter > and those other signals are not there or heavily suppressed, so > can't cause IM. > > >The headphone outputs are exceptionally clean as long as the > >audio amplifier level is kept below 2V peak (1.4V RMS) and > >the output impedance is not too low. In fact, noise in the > >audio amplifier (headphones) is 70 dB below the desired (CW > >at 500 Hz) signal +/- 250 Hz and 80 dB below the desired > >signal above that. All harmonics are down more than 60 dB > >as long as the headphone level is not at levels that could > >damage hearing (> 1.4V RMS). > > YES! My measurements of the headphone output, taken at about 1 > volt RMS, show harmonic distortion at about 0.02% and IM at less > than 0.1%. That is VERY VERY good! 1VRMS is LOUD! > > >The headphone output in the K3 is cleaner than any amateur > >receiver I have seen and certainly better than the current > >crop from Ikensu or Yaecomwood. > > Yes. > > 73, > > Jim > > > _______________________________________________ > Elecraft mailing list > Post to: [hidden email] > 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: [hidden email] 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 |
RE: K3 Harmonic Distortion
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In reply to this post by Berni G0IDA
> W4TV: > I envy the K3 you have.... as there is 3rd product distortion > and never had this on any other rig... could there be a "bad > batch" or K3s? Just like to re-iterate that the thread is not > about how to set up your PC/LINE OUT or IN not to get distortion, > it is about 3rd harmonic distortion present on the headphone > socket and speaker with or without default settings! My point is that my K3 - s/n 622 (factory assembled) has absolutely no measurable harmonics on the headphone output unless I force the gain to a painful level. I use external speakers (two) but have made my measurements from the headphone jack (left) - I have checked with both SPKRS=2 and SPKRS=1 as well as SPKR+PH in both Yes and No. I have also checked with all AFX options and see no difference. Two sample Audio Spectrum plots are attached or may be downloaded at: www.microHAM-USA.com/Downloads/K3_Headphone_No_Signal.jpg and: www.microHAM-USA.com/Downloads/K3_Headphone_out.jpg. The "Headphone Out" capture is of an S-9 signal (1KHz audio) in DATA_A mode with AGC On, 2.8 KHz 1st IF filter and 2.8 KHz DSP bandwidth. This shows signal at 70 dB above the noise floor, second harmonic at -73 dB and third harmonic at -81 dB with no intermodulation. I made similar measurements at 500 Hz in data mode and again all harmonic and distortion products are down more than 60 dB. To confirm that the issue was not one that was present only in CW mode, I also made measurements at 500 Hz and 800 Hz in CW - again. 2nd, 3rd, 4th, 6th, 8th and 10th harmonics were visible in the I will make similar measurements with a second K3 (s/n 1450) and KRX3 when I finish assembly. 73, ... Joe, W4TV > -----Original Message----- > From: [hidden email] > [mailto:[hidden email]] On Behalf Of Berni G0IDA > Sent: Monday, September 01, 2008 3:20 PM > To: [hidden email] > Subject: Re: [Elecraft] K3 Harmonic Distortion > > > Thanks everyone for the replies. > > I just would like to put this thread back onto its tracks..... The > problem is with CW (although SSB does suffer too) and the > main problem > is that I can hear the 3rd harmonic which when mixed with the > fundamental makes a rough note on CW especially when tuning > away going > up in frequency. > > I only used the waterfall program to confirm and to see at which > harmonic it occurred and line levels, AGC, PC cards > etc...etc... have no > baring on this as I'm not measuring anything, just confirming > that it is > there. > > I compared 2 K3s and both had the same effect. > > I'm using a Hiel headset to listen to CW it is also noticeable on the > main speaker but less so due to its design. > > When confirming on the waterfall and indeed with my ears the > rig is at > default setting & no amount of tweaking helps. Even with 1KHz of > filtering a 3rd harmonic is present. > > K9YC: > 1) Yes > 2) Line level is irrelevant as I'm just confirming that it is > there and > at which harmonic so as to give feedback to the reflector. > 3) as above. > > N4LQ: > I agree with you, nothing seems to help and I've never had > this with the > FT1000MP or my recent Mk v. > > W4TV: > I envy the K3 you have.... as there is 3rd product distortion > and never > had this on any other rig... could there be a "bad batch" or > K3s? Just like to re-iterate that the thread is not about how > to set up your > PC/LINE OUT or IN not to get distortion, it is about 3rd harmonic > distortion present on the headphone socket and speaker with > or without > default settings! > > Jim: > PSK + RTTY might have its own problems & its not part of my > discussion, > I'm trying to concentrate this thread on just one mode CW where this > problem is significant as at times it is unpleasant to listen to. SSB > also has this unpleasant distortion. > > There is one option a friend suggested.... wait until I get older and > the hearing drops off in frequency.... at the moment it seems > the only > option..hi..hi..hi.. > > 73s > > Berni > G0IDA > > > > > Jim Brown wrote: > > On Mon, 01 Sep 2008 14:30:45 +0100, Berni G0IDA wrote: > > > > > >> I hope there is a cure for this as it's frustrating > listening to CW > >> with > >> this sort of distortion. > >> > > > > There are three things you should do. > > > > 1) Make sure that the AGC is on, and that the CONFIG AGC > settings are > > at the > > defaults. > > > > 2) Reduce the LINEOUT GAIN (on the CONFIG menu) to a value > less than > > about 4. > > This prevents distortion that could occur in the output transformer. > > > > 3) Adjust the input gain of your computer so that you have enough > > signal for > > the decoder to function, but not enough to cause distortion. > > > > This should correct any problems. > > > > 73, > > > > Jim K9YC > > > > > > _______________________________________________ > > Elecraft mailing list > > Post to: [hidden email] > > 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: [hidden email] > 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: [hidden email] 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 |
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In reply to this post by Julian, G4ILO
I've found that the LIN OUT port has typical third harmonic levels
around -45 dB from the fundamental, with the LIN OUT level set at 10, the factory default. The headphone port, under the same conditions, will show the third harmonic down about 70 dB or so at levels appropriate for my Sony high sensitivity headphones. Cranking the audio level up will cause higher distortion on the headphone port, but only at levels that are impossible to listen to as they are so loud as to be unbearable. I've also seen some non-harmonic artifacts, particularly when very strong signals are pumped into the K3's antenna port. Jack K8ZOA Julian, G4ILO wrote: > I think it was me who used the term "ghost" signals when referring to the > harmonically related CW traces I could see on the CW Skimmer display. I > probably would have been completely unaware of it if I had never tried this > program. It was only obvious as I was listening to CW with a narrow filter > and the "ghost" traces were appearing in the part of the waterfall that you > would be expect to be dark because it was outside of the passband. I would > agree with the suggestion that the harmonics are at a low level relative to > the main signal because they are masked by band noise when you open the > filter up. I don't think there is much risk of calling someone on the third > harmonic by mistake. I don't know what the voltage level of the line output > is but the traces disappear if you turn the level down to 2, which > unfortunately is too low for most sound card programs. > > I don't know if those same harmonics are present on the speaker or headphone > outputs, as distinct from the computer audio feed. I can only say that I > find the K3 audio exceptionally pleasant to listen to. I much prefer it to > the K2, or the FT-817, which are the only other radios I have. The only > other radio I have had that sounded as clean and low-distortion as the K3 > was an IC-756PRO that I had many years ago. > > If the harmonics are down by the kind of amounts that others have measured > then the distortion figure is still within the specification for what after > all is not meant to be an audiophile quality hi-fi output stage. > > ----- > Julian, G4ILO. K2 #392 K3 #222. > http://www.g4ilo.com/ G4ILO's Shack http://www.ham-directory.com/ Ham > Directory http://www.g4ilo.com/kcomm.html KComm for Elecraft K2 and K3 > Elecraft mailing list Post to: [hidden email] 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 |
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In reply to this post by Joe Subich, W4TV-3
Yes indeed it would be a sorry situation if an operator can't tell the
difference between a desired signal and an audio harmonic, fortunately my thread is not about that. Anyway, the "noise/distortion" is still there coming out of the headphone socket. Berni Joe Subich, W4TV wrote: > Jim, > > >> Insignificant depends on the decoder, what you are decoding (PSK >> or RTTY), band conditions, and the operator. If a PSK operator is >> using the IF with a broadband setting and tries to work a signal >> that's really a harmonic, it won't work -- he'll be transmitting >> on a frequency displaced from the signal he thinks he's working >> (displaced by 2X the audio frequency of the actual signal if it's >> a third harmonic, 1X if it't the second harmonic). If it's a >> crowded RTTY contest, there can be lots of big signals creating >> that IM. Or the operator could be using a narrow roofing filter >> and those other signals are not there or heavily suppressed, so >> can't cause IM. >> > > It would be a sorry situation if an operator can't tell the > difference between a desired signal and an audio harmonic down > 50 dB. K3_Line_out.jpg shows the line out spectrum of my K3 > at 1 KHz, Data_A, 2.8 KHz 1st IF filter and 4 KHz filter. The > third harmonic is -62 dB and the fifth harmonic is - 80 dB. > See: www.microHAM-USA.com/Downloads/K3_Line_Out.jpg. > > A typical waterfall does not show the spurious signals at the > soundcard input (noise on the cables) which is well below the > "band noise" - typically around -60 dBu. > > 73, > > ... Joe, W4TV > > > > > >> -----Original Message----- >> From: [hidden email] >> [mailto:[hidden email]] On Behalf Of Jim Brown >> Sent: Monday, September 01, 2008 1:33 PM >> To: [hidden email] >> Subject: RE: [Elecraft] K3 Harmonic Distortion >> >> >> On Mon, 1 Sep 2008 12:38:31 -0400, Joe Subich, W4TV wrote: >> >> >>> Jim is entirely correct although we will disagree a bit about >>> the need to keep the line out as low as he suggests. My own >>> measurements say the harmonic distortion is insignificant as >>> long as the Line Out levels stay below .5V RMS. >>> >> Insignificant depends on the decoder, what you are decoding (PSK >> or RTTY), band conditions, and the operator. If a PSK operator is >> using the IF with a broadband setting and tries to work a signal >> that's really a harmonic, it won't work -- he'll be transmitting >> on a frequency displaced from the signal he thinks he's working >> (displaced by 2X the audio frequency of the actual signal if it's >> a third harmonic, 1X if it't the second harmonic). If it's a >> crowded RTTY contest, there can be lots of big signals creating >> that IM. Or the operator could be using a narrow roofing filter >> and those other signals are not there or heavily suppressed, so >> can't cause IM. >> >> >>> The headphone outputs are exceptionally clean as long as the >>> audio amplifier level is kept below 2V peak (1.4V RMS) and >>> the output impedance is not too low. In fact, noise in the >>> audio amplifier (headphones) is 70 dB below the desired (CW >>> at 500 Hz) signal +/- 250 Hz and 80 dB below the desired >>> signal above that. All harmonics are down more than 60 dB >>> as long as the headphone level is not at levels that could >>> damage hearing (> 1.4V RMS). >>> >> YES! My measurements of the headphone output, taken at about 1 >> volt RMS, show harmonic distortion at about 0.02% and IM at less >> than 0.1%. That is VERY VERY good! 1VRMS is LOUD! >> >> >>> The headphone output in the K3 is cleaner than any amateur >>> receiver I have seen and certainly better than the current >>> crop from Ikensu or Yaecomwood. >>> >> Yes. >> >> 73, >> >> Jim >> >> >> _______________________________________________ >> Elecraft mailing list >> Post to: [hidden email] >> 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: [hidden email] > 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: [hidden email] 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 |
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In reply to this post by Julian, G4ILO
Julian, G4ILO wrote: >I think it was me who used the term "ghost" signals when referring to the harmonically related CW traces >I could see on the CW Skimmer display. Julian, About 6 months ago I found a similar situation with another radio and another program. In that case the distortion was definitely caused by the sound card input being overdriven, not by the radio. I am not saying that that is happening for you, only that it CAN happen with certain equipment. Here are the details if you want to know. I was building a new interface that lets me operate PSK-31 and other modes (including pactor 2) with switching between any of two radios and any two hardware modems and soundcard. It is also designed to work with both my desktop computer and my laptop (HP ZT-3000) by manually moving the cable. Serial port was switched along with the modems. The radios were FT-1000D and TS-570, both interfaced through the connector on the back. The 1000D (now sold to finance K3) has a single fixed output level, the 570 three selectable levels. I selected the level most closely matching the 1000D. The software was MixW running on the HP laptop. I found that I could not only see a give station in two places, but copy their PSK-31 in both places! The second frequency was outside (above) the filter cutoff, but the signal was about as strong as the one in the passband. I don't remember the actual frequencies, but there was a big difference in them, such as double or triple. I didn't determine if the ghost was created as a harmonic or by mixing, but it was good copy and strong. (Hmmm,... wonder if PSK would be copiable on a harmonic?) My interface has a volume control for the output (as well as input) of each radio. When I turned down the output at the interface (not touching the radio), the ghost went away. On a tangent topic: I had previously run the 570 with the laptop using a much simpler interface, and somewhat marginal results (did not run into any ghost, was probably using a lower output level selected on the radio). That interface had short audio cables. The new interface has long cables for flexibility in placing the equipment around the shack. When I first tried to transmit, there was a horrible hum on the signal. I had tied together the 3 grounds of the 570 at the aux connector. I solved the problem completely by running separate 3 grounds from the 570 to the interface box with its transformers. The 1000D had no such need, maybe because its PSU was built-in) but I implemented both radio cables with separate grounds to be prepared for future radios. I should be covered for the K3, whether it behaves like a 1000D or like a 570. I wonder though if the K3 is more similar to one or the other in its grounding scheme... 73, Erik K7TV KX-1 T-1 K3 on order |
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In reply to this post by Jack Smith-6
On Mon, 01 Sep 2008 18:45:36 -0400, Jack Smith wrote:
>I've found that the LIN OUT port has typical third harmonic levels >around -45 dB from the fundamental, with the LIN OUT level set at 10, >the factory default. The headphone port, under the same conditions, will >show the third harmonic down about 70 dB or so at levels appropriate for >my Sony high sensitivity headphones. Cranking the audio level up will >cause higher distortion on the headphone port, but only at levels that >are impossible to listen to as they are so loud as to be unbearable. >I've also seen some non-harmonic artifacts, particularly when very >strong signals are pumped into the K3's antenna port. Jack, I assembled the first of the following reports in June after getting my first K3 running, and sent privately to the guys at Elecraft. That's why the new default LIN OUT gain is 10 rather than 50. It's also why there's a note in the new manual about LIN OUT level. http://audiosystemsgroup.com/K3FilterStudy.pdf A month or two later, I prepared a report on filters in my Yaesu FT1000MPs (mostly Inrads) and my K3. http://audiosystemsgroup.com/FilterTestNotes.pdf This second report describes the test methodology use for the earlier work, which uses rather a high quality pro audio FFT system (EASERA SysTun). My measurements compare pretty well with yours, but use a very different measurement method that is not dependent on the distortion of a signal generator. My method also makes the IM stick out like a sore thumb! As you can see from the first graph in the first pdf, distortion at the headphone output (the black curve) is 0.02% 2nd harmonic, 0.014% 3rd harmonic, and IM on the order of 0.1%. This was done at about 1 VRMS, and was done after the LIN OUT measurements without changing levels. The only difference between Joe's measurements and mine is that my analyzer has a bit more resolution, but we're all getting the same result. The headphone out is VERY VERY VERY good, but the LiN Out starts producing distortion at a rather low level. BUT, that low level is quite sufficient to drive a sound card. As to the setting of 3 or 10. The distortion is mainly caused by the output transformer, and distortion in an output transformer increases rapidly at low frequencies when it approaches its amplitude limit. The data output is MOSTLY intended for decoding digital signals, especially RTTY, and the distortion at 2 kHz is a LOT less than at 400 Hz for the same levels. But distortion is excited not only from signal, but from noise, and impulse noise can get pretty high. Taking all of this into account, I run my LIN OUT gain at 3, and recommend that setting. 73, Jim K9YC _______________________________________________ Elecraft mailing list Post to: [hidden email] 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 |
RE: K3 Harmonic Distortion
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In reply to this post by Berni G0IDA
> Anyway, the "noise/distortion" is still there coming out of the > headphone socket. The spectrum display you sent me shows an excessive level of 50 Hz harmonics - some 15 dB above the noise floor and only 40 dB below the desired signal from 150 Hz to above 3 KHz. That strongly indicates serious grounding issues, power supply filtering problems, improper power supply decoupling and/or soundcard instability. I suggest you read K9YC's information on interfacing and RFI www.audiosystemsgroup.com/publish.htm and resolve that noise issue first. I have seen the K3 audio output "go spurious" when presented a bad load or encountering regeneration (feedback from powered speakers) due to bad grounds. > -----Original Message----- > From: [hidden email] > [mailto:[hidden email]] On Behalf Of Berni G0IDA > Sent: Monday, September 01, 2008 7:13 PM > To: [hidden email] > Subject: Re: [Elecraft] K3 Harmonic Distortion > > > Yes indeed it would be a sorry situation if an operator can't > tell the difference between a desired signal and an audio > harmonic, fortunately > my thread is not about that. > > Anyway, the "noise/distortion" is still there coming out of the > headphone socket. > > Berni > > Joe Subich, W4TV wrote: > > Jim, > > > > > >> Insignificant depends on the decoder, what you are decoding (PSK > >> or RTTY), band conditions, and the operator. If a PSK operator is > >> using the IF with a broadband setting and tries to work a signal > >> that's really a harmonic, it won't work -- he'll be transmitting > >> on a frequency displaced from the signal he thinks he's working > >> (displaced by 2X the audio frequency of the actual signal if it's > >> a third harmonic, 1X if it't the second harmonic). If it's a > >> crowded RTTY contest, there can be lots of big signals creating > >> that IM. Or the operator could be using a narrow roofing filter > >> and those other signals are not there or heavily suppressed, so > >> can't cause IM. > >> > > > > It would be a sorry situation if an operator can't tell the > > difference between a desired signal and an audio harmonic down > > 50 dB. K3_Line_out.jpg shows the line out spectrum of my K3 > > at 1 KHz, Data_A, 2.8 KHz 1st IF filter and 4 KHz filter. The > > third harmonic is -62 dB and the fifth harmonic is - 80 dB. > > See: www.microHAM-USA.com/Downloads/K3_Line_Out.jpg. > > > > A typical waterfall does not show the spurious signals at the > > soundcard input (noise on the cables) which is well below the > > "band noise" - typically around -60 dBu. > > > > 73, > > > > ... Joe, W4TV > > > > _______________________________________________ Elecraft mailing list Post to: [hidden email] 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 |
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The spectrum display you sent me shows an excessive level of
50 Hz harmonics - some 15 dB above the noise floor and only 40 dB below the desired signal from 150 Hz to above 3 KHz. That strongly indicates serious grounding issues, power supply filtering problems, improper power supply decoupling and/or soundcard instability. I suggest you read K9YC's information on interfacing and RFI www.audiosystemsgroup.com/publish.htm and resolve that noise issue first. I have seen the K3 audio output "go spurious" when presented a bad load or encountering regeneration (feedback from powered speakers) due to bad grounds. There is another possible cause of this. The VFO could be being modulated by the magnetic field from an adjoining power supply transformer. I had this happen to me (not with the K3) and the result was a "rough" sounding note. It's easy to check for - just move the radio as far away from the PSU as it will go.
Julian, G4ILO. K2 #392 K3 #222 KX3 #110
* G4ILO's Shack - http://www.g4ilo.com * KComm - http://www.g4ilo.com/kcomm.html * KTune - http://www.g4ilo.com/ktune.html |
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