Hi Conrad: I'm looking forward to your tests. I have things set up per Don's and Bob's suggestions at the moment.
Windows level: -14.7db fldigi level: -15.7 db K3s level: 31 Again, I have not way to test quantitatively but the couple of comments seems to indicate things are fine. I have this old KK7UQ IMD Meter which I used to trust but it seems it's not working well or I need a new battery in it. It's reading around -19 db IMD while my old rigs were at -30 easy. I'm not trusting the meter at the moment. Kev On Mon, Jun 17, 2019 at 11:50 AM Conrad PA5Y <[email protected]> wrote: > Don, it depends on the hardware. I would be very surprised if the Audio > codec used in the K3S can reach full scale with the windows mixer at max. I > expect that it is limited to -1dB FS. Also I believe that there are further > limits imposed i WSJT-X. Therefore there should be no reason for clipping > to occur in the CODEC. I expect that there is sufficient range in the mic > gain (or whatever it is called) on the K3S. This gives the input signal the > maximum SNR which is the socially responsible thing to do. > > Until I have checked the behaviour of the windows mixer with the CODEC I > will not be using it. As I have said previously I don't trust the windows > mixer not to degrade the audio due This may well have been resolved but > historically was of concern. > > I think that I will decide what to do when I have made some proper > measurements. It's not that I don't believe you, I just like to check > things for myself. > > 73 > > Conrad PA5Y > > > ________________________________ > From: Don Wilhelm <[email protected]> > Sent: 17 June 2019 17:31 > To: Conrad PA5Y; [email protected] > Subject: Re: [Elecraft] Next Question: DATA A with K3s and Fldigi > > Conrad, > > Do check and adjust the Windows soundcard controls to mid-range. When > set to extremes, it can cause clipping and distortion. > > With the K3S, the internal soundcard will identify as USB AUDIO CODEC. > > 73, > Don W3FPR > > On 6/17/2019 11:21 AM, Conrad PA5Y wrote: > > Don of course it is not a power control, that is obvious to me. > > > > I am very fortunate to have a lot of RF and Audio test equipment > > available both at home and at work so I will measure what works best > > and try to understand why. I will be happy to share my findings. I > > will of course read your article. I am loathe to use the Windows audio > > mixer, I would rather use an external passive attenuator. Maybe the > > Windows mixer has improved, I need to check that with an audio > > analyser. It used to be awful so I built an external passive > > attenuator some years ago. > > > > I will be interested to see what happens to the K3S TX composite noise > > when the power control is used. There is a certain very popular radio > > where the AM noise comes up by 20 dB when the power is reduced from > > 100W to 30W. I would be really pleased if the K3S power control works > > properly! > > > > I bought the K3S purely for its TX PN performance. > > > > 73 > > > > Conrad PA5Y > > ------------------------------------------------------------------------ > > *From:* Don Wilhelm <[email protected]> > > *Sent:* 17 June 2019 16:03:02 > > *To:* Conrad PA5Y; [email protected] > > *Subject:* Re: [Elecraft] Next Question: DATA A with K3s and Fldigi > > Conrad and all, > > > > The POWER control in WSJT-X is a misnomer. It is actually an audio > > level control. Do NOT use it to control the power with an Elecraft > > transceiver - set the audio correctly and use the power knob to control > > the power. > > > > While other amateur transceivers can be made to control the power by > > varying the audio level, that can be disastrous for Elecraft transceiver > > Power Control. Read the relevant article on my website www.w3fpr.com< > http://www.w3fpr.com> > > <http://www.w3fpr.com> > > for a full explanation. > > > > Set the WSJT-X POWER control for 30% to 50% and do the same for the > > soundcard control in Windows Mixer, then set the LINE IN gain in the > > K3/S to somewhere near mid-range. By manipulation of those 3 audio > > level controls, you should be able to achieve the 'magic' indication of > > 4 bars solid on the ALC meter with the 5th bar flashing - that is the > > "NO ALC" point for the K3/S, KX3, and KX2 transeivers. The lower 4 bars > > of the "ALC" meter are there as an aid for setting the audio levels. > > Set the desired power output with the POWER knob - do NOT vary the audio > > level. > > > > 73, > > Don W3FPR > > > > On 6/17/2019 9:38 AM, Conrad PA5Y wrote: > > > > > > Historically there were all kinds of low level artefacts produced by > > Windows audio algorithms, including the volume control. This was > > caused by insufficient precision leading to truncation artefacts. I > > have not tested it for a while and so it may no longer be the case. > > The result when I did test it was spectral smearing and some AM on > > what should be a constant envelope signal. I trust the power control > > in WSJT-X far more than that from the Windows mixer. These effects > > only really matter during weak signal conditions when your TX signal > > is on or near the noise floor. at the receiving station However they > > do make your signal wider. > > > > > > Also be careful how you vary power, reducing audio carelessly will > > invariably decrease the signal to noise on your TX signal which will > > also affect a stations ability to receive you. > > > > > > My K3S arrives this week and I will make some tests to see exactly > > what happens with TX composite noise when power is reduced with the > > power control and by reducing audio drive from the PC. Unless someone > > else has measured this already? > > > > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[email protected] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to [email protected] > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [email protected]
