RX Test (long)
Locked
 
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Hi, Everybody,
What great comments I got from you in private e-mail messages. It's highly interesting getting your perspectives on receivers and listening. Due to day job and family I can't respond to every observation and objection but in particular Doug KR2Q-- who has some of the best ears in ham radio-- did tell me something I had already thought about which was that it might be better to record a signal instead of just noise. Let me tell you why I chose not to do that, at least for this first run of the test. Sticking with a signal-free CW passband allowed me to keep the test as equal as possible between the receivers. I was able to set the record levels within about 1 dB, and since noise isn't affected by QSB making all of the recordings on the same frequency in a period of a few minutes helped to equalize the test as well. In other words I came as close as I could to simultaneously recording the same thing on all three receivers. Most importantly, I was hoping to hear from those folks who can hear tones, digital artifacts, and other noise up around 10 kHz which is what started this whole "noisy K3" thread in the first place, and we certainly don't need a signal present to do that. In short, this was not a real-world test, it was a contrived laboratory test to listen for one specific thing (noises) independent of any signals. On purpose. Remember, the whole point of this is, given that the K3 has measurable noises that irritate many operators, we would like to find out if in a double-blind type of test whether these noises are significant enough to enable a positive identification, without looking at a spectrum analyzer, without post-processing the audio, without making any other measurements, just by trusting what your ears are telling you. So if you want to play, no performance-enhancing substances are allowed. :^) Many folks can identify a Chevy 350 engine or a Stradivarius violin while blindfolded because they hear a unique signature in those sounds. Could the same be true of a K3? These tests will tell us if the high frequency digital artifacts that many claim to hear are the fingerprint that betray a K3. We'll run another test very shortly. Please stay tuned. I hope you think this is fun. Regards, Al W6LX ______________________________________________________________ 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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Al,
From the tests I have done, I discovered that the K3 has a flat passband and very sharp filter skirts - in fact, very close to the "ideal" filter sought by many in past years. Other receivers tested (K2, Yaesu FT-900, FT-817) showed that their passband was not flat, but tapered smoothly to a lower response at higher audio frequencies. The K3 is very much quieter out of the passband than other receivers (the K2 is close) - the response is down at least 60 dB as opposed to the out of passband 'garbage' in other receivers only about 30 dB down. So my supposition is that we are not accustomed to hearing an "ideal" filter response - we are accustomed to hearing that tapered response, and as a result the K3 is judged to be "noisy", when in fact, it is very quiet for out of passband response and is faithfully reproducing the in-passband response that is actually present. We may not like to hear what is actually present, but in my mind, the K3 is faithful in re-producing it without distortion - that in my mind is the definition of a High Fidelity receiver. 73, Don W3FPR Al Lorona wrote: > Hi, Everybody, > > What great comments I got from you in private e-mail messages. It's highly interesting getting your perspectives on receivers and listening. > > Due to day job and family I can't respond to every observation and objection but in particular Doug KR2Q-- who has some of the best ears in ham radio-- did tell me something I had already thought about which was that it might be better to record a signal instead of just noise. Let me tell you why I chose not to do that, at least for this first run of the test. > > Sticking with a signal-free CW passband allowed me to keep the test as equal as possible between the receivers. I was able to set the record levels within about 1 dB, and since noise isn't affected by QSB making all of the recordings on the same frequency in a period of a few minutes helped to equalize the test as well. In other words I came as close as I could to simultaneously recording the same thing on all three receivers. Most importantly, I was hoping to hear from those folks who can hear tones, digital artifacts, and other noise up around 10 kHz which is what started this whole "noisy K3" thread in the first place, and we certainly don't need a signal present to do that. In short, this was not a real-world test, it was a contrived laboratory test to listen for one specific thing (noises) independent of any signals. On purpose. > > Remember, the whole point of this is, given that the K3 has measurable noises that irritate many operators, we would like to find out if in a double-blind type of test whether these noises are significant enough to enable a positive identification, without looking at a spectrum analyzer, without post-processing the audio, without making any other measurements, just by trusting what your ears are telling you. So if you want to play, no performance-enhancing substances are allowed. :^) Many folks can identify a Chevy 350 engine or a Stradivarius violin while blindfolded because they hear a unique signature in those sounds. Could the same be true of a K3? > > These tests will tell us if the high frequency digital artifacts that many claim to hear are the fingerprint that betray a K3. We'll run another test very shortly. Please stay tuned. I hope you think this is fun. > > Regards, > > Al W6LX > > 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 alorona
I might add - perception is 99% of reality. I write of theoretical
terms, but how the human ear/brain combination perceives things of this nature is indeed a subject for reflection and discussion. I expect that there will be many on both 'sides of the fence'. 73, Don W3FPR Al, From the tests I have done, I discovered that the K3 has a flat passband and very sharp filter skirts - in fact, very close to the "ideal" filter sought by many in past years. Other receivers tested (K2, Yaesu FT-900, FT-817) showed that their passband was not flat, but tapered smoothly to a lower response at higher audio frequencies. The K3 is very much quieter out of the passband than other receivers (the K2 is close) - the response is down at least 60 dB as opposed to the out of passband 'garbage' in other receivers only about 30 dB down. So my supposition is that we are not accustomed to hearing an "ideal" filter response - we are accustomed to hearing that tapered response, and as a result the K3 is judged to be "noisy", when in fact, it is very quiet for out of passband response and is faithfully reproducing the in-passband response that is actually present. We may not like to hear what is actually present, but in my mind, the K3 is faithful in re-producing it without distortion - that in my mind is the definition of a High Fidelity receiver. 73, Don W3FPR Al Lorona wrote: > Hi, Everybody, > > What great comments I got from you in private e-mail messages. It's highly interesting getting your perspectives on receivers and listening. > > Due to day job and family I can't respond to every observation and objection but in particular Doug KR2Q-- who has some of the best ears in ham radio-- did tell me something I had already thought about which was that it might be better to record a signal instead of just noise. Let me tell you why I chose not to do that, at least for this first run of the test. > > Sticking with a signal-free CW passband allowed me to keep the test as equal as possible between the receivers. I was able to set the record levels within about 1 dB, and since noise isn't affected by QSB making all of the recordings on the same frequency in a period of a few minutes helped to equalize the test as well. In other words I came as close as I could to simultaneously recording the same thing on all three receivers. Most importantly, I was hoping to hear from those folks who can hear tones, digital artifacts, and other noise up around 10 kHz which is what started this whole "noisy K3" thread in the first place, and we certainly don't need a signal present to do that. In short, this was not a real-world test, it was a contrived laboratory test to listen for one specific thing (noises) independent of any signals. On purpose. > > Remember, the whole point of this is, given that the K3 has measurable noises that irritate many operators, we would like to find out if in a double-blind type of test whether these noises are significant enough to enable a positive identification, without looking at a spectrum analyzer, without post-processing the audio, without making any other measurements, just by trusting what your ears are telling you. So if you want to play, no performance-enhancing substances are allowed. :^) Many folks can identify a Chevy 350 engine or a Stradivarius violin while blindfolded because they hear a unique signature in those sounds. Could the same be true of a K3? > > These tests will tell us if the high frequency digital artifacts that many claim to hear are the fingerprint that betray a K3. We'll run another test very shortly. Please stay tuned. I hope you think this is fun. > > Regards, > > Al W6LX > > ______________________________________________________________ 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 Don Wilhelm-4
I've also considered that theory. It would be interesting (and easy
with an external audio mixer) to add a little pink noise to the audio output to see if that "mellows" the sound a bit. 73 -- Joe KB8AP On Jan 8, 2010, at 6:05 PM, Don Wilhelm wrote: > So my supposition is that we are not accustomed to hearing an "ideal" > filter response - we are accustomed to hearing that tapered response, > and as a result the K3 is judged to be "noisy", when in fact, it is > very > quiet for out of passband response and is faithfully reproducing the > in-passband response that is actually present. We may not like to > hear > what is actually present, but in my mind, the K3 is faithful in > re-producing it without distortion - that in my mind is the definition > of a High Fidelity receiver. > > 73, > Don W3FPR ______________________________________________________________ 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 alorona
Why would you not want to look at the noise footprints with a spectrum analyzer? Your ear may tell you that there is something there that you don't like, but the spectrum analyzer will tell you what it is. If you are making audio files, send me a copy and I'll take a look at them for you and send you picture of each of the displays. It would be nice to get to the bottom of this topic. 73, Dave AB7E Al Lorona wrote: > Hi, Everybody, > > What great comments I got from you in private e-mail messages. It's highly interesting getting your perspectives on receivers and listening. > > Due to day job and family I can't respond to every observation and objection but in particular Doug KR2Q-- who has some of the best ears in ham radio-- did tell me something I had already thought about which was that it might be better to record a signal instead of just noise. Let me tell you why I chose not to do that, at least for this first run of the test. > > Sticking with a signal-free CW passband allowed me to keep the test as equal as possible between the receivers. I was able to set the record levels within about 1 dB, and since noise isn't affected by QSB making all of the recordings on the same frequency in a period of a few minutes helped to equalize the test as well. In other words I came as close as I could to simultaneously recording the same thing on all three receivers. Most importantly, I was hoping to hear from those folks who can hear tones, digital artifacts, and other noise up around 10 kHz which is what started this whole "noisy K3" thread in the first place, and we certainly don't need a signal present to do that. In short, this was not a real-world test, it was a contrived laboratory test to listen for one specific thing (noises) independent of any signals. On purpose. > > Remember, the whole point of this is, given that the K3 has measurable noises that irritate many operators, we would like to find out if in a double-blind type of test whether these noises are significant enough to enable a positive identification, without looking at a spectrum analyzer, without post-processing the audio, without making any other measurements, just by trusting what your ears are telling you. So if you want to play, no performance-enhancing substances are allowed. :^) Many folks can identify a Chevy 350 engine or a Stradivarius violin while blindfolded because they hear a unique signature in those sounds. Could the same be true of a K3? > > These tests will tell us if the high frequency digital artifacts that many claim to hear are the fingerprint that betray a K3. We'll run another test very shortly. Please stay tuned. I hope you think this is fun. > > Regards, > > Al W6LX > ______________________________________________________________ > 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 Don Wilhelm-4
> The K3 is very much quieter out of the passband than other > receivers (the K2 is close) - the response is down at least > 60 dB as opposed to the out of passband 'garbage' in other > receivers only about 30 dB down. Here is the genesis of the complaint that the K3 is more fatiguing than other receivers. The out of band noise (noise above 5 KHz) in the K3 is, as you say, at least 60 dB below the peak audio level (actually, I measure it at more than 90dB down above 5 KHz). However, the stopband also has many leakage products (DAC artifacts) in the stopband some of which are as much as 50 dB ABOVE the noise floor. While these products are well below the desired audio in the passband, they are "in the clear" as far a local noise. This requires the ear/brain system to subconsciously work to reject (filter) the undesired discrete frequency products. With other receivers (e.g., the FT-1000MP MKV) any undesired discrete frequency products (and much of the general audio IMD) is buried (or masked) by the slow roll off of the IF noise which is only 50-60 dB below peak audio response well into the 10 KHz range. With the masking noise, the ear/brain system does not need to be engaged to reject the other "signals" even though the overall noise level is higher. I can see the other "noise" effect using an audio spectrum analyzer but I have not been able to determine its cause - I suspect it may be some form of DSP related aliasing or overflow. In any case it is quite visible in CW (with a narrow filter) and responds dramatically to reductions in the RF gain. In essence, I can reduce the stopband noise in the 900 - 2000 Hz range significantly without reducing the peak audio level of the desired CW signal simply by reducing the RF Gain (or engaging the attenuator). Since engaging the attenuator will drop the noise by more than 10 dB, my suspicion is that it is some form of IMD but until I receive my lowpass filters and finish all of the audio updates (with appropriate before/after documentation) I will not speculate as to the source. 73, ... Joe, W4TV > -----Original Message----- > From: [hidden email] > [mailto:[hidden email]] On Behalf Of Don Wilhelm > Sent: Friday, January 08, 2010 9:06 PM > To: Al Lorona > Cc: Elecraft Reflector > Subject: Re: [Elecraft] RX Test (long) > > > Al, > > From the tests I have done, I discovered that the K3 has a flat > passband and very sharp filter skirts - in fact, very close to the > "ideal" filter sought by many in past years. Other receivers tested > (K2, Yaesu FT-900, FT-817) showed that their passband was not > flat, but > tapered smoothly to a lower response at higher audio frequencies. > > The K3 is very much quieter out of the passband than other receivers > (the K2 is close) - the response is down at least 60 dB as opposed to > the out of passband 'garbage' in other receivers only about > 30 dB down. > > So my supposition is that we are not accustomed to hearing an "ideal" > filter response - we are accustomed to hearing that tapered response, > and as a result the K3 is judged to be "noisy", when in fact, > it is very > quiet for out of passband response and is faithfully reproducing the > in-passband response that is actually present. We may not > like to hear > what is actually present, but in my mind, the K3 is faithful in > re-producing it without distortion - that in my mind is the > definition > of a High Fidelity receiver. > > 73, > Don W3FPR > ______________________________________________________________ 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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So what you are saying is the K3 is too quiet for its own good, and that's what makes it so noisy!
----- Original Message ---- From: "Joe Subich, W4TV" <[hidden email]> To: [hidden email]; Al Lorona <[hidden email]> Cc: Elecraft Reflector <[hidden email]> Sent: Fri, January 8, 2010 8:46:21 PM Subject: RE: [Elecraft] RX Test (long) However, the stopband also has many leakage products (DAC artifacts) in the stopband some of which are as much as 50 dB ABOVE the noise floor. While these products are well below the desired audio in the passband, they are "in the clear" as far a local noise. This requires the ear/brain system to subconsciously work to reject (filter) the undesired discrete frequency products. ______________________________________________________________ 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 Joe Subich, W4TV-4
But these "artifacts", at least in my observation, are only present when a signal is present. If they are there when only noise is being received, they are below the extremely low out of band noise level. Therefore, whilst I can see that they could contribute to unpleasant or tiring sounding audio for those blessed with acute hearing, I can't see that they would result in the receiver sounding noisy.
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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If the K3 is being used by a contest group or dxpedition, for instance, you
will have a wider range of hearing sensitivities and these activities force us to concentrate a lot more and use a radio for long periods. On this basis, fatigue due to these artefacts should be eliminated for the benefit of the group, particularly those listening to weak signals. I think the extra filter would be a good investment. David G3UNA > > > > Joe Subich, W4TV-4 wrote: >> >> >> Here is the genesis of the complaint that the K3 is more >> fatiguing than other receivers. The out of band noise >> (noise above 5 KHz) in the K3 is, as you say, at least 60 dB >> below the peak audio level (actually, I measure it at more >> than 90dB down above 5 KHz). However, the stopband also has >> many leakage products (DAC artifacts) in the stopband some >> of which are as much as 50 dB ABOVE the noise floor. >> >> While these products are well below the desired audio in the >> passband, they are "in the clear" as far a local noise. >> This requires the ear/brain system to subconsciously work >> to reject (filter) the undesired discrete frequency products. >> >> > > But these "artifacts", at least in my observation, are only present when a > signal is present. If they are there when only noise is being received, > they > are below the extremely low out of band noise level. Therefore, whilst I > can > see that they could contribute to unpleasant or tiring sounding audio for > those blessed with acute hearing, I can't see that they would result in > the > receiver sounding noisy. > > ----- > Julian, G4ILO. K2 #392 K3 #222. ______________________________________________________________ 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 Julian, G4ILO
Sorry, I don't buy the theory that the low-level stopband artifacts are responsible for the perception of the K3 being "noisy". To my ears and tests I've conducted multiple times, the artifacts are audibly masked in listening, even without the LPF.
On spectrum analysis, I see artifacts in descending order at 12Khz, 18Khz and 14.1Khz. To make the strongest of these (12Khz) just barely audible, I have to apply a full 20dB of boost (via narrow parametric EQ filtering). Perhaps it can be argued that the artifacts are responsible for a subtle sense of listener fatigue (I'm skeptical), but not the "noisiness" discussed ad nauseum on the reflector. I am convinced that "noisiness" is due to improper gain adjustment. 73, Barry N1EU
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In reply to this post by alorona
I suspect that's about it in a nutshell.
People have gotten used to listening to a certain level and quality of noise from the YaeKenIcom crowd that when presented with a receiver this good they are convinced it's "noisier". Noise, which used to be covered up or attenuated by phase noise or other crud in the other rigs isn't in the K3. People simply haven't been hearing true reproductions of band noise etc... with the other rigs. My own pet theory. Al Lorona wrote: > So what you are saying is the K3 is too quiet for its own good, and that's what makes it so noisy! > > > > ----- Original Message ---- > From: "Joe Subich, W4TV" <[hidden email]> > To: [hidden email]; Al Lorona <[hidden email]> > Cc: Elecraft Reflector <[hidden email]> > Sent: Fri, January 8, 2010 8:46:21 PM > Subject: RE: [Elecraft] RX Test (long) > > > > However, the stopband also has > many leakage products (DAC artifacts) in the stopband some > of which are as much as 50 dB ABOVE the noise floor. > > While these products are well below the desired audio in the > passband, they are "in the clear" as far a local noise. > This requires the ear/brain system to subconsciously work > to reject (filter) the undesired discrete frequency products. > ______________________________________________________________ > 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 > > -- R. Kevin Stover ACØH ______________________________________________________________ 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 David Cutter
Hmmmm!!!!!!!!
I suppose I am in the category where my hearing is "impaired". At least my wife informs me near daily that such is the case. I was the oldest of the 13 operators blessed with 7 early production K-3s to perform a task nearly identical to that described by David. The two youngest operators (one just recently married at that time) as well as the majority of the VP6DX DX-pedition crew are among the elite of current contesters. Thirteen opertors taking care of SEVEN operating positions 24/7 for nearly 17 days; non-stop, day and night, three modes, Topband through 10 Meters, on an uninhabitated atoll with generator power was the task. The results speak for themselves; both for the operators and the equipment employed. I did not and have not ever heard any of the other 12 operators mention anything about the perceived noise problem. Suffice it to say that apparently the "noise" does exist for some small percentage of K-3 users with very acute hearing. BUT, my point is that there was NOT a problem with this "problem" for the very wide range of age and capabilities of the VP6DX team. Likewise, I have never perceived such an annoyance or distraction with my personal K-3, or other K-3's that I have operated. There is a difference of some subtle manner re the transceiver RX "sound" that I had been used to with the name brand and model radios I had used for the previous 13-14 years. But it certainly is not detrimental; in fact I can say that it is advantageous to ME. That is my observation and report, and MHO. Happy New Year to all. Milt, N5IA ----- Original Message ----- From: "David Cutter" <[hidden email]> To: "Julian, G4ILO" <[hidden email]>; <[hidden email]> Sent: Saturday, January 09, 2010 3:30 AM Subject: Re: [Elecraft] RX Test (long) > If the K3 is being used by a contest group or dxpedition, for instance, > you > will have a wider range of hearing sensitivities and these activities > force > us to concentrate a lot more and use a radio for long periods. On this > basis, fatigue due to these artefacts should be eliminated for the benefit > of the group, particularly those listening to weak signals. ______________________________________________________________ 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 ac0h
I think the noisy issue derives out of our quite old analog listening
habits and expectations. I would estimate for easily half of the reflector population (my real guess is 75%), that their listening to radio career began with an analog HF radio that didn't have enough gain to present ambient antenna noise over receiver noise except on the lowest bands. Without exception, these were tube radios whose circuits didn't flat-top overdrive, just round it off, and whose audio transformers' response gradually died over 4 khz. There were no sudden transitions in any of them save the few lucky enough to have a crystal filter for narrow reception on CW. As another has stated, the sharp limits of selectivity, vast extents of audio response, and enough receiver system gain to bring anyone's 10 meter outside ambient noise up to full audio, were ideals, frankly just not attained, or in some modern radios curiously avoided (knew something?). Quite a lot of posted complaints here had at their roots one single issue: on the lower bands, a typical metropolitan area RESTING outside ambient noise level is S2 S4 and S8 on 40, 80 and 160 meters. In the K3 attenuator off, preamp on, and RF gain at full results in ambient noise fully engaging the AGC and remaining at full audio on 160 through 40 and possibly on 20 as well. If RF gain is full, and preamp is on, the receiver is set to present a quarter microvolt as full loudness, and anything higher than that REDUCED to full loudness. This means that outside ambient noise on 160 will always be at full loudness, and also at full "shrill" given the wide audio response. This was the first complaint about our contest group's first exposure to an Orion, and for all practical purposes the ONLY one. Nothing in second or third place. Once we knew we had to PURPOSEFULLY REDUCE the receiver gain (settings for preamp, attenuator, RF gain) for the lower bands to reduce the outside ambient noise to 1/4 full volume, the Orion became imminently superior to the MP's we were using at the time. This remains true with the K3, even though some stubbornly continue to insist they shouldn't have to reduce the RF gain. With the Orion, those settings (including the RF gain) could be remembered by band. Many Orion users will tell you that the RF gain, once set moderately for their locale's ambient noise per band, is never touched again. In effect it was "calibrated" to their local noise. Remembering ATT and PREAMP by band is close to the Orion's flexibility. On my K3, to set 160m ambient noise in a 500 Hz bandwidth to 1/4 audio, I have to turn off the preamp, turn on the attenuator, and reduce RF gain to 2 oclock. Then it's just as quiet as my ancient tube analog receiver. The discussion about fatiguing audio becomes a completely different subject, once proper reduction of gain to match ambient noise is taken care of. 73, Guy. On Sat, Jan 9, 2010 at 8:08 AM, R. Kevin Stover <[hidden email]> wrote: > I suspect that's about it in a nutshell. > People have gotten used to listening to a certain level and quality of > noise from the YaeKenIcom crowd that when presented with a receiver this > good they are convinced it's "noisier". Noise, which used to be covered > up or attenuated by phase noise or other crud in the other rigs isn't in > the K3. > > People simply haven't been hearing true reproductions of band noise > etc... with the other rigs. > > My own pet theory. > > Al Lorona wrote: >> So what you are saying is the K3 is too quiet for its own good, and that's what makes it so noisy! >> >> >> >> ----- Original Message ---- >> From: "Joe Subich, W4TV" <[hidden email]> >> To: [hidden email]; Al Lorona <[hidden email]> >> Cc: Elecraft Reflector <[hidden email]> >> Sent: Fri, January 8, 2010 8:46:21 PM >> Subject: RE: [Elecraft] RX Test (long) >> >> >> >> However, the stopband also has >> many leakage products (DAC artifacts) in the stopband some >> of which are as much as 50 dB ABOVE the noise floor. >> >> While these products are well below the desired audio in the >> passband, they are "in the clear" as far a local noise. >> This requires the ear/brain system to subconsciously work >> to reject (filter) the undesired discrete frequency products. >> ______________________________________________________________ >> 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 >> >> > > -- > R. Kevin Stover > > ACØH > > ______________________________________________________________ > 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 alorona
> So what you are saying is the K3 is too quiet for its own > good, and that's what makes it so noisy! No, the low stopband noise with (relatively) high levels of DAC leakage products is what makes the receiver tiring. It's the additional "noise" is in the 1000 - 3000 Hz range (with CW filter) that can be eliminated by reducing the RF gain that makes the receiver "noisy." 73, ... Joe, W4TV > -----Original Message----- > From: Al Lorona [mailto:[hidden email]] > Sent: Saturday, January 09, 2010 1:45 AM > To: [hidden email] > Cc: Elecraft Reflector > Subject: Re: [Elecraft] RX Test (long) > > > So what you are saying is the K3 is too quiet for its own > good, and that's what makes it so noisy! > > > > ----- Original Message ---- > From: "Joe Subich, W4TV" <[hidden email]> > To: [hidden email]; Al Lorona <[hidden email]> > Cc: Elecraft Reflector <[hidden email]> > Sent: Fri, January 8, 2010 8:46:21 PM > Subject: RE: [Elecraft] RX Test (long) > > > > However, the stopband also has > many leakage products (DAC artifacts) in the stopband some > of which are as much as 50 dB ABOVE the noise floor. > > While these products are well below the desired audio in the > passband, they are "in the clear" as far a local noise. > This requires the ear/brain system to subconsciously work > to reject (filter) the undesired discrete frequency products. ______________________________________________________________ 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 Julian, G4ILO
> But these "artifacts", at least in my observation, are only > present when a signal is present. If they are there when only > noise is being received, they are below the extremely low out > of band noise level. I see 7.8 and 12 KHz products clearly at about 10 dB above the stopband noise with no signal present. They get much stronger with signals present and additional products appear. Even though the maximum level is still 60 dB below the listening level, they are still clearly above the "masking" level and they will be audible to someone with normal hearing with "full range" headphones and/or speaker. 73, ... Joe, W4TV > -----Original Message----- > From: [hidden email] > [mailto:[hidden email]] On Behalf Of Julian, G4ILO > Sent: Saturday, January 09, 2010 5:11 AM > To: [hidden email] > Subject: Re: [Elecraft] RX Test (long) > > > > > > Joe Subich, W4TV-4 wrote: > > > > > > Here is the genesis of the complaint that the K3 is more > > fatiguing than other receivers. The out of band noise > > (noise above 5 KHz) in the K3 is, as you say, at least 60 dB > > below the peak audio level (actually, I measure it at more > > than 90dB down above 5 KHz). However, the stopband also has > > many leakage products (DAC artifacts) in the stopband some > > of which are as much as 50 dB ABOVE the noise floor. > > > > While these products are well below the desired audio in the > > passband, they are "in the clear" as far a local noise. > > This requires the ear/brain system to subconsciously work > > to reject (filter) the undesired discrete frequency products. > > > > > > But these "artifacts", at least in my observation, are only > present when a signal is present. If they are there when only > noise is being received, they are below the extremely low out > of band noise level. Therefore, whilst I can see that they > could contribute to unpleasant or tiring sounding audio for > those blessed with acute hearing, I can't see that they would > result in the receiver sounding noisy. > > ----- > Julian, G4ILO. K2 #392 K3 #222. > * G4ILO's Shack - http://www.g4ilo.com > * KComm - http://www.g4ilo.com/kcomm.html > * KTune - http://www.g4ilo.com/ktune.html > > -- > View this message in context: > http://n2.nabble.com/RX-Test-long-tp4275854p4277032.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 Milt -- N5IA
Noise or no noise vs opertional ability to hear.
For me the K3 and it's DSP, NR and NB has help me over come the hearing problem of being old and with teninous. The tone in my ears is so bad that I could NOT pass the CW requirement test for an extra class license. My previous radios with all the filter and DSP did not help. The tone in my head is verified at 1150Hz. It made coping a signal that was in normal noise very difficult. It resonanted with my internal tone at about 15WPM. I've used one or the other CW encoding programs for years. I now find that with the K3 CW is getting easier to copy. I'm looking forward to the Rev D and expect further improvement. Maybe I'll be able to get rid of the encodeds soon de K2GN K3 S/N 3278 ----- Original Message ----- From: "Milt, N5IA" <[hidden email]> To: "David Cutter" <[hidden email]>; "Julian, G4ILO" <[hidden email]>; <[hidden email]> Sent: Saturday, January 09, 2010 8:55 AM Subject: Re: [Elecraft] RX Test (long) > Hmmmm!!!!!!!! > > I suppose I am in the category where my hearing is "impaired". At least > my > wife informs me near daily that such is the case. > > I was the oldest of the 13 operators blessed with 7 early production K-3s > to > perform a task nearly identical to that described by David. The two > youngest operators (one just recently married at that time) as well as the > majority of the VP6DX DX-pedition crew are among the elite of current > contesters. > > Thirteen opertors taking care of SEVEN operating positions 24/7 for nearly > 17 days; non-stop, day and night, three modes, Topband through 10 Meters, > on > an uninhabitated atoll with generator power was the task. > > The results speak for themselves; both for the operators and the equipment > employed. > > I did not and have not ever heard any of the other 12 operators mention > anything about the perceived noise problem. Suffice it to say that > apparently the "noise" does exist for some small percentage of K-3 users > with very acute hearing. > > BUT, my point is that there was NOT a problem with this "problem" for the > very wide range of age and capabilities of the VP6DX team. > > Likewise, I have never perceived such an annoyance or distraction with my > personal K-3, or other K-3's that I have operated. There is a difference > of > some subtle manner re the transceiver RX "sound" that I had been used to > with the name brand and model radios I had used for the previous 13-14 > years. But it certainly is not detrimental; in fact I can say that it is > advantageous to ME. > > That is my observation and report, and MHO. Happy New Year to all. > > Milt, N5IA > > ----- Original Message ----- > From: "David Cutter" <[hidden email]> > To: "Julian, G4ILO" <[hidden email]>; <[hidden email]> > Sent: Saturday, January 09, 2010 3:30 AM > Subject: Re: [Elecraft] RX Test (long) > > >> If the K3 is being used by a contest group or dxpedition, for instance, >> you >> will have a wider range of hearing sensitivities and these activities >> force >> us to concentrate a lot more and use a radio for long periods. On this >> basis, fatigue due to these artefacts should be eliminated for the >> benefit >> of the group, particularly those listening to weak signals. > > ______________________________________________________________ > 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 Joe Subich, W4TV-4
I agree. These artificacts have "sidebands" that increase and
decrease with content in the normal passband, but their separation and frequency span is as if the frequency content (not the amplitude) of the normal passband were divided by 2 or 4. They are way down, and do not exceed the amplitude of the 7.8 and 12 artifacts. 73, Guy. On Sat, Jan 9, 2010 at 9:53 AM, Joe Subich, W4TV <[hidden email]> wrote: > I see 7.8 and 12 KHz products clearly at about 10 dB above the > stopband noise with no signal present. They get much stronger > with signals present and additional products appear. Even > though the maximum level is still 60 dB below the listening > level, they are still clearly above the "masking" level and > they will be audible to someone with normal hearing with > "full range" headphones and/or speaker. > > 73, > > ... Joe, W4TV 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 Don Wilhelm-4
As I recall it was RCA at the dawn of HI-FI who did a test using a
live orchestra and a physical passband filter to garner listener response. The audience did not know whether the filter was in or not The results were that people found the orchestra without the filter sounded unnatural. Their conclusion was that people had become so used to listening to the limited frequency response of the radios of the day that the real thing did not sound right. Caveat: That is my recollection. If I remembered wrong it still makes a good story. David K0LUM At 9:05 PM -0500 1/8/10, Don Wilhelm wrote: > > >So my supposition is that we are not accustomed to hearing an "ideal" >filter response - we are accustomed to hearing that tapered response, >and as a result the K3 is judged to be "noisy", when in fact, it is very >quiet for out of passband response and is faithfully reproducing the >in-passband response that is actually present. We may not like to hear >what is actually present, but in my mind, the K3 is faithful in >re-producing it without distortion - that in my mind is the definition >of a High Fidelity receiver. > >73, >Don W3FPR 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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