++++++++++++++++++++ Date: Mon, 02 Jun 2003 12:51:03 -0700 From: Vic Rosenthal Organization: Transparent Software To: la3za at qsl.net Cc: elecraft at mailman.qth.net Subject: Re: [Elecraft] Realign xtal filter for changed sidetone frequency? Sverre Holm wrote: > A simple question, do I have to realign the CW filter's BFO settings if > I change the sidetone? > > I have 600 Hz today, and have heard some advantages of going lower. This > could be a simple thing to experiment with if the K2 processor > recomputes all the BFO frequencies accordingly. > And a very complex operation with Spectrogram etc if it does not. If you change the pitch of the sidetone, the location of the signal in the passband will change, so if you want to maintain the same relative location (which you certainly will want to do with narrow bandwidths), then you must readjust the filters. I've gotten very good at doing this with Spectrogram; I can do the whole thing in a couple of minutes! -- 73, Vic, K2VCO Fresno CA +++++++++++++++++++ To: la3za at qsl.net, elecraft at mailman.qth.net Date: Mon, 2 Jun 2003 13:28:17 -0700 Subject: Re: [Elecraft] Realign xtal filter for changed sidetone frequency? From: k6se at juno.com Sverre, LA3ZA wrote: "A simple question, do I have to realign the CW filter's BFO settings if I change the sidetone?" ========== Yes, you do, but it's very easy to do using Spectrogram. I have my K2's sidetone set to 400Hz, so I put a marker at 400Hz in Spectrogram to center the narrow filter passbands on while adjusting the BFO. 73, de Earl, K6SE ++++++++++++++++++++ From: "Don Brown" To: , Subject: Re: [Elecraft] K2 Recommended Side Tone Freq Date: Sun, 29 Dec 2002 19:14:21 -0600 Hi The side tone generator circuit is done in the MPU and is a square wave. There is a shaping circuit on the output of the MPU to make the sidetone into a sinewave. This circuit works better a the higher frequencies above 500 Hz. You can use the lower frequencies it's just the output on the sidetone will need to be adjusted a little louder for the same signal level and the sinewave will not be as pure. I know a ham that likes 440 Hz an it works fine. The default is 600 Hz but you can put it anywhere you like from 400 to 800. Don Brown KD5NDB ----- Original Message ----- From: "Nigel Hayton" To: Sent: Sunday, December 29, 2002 7:02 PM Subject: [Elecraft] K2 Recommended Side Tone Freq > Greetings > > I will soon be building #3029 and as one getting back to "hands on" > construction after a long break - the last one was 45 years ago and had > two 6L6s in the final - I have found the wealth of information on the > list very helpful - Thank you. > > An aspect I would like to understand better. > > On page 71 Owners Manual Rev D Oct 22 2002 > > "pitch can be set from 400 to 800 Hz, although 500-600 Hz is > recommended." > > What is the reason for this recommendation? Is because of a technical > reason related to the K2 or is it based on CW operators experience in > actual band conditions. The Code teaching program I am using to > refresh my CW skills suggests to use 750 to 800Hz. > > Any advice and suggestions would be appreciated, > > 73 > > Nigel ++++++++++++++++ Date: Sun, 29 Dec 2002 19:29:52 -0600 To: , elecraft at mailman.qth.net From: Tom Hammond =?iso-8859-1?Q?N=D8SS?= Subject: Re: [Elecraft] K2 Recommended Side Tone Freq Hi Nigel: >An aspect I would like to understand better. > >On page 71 Owners Manual Rev D Oct 22 2002 > >"pitch can be set from 400 to 800 Hz, although 500-600 Hz is >recommended." > >What is the reason for this recommendation? Is because of a technical >reason related to the K2 or is it based on CW operators experience in >actual band conditions. The Code teaching program I am using to >refresh my CW skills suggests to use 750 to 800Hz. Personal opinion follows... Those of us who have a bit of gray in what few hairs we have left, generally find that our hearing seems to respond better to CW notes (and sidetones) around 600Hz, rather than the higher pitches. This having been said, the builder is free to choose (within the available range) whatever CW note (and matching sidetone frequency) he chooses to use. They all work. 73, Tom Hammond N0SS +++++++++++++++++ From: "Tom Whiteside" To: Date: Sun, 29 Dec 2002 20:27:01 -0600 Subject: [Elecraft] Sidetone recommendation for the K2 >An aspect I would like to understand better. > >On page 71 Owners Manual Rev D Oct 22 2002 > >"pitch can be set from 400 to 800 Hz, although 500-600 Hz is >recommended." > >What is the reason for this recommendation? Is because of a technical >reason related to the K2 or is it based on CW operators experience in >actual band conditions. The Code teaching program I am using to >refresh my CW skills suggests to use 750 to 800Hz. I'd have to agree with Tom that 600Hz is a good choice. Mine is set at 500Hz here. What I have found is that higher pitch notes are fatiguing to my ears. Also, the lower the frequency, the better our ears can distinguish stations calling in a pileup - a 10Hz shift is a bigger percentage difference for a 500Hz shift than a 700Hz shift so we can distinguish individual stations more easily when multiple folks are calling in. But having said that, I'm a low band nut and it gets more difficult/fatiguing in a noisy/staticy band as the shift approaches zero. Nice thing about the K2 is that it is not tough to try a given sidetone and then change it later if you prefer - Many folks operating here complain a little bit about my 500Hz setting because they are used to something higher - so you also have that to contend with if you get used to something different than the masses - I'd set it to 600Hz for starters I think... Tom Whiteside N5TW Georgetown, TX ++++++++++++++++++ To: elecraft at mailman.qth.net Date: Sun, 29 Dec 2002 18:52:19 -0800 Subject: Re: [Elecraft] K2 Recommended Side Tone Freq From: k6se at juno.com Nigel, ZL2DF wrote: "On page 71 Owners Manual Rev D Oct 22 2002 "pitch can be set from 400 to 800 Hz, although 500-600 Hz is recommended. What is the reason for this recommendation? Is [it] because of a technical reason related to the K2 or is it based on CW operators experience in actual band conditions." ========== Good question!! I was wondering myself. I prefer a 400 Hz pitch (or lower) as most 160-meter DXers do. We find that weak signals in a noisy band are easier to copy with the CW tone set to a lower-frequency pitch. Perhaps this is because of the high-pitch characteristics of the "band noise", I don't know. I DO know that it works. This has nothing to do with the age of the operator, as N0SS suggested, BTW. I was taught by Brazil's #1 160-meter DXer (PY1RO) about this "trick" back in the early 1960s when he was in his early 20s and I was in my late 20s. In the early 1970s I preferred a 200-Hz pitch note on my Drake R-4C. Why does Elecraft recommend 500-600 HZ??? Cetainly the square-wave sidetone, as KD5NDB suggested was the reason for this, has absolutely nothing to do with the most important issue -- which is how well you can copy a weak CW signal in noise. 73, de Earl, K6SE ++++++++++++++++ From: "Linden, Mike (BRC-Hes)" To: elecraft at mailman.qth.net Date: Fri, 9 May 2003 12:52:02 -0500 Subject: [Elecraft] Why is 600Hz Suggested For K2 CW I read somewhere in the K2 manuals (plan on ordering my relatively-loaded K2 this fall) that 600Hz is suggested for CW operation even though the radio would be capable of doing 700Hz. Does anyone know why 600Hz is "preferred"? I would have a tendency to configure the K2 for 700Hz to match my Kenwood TS-930SAT, but would be willing to configure it for 600Hz if performance would be "better". Just curious, Michael N9BDF ++++++++++++++++ From: "Bozidar Benc" To: Subject: RE: [Elecraft] Why is 600Hz Suggested For K2 CW Date: Fri, 9 May 2003 20:46:03 +0200 > I read somewhere in the K2 manuals (plan on ordering my > relatively-loaded > K2 this fall) that 600Hz is suggested for CW operation even > though the radio > would be capable of doing 700Hz. Does anyone know why 600Hz is > "preferred"? I would say that it's just an average of what people use. My preference is 500 Hz. It's the most pleasing for my ears. 73 Bole, 9A3RR ++++++++++++++++ Date: Fri, 09 May 2003 12:39:49 -0700 From: Vic Rosenthal Organization: Transparent Software To: Daniel Reynolds Cc: "Linden, Mike (BRC-Hes)" , elecraft at mailman.qth.net Subject: Re: [Elecraft] Why is 600Hz Suggested For K2 CW Daniel Reynolds wrote: > I set up mine for 700 Hz - and it is a matter of personal preferance. I like 550 Hz. Some people feel that the ear is more selective at lower frequencies; the argument is that a difference of 50 Hz in pitch is 10% of 500 Hz but only 6.25% of 800 Hz. It's an interesting neuro-psychological question that I'm not qualified to speculate about! As you say it's a personal preference, and it's easy to change. 73 Vic K2VCO ++++++++++++++++ From: "Bob Tellefsen" To: "Elecraft Mail List" Date: Fri, 9 May 2003 12:48:49 -0700 Subject: [Elecraft] Why 600Hz? This is just a recommendation. The KDSP2 allows you to set any center frequency that you prefer. Studies (I have been told) show that it is easier to distinguish two tones close together if they are both low in pitch. Say you have 580 Hz and 600 Hz to separate. Compare that to perhaps 1000 Hz and 1020 Hz. The lower pitches are easier to tell apart. Another factor enters the equation. As we get older, at least some of us prefer a lower pitch because it is easier for us to hear. Seems like the higher frequencies in hearing are the first to fade. I have been using 580 Hz, because that's where my acustic filter speaker resonates. I'm going to try to retune it to 550 Hz, because the DSP unit works in 50 Hz steps. 73, Bob N6WG ++++++++++++++++ To: elecraft at mailman.qth.net Date: Fri, 9 May 2003 13:30:33 -0700 Subject: Re: [Elecraft] Why is 600Hz Suggested For K2 CW From: k6se at juno.com I like 400Hz. Setting the filters so that they are centered at this lower-pitched tone makes copying weak CW signals easier because any high-pitched hiss or noise is less disturbing. It also eliminates the "ringing" that some hear when using narrow CW filters and higher-pitched offsets. However, it appears (to me) that the audio circuitry in the K2 has more ooomph at a higher pitch. Therefore you might prefer 500Hz or 600Hz for the CW offset/pitch (therefore not require having the AF gain turned up high as I need with 400Hz offset). 73, de Earl, K6SE +++++++++++++++++ Date: Sat, 10 May 2003 08:41:06 -0600 From: "James R. Duffey" To: elecraft at mailman.qth.net Subject: [Elecraft] CW Listening Tones Mike - Interesting question. There is some very nice data in a psychological (physiological?) study that shows the ear's ability to distinguish between tones is a function of the frequency of the tones. There is a broad minimum from about 400 Hz to 600 Hz. Interestingly, there are slightly different curves for the use of two ears and the use of one ear.I have a copy of the data somewhere and can dig up the reference for you if you like. Having said that, another consideration in receiver design is the steepness of the crystal filter slopes. As one reduces the center frequency of the bandpass, the requirements for opposite sideband rejection become more and more stringent. The use of a 700 Hz side tone in a rig with simple filtering improves the opposite sideband rejection immensely. It probably has less effect on a rig with a good filter like the K-2. Before it was easy to vary the side tone, 700 Hz was the de facto Ham standard, although the side tones varied all over the map. I think that the Heath SB/HW-10X series had a 1000 Hz side tone. At least the one on my SB-110A is quite high. A too high frequency is tiring in the long run, particularly with narrow filters. Someone at an RSGB convention a number of years ago took data on the tone that CW operators liked to listen to. The ops could set the tone at their choosing. They were asked to write down what tone they normally used to listen to CW first. Almost all used a tone between 400 and 600 Hz, all used a tone lower than they wrote down (except a professional musician with perfect pitch), and most used a lower tone when the signal to noise ratio was low. I hope that you found this rambling interesting and useful - Dr. Megacycle KK6MC/5 ______________________ James R. Duffey KK6MC/5 Cedar Crest NM 87009 DM65 +++++++++++++++ Date: Sat, 10 May 2003 08:03:59 -0700 From: Wayne Burdick Organization: Elecraft To: "James R. Duffey" Cc: elecraft at mailman.qth.net Subject: [Elecraft] Re: CW Listening Tones "James R. Duffey" wrote: > There is some very nice data in a psychological (physiological?) study that > shows the ear's ability to distinguish between tones is a function of the > frequency of the tones. Independent of the "aging operator" theory, there's an intuitive interpretation of why a serious CW op might prefer a lower pitch on receive. Consider two signal separated by only 10 Hz. If one is 1000 Hz and the other 1010, the difference between the two is just 1 percent. But if one is 500 Hz and the other 510, the difference is 2 percent. I haven't tried this under controlled conditions. But based on on-air experiments, it does appear that when two signals are close-spaced and interfering with each other, tuning them to a lower pitch improves copy. (The K2 facilitates experimenting with this since you can set up two filters with the same bandwidth but widely spaced BFO frequencies.) > Having said that, another consideration in receiver design is the steepness > of the crystal filter slopes. As one reduces the center frequency of the > bandpass, the requirements for opposite sideband rejection become more and > more stringent. The use of a 700 Hz side tone in a rig with simple filtering > improves the opposite sideband rejection immensely. It probably has less > effect on a rig with a good filter like the K-2. This is an excellent point that applies to some inexpensive QRP rigs *and* certain large desk-top rigs from the past. If a manufacturer knew they had poor opposite sideband rejection, it was to their advantage to move the sidetone pitch up. This may have had something to do with 700 to 800 Hz becoming the industry standard. 73, Wayne N6KR +++++++++++++ Date: Sat, 10 May 2003 09:35:53 -0600 From: "James R. Duffey" To: Wayne Burdick Cc: elecraft at mailman.qth.net Subject: [Elecraft] Re: CW Listening Tones Wayne - Thanks for the quick reply and interesting comments. Your comments about the same separation being a larger fraction of the listening tone at lower frequencies as an explanation to prefer lower tones is interesting. However, it does not explain the greater difficulty in separating tones observed as the frequency is further lowered below 400 Hz, nor does it explain why the ability to separate tones is different with two ears than one. Now if we could only duplicate the ear/brain processing in a DSP. :^) I find listening at a 500 to 550 Hz tone best for me. If you haven't tried listening at a lower tone, you might give it a try. As Wayne points out it is easy to do on the K-2. I think that you will find it easier on the ears and more efficient at dealing with interference. - Dr. Megacycle KK6MC/5 ______________________ James R. Duffey KK6MC/5 Cedar Crest NM 87009 DM65 ++++++++++++++++++ From: "Thomas M. Beaudry" To: Subject: Re: [Elecraft] Re: CW Listening Tones Date: Sun, 11 May 2003 23:24:00 -0400 There was an article in QST a good many years ago about close spaced tones being easier to seperate at lower frequencies. They cited a physiology reference that our ability to distinguish seperate tones is based on the percentage of seperation and not the absolute seperation... > > Independent of the "aging operator" theory, there's an intuitive interpretation > of why a serious CW op might prefer a lower pitch on receive. Consider two > signal separated by only 10 Hz. If one is 1000 Hz and the other 1010, the > difference between the two is just 1 percent. But if one is 500 Hz and the other > 510, the difference is 2 percent. I haven't tried this under controlled > conditions. -- snip -- +++++++++++++++++++ From: "Andreas KU7T" To: Date: Fri, 30 May 2003 11:01:45 -0700 Subject: [Elecraft] K2 CW sidetone pitch - what do you use? Hi, I have set up my K2 to use 650 Hz as my sidetone pitch. I took part in = the WPX last weekend using another rig (ICOM 775) and the pitch was way = lower, somwhere around 450 or so. I did like it, it seemed to be easier = on my ears/brain etc. I know that there are many opinions out there about which is the best = pitch for DX or contesting. I did some investigations in the newsgroups = and it seems that all those opinions are personal preferences and no = scientifically based facts. And many rig manufacturers are using 800 Hz = as the default setting. Now, what do other K2 owners use? And, does the K2 (and its filters, DSP, etc) support going down as low = as say 450 Hz? 73, Andreas, KU7T +++++++++++++++++++ From: "Lyle Johnson" To: Subject: RE: [Elecraft] K2 CW sidetone pitch - what do you use? Date: Fri, 30 May 2003 11:18:58 -0700 Hello Andreas! > Now, what do other K2 owners use? Use what works best for you. > And, does the K2 (and its filters, DSP, etc) support going down > as low as say 450 Hz? The K2 sidetone goes down to 400 Hz. The KDSP2 CW filter center frequencies go down to 400 Hz as well. 73, Lyle KK7P +++++++++++++++++ Reply-To: From: "Ron D'Eau Claire" To: Subject: RE: [Elecraft] K2 CW sidetone pitch - what do you use? Date: Fri, 30 May 2003 11:46:38 -0700 It's a very much a personal preference, Andreas. Historically, there = have been sound reasons for certain choices based on the capabilities of the receiver.=20 When I was first tinkering around after WWII, 1 kHz was a very common sidetone to use. I always found it too high. Dits and dahs tended to = blur at such a high frequency for me but I know that some other OT's still = 'swear by it'. Using such a high frequency had some specific advantages for the receivers of the day that are no longer a factor.=20 By the 70's the most common sidetones I heard were in the 600 to 800 Hz range among the "commercial" gear.=20 I prefer a lower frequency - in the 500 Hz range. Like you said, it's = just "easier on my ears".=20 There is a slight advantage to the lower frequencies too. Our ability to pick one signal out of the QRM when there are several signals in the passband is based on how much different they are in frequency. The importance is in the percentage of difference, not the number of Hz. For example, it's pretty easy to distinguish by ear between two similar = level signals producing sidetones at 400 and 600 Hz - only 200 Hz apart. But = it's much harder to distinguish between the same two signals if they produce tones of 1000 and 1200 Hz. The percentage difference between them is = less at the higher frequency and our brains have more trouble separating them. Ron AC7AC K2 # 1289 +++++++++++++++ To: elecraft at mailman.qth.net Cc: ku7t at ku7t.org Date: Fri, 30 May 2003 12:37:24 -0700 Subject: Re: [Elecraft] K2 CW sidetone pitch - what do you use? From: k6se at juno.com Andreas, KU7T wrote: "I know that there are many opinions out there about which is the best pitch for DX or contesting. Now, what do other K2 owners use? And, does the K2 (and its filters, DSP, etc) support going down as low as say 450 Hz?" ========== Many prefer a lower pitch for various reasons. I like a low pitch because it makes copying weak DX signals easier, apparently because that pitch is farther removed from the higher-pitch band noise. I have the pitch set at 400 Hz on my K2. 73, de Earl, K6SE ++++++++++++++++ To: la3za at qsl.net Cc: Elecraft at mailman.qth.net Date: Wed, 4 Jun 2003 13:28:52 -0700 Subject: Re: [Elecraft] Realign xtal filter for changed sidetone frequency? From: k6se at juno.com Hi, Sverre, You wrote: "I envy those of you who can realign those filters quickly and accurately though. This is the one single issue with the K2 that I never seem to get comfortable with. I have tried Spectogram and other methods." ---------- Usually the BFO settings that the manual gives in the tables for the number on the pack the BFO xtals came in is close enough for SSB. For CW you should set up a marker in Spectrogram at the frequency of your sidetone pitch and adjust the filter BFO settings (on noise only, using either the 0 to 255 readout or the actual BFO frequency readout) so that the center of the filter passband is at the marker. Do this for all 4 CW filters on both CW Normal and CW Reverse (8 times). ========== "My filters may be fine when aligned, but I get the feeling that they drift out of tune after a while - even after I installed the reduced drift-modification for the BFO." ---------- Temperature drift of the BFO oscillator was a big problem in my K2 originally. It would drift enough so that the received signal (when tuned in at the sidetone pitch) was no longer in the center of the CW filter passbands when the temperature inside the cabinet was not where it was when I set up my filters. The new toroid in the BFO circuit eliminated any noticeable temperature drift in my K2 and I no longer have that problem. 73, de Earl, K6SE +++++++++++++++