[Elecraft] Auto-spot, tuning aids, and the arcane history of CW pitch-matching
Elecraft's auto-spot and CWT features -- available on the K3/K3S/KX2/KX3 -- are very useful tools for CW operators, especially those not experienced in pitch-matching. Here's a bit of history on where these features came from and how they work. CW Spotting History When a station finishes a CQ in CW mode, the operator faces the challenge of copying someone who's calling back. Callers may be weak or obscured by QRM; the op can usually deal with both problems by narrowing the filter passband. However, callers may also be off frequency. A calling station may be using a wide filter passband themselves, not attempting to carefully match their VFO frequency to that of the CQing station. The result may be no QSO, even when propagation is excellent. In the Days of Yore, a frequency offset between stations didn't always matter. Sometimes both stations used crystal-controlled transmitters, so operators had to patient tune around after calling CQ. As a 14-year-old novice I embraced this operating style for a year or so, armed with a dozen or so crusty FT-243 crystals for my Heath HW-16. I nearly wore out the socket swapping them in and out. After calling CQ, it was not unusual to find a caller 30 or more kHz away! (Away from "where" was a poorly answered question, as my Hallicrafters receiver dial wasn't exactly digital.) Fortunately I soon acquired an outboard VFO, a life-changing addition to my station. Jealous friends doubled up on their paper routes to pay for their own. Girls suddenly paid more attention to me. These days virtually everyone has a VFO, along with the expectation that they won't have to tune theirs very far, if at all, to tune you in. Not only that, they're stable and well calibrated, not like the beasts we had to skillfully tame. Progress! Manual Spotting (SPOT switch) Once I had a VFO I quickly learned to do *manual* pitch matching. Older rigs did't provide a way to do that explicitly, so you'd improvise. Basically, you had to coerce a very weak signal out of your own transmitter, say by turning on only the driver, then tune the transmit VFO until you could hear your signal on your own receiver -- superimposed on the calling station, at the same pitch. This is what we call spotting. Of course spotting is a lot more convenient these days, as many rigs include a SPOT switch. This function is easy for a modern transceiver designer to add, because the radio's firmware is quite capable of turning on only the CW sidetone without transmitting. That is the purpose of the SPOT switch on all Elecraft transceivers. Tap SPOT, and you'll hear your sidetone pitch. Most people can do a good job of adjusting the VFO such that the CQing station's pitch matches that of the SPOT tone. This ensures that when you call them, you'll be close to their own frequency. Tuning Aids: Filtering (APF), PLL (NE567), and Spectral (CWT) Since not everyone has an inherent musical ear, various hardware-enhanced means of tuning in CW signals have been developed. The simplest method is to just narrow your receiver passband so much that, if you can hear a station calling CQ at all, you're guaranteed to be "right on top of him." This assumes that your transceiver enforces alignment between its transmit and receive pitch...true of all Elecraft gear. Narrow filtering has gone through decades of evolution. Some filters were based on op-amps (active filters), while others were based on LC filtering, conscripting humongous toroidal cores scavenged from telco equipment. I acquired my stash of these from a haphazard mound of old switching racks, decaying in an abandoned aircraft hanger on the Bermuda U.S. Navy base. (That irresistible junk pile was also a mother load of TO5 transistors, multi-pound electrolytic capacitors, and tetanus, but that's another story.) Typically the toroids were 88 millihenries -- a huge value for a high-Q inductor, permitting resonance in the low audio range. Later, such filters migrated to digital signal processing, in the form of switched-capacitor ICs or DSPs. You can still buy these switched-capacitor chips, like the MF10, from various sources. It's instructive to roll your own tunable filter, just for fun. Whether passive or active, the goal of filtering is typically to achieve a narrow passband, say 250 Hz or less. With DSP, nearly perfect filters with "brick wall" passbands can be created. But these have the disadvantage of ringing like a bell when pinged by a CW signal or noise, making copy difficult. One solution incorporated into the K-line and KX-line is the Audio Peaking Filter (APF), which provides a 30-Hz bandwidth at -3 dB, but broad skirts, preventing ringing from occurring. As our customers will attest, APF works like magic on weak signals obscured by noise. Another forerunner to DSP techniques was the audio phase-locked-loop, using inexpensive ICs like the legendary LM567. When locked on a signal that matched its cen
[Elecraft] Auto-spot, tuning aids, and the arcane history of CW pitch-matching
A history of CW pitch matching would seem to be incomplete without a mention of the BFO (Beat Frequency Oscillator). When I started operating CW I had separate TX and RX. TX was homebrew and the RX was an AR-88D.A common technique for tuning a CW station was to set the BFO to zero offset, tune the station for zero beat, and then offset the BFO to give the desired pitch. In my case that pitch was the frequency that resonated the diaphragms of the headphones. Having independent RX and TX meant there was no risk of 2 stations chasing each other up or down the band. Thanks for the nostalgia trip. Andy, k3wyc __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
[Elecraft] Auto-spot, tuning aids, and the arcane history of CW pitch-matching
"Find a signal, turn on CWT, then tap SPOT to tune it in. A second tap of SPOT may get even closer, especially if there's a lot of band noise." and "I'm a great fan of using the auto-spot feature, and love to show it off to all shack visitors, as an example of yet another reason they need to upgrade to Elecraft," I must be missing something. How is this 2 step activated spot feature better than a single press of Kenwood's CWT? I often use CWT on my TS-590S but almost always with a spit or XIT offset (I didn't know that was a secret). Andy, k3wyc __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Auto-spot, tuning aids, and the arcane history of CW pitch-matching
Wayne, thanks for this historical description. I have used these tools myself a lot over the years. They are one reason I have purchased my K3, K3S and KX3(however sold to purchase K3S). Now, one thing you missed... when you’re working a big pileup and you feel you just can’t get through, it may be that all your “buddies” are doing the same thing, using Auto-Spot! Now turn on XIT and set it to 12-20 Hz either way. Now your signal will be just a little different from all the others and you have a better chance of being heard. Sent from my iPhone ...nr4c. bill > On Jan 22, 2019, at 12:09 AM, Wayne Burdick wrote: > > Elecraft's auto-spot and CWT features -- available on the K3/K3S/KX2/KX3 -- > are very useful tools for CW operators, especially those not experienced in > pitch-matching. Here's a bit of history on where these features came from and > how they work. > > > CW Spotting History > > When a station finishes a CQ in CW mode, the operator faces the challenge of > copying someone who's calling back. Callers may be weak or obscured by QRM; > the op can usually deal with both problems by narrowing the filter passband. > However, callers may also be off frequency. A calling station may be using a > wide filter passband themselves, not attempting to carefully match their VFO > frequency to that of the CQing station. The result may be no QSO, even when > propagation is excellent. > > In the Days of Yore, a frequency offset between stations didn't always > matter. Sometimes both stations used crystal-controlled transmitters, so > operators had to patient tune around after calling CQ. > > As a 14-year-old novice I embraced this operating style for a year or so, > armed with a dozen or so crusty FT-243 crystals for my Heath HW-16. I nearly > wore out the socket swapping them in and out. After calling CQ, it was not > unusual to find a caller 30 or more kHz away! (Away from "where" was a poorly > answered question, as my Hallicrafters receiver dial wasn't exactly digital.) > > Fortunately I soon acquired an outboard VFO, a life-changing addition to my > station. Jealous friends doubled up on their paper routes to pay for their > own. Girls suddenly paid more attention to me. > > These days virtually everyone has a VFO, along with the expectation that they > won't have to tune theirs very far, if at all, to tune you in. Not only that, > they're stable and well calibrated, not like the beasts we had to skillfully > tame. Progress! > > > Manual Spotting (SPOT switch) > > Once I had a VFO I quickly learned to do *manual* pitch matching. Older rigs > did't provide a way to do that explicitly, so you'd improvise. Basically, you > had to coerce a very weak signal out of your own transmitter, say by turning > on only the driver, then tune the transmit VFO until you could hear your > signal on your own receiver -- superimposed on the calling station, at the > same pitch. This is what we call spotting. > > Of course spotting is a lot more convenient these days, as many rigs include > a SPOT switch. This function is easy for a modern transceiver designer to > add, because the radio's firmware is quite capable of turning on only the CW > sidetone without transmitting. > > That is the purpose of the SPOT switch on all Elecraft transceivers. Tap > SPOT, and you'll hear your sidetone pitch. Most people can do a good job of > adjusting the VFO such that the CQing station's pitch matches that of the > SPOT tone. This ensures that when you call them, you'll be close to their own > frequency. > > > Tuning Aids: Filtering (APF), PLL (NE567), and Spectral (CWT) > > Since not everyone has an inherent musical ear, various hardware-enhanced > means of tuning in CW signals have been developed. > > The simplest method is to just narrow your receiver passband so much that, if > you can hear a station calling CQ at all, you're guaranteed to be "right on > top of him." This assumes that your transceiver enforces alignment between > its transmit and receive pitch...true of all Elecraft gear. > > Narrow filtering has gone through decades of evolution. Some filters were > based on op-amps (active filters), while others were based on LC filtering, > conscripting humongous toroidal cores scavenged from telco equipment. I > acquired my stash of these from a haphazard mound of old switching racks, > decaying in an abandoned aircraft hanger on the Bermuda U.S. Navy base. (That > irresistible junk pile was also a mother load of TO5 transistors, multi-pound > electrolytic capacitors, and tetanus, but that's another story.) Typically > the toroids were 88 millihenries -- a huge value for a high-Q inductor, > permitting resonance in the low audio range. > > Later, such filters migrated to digital signal processing, in the form of > switched-capacitor ICs or DSPs. You can still buy these switched-capacitor > chips, like the MF10, from various sources. It's instructi
Re: [Elecraft] Auto-spot, tuning aids, and the arcane history of CW pitch-matching
Yet another trick learnt by hard experience given away for free :-( Regards, Mike VP8NO On 22/01/2019 11:14, Nr4c wrote: Now, one thing you missed... when you’re working a big pileup and you feel you just can’t get through, it may be that all your “buddies” are doing the same thing, using Auto-Spot! Now turn on XIT and set it to 12-20 Hz either way. Now your signal will be just a little different from all the others and you have a better chance of being heard. Sent from my iPhone ...nr4c. bill __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Auto-spot, tuning aids, and the arcane history of CW pitch-matching
Wayne, you forgot clicking on the DX Cluster spot. ;) I'm being facetious, of course, but the practice of simply clicking on a cluster spot does point out a problem with zero beating by any means ... if every calling station is zero beat the station calling CQ isn't going to copy anyone. Zero beat isn't always a good thing. 73, Dave AB7E On 1/21/2019 10:09 PM, Wayne Burdick wrote: Elecraft's auto-spot and CWT features -- available on the K3/K3S/KX2/KX3 -- are very useful tools for CW operators, especially those not experienced in pitch-matching. Here's a bit of history on where these features came from and how they work. CW Spotting History When a station finishes a CQ in CW mode, the operator faces the challenge of copying someone who's calling back. Callers may be weak or obscured by QRM; the op can usually deal with both problems by narrowing the filter passband. However, callers may also be off frequency. A calling station may be using a wide filter passband themselves, not attempting to carefully match their VFO frequency to that of the CQing station. The result may be no QSO, even when propagation is excellent. In the Days of Yore, a frequency offset between stations didn't always matter. Sometimes both stations used crystal-controlled transmitters, so operators had to patient tune around after calling CQ. As a 14-year-old novice I embraced this operating style for a year or so, armed with a dozen or so crusty FT-243 crystals for my Heath HW-16. I nearly wore out the socket swapping them in and out. After calling CQ, it was not unusual to find a caller 30 or more kHz away! (Away from "where" was a poorly answered question, as my Hallicrafters receiver dial wasn't exactly digital.) Fortunately I soon acquired an outboard VFO, a life-changing addition to my station. Jealous friends doubled up on their paper routes to pay for their own. Girls suddenly paid more attention to me. These days virtually everyone has a VFO, along with the expectation that they won't have to tune theirs very far, if at all, to tune you in. Not only that, they're stable and well calibrated, not like the beasts we had to skillfully tame. Progress! Manual Spotting (SPOT switch) Once I had a VFO I quickly learned to do *manual* pitch matching. Older rigs did't provide a way to do that explicitly, so you'd improvise. Basically, you had to coerce a very weak signal out of your own transmitter, say by turning on only the driver, then tune the transmit VFO until you could hear your signal on your own receiver -- superimposed on the calling station, at the same pitch. This is what we call spotting. Of course spotting is a lot more convenient these days, as many rigs include a SPOT switch. This function is easy for a modern transceiver designer to add, because the radio's firmware is quite capable of turning on only the CW sidetone without transmitting. That is the purpose of the SPOT switch on all Elecraft transceivers. Tap SPOT, and you'll hear your sidetone pitch. Most people can do a good job of adjusting the VFO such that the CQing station's pitch matches that of the SPOT tone. This ensures that when you call them, you'll be close to their own frequency. Tuning Aids: Filtering (APF), PLL (NE567), and Spectral (CWT) Since not everyone has an inherent musical ear, various hardware-enhanced means of tuning in CW signals have been developed. The simplest method is to just narrow your receiver passband so much that, if you can hear a station calling CQ at all, you're guaranteed to be "right on top of him." This assumes that your transceiver enforces alignment between its transmit and receive pitch...true of all Elecraft gear. Narrow filtering has gone through decades of evolution. Some filters were based on op-amps (active filters), while others were based on LC filtering, conscripting humongous toroidal cores scavenged from telco equipment. I acquired my stash of these from a haphazard mound of old switching racks, decaying in an abandoned aircraft hanger on the Bermuda U.S. Navy base. (That irresistible junk pile was also a mother load of TO5 transistors, multi-pound electrolytic capacitors, and tetanus, but that's another story.) Typically the toroids were 88 millihenries -- a huge value for a high-Q inductor, permitting resonance in the low audio range. Later, such filters migrated to digital signal processing, in the form of switched-capacitor ICs or DSPs. You can still buy these switched-capacitor chips, like the MF10, from various sources. It's instructive to roll your own tunable filter, just for fun. Whether passive or active, the goal of filtering is typically to achieve a narrow passband, say 250 Hz or less. With DSP, nearly perfect filters with "brick wall" passbands can be created. But these have the disadvantage of ringing like a bell when pinged by a CW signal or noise, making copy difficult. One solution incorporated into the K-line and KX
Re: [Elecraft] Auto-spot, tuning aids, and the arcane history of CW pitch-matching
Back in my college days at W9YT, we had a Drake line, separate transmitter and receivers. When searching and pouncing in a contest, you had to spot the transmitter before every contact. Spotting required turning one of the rotary switches on the transmitter, a cumbersome process. Imagine doing that a couple thousand times in a weekend. At some point, we came up with the idea to hook a foot switch up to do the spotting, which made it much easier, and save a lot of wear and tear on the rotary switch, not to mention the operator's wrist. In those days, 40-50 years ago, transceivers just didn't work well on CW, so almost all CW operators used separate transmitters and receivers. Some, like the Drake line, could transceive, but had the same problem on CW. Transceivers didn't account for the BFO offset, and there was no RIT or XIT. If you called another station in transceive mode, you would be 700 Hz or so off frequency. Two transceivers pretty much couldn't work each other at all. Sometime while I was inactive in the late 70's and 80's, that problem was solved, and we no longer had to spot before every contact. I think that solution had to wait for frequency synthesis, as it otherwise would have required additional (expensive) crystals. Does anyone know of a non-synthesized transceiver that didn't have the CW offset problem? 73, Scott K9MA On 1/21/2019 23:09, Wayne Burdick wrote: Elecraft's auto-spot and CWT features -- available on the K3/K3S/KX2/KX3 -- are very useful tools for CW operators, especially those not experienced in pitch-matching. Here's a bit of history on where these features came from and how they work. -- Scott K9MA k...@sdellington.us __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Auto-spot, tuning aids, and the arcane history of CW pitch-matching
On 1/22/2019 10:59, David Gilbert wrote: Wayne, you forgot clicking on the DX Cluster spot. ;) Everyone zero beat was, I think, a bigger problem before skimmers. Skimmer spots often seem to be quite a ways off frequency, probably because their SDR receivers aren't all that stable. Some may be in unheated buildings, too. 73, Scott K9MA -- Scott K9MA k...@sdellington.us __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Auto-spot, tuning aids, and the arcane history of CW pitch-matching
The transceive problem didn't seem to exist on any older non-synthesized transceiver that I have used, including FT-101 series, TS-520/820 and later, KW Electronics KW-2000E. these were all '70s era transceivers. -- 73 Chris Cox, N0UK, G4JEC chr...@chris.org __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Auto-spot, tuning aids, and the arcane history of CW pitch-matching
-- 73 Chris Cox, N0UK, G4JEC chr...@chris.org On Tue, 22 Jan 2019, K9MA wrote: > transmitter before every contact. Spotting required turning one of the rotary > switches on the transmitter, a cumbersome process. Imagine doing that a couple > thousand times in a weekend. At some point, we came up with the idea to hook a > foot switch up to do the spotting, which made it much easier, and save a lot > of wear and tear on the rotary switch, not to mention the operator's wrist. > > In those days, 40-50 years ago, transceivers just didn't work well on CW, so > almost all CW operators used separate transmitters and receivers. Some, like > the Drake line, could transceive, but had the same problem on CW. Transceivers > didn't account for the BFO offset, and there was no RIT or XIT. If you called > another station in transceive mode, you would be 700 Hz or so off frequency. > Two transceivers pretty much couldn't work each other at all. Sometime while I > was inactive in the late 70's and 80's, that problem was solved, and we no > longer had to spot before every contact. I think that solution had to wait for > frequency synthesis, as it otherwise would have required additional > (expensive) crystals. Does anyone know of a non-synthesized transceiver that > didn't have the CW offset problem? > > 73, > Scott K9MA > > > On 1/21/2019 23:09, Wayne Burdick wrote: > > Elecraft's auto-spot and CWT features -- available on the K3/K3S/KX2/KX3 -- > > are very useful tools for CW operators, especially those not experienced in > > pitch-matching. Here's a bit of history on where these features came from > > and how they work. > > > -- > Scott K9MA > > k...@sdellington.us > > __ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to chr...@chris.org > __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Auto-spot, tuning aids, and the arcane history of CW pitch-matching
Another trick which works well. Tune to a WWV frequency in CW mode. Press SPOT and the radio will jump on the exact carrier frequency. The SPOT function can pull on to the WWV frequency as far away as about 100 Hz. Once the radio has resolved SPOT, the readout / display is the frequency of WWV +/- the error in Hz. Thus the readout of 9.999.992 is indicating being 8 Hz low. From a cold start, FP being 19°C, I find -8 Hz error on 10 MHz WWV. After about 15 minutes the FP is 25°C and the error is -1 Hz. I've tweaked the REF CAL such that after 1/2 hr. in receive tuning to WWV from both higher and lower will produce a reading of 10.000.000. Will all stations pse QNZ QNN. 73 Bob, K4TAX __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Auto-spot, tuning aids, and the arcane history of CW pitch-matching
In that era, SSB capable transceivers often offset the BFO by using a different BFO crystal for CW transmit or CW receive - but that technique slaved you to one sideband and one CW pitch. There were other ways of doing the offset as well, but it was usually done by shifting the BFO frequency. 73, Don W3FPR On 1/22/2019 1:54 PM, Chris Cox, N0UK wrote: The transceive problem didn't seem to exist on any older non-synthesized transceiver that I have used, including FT-101 series, TS-520/820 and later, KW Electronics KW-2000E. these were all '70s era transceivers. -- 73 Chris Cox, N0UK, G4JEC chr...@chris.org __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to donw...@embarqmail.com __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Auto-spot, tuning aids, and the arcane history of CW pitch-matching
Re: "Does anyone know of a non-synthesized transceiver that didn't have the CW offset problem?" My TenTec 540 doesn't have that problem, but my much older TenTec PM-3A does. If my memory is correct, the Heathkit HW8 has the problem, but they fixed it in the HW9 with a small capacitor that switches in and out for RX/TX to shift the VFO. There are others. Mark KE6BB Sent via the Samsung Galaxy Tab E, an AT&T 4G LTE tablet Original message From: K9MA Date: 1/22/19 9:11 AM (GMT-08:00) To: elecraft@mailman.qth.net Subject: Re: [Elecraft] Auto-spot, tuning aids, and the arcane history of CW pitch-matching Back in my college days at W9YT, we had a Drake line, separate transmitter and receivers. When searching and pouncing in a contest, you had to spot the transmitter before every contact. Spotting required turning one of the rotary switches on the transmitter, a cumbersome process. Imagine doing that a couple thousand times in a weekend. At some point, we came up with the idea to hook a foot switch up to do the spotting, which made it much easier, and save a lot of wear and tear on the rotary switch, not to mention the operator's wrist. In those days, 40-50 years ago, transceivers just didn't work well on CW, so almost all CW operators used separate transmitters and receivers. Some, like the Drake line, could transceive, but had the same problem on CW. Transceivers didn't account for the BFO offset, and there was no RIT or XIT. If you called another station in transceive mode, you would be 700 Hz or so off frequency. Two transceivers pretty much couldn't work each other at all. Sometime while I was inactive in the late 70's and 80's, that problem was solved, and we no longer had to spot before every contact. I think that solution had to wait for frequency synthesis, as it otherwise would have required additional (expensive) crystals. Does anyone know of a non-synthesized transceiver that didn't have the CW offset problem? 73, Scott K9MA On 1/21/2019 23:09, Wayne Burdick wrote: > Elecraft's auto-spot and CWT features -- available on the K3/K3S/KX2/KX3 -- > are very useful tools for CW operators, especially those not experienced in > pitch-matching. Here's a bit of history on where these features came from and > how they work. -- Scott K9MA k...@sdellington.us __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to rv6am...@yahoo.com __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Auto-spot, tuning aids, and the arcane history of CW pitch-matching
When I upgraded from my K3 to a K3s, I took the opportunity to order a 10 MHz Ref In option. I finally got around to hooking it up to a Leo Bodnar GPS receiver I picked up at Dayton a year ago, and now the K3s is rock solid spot on frequency. Don't know how i did without it all these years... 73, -- Dave, N8SBE Original Message Subject: Re: [Elecraft] Auto-spot, tuning aids, and the arcane history of CW pitch-matching From: Bob McGraw K4TAX Date: Tue, January 22, 2019 3:14 pm To: elecraft@mailman.qth.net Another trick which works well. Tune to a WWV frequency in CW mode. Press SPOT and the radio will jump on the exact carrier frequency. The SPOT function can pull on to the WWV frequency as far away as about 100 Hz. Once the radio has resolved SPOT, the readout / display is the frequency of WWV +/- the error in Hz. Thus the readout of 9.999.992 is indicating being 8 Hz low. From a cold start, FP being 19°C, I find -8 Hz error on 10 MHz WWV. After about 15 minutes the FP is 25°C and the error is -1 Hz. I've tweaked the REF CAL such that after 1/2 hr. in receive tuning to WWV from both higher and lower will produce a reading of 10.000.000. Will all stations pse QNZ QNN. 73 Bob, K4TAX __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Auto-spot, tuning aids, and the arcane history of CW pitch-matching
I'm a great fan of using the auto-spot feature, and love to show it off to all shack visitors, as an example of yet another reason they need to upgrade to Elecraft, from whatever boat anchor they are still using... 73, -- Dave, N8SBE __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Auto-spot, tuning aids, and the arcane history of CW pitch-matching
Are you serious? Wes N7WS On 1/22/2019 1:45 PM, Dave New, N8SBE wrote: Don't know how i did without it all these years... 73, -- Dave, N8SBE __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Auto-spot, tuning aids, and the arcane history of CW pitch-matching
Hi all, Agreed; the problem can easily be solved in analog radios without frequency synthesis by offsetting the BFO frequency by those 700Hz or so in transmit. In down conversion machines with a single IF in the 8-9MHz range that could easily be done by pulling the BFO crystal. The Drake TR4 undoubtedly worked this way. I bought my first transceiver in 1969 (I think), a Yaesu FT-200, I think it was called in the US. In Europe it was sold as Sommerkamp FT-250. As the Drake TR4 it was down conversion with a single 9MHz IF and worked CW by pulling the BFO crystal into the passband of the 9MHz crystal filter on transmit. Another technical solution, which was used in the Collins KWM2 (and probably KWM1) was to keep the balanced (de)modulator balanced and inject an audio tone into it on transmit. Clearly the spectral purity of the CW signal would be less than ideal in this case, but I am not sure if FCC type approval was needed in those days. Nor am I sure what the the FCC spec for "inband" (read close in) spurs would be. AB2TC - Knut n0uk wrote > The transceive problem didn't seem to exist on any older non-synthesized > transceiver that I have used, including FT-101 series, TS-520/820 and > later, KW Electronics KW-2000E. these were all '70s era transceivers. > > > > -- > 73 Chris Cox, N0UK, G4JEC > chrisc@ > > _ > -- Sent from: http://elecraft.365791.n2.nabble.com/ __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Auto-spot, tuning aids, and the arcane history of CW pitch-matching
On 1/22/2019 14:14, Bob McGraw K4TAX wrote: Another trick which works well. Tune to a WWV frequency in CW mode. Press SPOT and the radio will jump on the exact carrier frequency. You can do the same thing, of course, by listening to the beat between the sidetone and the carrier. I was able to get 3 Hz closer that way, within the 1 Hz tuning resolution. 3 Hz is close enough, though. When listening for the beats, you have to match the volume of the sidetone and carrier, or you won't hear them. You don't need a musical ear, just a functioning one. 73, Scott K9MA -- Scott K9MA k...@sdellington.us __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Auto-spot, tuning aids, and the arcane history of CW pitch-matching
For N1MM, use the up and down arrow keys to get close in S&P operation and then
press F11 to zero beat -
F11 Z B,{CATA1ASC SWT42;}
If it is a dense pile, a little XIT offset is a big help.
73,
Bob R
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Re: [Elecraft] Auto-spot, tuning aids, and the arcane history of CW pitch-matching
I must admit, most of my CW tuning is done with the P3/SVGA and getting the pitch "right" in my earphones. (With RTTY, I can get very close to the correct pitch by ear. Then I used the crossed loop tuning aid for the final few Hz.) 73 Bill AE6JV --- Bill Frantz| "I wish there was a knob on the TV to turn up the 408-356-8506 | intelligence. There's a knob called "brightness", but www.pwpconsult.com | it doesn't work. -- Gallagher __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Auto-spot, tuning aids, and the arcane history of CW pitch-matching
Thanks, Wayne! This is one of the best entries into these threads I’ve ever read. And, yes, I've experimented with Auto Spot in CWT mode. And: > “the Audio Peaking Filter (APF), …provides a 30-Hz bandwidth at -3 dB, but broad skirts, preventing ringing from occurring. As our customers will attest, APF works like magic on weak signals obscured by noise…” To which I also attest! ^_^ And, the VFO and IF passband tracking exactly on the user setable CW sidetone (A 440, in my case) is one of the main things which made me fall in love with Elecraft. 72 de KX2CW .. ~Joan Darmok and Jalad at Tanagra, said Piglet. Shaka, when the walls fell, said Pooh. > On Jan 21, 2019, at 21:09, Wayne Burdick wrote: > > Elecraft's auto-spot and CWT features -- available on the K3/K3S/KX2/KX3 -- > are very useful tools for CW operators, especially those not experienced in > pitch-matching. Here's a bit of history on where these features came from and > how they work. > > > CW Spotting History > > When a station finishes a CQ in CW mode, the operator faces the challenge of > copying someone who's calling back. Callers may be weak or obscured by QRM; > the op can usually deal with both problems by narrowing the filter passband. > However, callers may also be off frequency. A calling station may be using a > wide filter passband themselves, not attempting to carefully match their VFO > frequency to that of the CQing station. The result may be no QSO, even when > propagation is excellent. > > In the Days of Yore, a frequency offset between stations didn't always > matter. Sometimes both stations used crystal-controlled transmitters, so > operators had to patient tune around after calling CQ. > > As a 14-year-old novice I embraced this operating style for a year or so, > armed with a dozen or so crusty FT-243 crystals for my Heath HW-16. I nearly > wore out the socket swapping them in and out. After calling CQ, it was not > unusual to find a caller 30 or more kHz away! (Away from "where" was a poorly > answered question, as my Hallicrafters receiver dial wasn't exactly digital.) > > Fortunately I soon acquired an outboard VFO, a life-changing addition to my > station. Jealous friends doubled up on their paper routes to pay for their > own. Girls suddenly paid more attention to me. > > These days virtually everyone has a VFO, along with the expectation that they > won't have to tune theirs very far, if at all, to tune you in. Not only that, > they're stable and well calibrated, not like the beasts we had to skillfully > tame. Progress! > > > Manual Spotting (SPOT switch) > > Once I had a VFO I quickly learned to do *manual* pitch matching. Older rigs > did't provide a way to do that explicitly, so you'd improvise. Basically, you > had to coerce a very weak signal out of your own transmitter, say by turning > on only the driver, then tune the transmit VFO until you could hear your > signal on your own receiver -- superimposed on the calling station, at the > same pitch. This is what we call spotting. > > Of course spotting is a lot more convenient these days, as many rigs include > a SPOT switch. This function is easy for a modern transceiver designer to > add, because the radio's firmware is quite capable of turning on only the CW > sidetone without transmitting. > > That is the purpose of the SPOT switch on all Elecraft transceivers. Tap > SPOT, and you'll hear your sidetone pitch. Most people can do a good job of > adjusting the VFO such that the CQing station's pitch matches that of the > SPOT tone. This ensures that when you call them, you'll be close to their own > frequency. > > > Tuning Aids: Filtering (APF), PLL (NE567), and Spectral (CWT) > > Since not everyone has an inherent musical ear, various hardware-enhanced > means of tuning in CW signals have been developed. > > The simplest method is to just narrow your receiver passband so much that, if > you can hear a station calling CQ at all, you're guaranteed to be "right on > top of him." This assumes that your transceiver enforces alignment between > its transmit and receive pitch...true of all Elecraft gear. > > Narrow filtering has gone through decades of evolution. Some filters were > based on op-amps (active filters), while others were based on LC filtering, > conscripting humongous toroidal cores scavenged from telco equipment. I > acquired my stash of these from a haphazard mound of old switching racks, > decaying in an abandoned aircraft hanger on the Bermuda U.S. Navy base. (That > irresistible junk pile was also a mother load of TO5 transistors, multi-pound > electrolytic capacitors, and tetanus, but that's another story.) Typically > the toroids were 88 millihenries -- a huge value for a high-Q inductor, > permitting resonance in the low audio range. > > Later, such filters migrated to digital signal processing, in the form of > switched-capacitor ICs or DSPs. You can still buy the
Re: [Elecraft] Auto-spot, tuning aids, and the arcane history of CW pitch-matching
> Are you serious? > Wes N7WS Wes, Yes. I'm a stickler for accuracy. It always bothered me that the so-called 'temperature compensated' LO in the K3 was not actively being steered by temperature compensation (i.e. I could only put static temperature offsets into the rig memory from the data sheet that came with the oscillator). That was a 'feature' that was never released. At HF frequencies, it was only an annoyance, but using UHF transverters, the error compounds (I'm using a crystal oven in my UHF transverter, but the lack of one in the K3 caused drifting). I use a Citizen watch with WWVB reception, so the time on my wrist is never more than 50 ms off. Anally yours, -- Dave, N8SBE On 1/22/2019 1:45 PM, Dave New, N8SBE wrote: > Don't know how i did without it all these years... > > 73, > > -- Dave, N8SBE > __ __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Auto-spot, tuning aids, and the arcane history of CW pitch-matching
You should be subscribed to Timenuts. But clearly one of us is confused. If you're using an OCXO in your transverter and up converting the K3, how does K3 drift/inaccuracy "compound" at UHF? Can you read that watch to 50 ms? What are you going to do when WWVB goes QRT? Wes N7WS On 1/23/2019 12:26 PM, Dave New, N8SBE wrote: Wes, Yes. I'm a stickler for accuracy. It always bothered me that the so-called 'temperature compensated' LO in the K3 was not actively being steered by temperature compensation (i.e. I could only put static temperature offsets into the rig memory from the data sheet that came with the oscillator). That was a 'feature' that was never released. At HF frequencies, it was only an annoyance, but using UHF transverters, the error compounds (I'm using a crystal oven in my UHF transverter, but the lack of one in the K3 caused drifting). I use a Citizen watch with WWVB reception, so the time on my wrist is never more than 50 ms off. Anally yours, -- Dave, N8SBE __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Auto-spot, tuning aids, and the arcane history of CW pitch-matching
Dave, Put the external reference oscillator input option on your K3 and avoid that situation with an external 10 MHz reference oscillator. The K3 Reference Oscillator temperature steering is from the static temperature offsets. If you have equipment to do better than the Data Sheet, you can determine your own values, but for those without that equipment, the data sheet provides a good index for various temperatures. 73, Don W3FPR Yes. I'm a stickler for accuracy. It always bothered me that the so-called 'temperature compensated' LO in the K3 was not actively being steered by temperature compensation (i.e. I could only put static temperature offsets into the rig memory from the data sheet that came with the oscillator). That was a 'feature' that was never released. At HF frequencies, it was only an annoyance, but using UHF transverters, the error compounds (I'm using a crystal oven in my UHF transverter, but the lack of one in the K3 caused drifting). __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Auto-spot, tuning aids, and the arcane history of CW pitch-matching
Hi, It doesn't "compound". A 10Hz drift at the antenna output of the K3, will be reflected as a 10Hz drift at the output of any transverter, be it VHF, UHF or microwave. At the higher frequencies even a transverter with an OCXO its drift would probably dominate. AB2TC - Knut Wes Stewart-2 wrote > You should be subscribed to Timenuts. > > But clearly one of us is confused. If you're using an OCXO in your > transverter > and up converting the K3, how does K3 drift/inaccuracy "compound" at UHF? > > Can you read that watch to 50 ms? What are you going to do when WWVB goes > QRT? > > Wes N7WS > > On 1/23/2019 12:26 PM, Dave New, N8SBE wrote: >> >> Wes, >> >> Yes. I'm a stickler for accuracy. It always bothered me that the > -- Sent from: http://elecraft.365791.n2.nabble.com/ __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Auto-spot, tuning aids, and the arcane history of CW pitch-matching
I've never had a drift issue with any of my modern transceivers on 28MHz as the IF. Now the TCXO drift in the transverters is real issue. Bob, K4TAX Sent from my iPhone > On Jan 23, 2019, at 7:08 PM, ab2tc wrote: > > Hi, > > It doesn't "compound". A 10Hz drift at the antenna output of the K3, will be > reflected as a 10Hz drift at the output of any transverter, be it VHF, UHF > or microwave. At the higher frequencies even a transverter with an OCXO its > drift would probably dominate. > > AB2TC - Knut > > > Wes Stewart-2 wrote >> You should be subscribed to Timenuts. >> >> But clearly one of us is confused. If you're using an OCXO in your >> transverter >> and up converting the K3, how does K3 drift/inaccuracy "compound" at UHF? >> >> Can you read that watch to 50 ms? What are you going to do when WWVB goes >> QRT? >> >> Wes N7WS >> >>> On 1/23/2019 12:26 PM, Dave New, N8SBE wrote: >>> >>> Wes, >>> >>> Yes. I'm a stickler for accuracy. It always bothered me that the >> > > > > > > -- > Sent from: http://elecraft.365791.n2.nabble.com/ > __ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to rmcg...@blomand.net __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Auto-spot, tuning aids, and the arcane history of CW pitch-matching
Of course I know that. Mine was a rhetorical question. On 1/23/2019 6:08 PM, ab2tc wrote: Hi, It doesn't "compound". A 10Hz drift at the antenna output of the K3, will be reflected as a 10Hz drift at the output of any transverter, be it VHF, UHF or microwave. At the higher frequencies even a transverter with an OCXO its drift would probably dominate. AB2TC - Knut Wes Stewart-2 wrote You should be subscribed to Timenuts. But clearly one of us is confused. If you're using an OCXO in your transverter and up converting the K3, how does K3 drift/inaccuracy "compound" at UHF? Can you read that watch to 50 ms? What are you going to do when WWVB goes QRT? Wes N7WS On 1/23/2019 12:26 PM, Dave New, N8SBE wrote: Wes, Yes. I'm a stickler for accuracy. It always bothered me that the -- Sent from: http://elecraft.365791.n2.nabble.com/ __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to wes_n...@triconet.org __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Auto-spot, tuning aids, and the arcane history of CW pitch-matching
Dave, Pretty much no-issue if using the transverter interface at mw level as that causes no heating in transmit. TCXO-3 plus EXREF keeps 28 MHz within 2-Hz* and that is additive to transverter freq error not multiplicative. Xtal LO in UHF transverters are typically multiplied so using good temp practises or locking with a PLL are helpful. My 432 and 1296 transverters are locked to 10-MHz reference and K3 has EXREF so total drift is < +/- 2 Hz on 432 and 1296. If your K3 has the TCXO-1 with 5ppm then you may see freq offsets as high as 5*28 = 140 Hz. With TCXO-3 1ppm is 28 Hz and EXREF is 0.1ppm or 2.8 Hz. Actually the TCXO-3 runs nearer to 0.5ppm without reference correction. * http://www.kl7uw.com/K3EXREF.htm 73, Ed - KL7UW --- Yes. I'm a stickler for accuracy. It always bothered me that the so-called 'temperature compensated' LO in the K3 was not actively being steered by temperature compensation (i.e. I could only put static temperature offsets into the rig memory from the data sheet that came with the oscillator). That was a 'feature' that was never released. At HF frequencies, it was only an annoyance, but using UHF transverters, the error compounds (I'm using a crystal oven in my UHF transverter, but the lack of one in the K3 caused drifting). I use a Citizen watch with WWVB reception, so the time on my wrist is never more than 50 ms off. Anally yours, -- Dave, N8SBE 73, Ed - KL7UW http://www.kl7uw.com Dubus-NA Business mail: dubus...@gmail.com __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Auto-spot, tuning aids, and the arcane history of CW pitch-matching
Don, Ed, Wes, et al, Thanks, guys, I misspoke. I was thinking of the old multiplicative CW-only designs that have been floating around, but of course, the Elecraft ones don't do that. My bad. Yes, it would be nice to sync the Elecraft transverters to a 10 MHz signal. Which ones do you guys have that have a PLL-locked 10 MHz ref in? Don, I do have the TCXO-3 and also the XREF in my K3S. It works very nice with my Leo Bodnar GPS 10 MHz frequency source. 73, -- Dave, N8SBE __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
