Re: [Elecraft] CW rise time mod topic
Hi everyone: I have Thunderbird check for the magic characters K3 in the subject. When they are found, those emails are put into a separate folder. Not owning a K3, that makes it easier for me to quickly scan through topics that probably aren't of interest to me. Some folks don't bother to put K3 in the subject, although the topic refers to some aspect of that radio. That's OK. I'm not complaining about that. However, when people start talking about radio mods, it seems imperative to me that they mention somewhere, preferably in the subject line, which radio they are referring to. In this case, there are CW mods for both the K2 and K3 (and probably K1 and KX1 as well). This was not meant to be a criticism. It's just a suggestion to possibly prevent unnecessary confusion. 73's, John AA0VE ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] CW rise time mod topic
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 I agree John. The list moderators have asked, on several occasions, for people to put the model of elecraft product in the subject line. It was suggested that doing this would allow people to use the filtering capabilities of their mail clients to sort through all the mail and stick it in the right spots. It was also one of the excuses put forward to keep Elecraft from having forums where it's pretty simple to stick your message in the right spot. Got a K3 question, stick it in the K3 forum, Couldn't care less about the K3, don't read the K3 forum. How hard it it to put K3, K2, K1, KX1 in the subject line? My six year old granddaughter can do it. John R. Lonigro wrote: | Hi everyone: | I have Thunderbird check for the magic characters K3 in the subject. | When they are found, those emails are put into a separate folder. Not | owning a K3, that makes it easier for me to quickly scan through topics | that probably aren't of interest to me. Some folks don't bother to put | K3 in the subject, although the topic refers to some aspect of that | radio. That's OK. I'm not complaining about that. However, when | people start talking about radio mods, it seems imperative to me that | they mention somewhere, preferably in the subject line, which radio they | are referring to. In this case, there are CW mods for both the K2 and | K3 (and probably K1 and KX1 as well). | | This was not meant to be a criticism. It's just a suggestion to | possibly prevent unnecessary confusion. | | 73's, | John AA0VE - -- R. Kevin Stover, ACØH -BEGIN PGP SIGNATURE- Version: GnuPG v1.4.7 (MingW32) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iD8DBQFH8ihG11jxjloa2wsRAqBYAKC9gZ8xoULyy4ChO8K4U8R7+TKgywCeKf96 hdoh0Ab5PmArSy8i6L+T9lA= =0+jA -END PGP SIGNATURE- ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
RE: [Elecraft] CW rise time mod
While the impact on a receiver might cause clicks to be heard, that's a failing of the receiver, not the transmitter. The real issue about the CW keying waveform is the production of sidebands around the CW signal at the transmitter. All amplitude-modulated signals, which CW is one type, have sidebands. The only way to prevent them entirely is to not modulate the signal. Since the rate of the modulation is much less with CW than it is with a spectrum of voice covering, say, 300 to 3000 Hz, the sidebands produced by CW keying are much, much smaller than those produced by voice modulation. But that doesn't mean the sidebands produced by CW keying can be ignored, especially in today's world of very selective receivers that allow signals to be much closer to each other than in the past. Without the sidebands, the CW would be unreadable. It's a question of how wide the sidebands must be and how the energy is distributed in them to produce an easy-to-copy signal that is not wider than necessary. Easy-to-copy is a value judgment. There are no absolute values. Exotic computer-controlled keying circuits with linear RF amplifiers have given designers the ability to control the keying waveform and the energy distribution in the sidebands to a degree never contemplated only a few years ago. But the underlying question is unchanged: what is the best tradeoff between bandwidth and readability of a CW signal? It's still a judgment call. Ron AC7AC -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED] Sent: Monday, March 31, 2008 9:16 PM To: [EMAIL PROTECTED]; elecraft@mailman.qth.net Subject: Re: [Elecraft] CW rise time mod It's not that 3ms is a lot of time in terms of human scale. But, it is the rise time of an electronic pulse. This can have a lot of impact on the transient waveform that results in an audio demodulator - i.e. receiver. The difference is noticeable enough to make the difference in a crowded band weak signal situation when the receiving station is differentiating what he hears. That's why a banjo sounds different than a guitar or violin. Al WA6VNN + In a message dated 3/29/2008 5:34:22 P.M. Pacific Daylight Time, [EMAIL PROTECTED] writes: People, 8 ms.- 5 ms.= 3 ms., does it matter in any practical sense? I would really like to know who cares, and why? Can anyone hear the difference? Three-thousanths of a second? Not my old brain. 73, John, W2GW K3 #384 - Original Message - From: Lyle Johnson [EMAIL PROTECTED] To: Elecraft Reflector elecraft@mailman.qth.net Sent: Saturday, March 29, 2008 5:21 PM Subject: Re: [Elecraft] CW rise time mod Or do Rev A RF boards have a lower value for C222 than that shown on the schematic? Early production K3 RF boards have a 1 uF capacitor instead of a 0.1 uF capacitor installed at C222. Yes, the published schematics show a 0.1 uF capacitor. The effect of the larger capacitor is to increase the TX waveform rise time to about 8 ms instead of 5 ms. Rev B RF boards have the correct 0.1 uF value installed. Sometime during Rev A RF board production, the value installed on the board was changed from 1 uF to 0.1 uF. Surface mount ceramic capacitors are not marked with a value, so you cannot tell which you have by visual inspection. You can determine if you have a 1 uF rather than a 0.1 uF by: 1) Measuring the capacitance if you have a capacitance meter. 2) Looking at the Tx output RF envelope on an oscilloscope or station monitor scope. If the fall time and the rise time look very similar in duration, you have the 0.1 uF cap. If the rise time is about 50% longer than the fall time, you have the 1 uF capacitor. You don't need an oscilloscope with an accurate time base to make this comparative measurement. If your oscilloscope has a low bandwidth (2 to 10 MHz), use the 160 meter band. 3) If you are concerned that your unit may have the 1 uF capacitor and you have no way to determine it otherwise, you can just replace it with the 0.1 uF part and sleep better at night :-) If you don't change it, you will not damage anything. Your K3 will just have slightly softer keying and an upcoming firmware adjustment of the keying time will be less accurate. 73, Lyle KK7P ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub
Re: [Elecraft] CW rise time mod
It's not that 3ms is a lot of time in terms of human scale. But, it is the rise time of an electronic pulse. This can have a lot of impact on the transient waveform that results in an audio demodulator - i.e. receiver. The difference is noticeable enough to make the difference in a crowded band weak signal situation when the receiving station is differentiating what he hears. That's why a banjo sounds different than a guitar or violin. Al WA6VNN + In a message dated 3/29/2008 5:34:22 P.M. Pacific Daylight Time, [EMAIL PROTECTED] writes: People, 8 ms.- 5 ms.= 3 ms., does it matter in any practical sense? I would really like to know who cares, and why? Can anyone hear the difference? Three-thousanths of a second? Not my old brain. 73, John, W2GW K3 #384 - Original Message - From: Lyle Johnson [EMAIL PROTECTED] To: Elecraft Reflector elecraft@mailman.qth.net Sent: Saturday, March 29, 2008 5:21 PM Subject: Re: [Elecraft] CW rise time mod Or do Rev A RF boards have a lower value for C222 than that shown on the schematic? Early production K3 RF boards have a 1 uF capacitor instead of a 0.1 uF capacitor installed at C222. Yes, the published schematics show a 0.1 uF capacitor. The effect of the larger capacitor is to increase the TX waveform rise time to about 8 ms instead of 5 ms. Rev B RF boards have the correct 0.1 uF value installed. Sometime during Rev A RF board production, the value installed on the board was changed from 1 uF to 0.1 uF. Surface mount ceramic capacitors are not marked with a value, so you cannot tell which you have by visual inspection. You can determine if you have a 1 uF rather than a 0.1 uF by: 1) Measuring the capacitance if you have a capacitance meter. 2) Looking at the Tx output RF envelope on an oscilloscope or station monitor scope. If the fall time and the rise time look very similar in duration, you have the 0.1 uF cap. If the rise time is about 50% longer than the fall time, you have the 1 uF capacitor. You don't need an oscilloscope with an accurate time base to make this comparative measurement. If your oscilloscope has a low bandwidth (2 to 10 MHz), use the 160 meter band. 3) If you are concerned that your unit may have the 1 uF capacitor and you have no way to determine it otherwise, you can just replace it with the 0.1 uF part and sleep better at night :-) If you don't change it, you will not damage anything. Your K3 will just have slightly softer keying and an upcoming firmware adjustment of the keying time will be less accurate. 73, Lyle KK7P ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com **Create a Home Theater Like the Pros. Watch the video on AOL Home. (http://home.aol.com/diy/home-improvement-eric-stromer?video=15ncid=aolhom000301) ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] CW rise time mod
Hi David: I measured C222 *in place* with my aade cap checker and it measured ~1 uF(actually 0.965 uF)... not the 0.1 in the schematic. I'm guessing that the schematic available for download is not current with production. Someone else here mentioned that C222 was 1 uF, but I don't remember who it was. 73, Ken K3IU David Pratt wrote: Elecraft says. Some owners prefer a faster CW keying waveform rise time. The rise time can be reduced from about 8 milliseconds to 5 milliseconds without affecting the fall time by replacing capacitor C222 on the K3 main RF board with a 0.1 uF capacitor. This change will also allow a future firmware revision to further reduce rise time via a menu entry. But the schematics of the RF Board Rev. A4 (Sheet 3 of 4), dated 9/19/07, show C222 as being 0.1 already. The instructions recommend removing the existing 0.1 and replacing it with another 0.1 !! Surely to reduce the rise time the existing capacitor should be shunted with another one. Or do Rev A RF boards have a lower value for C222 than that shown on the schematic? 73 ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] CW rise time mod
In a recent message, Ken Wagner [EMAIL PROTECTED] writes I measured C222 *in place* with my aade cap checker and it measured ~1 uF(actually 0.965 uF)... not the 0.1 in the schematic. I'm guessing that the schematic available for download is not current with production. Someone else here mentioned that C222 was 1 uF, but I don't remember who it was. Thanks Ken, and Dave G4AON, it looks as though a batch of RF boards were fitted with the wrong value of C222 SMD. Perhaps we should all measure C222 before changing the capacitor. 73 -- David G4DMP Leeds, England, UK ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] CW rise time mod
That was me .. My actual measurement was 0.985 microfarad when I checked the RF board in S/N 195 I rounded it up to 1 microfarad in my earlier report. Don K7FJ Someone else here mentioned that C222 was 1 uF, but I don't remember who it was. 73, Ken K3IU ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] CW rise time mod
Or do Rev A RF boards have a lower value for C222 than that shown on the schematic? Early production K3 RF boards have a 1 uF capacitor instead of a 0.1 uF capacitor installed at C222. Yes, the published schematics show a 0.1 uF capacitor. The effect of the larger capacitor is to increase the TX waveform rise time to about 8 ms instead of 5 ms. Rev B RF boards have the correct 0.1 uF value installed. Sometime during Rev A RF board production, the value installed on the board was changed from 1 uF to 0.1 uF. Surface mount ceramic capacitors are not marked with a value, so you cannot tell which you have by visual inspection. You can determine if you have a 1 uF rather than a 0.1 uF by: 1) Measuring the capacitance if you have a capacitance meter. 2) Looking at the Tx output RF envelope on an oscilloscope or station monitor scope. If the fall time and the rise time look very similar in duration, you have the 0.1 uF cap. If the rise time is about 50% longer than the fall time, you have the 1 uF capacitor. You don't need an oscilloscope with an accurate time base to make this comparative measurement. If your oscilloscope has a low bandwidth (2 to 10 MHz), use the 160 meter band. 3) If you are concerned that your unit may have the 1 uF capacitor and you have no way to determine it otherwise, you can just replace it with the 0.1 uF part and sleep better at night :-) If you don't change it, you will not damage anything. Your K3 will just have slightly softer keying and an upcoming firmware adjustment of the keying time will be less accurate. 73, Lyle KK7P ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] CW rise time mod
I guess I didn't say... my K3 is #202 73, Ken KIU Don Ehrlich wrote: That was me .. My actual measurement was 0.985 microfarad when I checked the RF board in S/N 195 I rounded it up to 1 microfarad in my earlier report. Don K7FJ Someone else here mentioned that C222 was 1 uF, but I don't remember who it was. 73, Ken K3IU ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
RE: [Elecraft] CW rise time mod
Hi, David: The original value for C222 was 0.01 uF. Wayne asked that it be changed to 0.1 uFd. I wasn't privy to the source of the comment that the rise time might be further shortened in firmware. If Wayne plans to control the keying in firmware, it's probably important that all the hardware be consistent with a 0.1uFd cap at C222 so the firmware works as planned. Ron AC7AC -Original Message- Elecraft says. Some owners prefer a faster CW keying waveform rise time. The rise time can be reduced from about 8 milliseconds to 5 milliseconds without affecting the fall time by replacing capacitor C222 on the K3 main RF board with a 0.1 uF capacitor. This change will also allow a future firmware revision to further reduce rise time via a menu entry. But the schematics of the RF Board Rev. A4 (Sheet 3 of 4), dated 9/19/07, show C222 as being 0.1 already. The instructions recommend removing the existing 0.1 and replacing it with another 0.1 !! Surely to reduce the rise time the existing capacitor should be shunted with another one. Or do Rev A RF boards have a lower value for C222 than that shown on the schematic? 73 -- David G4DMP Leeds, England, UK ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
RE: [Elecraft] CW rise time mod
Oops, make that originally a 1 uFD cap at C222. Now the recommended value is 0.1 uFd Ron -Original Message- From: Ron D'Eau Claire [mailto:[EMAIL PROTECTED] Sent: Saturday, March 29, 2008 2:26 PM To: 'David Pratt'; 'Elecraft Reflector' Subject: RE: [Elecraft] CW rise time mod Hi, David: The original value for C222 was 0.01 uF. Wayne asked that it be changed to 0.1 uFd. I wasn't privy to the source of the comment that the rise time might be further shortened in firmware. If Wayne plans to control the keying in firmware, it's probably important that all the hardware be consistent with a 0.1uFd cap at C222 so the firmware works as planned. Ron AC7AC ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] CW rise time mod
Measured C222 in my K3 s/n 285 a while back and it is .1uf. 73, Joe W2KJ QRP, therefore I am ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] CW rise time mod
David Pratt wrote: Elecraft says. Some owners prefer a faster CW keying waveform rise time. The rise time can be reduced from about 8 milliseconds to 5 milliseconds without affecting the fall time by replacing capacitor C222 on the K3 main RF board with a 0.1 uF capacitor. This change will also allow a future firmware revision to further reduce rise time via a menu entry. But the schematics of the RF Board Rev. A4 (Sheet 3 of 4), dated 9/19/07, show C222 as being 0.1 already. The instructions recommend removing the existing 0.1 and replacing it with another 0.1 !! Surely to reduce the rise time the existing capacitor should be shunted with another one. Or do Rev A RF boards have a lower value for C222 than that shown on the schematic? As I understand it, Wayne called for the modification earlier, but for some reason it didn't get reflected in production. That's why the schematic doesn't agree. The old value was 1 uf and it the new, correct value is 0.1 uf. -- 73, Vic, K2VCO Fresno CA http://www.qsl.net/k2vco ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] CW rise time mod
People, 8 ms.- 5 ms.= 3 ms., does it matter in any practical sense? I would really like to know who cares, and why? Can anyone hear the difference? Three-thousanths of a second? Not my old brain. 73, John, W2GW K3 #384 - Original Message - From: Lyle Johnson [EMAIL PROTECTED] To: Elecraft Reflector elecraft@mailman.qth.net Sent: Saturday, March 29, 2008 5:21 PM Subject: Re: [Elecraft] CW rise time mod Or do Rev A RF boards have a lower value for C222 than that shown on the schematic? Early production K3 RF boards have a 1 uF capacitor instead of a 0.1 uF capacitor installed at C222. Yes, the published schematics show a 0.1 uF capacitor. The effect of the larger capacitor is to increase the TX waveform rise time to about 8 ms instead of 5 ms. Rev B RF boards have the correct 0.1 uF value installed. Sometime during Rev A RF board production, the value installed on the board was changed from 1 uF to 0.1 uF. Surface mount ceramic capacitors are not marked with a value, so you cannot tell which you have by visual inspection. You can determine if you have a 1 uF rather than a 0.1 uF by: 1) Measuring the capacitance if you have a capacitance meter. 2) Looking at the Tx output RF envelope on an oscilloscope or station monitor scope. If the fall time and the rise time look very similar in duration, you have the 0.1 uF cap. If the rise time is about 50% longer than the fall time, you have the 1 uF capacitor. You don't need an oscilloscope with an accurate time base to make this comparative measurement. If your oscilloscope has a low bandwidth (2 to 10 MHz), use the 160 meter band. 3) If you are concerned that your unit may have the 1 uF capacitor and you have no way to determine it otherwise, you can just replace it with the 0.1 uF part and sleep better at night :-) If you don't change it, you will not damage anything. Your K3 will just have slightly softer keying and an upcoming firmware adjustment of the keying time will be less accurate. 73, Lyle KK7P ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
RE: [Elecraft] CW rise time mod
I certainly did not notice it on K3 S/N 10, nor did anyone I worked on CW. But I seldom operate CW above 25 WPM. IIRC, it was a high speed operator who noticed the 'soft' keying, probably working at rates well above 25 WPM. Still, I made the change because, as the notes on the web page suggest, there will be the ability to adjust the characteristic using the MENU commands in the future. But that firmware will assume a particular hardware configuration, and I wanted my hardware to match what the firmware expects. Ron AC7AC -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of John Reiser Sent: Saturday, March 29, 2008 5:33 PM To: Lyle Johnson; Elecraft Reflector Subject: Re: [Elecraft] CW rise time mod People, 8 ms.- 5 ms.= 3 ms., does it matter in any practical sense? I would really like to know who cares, and why? Can anyone hear the difference? Three-thousanths of a second? Not my old brain. 73, John, W2GW K3 #384 ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
