Re: [Elecraft] Measuring SWR (Long)
For a slightly different answer, take a look at my website www.w3fpr.com article on Antennas, Transmission Lines, and Tuners. You can also find that same article preserved at https://www.qsl.net/w3fpr/ant_article.htm. 73, Don W3FPR On 4/9/2019 8:56 PM, Don Sanders wrote: Since no one has answered your question. I will venture a supposition that many know but few will speak out. And some still remember their CB days and the erroneous advertising saying the power is lost. Reflected Power flows back down the feed line and is subjected to the normal feed line loss. It then is "reflected" back toward the antenna, again subject to the feed line loss, where some of it is radiated and some reflected again. This continues until the power is dissipated. The book "Reflections" has a very good but somewhat technical explanation. Therein also is the reference to forgetting about striving for the "Holy Grail" of 1:1 SWR. And concentrating on getting it low enough that the transmitter will supply full power output. Also using the best low loss feed line and proper matching when possible of the feed line to the antenna. Dr. Don W4BWS God Bless All Ham Radio does not make the world go round. Ham Radio is what makes the ride worthwhile. On Tue, Apr 9, 2019 at 6:43 PM Roy Koeppe wrote: "...Let's allow the reflected power to increase all the way to 10 watts! At that point, your SWR would be about 2 to 1. Sounds pretty bad, but surely if you were stranded in the desert and had to use your KX3 and a wire to get help, you'd be happy to have a match this good...(etc.)" From memory now, at 2 to 1...feedline voltage nodes and current nodes can double -- no small thing when power is 1500 watts; can stress antenna system components. 73, RoyK6XK __ 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 __ 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 __ 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
Re: [Elecraft] Measuring SWR (Long)
I agree except that even at 500KW a 2:1 or greater is the norm with open wire line. Sent from my iPhone > On Apr 9, 2019, at 19:10, Fred Jensen wrote: > > Well, the reflected power is created by a "virtual transmitter" at the > feedpoint of the antenna and heads down the coax which has a surge impedance > of Z0 ohms. It meets the SO-239 at the TX and sees an impedance of Z1, the > impedance presented by the PA and output filters. If Z1=Z0, the power is > dissipated as heat in the PA and associated RF circuitry. If Z1<>Z0, some is > dissipated and some is reflected, where some is radiated, and some is > reflected [virtual transmitter again]. Ad infinitum, and when forever is > over, it is all gone and everyone lives happily ever after. > > SWR and all the associated measuring equipment and concern with it only > became an issue when: 1) Coax replaced parallel lines and; 2) Resonant output > circuits were replaced by solid state amplifiers with non-resonant filters. > When I sat for the Extra in early 1956, the only question that involved > standing waves was one about how Lecher Lines could be used to measure > transmitter frequency. > > It's important today but calculating it hasn't changed. At 10 W, a 2:1 SWR > will probably work ok. At 1500 W, a solid state amplifier may not be happy > with the voltages developed at its output connector. > > 73, > Fred ["Skip"] K6DGW > Sparks NV DM09dn > Washoe County > >> On 4/9/2019 5:56 PM, Don Sanders wrote: >> Since no one has answered your question. I will venture a >> supposition that many know but few will speak out. >> And some still remember their CB days and the erroneous >> advertising saying the power is lost. >> Reflected Power flows back down the feed line and is subjected >> to the normal feed line loss. It then is "reflected" back toward the >> antenna, again subject to the feed line loss, where some of it is >> radiated and some reflected again. >> This continues until the power is dissipated. The book "Reflections" >> has a very good but somewhat technical explanation. >> Therein also is the reference to forgetting about striving for the >> "Holy Grail" of 1:1 SWR. >> And concentrating on getting it low enough that the transmitter will >> supply full power output. Also using the best low loss feed line and >> proper matching when possible of the feed line to the antenna. >> >> Dr. Don W4BWS >> > > __ > 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 __ 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
Re: [Elecraft] Measuring SWR (Long)
Well, the reflected power is created by a "virtual transmitter" at the feedpoint of the antenna and heads down the coax which has a surge impedance of Z0 ohms. It meets the SO-239 at the TX and sees an impedance of Z1, the impedance presented by the PA and output filters. If Z1=Z0, the power is dissipated as heat in the PA and associated RF circuitry. If Z1<>Z0, some is dissipated and some is reflected, where some is radiated, and some is reflected [virtual transmitter again]. Ad infinitum, and when forever is over, it is all gone and everyone lives happily ever after. SWR and all the associated measuring equipment and concern with it only became an issue when: 1) Coax replaced parallel lines and; 2) Resonant output circuits were replaced by solid state amplifiers with non-resonant filters. When I sat for the Extra in early 1956, the only question that involved standing waves was one about how Lecher Lines could be used to measure transmitter frequency. It's important today but calculating it hasn't changed. At 10 W, a 2:1 SWR will probably work ok. At 1500 W, a solid state amplifier may not be happy with the voltages developed at its output connector. 73, Fred ["Skip"] K6DGW Sparks NV DM09dn Washoe County On 4/9/2019 5:56 PM, Don Sanders wrote: Since no one has answered your question. I will venture a supposition that many know but few will speak out. And some still remember their CB days and the erroneous advertising saying the power is lost. Reflected Power flows back down the feed line and is subjected to the normal feed line loss. It then is "reflected" back toward the antenna, again subject to the feed line loss, where some of it is radiated and some reflected again. This continues until the power is dissipated. The book "Reflections" has a very good but somewhat technical explanation. Therein also is the reference to forgetting about striving for the "Holy Grail" of 1:1 SWR. And concentrating on getting it low enough that the transmitter will supply full power output. Also using the best low loss feed line and proper matching when possible of the feed line to the antenna. Dr. Don W4BWS __ 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
Re: [Elecraft] Measuring SWR (Long)
Since no one has answered your question. I will venture a supposition that many know but few will speak out. And some still remember their CB days and the erroneous advertising saying the power is lost. Reflected Power flows back down the feed line and is subjected to the normal feed line loss. It then is "reflected" back toward the antenna, again subject to the feed line loss, where some of it is radiated and some reflected again. This continues until the power is dissipated. The book "Reflections" has a very good but somewhat technical explanation. Therein also is the reference to forgetting about striving for the "Holy Grail" of 1:1 SWR. And concentrating on getting it low enough that the transmitter will supply full power output. Also using the best low loss feed line and proper matching when possible of the feed line to the antenna. Dr. Don W4BWS God Bless All Ham Radio does not make the world go round. Ham Radio is what makes the ride worthwhile. On Tue, Apr 9, 2019 at 6:43 PM Roy Koeppe wrote: > "...Let's allow the reflected power to increase all the way to 10 > watts! At that point, your SWR would be about 2 to 1. Sounds pretty bad, > but > surely if you were stranded in the desert and had to use your KX3 and a > wire > to get help, you'd be happy to have a match this good...(etc.)" > > > From memory now, at 2 to 1...feedline voltage nodes and current nodes can > double -- no small thing when power is 1500 watts; can stress antenna > system > components. > > 73, RoyK6XK > > > __ > 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 > __ 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
[Elecraft] KPA500 alarm
Thanks to Andy and Jack for replies on my question about the alarm on the KPA500. I have a couple of ways to go with this now, and am grateful for the help. 73, Steve KW3A __ 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
Re: [Elecraft] Measuring SWR (Long)
"...Let's allow the reflected power to increase all the way to 10 watts! At that point, your SWR would be about 2 to 1. Sounds pretty bad, but surely if you were stranded in the desert and had to use your KX3 and a wire to get help, you'd be happy to have a match this good...(etc.)" From memory now, at 2 to 1...feedline voltage nodes and current nodes can double -- no small thing when power is 1500 watts; can stress antenna system components. 73, RoyK6XK __ 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
Re: [Elecraft] Measuring SWR (Long)
Why does everyone seem to think all the secret, hollow mountains are in Nevada? I know of one in Colorado and another in Virginia. Umm ... maybe that's in West Virginia, not sure now. [:-)) 73, Fred ["Skip"] K6DGW Sparks NV DM09dn Washoe County I chose these scenarios deviously, to illustrate a kind of corner case, but I think you get the idea that errors always exist in any power measurement like SWR. You might say, "But my SuperDuper wattmeter is calibrated by aliens in a metrology lab deep inside a secret mountain in Nevada and I would bet my life on it." Great, cool, congratulations. But I'm afraid every last power meter has errors stemming from mismatch, directivity, nonlinearity and drift. Al W6LX __ 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
Re: [Elecraft] Measuring SWR (Long)
For an interesting discussion..."What happens to the power that's reflected?" On 4/9/2019 3:42 PM, Al Lorona wrote: There's always a lot of discussion about measuring SWR, low SWR values, SWR lights not lighting up, etc. Here's something that might give you a better 'feel' for SWR. Imagine that you measure your forward power at 100 W and your reflected power at only 1 W. You'd probably be very happy about this. Congratulations, your SWR would be 1.22 to 1. Pause for a moment and let it soak in that an SWR of 1.22 is fabulously good. Once you get to this point, below which we're dealing with reflected power that's less than 1% of your power, or four-hundredths of a dB, it's not worth doing any more to your antenna system to improve it. No trimming, cutting, raising, lowering, hanging stuff from it, adding remote tuned things, nothing. You're done for the day and can now get on the air! If the reflected power were 4 W, which would still look pretty small on the meter, the SWR would be 1.5 to 1. A lot of people might be bothered by an SWR of 1.5, but really this is still very good and it's probably not worth going back up to the antenna to mess with it any more. Most importantly, the station on the other end cannot possibly hear the difference between your 1.2 and 1.5. At this point you may be saying, "Yeah, but my rig/amplifier/other thing isn't happy unless the SWR is below 1.5 to 1, so I would still have to do more work." Okay, that's fine, but my point is that the absolute number 1.5 nonetheless represents a system that is working quite well. Let's allow the reflected power to increase all the way to 10 watts! At that point, your SWR would be about 2 to 1. Sounds pretty bad, but surely if you were stranded in the desert and had to use your KX3 and a wire to get help, you'd be happy to have a match this good. __ 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
Re: [Elecraft] Measuring SWR (Long)
Oh My God! A voice of reason! And from here of all places! How absolutely unexpected! Thank you sir. > On Apr 9, 2019, at 12:42 PM, Al Lorona wrote: > > There's always a lot of discussion about measuring SWR, low SWR values, SWR > lights not lighting up, etc. Here's something that might give you a better > 'feel' for SWR. > > Imagine that you measure your forward power at 100 W and your reflected power > at only 1 W. You'd probably be very happy about this. Congratulations, your > SWR would be 1.22 to 1. > > Pause for a moment and let it soak in that an SWR of 1.22 is fabulously good. > Once you get to this point, below which we're dealing with reflected power > that's less than 1% of your power, or four-hundredths of a dB, it's not worth > doing any more to your antenna system to improve it. No trimming, cutting, > raising, lowering, hanging stuff from it, adding remote tuned things, > nothing. You're done for the day and can now get on the air! > > If the reflected power were 4 W, which would still look pretty small on the > meter, the SWR would be 1.5 to 1. > > A lot of people might be bothered by an SWR of 1.5, but really this is still > very good and it's probably not worth going back up to the antenna to mess > with it any more. Most importantly, the station on the other end cannot > possibly hear the difference between your 1.2 and 1.5. > > At this point you may be saying, "Yeah, but my rig/amplifier/other thing > isn't happy unless the SWR is below 1.5 to 1, so I would still have to do > more work." > > Okay, that's fine, but my point is that the absolute number 1.5 nonetheless > represents a system that is working quite well. > > Let's allow the reflected power to increase all the way to 10 watts! > At that point, your SWR would be about 2 to 1. Sounds pretty bad, but surely > if you were stranded in the desert and had to use your KX3 and a wire to get > help, you'd be happy to have a match this good. > > Now, let's look at a certain type of SWR meter found in virtually every HF > rig out there that uses a directional bridge, a diode as a half-wave > rectifier, a filter capacitor, a resistor, and a readout of some kind - > analog meter, digital display, or other. > > These types of SWR meters are very common. There's one in the K2 (it's > actually in the KPA100), one in the K3, and probably every other rig out > there. And those Birds, MFJs and Daiwas have them, too. > > This type of circuit turns RF voltage into a DC current, usually using either > a germanium or Schottky diode, because these diodes have the best sensitivity > due to their low forward voltage drops: 0.3 V for the germanium, and 0.4 V > for the Schottky. > > Let's say that our directional bridge, when 100 W is in the forward > direction, delivers 10 V to the forward Schottky diode. In our example above > of 1 watt reflected, the reflected diode would see 1.0 volts from the > reflected port of the bridge. Since this is above the diode threshold > voltage, the diode would be happy and operating in its linear region where > we'd get about 1 volt out for 1 volt in. The meter would correctly read 1.22 > to 1. > > Now say you have your Elecraft rig set for TUN PWR = 10 W, so when you tune > up, forward power is 10 watts, and if the SWR is the aforementioned 1.2 to 1, > the forward power would produce a little more than 3 volts at the diode and > the 0.1 watts reflected would produce about 0.3 volts. Here is where we run > into trouble. > > Since a Schottky diode doesn't fully conduct until we exceed its 0.4 volt > threshold, expecting to get 0.3 V out for 0.3 V in isn't quite realistic. The > diode's output voltage won't be zero, but it'll be smaller than expected, > according to the nonlinear region around its "knee". I measured a Schottky > diode and got about 0.09 V at that level. The meter would indicate an SWR > of... 1.06 instead of the actual 1.22. This reading is false. > > There are some things that can be done to the circuit to compensate for this > error but I'm not sure how many rigs go through the trouble. Suffice it to > say that measurement of very low SWR has a large amount of uncertainty > because the detectors get more and more nonlinear as the thing they're trying > to measure (reflected power) gets smaller and smaller. Due to this effect > (and also due to directivity) every meter of this kind has a point below > which SWR measurements are probably wrong. > > When we see posts here by folks puzzled as to why low SWR measurements from > two different instruments don't agree, this undoubtedly is one of the reasons. > > I chose these scenarios deviously, to illustrate a kind of corner case, but I > think you get the idea that errors always exist in any power measurement like > SWR. You might say, "But my SuperDuper wattmeter is calibrated by aliens in a > metrology lab deep inside a secret mountain in Nevada and I would bet my life > on it."
Re: [Elecraft] D13 voltage test high?
What is the value of R4? It should be 100k. 73, Don W3FPR On 4/9/2019 4:54 PM, TI2/NA7U wrote: Manual says D13 (banded end) should show between 90-150V, mine measures 178V ... says U4 pin 8 should be between -5 to -25 V, mine measures -30V Still going through the receiver tests, up to the dual-supply tests and all seems well, so should I be concerned about those readings? __ 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
[Elecraft] D13 voltage test high?
Manual says D13 (banded end) should show between 90-150V, mine measures 178V ... says U4 pin 8 should be between -5 to -25 V, mine measures -30V Still going through the receiver tests, up to the dual-supply tests and all seems well, so should I be concerned about those readings? 73, TI2/NA7U - Cloud Warmer Ham Radio Blog -- 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
Re: [Elecraft] Measuring SWR (Long)
Thank you Al Lorona! 73 Bob, K4TAX On 4/9/2019 2:42 PM, Al Lorona wrote: There's always a lot of discussion about measuring SWR, low SWR values, SWR lights not lighting up, etc. Here's something that might give you a better 'feel' for SWR. Imagine that you measure your forward power at 100 W and your reflected power at only 1 W. You'd probably be very happy about this. Congratulations, your SWR would be 1.22 to 1. Pause for a moment and let it soak in that an SWR of 1.22 is fabulously good. Once you get to this point, below which we're dealing with reflected power that's less than 1% of your power, or four-hundredths of a dB, it's not worth doing any more to your antenna system to improve it. No trimming, cutting, raising, lowering, hanging stuff from it, adding remote tuned things, nothing. You're done for the day and can now get on the air! If the reflected power were 4 W, which would still look pretty small on the meter, the SWR would be 1.5 to 1. A lot of people might be bothered by an SWR of 1.5, but really this is still very good and it's probably not worth going back up to the antenna to mess with it any more. Most importantly, the station on the other end cannot possibly hear the difference between your 1.2 and 1.5. At this point you may be saying, "Yeah, but my rig/amplifier/other thing isn't happy unless the SWR is below 1.5 to 1, so I would still have to do more work." Okay, that's fine, but my point is that the absolute number 1.5 nonetheless represents a system that is working quite well. Let's allow the reflected power to increase all the way to 10 watts! At that point, your SWR would be about 2 to 1. Sounds pretty bad, but surely if you were stranded in the desert and had to use your KX3 and a wire to get help, you'd be happy to have a match this good. Now, let's look at a certain type of SWR meter found in virtually every HF rig out there that uses a directional bridge, a diode as a half-wave rectifier, a filter capacitor, a resistor, and a readout of some kind - analog meter, digital display, or other. These types of SWR meters are very common. There's one in the K2 (it's actually in the KPA100), one in the K3, and probably every other rig out there. And those Birds, MFJs and Daiwas have them, too. This type of circuit turns RF voltage into a DC current, usually using either a germanium or Schottky diode, because these diodes have the best sensitivity due to their low forward voltage drops: 0.3 V for the germanium, and 0.4 V for the Schottky. Let's say that our directional bridge, when 100 W is in the forward direction, delivers 10 V to the forward Schottky diode. In our example above of 1 watt reflected, the reflected diode would see 1.0 volts from the reflected port of the bridge. Since this is above the diode threshold voltage, the diode would be happy and operating in its linear region where we'd get about 1 volt out for 1 volt in. The meter would correctly read 1.22 to 1. Now say you have your Elecraft rig set for TUN PWR = 10 W, so when you tune up, forward power is 10 watts, and if the SWR is the aforementioned 1.2 to 1, the forward power would produce a little more than 3 volts at the diode and the 0.1 watts reflected would produce about 0.3 volts. Here is where we run into trouble. Since a Schottky diode doesn't fully conduct until we exceed its 0.4 volt threshold, expecting to get 0.3 V out for 0.3 V in isn't quite realistic. The diode's output voltage won't be zero, but it'll be smaller than expected, according to the nonlinear region around its "knee". I measured a Schottky diode and got about 0.09 V at that level. The meter would indicate an SWR of... 1.06 instead of the actual 1.22. This reading is false. There are some things that can be done to the circuit to compensate for this error but I'm not sure how many rigs go through the trouble. Suffice it to say that measurement of very low SWR has a large amount of uncertainty because the detectors get more and more nonlinear as the thing they're trying to measure (reflected power) gets smaller and smaller. Due to this effect (and also due to directivity) every meter of this kind has a point below which SWR measurements are probably wrong. When we see posts here by folks puzzled as to why low SWR measurements from two different instruments don't agree, this undoubtedly is one of the reasons. I chose these scenarios deviously, to illustrate a kind of corner case, but I think you get the idea that errors always exist in any power measurement like SWR. You might say, "But my SuperDuper wattmeter is calibrated by aliens in a metrology lab deep inside a secret mountain in Nevada and I would bet my life on it." Great, cool, congratulations. But I'm afraid every last power meter has errors stemming from mismatch, directivity, nonlinearity and drift. If you simply tune for minimum reflected power you should be good to go, and don't get too hung up on if the
Re: [Elecraft] Measuring SWR (Long)
My friend Al has described some interesting things about SWR measurement here. But not all power/swr meters behave this way. In fact the Elecraft W2 meter is in this class. The designer added an ingenious little circuit to the diodes to bias them into their linear region. What the smeans is that even at low power the W2 is giving accurate measurements not just of reflected power, but for forward power as well. this is important since the effect that Al describes is valid not just for reflected power, but also forward power at low levels. There is one other things to watch for that actually negates Al’s suggestion to always tune for lowest reflected power. As an ATU tunes, it provides different loads to the driver. This will greatly affect not just the reflected power, but forward power measurements as well, to the point that we may measure very low reflected power, but the forward power is very low as well. Thus when we tune we really do look for both maximum forward power in conjunction with minimum reflected power. One last point. The directional coupler measurements in the KPA500, KAT500 and KPA1500 are designed to handle large power levels since the devices are meant for high power. We don’t really try to be accurate at low levels. Indeed the KPA500 won’t even indicate power below 25 watts and the KAT500 needs something like 10 or 20 watts to work properly. This allows us to be accurate at high power levels and also avoid having to be concerned with the diodes workin in their non-linear mode. In other words, on these products you can pretty much believe the power levels the device is showing when it is showing them. Al, thanks for a nice write-up. 73! Jack, W6FB > On Apr 9, 2019, at 12:42 PM, Al Lorona wrote: > > There's always a lot of discussion about measuring SWR, low SWR values, SWR > lights not lighting up, etc. Here's something that might give you a better > 'feel' for SWR. > > Imagine that you measure your forward power at 100 W and your reflected power > at only 1 W. You'd probably be very happy about this. Congratulations, your > SWR would be 1.22 to 1. > > Pause for a moment and let it soak in that an SWR of 1.22 is fabulously good. > Once you get to this point, below which we're dealing with reflected power > that's less than 1% of your power, or four-hundredths of a dB, it's not worth > doing any more to your antenna system to improve it. No trimming, cutting, > raising, lowering, hanging stuff from it, adding remote tuned things, > nothing. You're done for the day and can now get on the air! > > If the reflected power were 4 W, which would still look pretty small on the > meter, the SWR would be 1.5 to 1. > > A lot of people might be bothered by an SWR of 1.5, but really this is still > very good and it's probably not worth going back up to the antenna to mess > with it any more. Most importantly, the station on the other end cannot > possibly hear the difference between your 1.2 and 1.5. > > At this point you may be saying, "Yeah, but my rig/amplifier/other thing > isn't happy unless the SWR is below 1.5 to 1, so I would still have to do > more work." > > Okay, that's fine, but my point is that the absolute number 1.5 nonetheless > represents a system that is working quite well. > > Let's allow the reflected power to increase all the way to 10 watts! > At that point, your SWR would be about 2 to 1. Sounds pretty bad, but surely > if you were stranded in the desert and had to use your KX3 and a wire to get > help, you'd be happy to have a match this good. > > Now, let's look at a certain type of SWR meter found in virtually every HF > rig out there that uses a directional bridge, a diode as a half-wave > rectifier, a filter capacitor, a resistor, and a readout of some kind - > analog meter, digital display, or other. > > These types of SWR meters are very common. There's one in the K2 (it's > actually in the KPA100), one in the K3, and probably every other rig out > there. And those Birds, MFJs and Daiwas have them, too. > > This type of circuit turns RF voltage into a DC current, usually using either > a germanium or Schottky diode, because these diodes have the best sensitivity > due to their low forward voltage drops: 0.3 V for the germanium, and 0.4 V > for the Schottky. > > Let's say that our directional bridge, when 100 W is in the forward > direction, delivers 10 V to the forward Schottky diode. In our example above > of 1 watt reflected, the reflected diode would see 1.0 volts from the > reflected port of the bridge. Since this is above the diode threshold > voltage, the diode would be happy and operating in its linear region where > we'd get about 1 volt out for 1 volt in. The meter would correctly read 1.22 > to 1. > > Now say you have your Elecraft rig set for TUN PWR = 10 W, so when you tune > up, forward power is 10 watts, and if the SWR is the aforementioned 1.2 to 1, > the forward power would
Re: [Elecraft] My "MFJ Posting"
Thank you, Jim N4ST, for expressing something which I had become afraid to (having been stung by wasps too many times) 73, Joan KX2CW Darmok and Jalad at Tanagra, said Piglet. Shaka, when the walls fell, said Pooh. > On Apr 8, 2019, at 10:41, Jim - N4ST wrote: > > Ken, > > The Internet has created a mob of hyper-sensitive hype-critical keyboard > warriors. > Any comment, including this one is likely to bring on the slings and arrows. > > With respect to ham gear, yes, roughly speaking you get what you pay for, > but sometimes marginal performance is much better than no performance. > Most of the MFJ stuff I have purchased has served the purpose, especially in > my younger years when more expensive alternatives were out of reach. > I also drive Fords & Chevys and not Range Rovers and Mercedes. > > ___ > 73, > Jim - N4ST > > -Original Message- > From: elecraft-boun...@mailman.qth.net On > Behalf Of Ken G Kopp > Sent: Monday, April 8, 2019 08:16 > To: Elecraft > Subject: [Elecraft] My "MFJ Posting" > > I am dismayed at the view some took of my posting. I intended absolutely no > racial or eletist content ... in any way ... and apologize to anyone who > read it that way. > > 73 ! > > Ken Kopp - K0PP > __ > 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 > > __ 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
Re: [Elecraft] new KPA1500 Manual
Fred: If you take a manual on a thumb drive, Staples can print it and spiral-bound it. Tom W4KX Sent from my iPad > On Apr 9, 2019, at 2:44 PM, Fred Jensen wrote: > > Yes, the USAF Technical Orders for a system could fill a bookcase if printed, > and they were printed then. I don't remember many of the volumes but the -1 > was "How to fly the airplane" [or operate the radio], -6 was the Illustrated > Parts Breakdown, I think -5 was the parts list. There was usually a volume > describing packaging for shipment of the myriad of modules in the system, and > maybe one for storage requirements of various parts. The well-worn joke was, > "When the weight of the paper equals the weight of the airplane, you're > cleared for takeoff." And, updates, in the form of page changes, could have > life/death consequences if not done. [see Boeing] > > However ... tech data for a ham transceiver is light years removed from that > environment and comparison really isn't fair or sensible. Elecraft's manual, > like all manufacturers', approaches the radio from the perspective of, "Here > are all the controls and here's what they do." There's some information > about how the radio works, but it's not anywhere near exhaustive. KE7X's > books approach it from the perspective of "Here are the things you may want > to do with your radio, and here's how to do them." Again, there's > information about what's inside and how it does it, but it's not exhaustive. > No ham manufacturer that I know of publishes page changes. > > Most of what I write in my station notebook is stuff I've learned about my > radios ... how to set up RTTY, how to switch from local to remote operation, > anomalies such as the P3 span issue when changing bands via SW commands, > TX/RX EQ and AGC settings, etc. It's not info Elecraft sends out. I annotate > the PDF manual with the volume/page in my notebook where the item is > described. For me at least, the Elecraft PDF, KE7X spiral-bound book, and > notes in my notebook work fine. I would have liked a printed spiral-bound K3 > manual that lays flat on the desk, but the PDF works. > > 73, > Fred ["Skip"] K6DGW > Sparks NV DM09dn > Washoe County > >> On 4/9/2019 4:46 AM, Bill Mader wrote: >> I agree with your comments on the amplifier's manual Peter. Getting tech >> data right is a challenge. I spent my last six years in the USAF at a >> Major Command HQ where I would visit our primary depot twice a year to >> discuss product improvement. Tech data was a key part of those meetings. >> > > __ > 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 __ 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
[Elecraft] Measuring SWR (Long)
There's always a lot of discussion about measuring SWR, low SWR values, SWR lights not lighting up, etc. Here's something that might give you a better 'feel' for SWR. Imagine that you measure your forward power at 100 W and your reflected power at only 1 W. You'd probably be very happy about this. Congratulations, your SWR would be 1.22 to 1. Pause for a moment and let it soak in that an SWR of 1.22 is fabulously good. Once you get to this point, below which we're dealing with reflected power that's less than 1% of your power, or four-hundredths of a dB, it's not worth doing any more to your antenna system to improve it. No trimming, cutting, raising, lowering, hanging stuff from it, adding remote tuned things, nothing. You're done for the day and can now get on the air! If the reflected power were 4 W, which would still look pretty small on the meter, the SWR would be 1.5 to 1. A lot of people might be bothered by an SWR of 1.5, but really this is still very good and it's probably not worth going back up to the antenna to mess with it any more. Most importantly, the station on the other end cannot possibly hear the difference between your 1.2 and 1.5. At this point you may be saying, "Yeah, but my rig/amplifier/other thing isn't happy unless the SWR is below 1.5 to 1, so I would still have to do more work." Okay, that's fine, but my point is that the absolute number 1.5 nonetheless represents a system that is working quite well. Let's allow the reflected power to increase all the way to 10 watts! At that point, your SWR would be about 2 to 1. Sounds pretty bad, but surely if you were stranded in the desert and had to use your KX3 and a wire to get help, you'd be happy to have a match this good. Now, let's look at a certain type of SWR meter found in virtually every HF rig out there that uses a directional bridge, a diode as a half-wave rectifier, a filter capacitor, a resistor, and a readout of some kind - analog meter, digital display, or other. These types of SWR meters are very common. There's one in the K2 (it's actually in the KPA100), one in the K3, and probably every other rig out there. And those Birds, MFJs and Daiwas have them, too. This type of circuit turns RF voltage into a DC current, usually using either a germanium or Schottky diode, because these diodes have the best sensitivity due to their low forward voltage drops: 0.3 V for the germanium, and 0.4 V for the Schottky. Let's say that our directional bridge, when 100 W is in the forward direction, delivers 10 V to the forward Schottky diode. In our example above of 1 watt reflected, the reflected diode would see 1.0 volts from the reflected port of the bridge. Since this is above the diode threshold voltage, the diode would be happy and operating in its linear region where we'd get about 1 volt out for 1 volt in. The meter would correctly read 1.22 to 1. Now say you have your Elecraft rig set for TUN PWR = 10 W, so when you tune up, forward power is 10 watts, and if the SWR is the aforementioned 1.2 to 1, the forward power would produce a little more than 3 volts at the diode and the 0.1 watts reflected would produce about 0.3 volts. Here is where we run into trouble. Since a Schottky diode doesn't fully conduct until we exceed its 0.4 volt threshold, expecting to get 0.3 V out for 0.3 V in isn't quite realistic. The diode's output voltage won't be zero, but it'll be smaller than expected, according to the nonlinear region around its "knee". I measured a Schottky diode and got about 0.09 V at that level. The meter would indicate an SWR of... 1.06 instead of the actual 1.22. This reading is false. There are some things that can be done to the circuit to compensate for this error but I'm not sure how many rigs go through the trouble. Suffice it to say that measurement of very low SWR has a large amount of uncertainty because the detectors get more and more nonlinear as the thing they're trying to measure (reflected power) gets smaller and smaller. Due to this effect (and also due to directivity) every meter of this kind has a point below which SWR measurements are probably wrong. When we see posts here by folks puzzled as to why low SWR measurements from two different instruments don't agree, this undoubtedly is one of the reasons. I chose these scenarios deviously, to illustrate a kind of corner case, but I think you get the idea that errors always exist in any power measurement like SWR. You might say, "But my SuperDuper wattmeter is calibrated by aliens in a metrology lab deep inside a secret mountain in Nevada and I would bet my life on it." Great, cool, congratulations. But I'm afraid every last power meter has errors stemming from mismatch, directivity, nonlinearity and drift. If you simply tune for minimum reflected power you should be good to go, and don't get too hung up on if the meter says "1.2" or "1.5" or "1.0". Remember, once you get down into this zone
Re: [Elecraft] Technical question on keying of an SDR radio
And some of today's software applications {HRD} have provision for
MCW. One must be careful how the interface between the computer and
radio is constructed so as not to have anything in the audio path which
would contribute to less than a pure sinewave signal. Actually this
is exactly how AFSK and other data modes work. A tone frequency is sent
to the radio to produce the MARK signal and a different frequency tone
is sent to produce a SPACE signal.
In all cases, a clean signal path between the computer and the radio is
found to be mandatory. Hum, buzz, clicks, pops and a mike left open
are all a NO NO!
73
Bob, K4TAX
On 4/9/2019 1:16 PM, Fred Jensen wrote:
A technique pioneered by Art Collins many years ago in the KWM2 and
S-line.
73,
Fred ["Skip"] K6DGW
Sparks NV DM09dn
Washoe County
On 4/9/2019 3:08 AM, Victor Rosenthal 4X6GP wrote:
Oh no! NOW you tell me that all these years that I have believed that
I have been operating CW, it's really SSB!
(Disclaimer to avoid the otherwise inevitable explanations that a
pure audio tone transmitted via SSB is identical with CW: I know that).
73,
Victor, 4X6GP
Rehovot, Israel
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Re: [Elecraft] new KPA1500 Manual
Yes, the USAF Technical Orders for a system could fill a bookcase if printed, and they were printed then. I don't remember many of the volumes but the -1 was "How to fly the airplane" [or operate the radio], -6 was the Illustrated Parts Breakdown, I think -5 was the parts list. There was usually a volume describing packaging for shipment of the myriad of modules in the system, and maybe one for storage requirements of various parts. The well-worn joke was, "When the weight of the paper equals the weight of the airplane, you're cleared for takeoff." And, updates, in the form of page changes, could have life/death consequences if not done. [see Boeing] However ... tech data for a ham transceiver is light years removed from that environment and comparison really isn't fair or sensible. Elecraft's manual, like all manufacturers', approaches the radio from the perspective of, "Here are all the controls and here's what they do." There's some information about how the radio works, but it's not anywhere near exhaustive. KE7X's books approach it from the perspective of "Here are the things you may want to do with your radio, and here's how to do them." Again, there's information about what's inside and how it does it, but it's not exhaustive. No ham manufacturer that I know of publishes page changes. Most of what I write in my station notebook is stuff I've learned about my radios ... how to set up RTTY, how to switch from local to remote operation, anomalies such as the P3 span issue when changing bands via SW commands, TX/RX EQ and AGC settings, etc. It's not info Elecraft sends out. I annotate the PDF manual with the volume/page in my notebook where the item is described. For me at least, the Elecraft PDF, KE7X spiral-bound book, and notes in my notebook work fine. I would have liked a printed spiral-bound K3 manual that lays flat on the desk, but the PDF works. 73, Fred ["Skip"] K6DGW Sparks NV DM09dn Washoe County On 4/9/2019 4:46 AM, Bill Mader wrote: I agree with your comments on the amplifier's manual Peter. Getting tech data right is a challenge. I spent my last six years in the USAF at a Major Command HQ where I would visit our primary depot twice a year to discuss product improvement. Tech data was a key part of those meetings. __ 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
Re: [Elecraft] Technical question on keying of an SDR radio
A technique pioneered by Art Collins many years ago in the KWM2 and S-line. 73, Fred ["Skip"] K6DGW Sparks NV DM09dn Washoe County On 4/9/2019 3:08 AM, Victor Rosenthal 4X6GP wrote: Oh no! NOW you tell me that all these years that I have believed that I have been operating CW, it's really SSB! (Disclaimer to avoid the otherwise inevitable explanations that a pure audio tone transmitted via SSB is identical with CW: I know that). 73, Victor, 4X6GP Rehovot, Israel __ 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
[Elecraft] [K3] PS0 enhancement request
It looks like the PS0 power off command still has the note about leaving the Power On pin on the accessory connector grounded for at least 100ms to ensure that no internal data is corrupted on the processor. I'm wondering how hard it would be for the PS0 command to coordinate that shutdown sequence without the need to manipulate the power on pin. It sure would make remote control much less cumbersome. Rick N1RM -- 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
Re: [Elecraft] Technical question on keying of an SDR radio
Not to worry, Victor. The really important part of generating and demodulating CW happens in your head. Eric KE6US On 4/9/2019 3:08 AM, Victor Rosenthal 4X6GP wrote: Oh no! NOW you tell me that all these years that I have believed that I have been operating CW, it's really SSB! (Disclaimer to avoid the otherwise inevitable explanations that a pure audio tone transmitted via SSB is identical with CW: I know that). 73, Victor, 4X6GP Rehovot, Israel Formerly K2VCO CWops no. 5 http://www.qsl.net/k2vco/ __ 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
Re: [Elecraft] K3: Using a K3 to route antenna signals to external devices...
Doug, Yes, thanks, you're right. I have the preamp set up to be active for the higher bands 12, 10, and 6 m, and in the bypass position otherwise. I use this to connect an old shortwave receiver (not an SDR) to my main antenna, so I guess it doesn't hurt for it with the extra gain. But I'll try both configurations, both before and after the preamp. - Sverre, LA3ZA K2 #2198, K3 #3391, LA3ZA Blog: http://la3za.blogspot.com, LA3ZA Unofficial Guide to K2 modifications: http://la3za.blogspot.com/p/la3za-unofficial-guide-to-elecraft-k2.html -- 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
Re: [Elecraft] Request - KXPD2, KXPD1 and KXB3080
David, Elecraft has the KXPD2, and at last check also has the KXB3080 kit. So the option that is not available is the KXPD1. 73, Don W3FPR On 4/9/2019 5:15 AM, David Cripps wrote: Hi Although I've been a ham for nearly 30 years, I've been out the hobby for the last 25 of them and am now learning Morse again to get into QRP. I have recently bought a KX1 and KX2 and would like to get the paddles for them, so if anybody has a KXPD2 or KXPD1 for sale please let me know (I'm in the UK if that makes any difference). The KX1 has the ATU but only 40M and 20M, so again if you have a KXB3080 for sale, let me know. __ 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
Re: [Elecraft] K3: Using a K3 to route antenna signals to external devices...
Sverre, That answer depends --- If you want to connect the SDR directly to the antenna, put the TEE between the ANT OUT and the preamp. OTOH, if you want to have the preamp in-line for the SDR input, put the TEE between the preamp output and the ANT IN connector. If you chose to use the preamp with the SDR, you may have to do some work on the powering and activation of the preamp. 73, Don W3FPR On 4/9/2019 6:48 AM, Sverre Holm (LA3ZA) wrote: But what if there is a PR6-10 preamp in this path. Where should the splitter/TEE-adapter be in that case? In brief, it takes a TEE adapter and 2 short pieces of coax. Put the adapter between the 2 pieces of coax, and then connect one coax to ANT OUT and the other to ANT IN. __ 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
Re: [Elecraft] K3: Using a K3 to route antenna signals to external devices...
Thanks, Joe. Works nicely and saved me the cost of something like the MFJ-1708B-SDR SDR RF sensing T/R switch! - Sverre, LA3ZA K2 #2198, K3 #3391, LA3ZA Blog: http://la3za.blogspot.com, LA3ZA Unofficial Guide to K2 modifications: http://la3za.blogspot.com/p/la3za-unofficial-guide-to-elecraft-k2.html -- 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
[Elecraft] Pushing hard in SSB?
"I've pushed my KPA1500 hard in two SSB contests already this year." I seldom connect a microphone so forgive my ignorance. How is is possible to push an amplifier hard in SSB (phone) without exceeding legal limit peak output by a huge margin? I'd understand "pushing hard" in RTTY or other digital modes but not SSB (phone). 73, 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
Re: [Elecraft] K3: Using a K3 to route antenna signals to external devices...
After the PR6/PR10 to gain the benefit of the PR6/PR10 for the SDR as well as the K3/KRX3 receiver(s). 73, ... Joe, W4TV On 2019-04-09 6:48 AM, Sverre Holm (LA3ZA) wrote: But what if there is a PR6-10 preamp in this path. Where should the splitter/TEE-adapter be in that case? In brief, it takes a TEE adapter and 2 short pieces of coax. Put the adapter between the 2 pieces of coax, and then connect one coax to ANT OUT and the other to ANT IN. - Sverre, LA3ZA K2 #2198, K3 #3391, LA3ZA Blog: http://la3za.blogspot.com, LA3ZA Unofficial Guide to K2 modifications: http://la3za.blogspot.com/p/la3za-unofficial-guide-to-elecraft-k2.html __ 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
Re: [Elecraft] new KPA1500 Manual
I agree with your comments on the amplifier's manual Peter. Getting tech data right is a challenge. I spent my last six years in the USAF at a Major Command HQ where I would visit our primary depot twice a year to discuss product improvement. Tech data was a key part of those meetings. Even though most of our troubleshooting stopped at the module replacement level, we had schematics for each module. One year while I was at the base level I got to train a pair of Iranian Air Force sergeants depot level troubleshooting and repair on a UHF ground-to-air transceiver. My background in ham radio gave me the needed understanding of electronics to do that. I will see Elecraft folks at the IDXC in Visalia this coming weekend. I'll likely have dinner with Bob, K6XX, the KPA1500 project manager Saturday night. I'll pass on your thoughts. BTW, I've pushed my KPA1500 hard in two SSB contests already this year. It has performed flawlessly. 73, Bill Mader, K8TE W6H NM Coordinator, Route 66 On-the-Air 7-15 Sep 2019 ARRL New Mexico Section Manager *ARRL - The national association for Amateur Radio**™* Duke City Hamfest BoD www.dukecityhamfest.org 20-22 Sep 2019 President, Albuquerque DX Association On Mon, Apr 8, 2019 at 11:52 PM Peter Hall wrote: > Bill, > > Having spent time, over many years, piecemeal updating Jeppersen and CASA > (the national aviation regulatory authority) pilot documents, I regard it > as wasted time I'll never get back. I hope that Elecraft does not go down > this path but agree absolutely that, these days, good searchable PDFs make > life much easier. One thing that is always useful is the update register > (already often used) and text markers indicating changes from the previous > edition (often vertical bars at affected paragraphs). > > On the subject of the KPA1500 manual, I have much appreciated the > additions to the original document but would like to see the block diagram > expanded to make it more useful in terms of appreciating the amplifier > topology and the relation to connectors, etc. For example, the current > very terse diagram does not show the pre-distortion coupler or its location > and, if you hadn't had a spectrum analyser on the amplifier, you might not > appreciate that it's not a direct output coupler. Of course, I'd like to > see the whole schematic but I understand that it must be a tricky > commercial IP balancing act with a new product. > > 73, Peter (VK6HP). > > > -Original Message- > From: elecraft-boun...@mailman.qth.net > On Behalf Of K8TE > Sent: Tuesday, 9 April 2019 2:34 AM > To: elecraft@mailman.qth.net > Subject: Re: [Elecraft] new KPA1500 Manual > > Right on! First, I have over two decades of experience with replacing > printed pages in Air Force Technical Orders. What a PITA, but necessary. > Today, those are distributed electronically and printed locally. Often, > it's not possible to make a change that affects only one page since the > change, often an addition, pushes information on to the next page. > > Thanks to Elecraft (not all manufactures do this), we can annotate the PDF > versions with the latest firmware notes, ideas from this reflector, our > just our own pointers. The PDF then becomes a current, searchable document > of great value! > > As I point out in my ham radio presentations, it's 2019. We do a lot of > things with computers now. Join the 21st century. The technology has > certain advantages, especially if you back-up your data. > > 73, Bill, K8TE > > > > -- > Sent from: > http://secure-web.cisco.com/1ly5jG_z3c_ghFK4l_kVBFZrlCKkrMidJYBdwHxcCu3z2lgrmQrao4hnCsJiXrJi0GQVeY5htK-Vh4dQ16ZnFIQU-gBLNh6WwLOG-Pobdsz2l7JPiP-RZfnKzhbShygqpsgyBIbiKZoHEfIG4ZavEgPnhBX124hZDghSJKQTxsh71sJ6EZ8YRh8rxDE9XfyHRiHT1L5tI6UEq-mq43tNLo37ylKZzIGeqbUGidwyuqwiWd1g7He9T7MuWFpLGW7trTaVoSyd23L_IO-4AvaRTaCrYHBtYK-f3Dd90aPLnsyuR2wQXsnHXTnSeOEwNLKL_ye1IsOk-ulrUpbgI-5U5sJjsDXugiwFsOWxQkuI2QHT-wWKA5XNhToEUZtd0r8JnXq9o51L1kiPSFnmlgDqW3ENGmGd2FtGAxrU9UQjmeBWXpyBYm0pkl0WpvaFfGiPUzqDdhKwKLQYBg7WAcp2GLQ-XHIYS_hNpcS5M5NIHPEQ/http%3A%2F%2Felecraft.365791.n2.nabble.com%2F > __ > Elecraft mailing list > Home: > http://secure-web.cisco.com/15Xu-tgWxGQXmtH17CkIuIwXVaL8qUYmdndVBK0xxyOmLymTGEAlA0Geea95i-no3tp_bPZBNggdFpXObVRtLe8WhkU5sWwCdt_anhUUszZE-jSAupHNd-5ONp_8CsgKAsSi2lpvNlqKZTbBSEHth92SLHqbEnyh6LClTOebVR9BiExmqTX_3W6qp1c9jnYlzmvX8X97TQUoo7mRBhoJ--dww3ybGz4fahocE3zYjz-RKP8XOF2qLAib_1H88L6vSMdLB8-gYJllrGE2m2pkekZK4oEI1CKRCrIVw9a2XFUQFUWmql3AvsNRAFMpqS_-DDVQrU9IZY9Jye6sHW-KP_Vw0N7lP0gQ6MkZxNe_cQvM1fF5s9wANN2NHXVYLcoaJUTYK6jgU1FH0DCOKMcEaF5YlXYRJZmjZybu5xMReoHxVeF80cgdW2zypuzn2OnK60AasxTi8gdRTZCiYNYGGEzTpa7XYQH7_aJSrblWPS4g/http%3A%2F%2Fmailman.qth.net%2Fmailman%2Flistinfo%2Felecraft > Help: >
Re: [Elecraft] K3: Using a K3 to route antenna signals to external devices...
But what if there is a PR6-10 preamp in this path. Where should the splitter/TEE-adapter be in that case? >In brief, it takes a TEE adapter and 2 short pieces of coax. Put the >adapter between the 2 pieces of coax, and then connect one coax to ANT >OUT and the other to ANT IN. - Sverre, LA3ZA K2 #2198, K3 #3391, LA3ZA Blog: http://la3za.blogspot.com, LA3ZA Unofficial Guide to K2 modifications: http://la3za.blogspot.com/p/la3za-unofficial-guide-to-elecraft-k2.html -- 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
Re: [Elecraft] Technical question on keying of an SDR radio
Oh no! NOW you tell me that all these years that I have believed that I have been operating CW, it's really SSB! (Disclaimer to avoid the otherwise inevitable explanations that a pure audio tone transmitted via SSB is identical with CW: I know that). 73, Victor, 4X6GP Rehovot, Israel Formerly K2VCO CWops no. 5 http://www.qsl.net/k2vco/ On 8 Apr 2019 08:24, Wayne Burdick wrote: Hi Phil, In the K2 the sidetone starts off as a squarewave created by the microcontroller. This is then shaped and injected into the AF amplifier. The sidetone is turned on/off at the same time as the carrier, which is generated by the LO (PLL synth) mixing with a gated TX BFO signal. In our DSP-based radios (K3/K3S and KX2/KX3), both the audio sidetone and the 15 kHz 2nd IF carrier are created by the DSP. Their rising edges are shaped mathematically using what's called a "raised cosine" or sigmodal waveform. We experimented to find the ideal waveform equation, the result being the cleaned signal possible, with virtually no key clicks. The DSP can of course do other things like apply amplitude or frequency modulation, generate voice and data mode signals, apply ALC and audio EQ, etc. CW is just the simplest case of what can be done. From the DSP, the digitized audio signal codes to a DAC (part of the audio CODEC IC), which then converts it to analog for injection into the AF amp. The 15 kHz 2nd IF carrier in the K3/K3S goes to a transmit mixer on the KREF4 module where it's up-converted to about 8215 kHz. It is then routed to the first IF mixer. The 8215 kHz signal passes through two crystal filters enroute mixer. In the KX2/KX3, the 15 kHz IF signal is converted to a pair of IQ signals (90 degrees out of phase with each other) to directly modulate a quadrature up-converter. The other input to the up-converter is a pair of balanced LO signals, again separated by 90 degrees. A result of IQ modulation is that one sideband is cancelled out, resulting in a single RF carrier at the desired frequency. In all cases, the rest of the T/R sequencing involves the usual amplifiers, PIN diodes, filter switching, etc. 73, Wayne N6KR __ 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
[Elecraft] Request - KXPD2, KXPD1 and KXB3080
Hi Although I've been a ham for nearly 30 years, I've been out the hobby for the last 25 of them and am now learning Morse again to get into QRP. I have recently bought a KX1 and KX2 and would like to get the paddles for them, so if anybody has a KXPD2 or KXPD1 for sale please let me know (I'm in the UK if that makes any difference). The KX1 has the ATU but only 40M and 20M, so again if you have a KXB3080 for sale, let me know. It's great to be back in the hobby and on the air (although I do feel like a novice, albeit with a Full or Advance licence!). Thanks and 73s David G7IDB __ 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
Re: [Elecraft] new KPA1500 Manual
On 4/8/2019 10:52 PM, Peter Hall wrote: Having spent time, over many years, piecemeal updating Jeppersen and CASA (the national aviation regulatory authority) pilot documents, I regard it as wasted time I'll never get back. I hope that Elecraft does not go down this path but agree absolutely that, these days, good searchable PDFs make life much easier. One thing that is always useful is the update register (already often used) and text markers indicating changes from the previous edition (often vertical bars at affected paragraphs). Yes. This is the modern equivalent of those update methods of yesteryear, and a manual that is in any decent publishing application that can produce a pdf is trivially easy to update and to highlight changes. I consider such practice, along with a "change" list in the form of an appendix or separate document, to be the right way to do it. Any competent tech writer ought to be able make the edits and load the updated manual in no more than a half hour after the editing is complete. I can get a new or updated document on my own website in half that time if there's already a link to it on the main page, another 10-15 minutes if it's a new document for which a new link is needed. 73, Jim K9YC __ 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
