Re: [Elecraft] K3: Receiver recovery time
Thank you Don!! I was trying to get a general feel for what to expect, a ms, or us type of answer... I was thinking of using the IF to avoid the DSP filters for just the reasons you cited. I am sure you are correct about testing-- time to break out the scope... Thanks again for your insight! 73s and thanks, Dave (NK7Z) https://www.nk7z.net Award Manager, 30MDG Grid Contest ARRL Technical Specialist ARRL Volunteer Examiner ARRL OOC for Oregon On 1/13/19 1:08 PM, Don Wilhelm wrote: Dave, I would be cautious about looking only at the IF. That is all in front of the DSP. Certainly the DSP creates some latency, but that is not what we are talking about. The DSP latency will delay all signals. So test in the configuration that you will likely use. If using the IF output, then test only at the IF. Your question relates to the recovery time for the entire receiver. And that does include the filters, both roofing filters and the DSP filtering. Don't forget that the Hardware AGC cannot be turned off, but that does not come into play until the signal is greater than S-9+60 As A result, I believe you need to do actual testing with your particular K3 under various filtering conditions. In other words, you are asking a very complex question, and you have not given us the other configuration settings and filters to be used - other than AGC OFF. For that reason, your K3 may have a different answer than others. 73, Don W3FPR On 1/13/2019 3:43 PM, Dave Cole (NK7Z) wrote: Hi Don, Thanks for the combined brain power! I have a plan for testing if it ever gets that far. I am just trying to see if the K3 receiver recovers sufficiently fast in a general sort of way first. I believe I could look at RF levels on the IF while transmitting, (using a different transmitter and a storage scope to look at the K3 IF), then just drop the carrier while still looking at the levels with that scope. When I see signals return to the IF I have the recovery time of the receiver. I am just trying to skip that step hoping someone actually knows the recovery time of the receiver, as opposed to actual testing. If the K3 is even close, I will set up test jig for it, if not, then I'll look for a better way. __ 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] K3: Receiver recovery time
Dave, I would be cautious about looking only at the IF. That is all in front of the DSP. Certainly the DSP creates some latency, but that is not what we are talking about. The DSP latency will delay all signals. So test in the configuration that you will likely use. If using the IF output, then test only at the IF. Your question relates to the recovery time for the entire receiver. And that does include the filters, both roofing filters and the DSP filtering. Don't forget that the Hardware AGC cannot be turned off, but that does not come into play until the signal is greater than S-9+60 As A result, I believe you need to do actual testing with your particular K3 under various filtering conditions. In other words, you are asking a very complex question, and you have not given us the other configuration settings and filters to be used - other than AGC OFF. For that reason, your K3 may have a different answer than others. 73, Don W3FPR On 1/13/2019 3:43 PM, Dave Cole (NK7Z) wrote: Hi Don, Thanks for the combined brain power! I have a plan for testing if it ever gets that far. I am just trying to see if the K3 receiver recovers sufficiently fast in a general sort of way first. I believe I could look at RF levels on the IF while transmitting, (using a different transmitter and a storage scope to look at the K3 IF), then just drop the carrier while still looking at the levels with that scope. When I see signals return to the IF I have the recovery time of the receiver. I am just trying to skip that step hoping someone actually knows the recovery time of the receiver, as opposed to actual testing. If the K3 is even close, I will set up test jig for it, if not, then I'll look for a better way. __ 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] K3: Receiver recovery time
Hi Don, Thanks for the combined brain power! I have a plan for testing if it ever gets that far. I am just trying to see if the K3 receiver recovers sufficiently fast in a general sort of way first. I believe I could look at RF levels on the IF while transmitting, (using a different transmitter and a storage scope to look at the K3 IF), then just drop the carrier while still looking at the levels with that scope. When I see signals return to the IF I have the recovery time of the receiver. I am just trying to skip that step hoping someone actually knows the recovery time of the receiver, as opposed to actual testing. If the K3 is even close, I will set up test jig for it, if not, then I'll look for a better way. Thanks again for your thoughts here! 73s and thanks, Dave (NK7Z) https://www.nk7z.net Award Manager, 30MDG Grid Contest ARRL Technical Specialist ARRL Volunteer Examiner ARRL OOC for Oregon On 1/13/19 11:53 AM, Don Wilhelm wrote: Dave, I am trying to think of how you might test it. The best I can think of is to listen to both a noise source and an XG3 sending a CW string of dots. Increase the speed of the CW sent by the XG3 until you can no longer hear the noise source between dits. Then either calculate the off times for the dits or measure it on an oscilloscope. 73, Don W3FPR On 1/13/2019 2:07 PM, Dave Cole (NK7Z) wrote: Hi again Scott, Thank you for your answer, but I am not being clear. Not during break in, just sitting there in receive... If the radio is hit with an S9+ signal, how long after the S9+ signal terminates before the K3 receiver recovers enough to show an weak signal on the IF... No T/R happening, just sitting there in receive. You are close to what I am looking for... I am investigating the possibility of using the K3 as the receiver portion in a homebrew bistatic radar setup running in the HF spectrum. __ 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] K3: Receiver recovery time
You ought to be able to measure it by simply looking at the audio output with a scope. Just send some dits and look at how long it takes for the noise to reappear. You might have to use a noise source, or a low level carrier at a slightly different frequency. Of course, with the AGC off and RF gain high enough to detect a weak signal, things are going to overload. I'd run the test first with a test signal which does not overload the receiver, and then one equivalent to a very strong signal. When actually listening to the radio with AGC off, of course, it is essential to use the audio clipper to prevent hearing damage. That may or may not affect recovery time. 73, Scott K9MA On 1/13/2019 13:53, Don Wilhelm wrote: Dave, I am trying to think of how you might test it. The best I can think of is to listen to both a noise source and an XG3 sending a CW string of dots. Increase the speed of the CW sent by the XG3 until you can no longer hear the noise source between dits. Then either calculate the off times for the dits or measure it on an oscilloscope. 73, Don W3FPR On 1/13/2019 2:07 PM, Dave Cole (NK7Z) wrote: Hi again Scott, Thank you for your answer, but I am not being clear. Not during break in, just sitting there in receive... If the radio is hit with an S9+ signal, how long after the S9+ signal terminates before the K3 receiver recovers enough to show an weak signal on the IF... No T/R happening, just sitting there in receive. You are close to what I am looking for... I am investigating the possibility of using the K3 as the receiver portion in a homebrew bistatic radar setup running in the HF spectrum. __ 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 k...@sdellington.us -- 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] K3: Receiver recovery time
Dave, I am trying to think of how you might test it. The best I can think of is to listen to both a noise source and an XG3 sending a CW string of dots. Increase the speed of the CW sent by the XG3 until you can no longer hear the noise source between dits. Then either calculate the off times for the dits or measure it on an oscilloscope. 73, Don W3FPR On 1/13/2019 2:07 PM, Dave Cole (NK7Z) wrote: Hi again Scott, Thank you for your answer, but I am not being clear. Not during break in, just sitting there in receive... If the radio is hit with an S9+ signal, how long after the S9+ signal terminates before the K3 receiver recovers enough to show an weak signal on the IF... No T/R happening, just sitting there in receive. You are close to what I am looking for... I am investigating the possibility of using the K3 as the receiver portion in a homebrew bistatic radar setup running in the HF spectrum. __ 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] K3: Receiver recovery time
Hi again Scott, Thank you for your answer, but I am not being clear. Not during break in, just sitting there in receive... If the radio is hit with an S9+ signal, how long after the S9+ signal terminates before the K3 receiver recovers enough to show an weak signal on the IF... No T/R happening, just sitting there in receive. You are close to what I am looking for... I am investigating the possibility of using the K3 as the receiver portion in a homebrew bistatic radar setup running in the HF spectrum. 73s and thanks, Dave (NK7Z) https://www.nk7z.net Award Manager, 30MDG Grid Contest ARRL Technical Specialist ARRL Volunteer Examiner ARRL OOC for Oregon On 1/13/19 10:25 AM, K9MA wrote: On 1/13/2019 12:10, Dave Cole (NK7Z) wrote: Is it faster than .0001 ms? Certainly not. I'm not sure whether it is recovery time or latency, but in full break-in mode, you hear nothing between the dits above something like 10 wpm. (Even with AGC off.) With other non-DSP receivers, one can hear between the dits up to at least 30 wpm with fast AGC. Perhaps it's just the price we pay for the power of DSP. Many years ago, when there were sunspots, I recall hearing multiple echos on 15 meters. I timed them, and the time interval was about 133 ms, just about the time it takes radio waves to circumnavigate the earth. I heard them go around at least twice, and that was receiving off the back of a beam. Talk about long path! That would not have been possible with a DSP receiver. 73, Scott K9MA __ 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] K3: Receiver recovery time
On 1/13/2019 12:10, Dave Cole (NK7Z) wrote: Is it faster than .0001 ms? Certainly not. I'm not sure whether it is recovery time or latency, but in full break-in mode, you hear nothing between the dits above something like 10 wpm. (Even with AGC off.) With other non-DSP receivers, one can hear between the dits up to at least 30 wpm with fast AGC. Perhaps it's just the price we pay for the power of DSP. Many years ago, when there were sunspots, I recall hearing multiple echos on 15 meters. I timed them, and the time interval was about 133 ms, just about the time it takes radio waves to circumnavigate the earth. I heard them go around at least twice, and that was receiving off the back of a beam. Talk about long path! That would not have been possible with a DSP receiver. 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] K3: Receiver recovery time
Is it faster than .0001 ms? 73s and thanks, Dave (NK7Z) https://www.nk7z.net Award Manager, 30MDG Grid Contest ARRL Technical Specialist ARRL Volunteer Examiner ARRL OOC for Oregon On 1/13/19 9:06 AM, Don Wilhelm wrote: Dave, That depends on slow or fast AGC and the setting of the AGC DCY menu parameter. Fast is very quick - just watch the S-meter to get some visual indication. 73, Don W3FPR On 1/13/2019 11:49 AM, Dave Cole (NK7Z) wrote: Hello, Anyone able to answer this question please? In the presence of a strong signal, say -75 db, (or around S9), once that signal ceases, how long does it take the K3 receiver to return to normal receive capability again? __ 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] K3: Receiver recovery time
Sorry, I forgot to add, AGC off... 73s and thanks, Dave (NK7Z) https://www.nk7z.net Award Manager, 30MDG Grid Contest ARRL Technical Specialist ARRL Volunteer Examiner ARRL OOC for Oregon On 1/13/19 9:06 AM, Don Wilhelm wrote: Dave, That depends on slow or fast AGC and the setting of the AGC DCY menu parameter. Fast is very quick - just watch the S-meter to get some visual indication. 73, Don W3FPR On 1/13/2019 11:49 AM, Dave Cole (NK7Z) wrote: Hello, Anyone able to answer this question please? In the presence of a strong signal, say -75 db, (or around S9), once that signal ceases, how long does it take the K3 receiver to return to normal receive capability again? __ 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] K3: Receiver recovery time
Dave, That depends on slow or fast AGC and the setting of the AGC DCY menu parameter. Fast is very quick - just watch the S-meter to get some visual indication. 73, Don W3FPR On 1/13/2019 11:49 AM, Dave Cole (NK7Z) wrote: Hello, Anyone able to answer this question please? In the presence of a strong signal, say -75 db, (or around S9), once that signal ceases, how long does it take the K3 receiver to return to normal receive capability again? __ 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] K3: Receiver recovery time
Hello, Anyone able to answer this question please? In the presence of a strong signal, say -75 db, (or around S9), once that signal ceases, how long does it take the K3 receiver to return to normal receive capability again? -- 73s and thanks, Dave (NK7Z) https://www.nk7z.net Award Manager, 30MDG Grid Contest ARRL Technical Specialist ARRL Volunteer Examiner ARRL OOC for Oregon __ 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
