Re: [Elecraft] Installed K3EXREF
Igor and Brett, Thanks, you've answered my questions. Regarding the application, I occasionally participate in FMT exercises/competitions and have always done pretty well (within 75 milliHertz) with nothing but on-air references like WWV, lots of FFT averaging, and linear interpolation of VFO error. Since the FMT pursuit is occasional, I don't want to invest too much to get the desired result since I still have to obtain a Trimble Thunderbolt or similar GPSDO 10 MHz reference. Thanks again. Dan AE9K -- View this message in context: http://elecraft.365791.n2.nabble.com/Installed-K3EXREF-tp6188288p6389309.html Sent from the Elecraft mailing list archive at 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] Installed K3EXREF
I was one of the beta testers and I tested the unit with the standard oscillator. I haven't run into any issues and found the fixed error across all bands to be quite nice. I never saw more than about 3Hz of error no matter the frequency on the VFO dial. Thats not to mean that if you have a standard oscillator that is at the outside of its bell that you may not have enough pull with the KEXTREF3 to pull things into place. Personally I never ran into this issue in my testing however I will probably also get the tighter tolerance rock for use when away from the 10Mhz reference. I find it really nice to know that the radio is on frequency... However the P3 still has to warm up before its frequency reference is accurate... ;) ~Brett (N7MG) On Fri, May 20, 2011 at 7:47 PM, Dan AE9K wrote: > Ed, > > Thanks for the response. Let me clarify my question. I'm wondering if the > KTCXO3 0.5 ppm oscillator can be omitted and still get great results with > the K3EXREF and the standard 5 ppm oscillator. This is of interest because > I intend to acquire the K3EXREF but do not have the KTCXO3 and would prefer > not to buy it if it doesn't add any benefit. > > My logic: If the K3EXREF adjusts the TCXO (via REF CAL) every 4 seconds, > then why not let it adjust the standard K3 TCXO instead of having it adjust > the optional KTCXO3 oscillator? > > Even though the two oscillators differ by an order of magnitude in their > error, does that error make a difference when the K3EXREF adjustments are > every four seconds? > > ps - During your beta testing were you using the standard K3 5 ppm > oscillator or the KTCXO3 0.5 ppm oscillator? I didn't find mention of that > on your web site. > > Dan > AE9K > > -- > View this message in context: > http://elecraft.365791.n2.nabble.com/Installed-K3EXREF-tp6188288p6388532.html > Sent from the Elecraft mailing list archive at 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 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] Installed K3EXREF
Dan, I cannot imagine ham radio application that requires stability and accuracy better than standard K3 oscillator with K3EXREF, provided your reference oscillator is good enough for the toughest amateur radio application. Don't forget, with K3EXREF you still need some external reference oscillator, either good calibrated OCXO, some kind of timing module based on GPS technology (like Thunderbolt etc.) or Rubidium oscillator, like Symmetricom/Datum LPRO or one of the FEI products. Note that in case of OCXO, it will need to be periodically calibrated against better reference. However, if you plan to use K3 on the go without k3EXREF and need better accuracy/stability, then you probably want to consider KTCXO3. Using permanently KTCXO3 with K3EXREF seems like waste of money, this will not give much advantage over same setup with standard K3 oscillator. 73, Igor, N1YX -Original Message- From: elecraft-boun...@mailman.qth.net [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Dan AE9K Sent: Friday, May 20, 2011 10:48 PM To: elecraft@mailman.qth.net Subject: Re: [Elecraft] Installed K3EXREF Ed, Thanks for the response. Let me clarify my question. I'm wondering if the KTCXO3 0.5 ppm oscillator can be omitted and still get great results with the K3EXREF and the standard 5 ppm oscillator. This is of interest because I intend to acquire the K3EXREF but do not have the KTCXO3 and would prefer not to buy it if it doesn't add any benefit. My logic: If the K3EXREF adjusts the TCXO (via REF CAL) every 4 seconds, then why not let it adjust the standard K3 TCXO instead of having it adjust the optional KTCXO3 oscillator? Even though the two oscillators differ by an order of magnitude in their error, does that error make a difference when the K3EXREF adjustments are every four seconds? ps - During your beta testing were you using the standard K3 5 ppm oscillator or the KTCXO3 0.5 ppm oscillator? I didn't find mention of that on your web site. Dan AE9K -- View this message in context: http://elecraft.365791.n2.nabble.com/Installed-K3EXREF-tp6188288p6388532.htm l Sent from the Elecraft mailing list archive at 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 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] Installed K3EXREF
I would use the KTCXO3 if I ever intended to use it apart from the reference source. I take my K3 to multi op contest weekends, field day, IOTA dxpedition class. On Fri, May 20, 2011 at 10:47 PM, Dan AE9K wrote: > Ed, > > Thanks for the response. Let me clarify my question. I'm wondering if the > KTCXO3 0.5 ppm oscillator can be omitted and still get great results with > the K3EXREF and the standard 5 ppm oscillator. This is of interest because > I intend to acquire the K3EXREF but do not have the KTCXO3 and would prefer > not to buy it if it doesn't add any benefit. > > My logic: If the K3EXREF adjusts the TCXO (via REF CAL) every 4 seconds, > then why not let it adjust the standard K3 TCXO instead of having it adjust > the optional KTCXO3 oscillator? > > Even though the two oscillators differ by an order of magnitude in their > error, does that error make a difference when the K3EXREF adjustments are > every four seconds? > > ps - During your beta testing were you using the standard K3 5 ppm > oscillator or the KTCXO3 0.5 ppm oscillator? I didn't find mention of that > on your web site. > > Dan > AE9K > > -- > View this message in context: > http://elecraft.365791.n2.nabble.com/Installed-K3EXREF-tp6188288p6388532.html > Sent from the Elecraft mailing list archive at 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 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] Installed K3EXREF
Ed, Thanks for the response. Let me clarify my question. I'm wondering if the KTCXO3 0.5 ppm oscillator can be omitted and still get great results with the K3EXREF and the standard 5 ppm oscillator. This is of interest because I intend to acquire the K3EXREF but do not have the KTCXO3 and would prefer not to buy it if it doesn't add any benefit. My logic: If the K3EXREF adjusts the TCXO (via REF CAL) every 4 seconds, then why not let it adjust the standard K3 TCXO instead of having it adjust the optional KTCXO3 oscillator? Even though the two oscillators differ by an order of magnitude in their error, does that error make a difference when the K3EXREF adjustments are every four seconds? ps - During your beta testing were you using the standard K3 5 ppm oscillator or the KTCXO3 0.5 ppm oscillator? I didn't find mention of that on your web site. Dan AE9K -- View this message in context: http://elecraft.365791.n2.nabble.com/Installed-K3EXREF-tp6188288p6388532.html Sent from the Elecraft mailing list archive at 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] Installed K3EXREF
Dan, The K3EXREF controls the TCXO-3 to maintain a near zero offset compared with an external frequency reference. The K3 synthesizers are still referenced to the TCXO-3 all the time. So during the interval between frequency corrections, roughly every four seconds, the radio frequency is controlled by the TCXO-3. So frequency drift rate is not affected by the K3EXREF during this interval and only periodically corrected. But this does keep the TCXO within 0.05 ppm vs 0.5 ppm. I was a beta tester and you can see my test results here: http://www.kl7uw.com/K3EXREF.htm The largest error observed was +2.5 Hz on 6m. -- Message: 29 Date: Fri, 20 May 2011 08:58:55 -0700 (PDT) From: Dan AE9K Subject: Re: [Elecraft] Installed K3EXREF To: elecraft@mailman.qth.net Message-ID: <1305907135916-6386626.p...@n2.nabble.com> Content-Type: text/plain; charset=us-ascii This may be a naive question but... If the K3EXREF keeps the K3's reference oscillator within 2 Hz, then what value is there in using the K3EXREF in conjunction with the KTCXO3 instead of just the native K3 oscillator? K3EXREF: 2 Hz error @ 14 MHz : 0.1 ppm K3TCXO3: 7 Hz error @ 14 MHz : 0.5 ppm Is the stability in ppm an instantaneous measurement of random error and not a measurement potential drift over some time delta? If this is true then using the K3EXREF alone presumably would exhibit the 5 ppm error of the native oscillator in the 4 to 8 second gaps between K3EXREF syncs. This would make the case for replacing the native oscillator with the K3TCXO3. If the stability is measured over time, however, then the K3EXREF and native oscillator would appear to be sufficient since oscillator drift is insignificant in the 4 to 8 second time span. Just curious. Dan AE9K 73, Ed - KL7UW, WD2XSH/45 == BP40IQ 500 KHz - 10-GHz www.kl7uw.com EME: 50-1.1kw?, 144-1.4kw, 432-100w, 1296-testing*, 3400-? DUBUS Magazine USA Rep dubus...@hotmail.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] Installed K3EXREF
This may be a naive question but... If the K3EXREF keeps the K3's reference oscillator within 2 Hz, then what value is there in using the K3EXREF in conjunction with the KTCXO3 instead of just the native K3 oscillator? K3EXREF: 2 Hz error @ 14 MHz : 0.1 ppm K3TCXO3: 7 Hz error @ 14 MHz : 0.5 ppm Is the stability in ppm an instantaneous measurement of random error and not a measurement potential drift over some time delta? If this is true then using the K3EXREF alone presumably would exhibit the 5 ppm error of the native oscillator in the 4 to 8 second gaps between K3EXREF syncs. This would make the case for replacing the native oscillator with the K3TCXO3. If the stability is measured over time, however, then the K3EXREF and native oscillator would appear to be sufficient since oscillator drift is insignificant in the 4 to 8 second time span. Just curious. Dan AE9K -- View this message in context: http://elecraft.365791.n2.nabble.com/Installed-K3EXREF-tp6188288p6386626.html Sent from the Elecraft mailing list archive at 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] Installed K3EXREF
You should try it. --- On Fri, 3/25/11, n...@n5ge.com wrote: > From: n...@n5ge.com > Subject: Re: [Elecraft] Installed K3EXREF > To: elecraft@mailman.qth.net > Date: Friday, March 25, 2011, 1:02 PM > > Glad you're going to give it a rest. > > N5GE > > On Fri, 25 Mar 2011 09:45:31 -0700 (PDT), Wes Stewart > > wrote: > > >I'm not picking on Paul, this is just a handy place to > reply. I'm going to say this one more time (the first time > was two years ago). > > > >I really don't understand all of the fuss about 1 Hz > accuracy when just changing the K3 Width and Shift controls > moves the frequency more than that and this is band > dependent. > > > >On ten-meters I can listen to a crystal-controlled > source and hear the beat note change as Shift and Width are > adjusted. > > > >Elecraft considers its frequency conversion scheme to > be proprietary but it's obvious that not all of the > oscillators are moving at the same rate. > > > >Wes N7WS > > > >--- On Sat, 3/19/11, Paul Christensen > wrote: > > > >> I installed it on Friday in about 30 > >> minutes, but I'm comfortable with my > >> way around the K3. I would think that most > users > >> could install it in about > >> an hour or less. Installation is actually very > simple > >> with very few parts > >> involved. K3EXREF came with an SMA connector and > SMA > >> to BNC between-series > >> adapter. > >> > >> Performance is exactly as promised by Elecraft. > >> Although K3EXREF will not > >> phase lock the K3 to the external frequency > source, I'm > >> finding that it > >> stays within 1 Hz on 20m when locked to CHU at > 14.670 > >> MHz. I'm also > >> finding that testing for zero-beat to WWV at 10 > MHz is not > >> a good idea in my > >> shack, and perhaps yours too. There are many 10 > MHz > >> signals being emitted > >> by nearby appliances, LAN routers, security > system, > >> Ethernet boards, etc. > >> That common, even frequency is everywhere in a > household > >> these days. > >> > >> In much of North America, CHU is an excellent > source for > >> testing since it > >> keeps cesium accuracy like WWV but the odd > frequency of CHU > >> is a real > >> benefit since the chance for beating against > extraneous > >> signals is much > >> smaller than at 10 MHz. Testing at a higher > frequency > >> rather than say the > >> MW broadcast band also provides for a reasonably > good > >> account of how the > >> K3EXREF performs. After installation, I > >> would also suggest not trying to > >> test zero beat K3EXREF against commercial MW or SW > BC > >> stations since their > >> carriers are allowed to deviate much more than > the > >> cesium-based time and > >> frequency standards of CHU and WWV. Commercial > AM > >> broadcast station > >> frequencies are typically only accurate to about > +/- 20 Hz > >> although most are > >> better than that. > >> > >> The K3's 49 MHz oscillator is only adjusted at > intervals > >> between 4 and 8 > >> seconds by K3EXREF in order to minimize jitter. > The > >> K3 retains its original > >> phase noise performance since the external > reference is not > >> used internal to > >> the K3's frequency generating scheme. Think of > it > >> this way -- K3EXREF is > >> like lightly touching the 49 MHz oscillator with a > feather > >> every few seconds > >> if necessary to keep it within 1 Hz or so. Also, > the > >> K3 frequency stays > >> accurate even at the moment of powering up the > K3. > >> Kinda' fun to watch the > >> 49 MHz oscillator display change during warm-up as > it's > >> being corrected and > >> compared against the external reference. > >> > >> External references: There are three primary > types, > >> and all can be > >> purchased for less than USD $150 on the used > market. > >> Cesium standards (a > >> fourth type) are also available but are generally > much more > >> expensive, > >> complicated, and won't offer any benefit to K3 > users since > >> K3EXREF limits > >> resolution and accuracy to about 1 H
Re: [Elecraft] Installed K3EXREF
Glad you're going to give it a rest. N5GE On Fri, 25 Mar 2011 09:45:31 -0700 (PDT), Wes Stewart wrote: >I'm not picking on Paul, this is just a handy place to reply. I'm going to say >this one more time (the first time was two years ago). > >I really don't understand all of the fuss about 1 Hz accuracy when just >changing the K3 Width and Shift controls moves the frequency more than that >and this is band dependent. > >On ten-meters I can listen to a crystal-controlled source and hear the beat >note change as Shift and Width are adjusted. > >Elecraft considers its frequency conversion scheme to be proprietary but it's >obvious that not all of the oscillators are moving at the same rate. > >Wes N7WS > >--- On Sat, 3/19/11, Paul Christensen wrote: > >> I installed it on Friday in about 30 >> minutes, but I'm comfortable with my >> way around the K3. I would think that most users >> could install it in about >> an hour or less. Installation is actually very simple >> with very few parts >> involved. K3EXREF came with an SMA connector and SMA >> to BNC between-series >> adapter. >> >> Performance is exactly as promised by Elecraft. >> Although K3EXREF will not >> phase lock the K3 to the external frequency source, I'm >> finding that it >> stays within 1 Hz on 20m when locked to CHU at 14.670 >> MHz. I'm also >> finding that testing for zero-beat to WWV at 10 MHz is not >> a good idea in my >> shack, and perhaps yours too. There are many 10 MHz >> signals being emitted >> by nearby appliances, LAN routers, security system, >> Ethernet boards, etc. >> That common, even frequency is everywhere in a household >> these days. >> >> In much of North America, CHU is an excellent source for >> testing since it >> keeps cesium accuracy like WWV but the odd frequency of CHU >> is a real >> benefit since the chance for beating against extraneous >> signals is much >> smaller than at 10 MHz. Testing at a higher frequency >> rather than say the >> MW broadcast band also provides for a reasonably good >> account of how the >> K3EXREF performs. After installation, I >> would also suggest not trying to >> test zero beat K3EXREF against commercial MW or SW BC >> stations since their >> carriers are allowed to deviate much more than the >> cesium-based time and >> frequency standards of CHU and WWV. Commercial AM >> broadcast station >> frequencies are typically only accurate to about +/- 20 Hz >> although most are >> better than that. >> >> The K3's 49 MHz oscillator is only adjusted at intervals >> between 4 and 8 >> seconds by K3EXREF in order to minimize jitter. The >> K3 retains its original >> phase noise performance since the external reference is not >> used internal to >> the K3's frequency generating scheme. Think of it >> this way -- K3EXREF is >> like lightly touching the 49 MHz oscillator with a feather >> every few seconds >> if necessary to keep it within 1 Hz or so. Also, the >> K3 frequency stays >> accurate even at the moment of powering up the K3. >> Kinda' fun to watch the >> 49 MHz oscillator display change during warm-up as it's >> being corrected and >> compared against the external reference. >> >> External references: There are three primary types, >> and all can be >> purchased for less than USD $150 on the used market. >> Cesium standards (a >> fourth type) are also available but are generally much more >> expensive, >> complicated, and won't offer any benefit to K3 users since >> K3EXREF limits >> resolution and accuracy to about 1 Hz. >> >> The first type is the GPS Disciplined Oscillator >> (GPS-DO). This type of >> standard locks itself onto the visible GPS satellites >> orbiting the sky. >> Requires a GPS antenna and is self-calibrating to the GPS >> satellites. The >> GPS-DO's time and frequency averages from the visible >> satellites, each >> satellite having it's own on-board cesium-based >> oscillator. Long-term >> accuracy is usually good to at least 1 x 10^-11. >> Extreme accuracy and only >> a magnitude or two behind cesium. Look for >> Hewlett-Packard Z3801A, Z3816A, >> Trimble Thunderbolt, Brandywine, Symmetricon, and Datum >> models. Short list, >> but many others available. >> >> Rubidium is the next type. No GPS tracking >> needed. Accuracy commensurate >> with GPS-DO. No antenna required. Long-term >> performance is highly >> dependent on the quality of the optical beam from the >> rubidium pump lamp. >> Look for EF Efratom, Datum, >> >> Third, is a high quality oven-controlled crystal oscillator >> (OCXO). >> Requires periodic calibration. Accuracy good to at >> least +/- 0.05 ppm and >> offer the best phase noise performance among the three >> types of oscillators, >> but as noted earlier, the excellent phase noise attributes >> of the OCXO will >> not be carried over to the K3. >> >> A shack reference oscillator is good for use with other >> equipment too (e.g., >> frequency count
Re: [Elecraft] Installed K3EXREF
Wes Stewart wrote: > I really don't understand all of the fuss about 1 Hz accuracy Because so many customers asked for it. I'll leave it to them to list their reasons, but in my case, I like being dead-on over a wide range of temperatures without having to occasionally recheck my manual REF CAL setting using a beat note with WWV. > when just changing the K3 Width and Shift controls moves the > frequency more than that SHIFT and WIDTH move the I.F. by an accurate amount, and should not introduce any error in the operating frequency beyond that of normal DDS granularity, which can be +/- 1 Hz or so depending on the band. > On ten-meters I can listen to a crystal-controlled source and hear > the beat note change as Shift and Width are adjusted. That is due to DDS granularity. There is no such error where phase coherency really counts--in diversity mode. In that case the two synthesizers are always phase-locked as long as the crystal filter offsets are matched. > Elecraft considers its frequency conversion scheme to be proprietary > but it's obvious that not all of the oscillators are moving at the > same rate. They are all subject to our DDS step size of aprox. 1/5th Hz. In diversity mode the DDS words are identical, but in other cases the two synths can be off by this amount in either direction, resulting in a small tuning error that is proportional to operating frequency. It amounts to about +/- 1 Hz. 73, Wayne __ 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] Installed K3EXREF
I'm not picking on Paul, this is just a handy place to reply. I'm going to say this one more time (the first time was two years ago). I really don't understand all of the fuss about 1 Hz accuracy when just changing the K3 Width and Shift controls moves the frequency more than that and this is band dependent. On ten-meters I can listen to a crystal-controlled source and hear the beat note change as Shift and Width are adjusted. Elecraft considers its frequency conversion scheme to be proprietary but it's obvious that not all of the oscillators are moving at the same rate. Wes N7WS --- On Sat, 3/19/11, Paul Christensen wrote: > I installed it on Friday in about 30 > minutes, but I'm comfortable with my > way around the K3. I would think that most users > could install it in about > an hour or less. Installation is actually very simple > with very few parts > involved. K3EXREF came with an SMA connector and SMA > to BNC between-series > adapter. > > Performance is exactly as promised by Elecraft. > Although K3EXREF will not > phase lock the K3 to the external frequency source, I'm > finding that it > stays within 1 Hz on 20m when locked to CHU at 14.670 > MHz. I'm also > finding that testing for zero-beat to WWV at 10 MHz is not > a good idea in my > shack, and perhaps yours too. There are many 10 MHz > signals being emitted > by nearby appliances, LAN routers, security system, > Ethernet boards, etc. > That common, even frequency is everywhere in a household > these days. > > In much of North America, CHU is an excellent source for > testing since it > keeps cesium accuracy like WWV but the odd frequency of CHU > is a real > benefit since the chance for beating against extraneous > signals is much > smaller than at 10 MHz. Testing at a higher frequency > rather than say the > MW broadcast band also provides for a reasonably good > account of how the > K3EXREF performs. After installation, I > would also suggest not trying to > test zero beat K3EXREF against commercial MW or SW BC > stations since their > carriers are allowed to deviate much more than the > cesium-based time and > frequency standards of CHU and WWV. Commercial AM > broadcast station > frequencies are typically only accurate to about +/- 20 Hz > although most are > better than that. > > The K3's 49 MHz oscillator is only adjusted at intervals > between 4 and 8 > seconds by K3EXREF in order to minimize jitter. The > K3 retains its original > phase noise performance since the external reference is not > used internal to > the K3's frequency generating scheme. Think of it > this way -- K3EXREF is > like lightly touching the 49 MHz oscillator with a feather > every few seconds > if necessary to keep it within 1 Hz or so. Also, the > K3 frequency stays > accurate even at the moment of powering up the K3. > Kinda' fun to watch the > 49 MHz oscillator display change during warm-up as it's > being corrected and > compared against the external reference. > > External references: There are three primary types, > and all can be > purchased for less than USD $150 on the used market. > Cesium standards (a > fourth type) are also available but are generally much more > expensive, > complicated, and won't offer any benefit to K3 users since > K3EXREF limits > resolution and accuracy to about 1 Hz. > > The first type is the GPS Disciplined Oscillator > (GPS-DO). This type of > standard locks itself onto the visible GPS satellites > orbiting the sky. > Requires a GPS antenna and is self-calibrating to the GPS > satellites. The > GPS-DO's time and frequency averages from the visible > satellites, each > satellite having it's own on-board cesium-based > oscillator. Long-term > accuracy is usually good to at least 1 x 10^-11. > Extreme accuracy and only > a magnitude or two behind cesium. Look for > Hewlett-Packard Z3801A, Z3816A, > Trimble Thunderbolt, Brandywine, Symmetricon, and Datum > models. Short list, > but many others available. > > Rubidium is the next type. No GPS tracking > needed. Accuracy commensurate > with GPS-DO. No antenna required. Long-term > performance is highly > dependent on the quality of the optical beam from the > rubidium pump lamp. > Look for EF Efratom, Datum, > > Third, is a high quality oven-controlled crystal oscillator > (OCXO). > Requires periodic calibration. Accuracy good to at > least +/- 0.05 ppm and > offer the best phase noise performance among the three > types of oscillators, > but as noted earlier, the excellent phase noise attributes > of the OCXO will > not be carried over to the K3. > > A shack reference oscillator is good for use with other > equipment too (e.g., > frequency counter). Although a bit lossy, > I currectly use a Mini-Circuits > passive three-way splitter, but one can purchase a > distribution amp to feed > many pieces of equipment from a single oscillator. > Unlike the splitter, a > DA offers unity
Re: [Elecraft] Installed K3EXREF
GEORGE, So they include the antenna, and what would the cost be for one without the gold case? W4ISH Bill On Mar 21, 2011, at 8:50 AM, George Dubovsky [via Elecraft] wrote: List, I know a thing or three about those Trimble T'bolts; I am a design engineer for the company that made the (previous generation) equipment that is now being surplussed in several parts of the world. There is no domestic or Chinese thunderbolt; there is the commercial version (silver and red case with internal dc-dc converter - runs off of 24 VDC) and the OEM version (thin gold case, sometimes with the original 3 dB splitter still attached to the case, no power supply). The OEM version being surplussed contains the same GPSDO guts as the commercial version, with two exceptions: the power connector is on the opposite side of the pwb, and one Zener diode is changed to move the trip point for the DC Power alarm to a lower value. Also, the newer units have a later date code Dallas Semi temp sensor that does not report temperature in the finer steps of the earlier date codes - this is not an issue for most folks. The OEM units require +5 , +12, and -7 to -12 VDC at modest current requirements. It is easy to find a surplus power supply that supports these units and it is just as easy to roll your own. I usually have a few tested OEM units available for sale, with or without the gold case (if you want to build it into your own cabinet). In addition, if you want the ultimate K3 accessory, I have a NIB Symmetricom Starloc II Plus, GPS-disciplined Rubidium oscillator for sale. Let me know if you want to know anything else about the Thunderbolt, or if you want one of your own. 73, geo - n4ua On Sun, Mar 20, 2011 at 9:05 PM, Jerry Muller <[hidden email]> wrote: > This was an excellent explanation. > > I got a Trimble Thunderbolt off eBay for less than 200 bucks. It came from > China and came with an antenna and power supply. If you are going to get > one > of the ones that come from China, make sure you get the power supply with > it. The domestic Thunderbolts have a unipolar supply but the ones from > China > were specials and require a special bipolar power supply. As long as you're > getting the power supply with it, you're OK. I have not noticed any noise > from the power supply from China. I expect ferrites may solve the problem > if > found. > > It works just fine with the stock Thunderbolt software. I've had mine for > about 6 months and I've run tests using the Thunderbolt software. The PC > monitoring software allows you to monitor the errors detected and log them. > The accuracy is quite good. Although I see occasional errors greater than 1 > part in 10^9, most of the measured errors are far less than 1 part in 10^9. > I can't find any of the spreadsheets I generated (from many hours of > operation) right now but I seem to recall that 1 sigma was down around 1 > part in 10^10. This translates into a 1 Hz error at 10 GHz. The +/- 1 Hz > error in the K3 is much greater than the accuracy of the GPSDO > > My primary reason for getting the GPSDO was for microwave and EME > operations. Being able to use it with the K3 is a plus. I'm likely to be an > early adopter of the production units when they become available. I will > probably order my second K3 with a K3EXREF. > > Jerry - K0TV > > - Original Message - > From: "Paul Christensen" <[hidden email]> > To: <[hidden email]> > Sent: Saturday, March 19, 2011 9:34 PM > Subject: Re: [Elecraft] Installed K3EXREF > > > >I installed it on Friday in about 30 minutes, but I'm comfortable with my > > way around the K3. I would think that most users could install it in > > about > > an hour or less. Installation is actually very simple with very few > parts > > involved. K3EXREF came with an SMA connector and SMA to BNC > > between-series > > adapter. > > > > Performance is exactly as promised by Elecraft. Although K3EXREF will > not > > phase lock the K3 to the external frequency source, I'm finding that it > > stays within 1 Hz on 20m when locked to CHU at 14.670 MHz. I'm also > > finding that testing for zero-beat to WWV at 10 MHz is not a good idea in > > my > > shack, and perhaps yours too. There are many 10 MHz signals being > emitted > > by nearby appliances, LAN routers, security system, Ethernet boards, etc. > > That common, even frequency is everywhere in a household these days. > > > > In much of North America, CHU is an excellent source for testing since it > > keeps cesium accuracy like WWV but the odd frequency of CHU is a real > > benefit since the chan
Re: [Elecraft] Installed K3EXREF
And EME at 23cm given the rest of my station can be linked to my G3RUH GPS stabilized 10MHz ref. 73, tom n4zpt On 3/20/2011 11:51 AM, Jim Miller wrote: > I'm guessing this is really useful for EME at UHF. > > jim ab3cv > __ > 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] Installed K3EXREF
List, I know a thing or three about those Trimble T'bolts; I am a design engineer for the company that made the (previous generation) equipment that is now being surplussed in several parts of the world. There is no domestic or Chinese thunderbolt; there is the commercial version (silver and red case with internal dc-dc converter - runs off of 24 VDC) and the OEM version (thin gold case, sometimes with the original 3 dB splitter still attached to the case, no power supply). The OEM version being surplussed contains the same GPSDO guts as the commercial version, with two exceptions: the power connector is on the opposite side of the pwb, and one Zener diode is changed to move the trip point for the DC Power alarm to a lower value. Also, the newer units have a later date code Dallas Semi temp sensor that does not report temperature in the finer steps of the earlier date codes - this is not an issue for most folks. The OEM units require +5 , +12, and -7 to -12 VDC at modest current requirements. It is easy to find a surplus power supply that supports these units and it is just as easy to roll your own. I usually have a few tested OEM units available for sale, with or without the gold case (if you want to build it into your own cabinet). In addition, if you want the ultimate K3 accessory, I have a NIB Symmetricom Starloc II Plus, GPS-disciplined Rubidium oscillator for sale. Let me know if you want to know anything else about the Thunderbolt, or if you want one of your own. 73, geo - n4ua On Sun, Mar 20, 2011 at 9:05 PM, Jerry Muller wrote: > This was an excellent explanation. > > I got a Trimble Thunderbolt off eBay for less than 200 bucks. It came from > China and came with an antenna and power supply. If you are going to get > one > of the ones that come from China, make sure you get the power supply with > it. The domestic Thunderbolts have a unipolar supply but the ones from > China > were specials and require a special bipolar power supply. As long as you're > getting the power supply with it, you're OK. I have not noticed any noise > from the power supply from China. I expect ferrites may solve the problem > if > found. > > It works just fine with the stock Thunderbolt software. I've had mine for > about 6 months and I've run tests using the Thunderbolt software. The PC > monitoring software allows you to monitor the errors detected and log them. > The accuracy is quite good. Although I see occasional errors greater than 1 > part in 10^9, most of the measured errors are far less than 1 part in 10^9. > I can't find any of the spreadsheets I generated (from many hours of > operation) right now but I seem to recall that 1 sigma was down around 1 > part in 10^10. This translates into a 1 Hz error at 10 GHz. The +/- 1 Hz > error in the K3 is much greater than the accuracy of the GPSDO > > My primary reason for getting the GPSDO was for microwave and EME > operations. Being able to use it with the K3 is a plus. I'm likely to be an > early adopter of the production units when they become available. I will > probably order my second K3 with a K3EXREF. > > Jerry - K0TV > > - Original Message - > From: "Paul Christensen" > To: > Sent: Saturday, March 19, 2011 9:34 PM > Subject: Re: [Elecraft] Installed K3EXREF > > > >I installed it on Friday in about 30 minutes, but I'm comfortable with my > > way around the K3. I would think that most users could install it in > > about > > an hour or less. Installation is actually very simple with very few > parts > > involved. K3EXREF came with an SMA connector and SMA to BNC > > between-series > > adapter. > > > > Performance is exactly as promised by Elecraft. Although K3EXREF will > not > > phase lock the K3 to the external frequency source, I'm finding that it > > stays within 1 Hz on 20m when locked to CHU at 14.670 MHz. I'm also > > finding that testing for zero-beat to WWV at 10 MHz is not a good idea in > > my > > shack, and perhaps yours too. There are many 10 MHz signals being > emitted > > by nearby appliances, LAN routers, security system, Ethernet boards, etc. > > That common, even frequency is everywhere in a household these days. > > > > In much of North America, CHU is an excellent source for testing since it > > keeps cesium accuracy like WWV but the odd frequency of CHU is a real > > benefit since the chance for beating against extraneous signals is much > > smaller than at 10 MHz. Testing at a higher frequency rather than say > the > > MW broadcast band also provides for a reasonably good account of how the > > K3EXREF performs. After installation, I would also suggest not trying > to > > test zero be
[Elecraft] Installed K3EXREF
Hello Edward, Just a quick question. Would the existing K3 + TCXO3-1 + K144V be good enough for casual SSB operation in 2m? How would this combination be compared with modern V/U radio equipped with OCXO such as Icom IC9100 in terms of frequency stability in 2 m ? Can I understand that K3EXPEF is only required for GHz operation? Thanks for your advice in advance. cheers, Johnny VR2XMC 寄件人﹕ Edward R. Cole 收件人﹕ Elecraft@mailman.qth.net 傳送日期﹕ 2011/3/21 (一) 7:51:37 PM 主題： [Elecraft] Installed K3EXREF Matt, I agree that the biggest challenge is getting UHF and mw LO's to be on frequency. Due to the multiplication of the LO, any inaccuracy or instability is magnified. But it is just as important that the IF radio used with those transverters have good frequency characteristics as they are translated up to the operating frequency. Another little annoyance is operating on nets where stations are all over the place in frequency. As NC it is tough to keep tuning each offset out in a quick paced round table style net. I host a 2m-SSB net where a couple stations insist on being 100-Hz low (they maintain their radio dial says they are "on-freq"). With the K3EXREF and a PLL locked transverter I can be assured that my frequency is correct. Also, operating any mode that has a high duty cycle of key-down causes temperature related drift. K3EXREF will solve that. The K3EXREF is both accurate and stabile in freq. 73, Ed - KL7UW -- Message: 37 Date: Sun, 20 Mar 2011 18:40:52 -0700 From: Matt Zilmer Subject: Re: [Elecraft] Installed K3EXREF To: "Jerry Muller" Cc: elecraft@mailman.qth.net Message-ID: Content-Type: text/plain; charset=us-ascii Most of the applications where "extreme accuracy" is really needed are transverters at microwave freqs. That is a lot of the feedback received here. I believe that. It makes the most sense. A couple of PPM is plenty good for HF, imho. But there are those of us that have the frequency fetish. See the FMT for example. Dunno how many OO's have the capability to measure overall output to within a few Hz, nor how many can measure amplitudes to required levels of suppression. There must be some, and some are K3 owners. I got cited once, in 1973 by the FCC monitoring station in Kingsville, TX, when my dial marker was off by about 1 KHz. With the K3, nothing like that is a worry. But the K3EXREF makes it a certainty that you will have no excuse 73, matt W6NIA K3 #24 73, Ed - KL7UW, WD2XSH/45 == BP40IQ 500 KHz - 10-GHz www.kl7uw.com EME: 144-1.4kw, 432-100w, 1296-testing*, 3400-winter? DUBUS Magazine USA Rep dubus...@hotmail.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 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] Installed K3EXREF
Matt, I agree that the biggest challenge is getting UHF and mw LO's to be on frequency. Due to the multiplication of the LO, any inaccuracy or instability is magnified. But it is just as important that the IF radio used with those transverters have good frequency characteristics as they are translated up to the operating frequency. Another little annoyance is operating on nets where stations are all over the place in frequency. As NC it is tough to keep tuning each offset out in a quick paced round table style net. I host a 2m-SSB net where a couple stations insist on being 100-Hz low (they maintain their radio dial says they are "on-freq"). With the K3EXREF and a PLL locked transverter I can be assured that my frequency is correct. Also, operating any mode that has a high duty cycle of key-down causes temperature related drift. K3EXREF will solve that. The K3EXREF is both accurate and stabile in freq. 73, Ed - KL7UW -- Message: 37 Date: Sun, 20 Mar 2011 18:40:52 -0700 From: Matt Zilmer Subject: Re: [Elecraft] Installed K3EXREF To: "Jerry Muller" Cc: elecraft@mailman.qth.net Message-ID: Content-Type: text/plain; charset=us-ascii Most of the applications where "extreme accuracy" is really needed are transverters at microwave freqs. That is a lot of the feedback received here. I believe that. It makes the most sense. A couple of PPM is plenty good for HF, imho. But there are those of us that have the frequency fetish. See the FMT for example. Dunno how many OO's have the capability to measure overall output to within a few Hz, nor how many can measure amplitudes to required levels of suppression. There must be some, and some are K3 owners. I got cited once, in 1973 by the FCC monitoring station in Kingsville, TX, when my dial marker was off by about 1 KHz. With the K3, nothing like that is a worry. But the K3EXREF makes it a certainty that you will have no excuse 73, matt W6NIA K3 #24 73, Ed - KL7UW, WD2XSH/45 == BP40IQ 500 KHz - 10-GHz www.kl7uw.com EME: 144-1.4kw, 432-100w, 1296-testing*, 3400-winter? DUBUS Magazine USA Rep dubus...@hotmail.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] Installed K3EXREF
Most of the applications where "extreme accuracy" is really needed are transverters at microwave freqs. That is a lot of the feedback received here. I believe that. It makes the most sense. A couple of PPM is plenty good for HF, imho. But there are those of us that have the frequency fetish. See the FMT for example. Dunno how many OO's have the capability to measure overall output to within a few Hz, nor how many can measure amplitudes to required levels of suppression. There must be some, and some are K3 owners. I got cited once, in 1973 by the FCC monitoring station in Kingsville, TX, when my dial marker was off by about 1 KHz. With the K3, nothing like that is a worry. But the K3EXREF makes it a certainty that you will have no excuse 73, matt W6NIA K3 #24 On Sun, 20 Mar 2011 21:12:19 -0400, you wrote: >Speaking of band edges > >During the recent ARRL DX SSB contest, there was a station operating on >7127. Because of the lower SB extending to 7124 (assuming 3k bandwidth) he >was operating out of the US phone band. He was a European but he was working >simplex. I bet there was an OO sitting there sending notices to every US >contact he made. > >If you KNOW your frequency to 1 Hz, you can legally operate with your dial >on 14149.9 and still be in the band. Likewise 7300.1. Also RTTY on 3601, >etc. etc. A super accurate transmitter has it's advantages :-) > >Jerry - K0TV > >- Original Message - >From: "Matt Zilmer" >To: "Rick Stealey" >Cc: >Sent: Sunday, March 20, 2011 6:48 PM >Subject: Re: [Elecraft] Installed K3EXREF > > >> The K3EXREF is in field test now, as far as I know. It might be a >> little while before Elecraft puts it up for sale. >> >> "Extreme accuracy" probably has two psychological and one scientific >> source: >> - The need to put the K3 dead-on frequency is reassuring to folks that >> aren't sure it stays that way mostly as-is with the TCXO. >> - The desire to be a frequency authority, and be able to help others >> when they're off-freq. Hams with older rigs sometimes end up shifted >> off freq. On HF, I hear this a lot. >> - Knowing exactly what frequency you're on helps with band-edge >> issues, for example between the Extra-only CW sub-bands and the >> general CW sub-band. With a 1 Hz readout, this is seldom a problem, >> but it gets even better when the last digit also indicates the actual >> carrier freq. >> >> The K3 with just the stock TCXO holds the reference at somewhere below >> 1 PPM anyway. This is probably accurate enough for almost everyone, >> but some want near-perfect accuracy. GPS time has an uncertainty of >> around 0.3 nS, which is pretty low compared to 1PPM. No TCXO can beat >> that, but maybe an OCXO can? >> >> 73, >> matt W6NIA >> >> >> >> On Sun, 20 Mar 2011 14:45:59 +, you wrote: >> >>> >>> >>>Excellent posting by W9AC, a great reference, to be saved. >>>Now I wonder if it would be possible for someone to enlighten me as to >>>the need for such extreme accuracy? Is it because my K3 reads out to 1 Hz >>>but I can't really believe the absolute accuracy of that number unless I >>>get a K3EXREF? But if that is the case, my question would still remain, >>>wouldn't it? >>>Not that I need something else to put on my list ahead of my P3 and >>>sub receiver. >>>Rick K2XT >>> >>>__ >>>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 __ 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] Installed K3EXREF
Jerry, RE: 14149.9 kHz --- I would not be comfortable cutting it that close in USB unless I was absolutely certain there was absolutely no energy in the SSB audio 0 to 100 Hz range. I would not trust any transmitter (no matter how good) in that regard. Keep it all within the band limits to be safe. 73, Don W3FPR On 3/20/2011 9:12 PM, Jerry Muller wrote: > Speaking of band edges > > During the recent ARRL DX SSB contest, there was a station operating on > 7127. Because of the lower SB extending to 7124 (assuming 3k bandwidth) he > was operating out of the US phone band. He was a European but he was working > simplex. I bet there was an OO sitting there sending notices to every US > contact he made. > > If you KNOW your frequency to 1 Hz, you can legally operate with your dial > on 14149.9 and still be in the band. Likewise 7300.1. Also RTTY on 3601, > etc. etc. A super accurate transmitter has it's advantages :-) > > Jerry - K0TV > __ 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] Installed K3EXREF
Speaking of band edges During the recent ARRL DX SSB contest, there was a station operating on 7127. Because of the lower SB extending to 7124 (assuming 3k bandwidth) he was operating out of the US phone band. He was a European but he was working simplex. I bet there was an OO sitting there sending notices to every US contact he made. If you KNOW your frequency to 1 Hz, you can legally operate with your dial on 14149.9 and still be in the band. Likewise 7300.1. Also RTTY on 3601, etc. etc. A super accurate transmitter has it's advantages :-) Jerry - K0TV - Original Message - From: "Matt Zilmer" To: "Rick Stealey" Cc: Sent: Sunday, March 20, 2011 6:48 PM Subject: Re: [Elecraft] Installed K3EXREF > The K3EXREF is in field test now, as far as I know. It might be a > little while before Elecraft puts it up for sale. > > "Extreme accuracy" probably has two psychological and one scientific > source: > - The need to put the K3 dead-on frequency is reassuring to folks that > aren't sure it stays that way mostly as-is with the TCXO. > - The desire to be a frequency authority, and be able to help others > when they're off-freq. Hams with older rigs sometimes end up shifted > off freq. On HF, I hear this a lot. > - Knowing exactly what frequency you're on helps with band-edge > issues, for example between the Extra-only CW sub-bands and the > general CW sub-band. With a 1 Hz readout, this is seldom a problem, > but it gets even better when the last digit also indicates the actual > carrier freq. > > The K3 with just the stock TCXO holds the reference at somewhere below > 1 PPM anyway. This is probably accurate enough for almost everyone, > but some want near-perfect accuracy. GPS time has an uncertainty of > around 0.3 nS, which is pretty low compared to 1PPM. No TCXO can beat > that, but maybe an OCXO can? > > 73, > matt W6NIA > > > > On Sun, 20 Mar 2011 14:45:59 +, you wrote: > >> >> >>Excellent posting by W9AC, a great reference, to be saved. >>Now I wonder if it would be possible for someone to enlighten me as to >>the need for such extreme accuracy? Is it because my K3 reads out to 1 Hz >>but I can't really believe the absolute accuracy of that number unless I >>get a K3EXREF? But if that is the case, my question would still remain, >>wouldn't it? >>Not that I need something else to put on my list ahead of my P3 and >>sub receiver. >>Rick K2XT >> >>__ >>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] Installed K3EXREF
This was an excellent explanation. I got a Trimble Thunderbolt off eBay for less than 200 bucks. It came from China and came with an antenna and power supply. If you are going to get one of the ones that come from China, make sure you get the power supply with it. The domestic Thunderbolts have a unipolar supply but the ones from China were specials and require a special bipolar power supply. As long as you're getting the power supply with it, you're OK. I have not noticed any noise from the power supply from China. I expect ferrites may solve the problem if found. It works just fine with the stock Thunderbolt software. I've had mine for about 6 months and I've run tests using the Thunderbolt software. The PC monitoring software allows you to monitor the errors detected and log them. The accuracy is quite good. Although I see occasional errors greater than 1 part in 10^9, most of the measured errors are far less than 1 part in 10^9. I can't find any of the spreadsheets I generated (from many hours of operation) right now but I seem to recall that 1 sigma was down around 1 part in 10^10. This translates into a 1 Hz error at 10 GHz. The +/- 1 Hz error in the K3 is much greater than the accuracy of the GPSDO My primary reason for getting the GPSDO was for microwave and EME operations. Being able to use it with the K3 is a plus. I'm likely to be an early adopter of the production units when they become available. I will probably order my second K3 with a K3EXREF. Jerry - K0TV - Original Message - From: "Paul Christensen" To: Sent: Saturday, March 19, 2011 9:34 PM Subject: Re: [Elecraft] Installed K3EXREF >I installed it on Friday in about 30 minutes, but I'm comfortable with my > way around the K3. I would think that most users could install it in > about > an hour or less. Installation is actually very simple with very few parts > involved. K3EXREF came with an SMA connector and SMA to BNC > between-series > adapter. > > Performance is exactly as promised by Elecraft. Although K3EXREF will not > phase lock the K3 to the external frequency source, I'm finding that it > stays within 1 Hz on 20m when locked to CHU at 14.670 MHz. I'm also > finding that testing for zero-beat to WWV at 10 MHz is not a good idea in > my > shack, and perhaps yours too. There are many 10 MHz signals being emitted > by nearby appliances, LAN routers, security system, Ethernet boards, etc. > That common, even frequency is everywhere in a household these days. > > In much of North America, CHU is an excellent source for testing since it > keeps cesium accuracy like WWV but the odd frequency of CHU is a real > benefit since the chance for beating against extraneous signals is much > smaller than at 10 MHz. Testing at a higher frequency rather than say the > MW broadcast band also provides for a reasonably good account of how the > K3EXREF performs. After installation, I would also suggest not trying to > test zero beat K3EXREF against commercial MW or SW BC stations since their > carriers are allowed to deviate much more than the cesium-based time and > frequency standards of CHU and WWV. Commercial AM broadcast station > frequencies are typically only accurate to about +/- 20 Hz although most > are > better than that. > > The K3's 49 MHz oscillator is only adjusted at intervals between 4 and 8 > seconds by K3EXREF in order to minimize jitter. The K3 retains its > original > phase noise performance since the external reference is not used internal > to > the K3's frequency generating scheme. Think of it this way -- K3EXREF is > like lightly touching the 49 MHz oscillator with a feather every few > seconds > if necessary to keep it within 1 Hz or so. Also, the K3 frequency stays > accurate even at the moment of powering up the K3. Kinda' fun to watch > the > 49 MHz oscillator display change during warm-up as it's being corrected > and > compared against the external reference. > > External references: There are three primary types, and all can be > purchased for less than USD $150 on the used market. Cesium standards (a > fourth type) are also available but are generally much more expensive, > complicated, and won't offer any benefit to K3 users since K3EXREF limits > resolution and accuracy to about 1 Hz. > > The first type is the GPS Disciplined Oscillator (GPS-DO). This type of > standard locks itself onto the visible GPS satellites orbiting the sky. > Requires a GPS antenna and is self-calibrating to the GPS satellites. The > GPS-DO's time and frequency averages from the visible satellites, each > satellite having it's own on-board cesium-based oscillator. Long-term > accuracy is usually good to at least 1 x 10^
Re: [Elecraft] Installed K3EXREF
The K3EXREF is in field test now, as far as I know. It might be a little while before Elecraft puts it up for sale. "Extreme accuracy" probably has two psychological and one scientific source: - The need to put the K3 dead-on frequency is reassuring to folks that aren't sure it stays that way mostly as-is with the TCXO. - The desire to be a frequency authority, and be able to help others when they're off-freq. Hams with older rigs sometimes end up shifted off freq. On HF, I hear this a lot. - Knowing exactly what frequency you're on helps with band-edge issues, for example between the Extra-only CW sub-bands and the general CW sub-band. With a 1 Hz readout, this is seldom a problem, but it gets even better when the last digit also indicates the actual carrier freq. The K3 with just the stock TCXO holds the reference at somewhere below 1 PPM anyway. This is probably accurate enough for almost everyone, but some want near-perfect accuracy. GPS time has an uncertainty of around 0.3 nS, which is pretty low compared to 1PPM. No TCXO can beat that, but maybe an OCXO can? 73, matt W6NIA On Sun, 20 Mar 2011 14:45:59 +, you wrote: > > >Excellent posting by W9AC, a great reference, to be saved. >Now I wonder if it would be possible for someone to enlighten me as to >the need for such extreme accuracy? Is it because my K3 reads out to 1 Hz >but I can't really believe the absolute accuracy of that number unless I >get a K3EXREF? But if that is the case, my question would still remain, >wouldn't it? >Not that I need something else to put on my list ahead of my P3 and >sub receiver. >Rick K2XT > >__ >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] Installed K3EXREF
Another benefit of the GPS-DO is that routine calibration to ensure long-term accuracy is the responsibility of the U.S. Department of Defense, and funded by U.S. tax payers. Unless there's a hardware-related problem with the GPS-DO, calibration is someone else's problem and expense. The user need only care that the unit has attained "Lock" status. Paul, W9AC __ 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] Installed K3EXREF
Rick, For the majority who only do CW/SSB on HF, adding the EXREF is probably unnecessary. The TCXO-3 holds the K3 within 14-Hz on 28-MHz. The EXREF improves that by an order of magnitude to 1.4 Hz. This becomes necessary for some digital modes like JT-65. That is mainly used on eme on 144 and higher bands. If you operate on the microwave bands oscillator error is mulitplied so that is becomes hard to get much freq. accuracy or stability. On 1296 I use a transverter that has an external locked PLL LO. That keeps it within 1-Hz. Typically one would not have better than a few KHz with a xtal oscillator on 105.67 MHz multiplied x12 = 1268 MHz. Getting the accuracy on the transverter LO without also having it on 28-MHz IF radio is kind of being only "Half-done". With the K3 EXREF my combined 1296 freq. will equal that of the K3. That is important when eme signals are so weak they cannot be detected by ear. Add frequency errors to that and the task becomes very tough. Now consider doing that at 10-GHz. A few of us with K3's are mw'ers and/or eme'rs so the accuracy is very important to us. Sidenote: Use of 10-MHz WWV is nearly impossible if you run a 10-MHz station reference oscillator. I have a mw freq.counter that uses a rubidium external reference. I use it to check the frequency of my 10-MHz OCXO which I run thru a 4-way distribution amp to feed things in the shack: 1) K3EXTREF 2) 144/28 Transverter (DEMI) 3) 1296/28 Transverter (DEMI) 4) future item The OCXO was bought off e-bay for $39.99+shipping, and is very stabile but does drift over months so I "tweak" it back to the Rubidium about 4 times a year. It runs 24/7 on a battery supply floated by a charger. All can be seen on my website (including newly added instructions for adding sub-Rx IF Out). 73, Ed - KL7UW -- Message: 33 Date: Sun, 20 Mar 2011 14:45:59 + From: Rick Stealey Subject: Re: [Elecraft] Installed K3EXREF To: Excellent posting by W9AC, a great reference, to be saved. Now I wonder if it would be possible for someone to enlighten me as to the need for such extreme accuracy? Is it because my K3 reads out to 1 Hz but I can't really believe the absolute accuracy of that number unless I get a K3EXREF? But if that is the case, my question would still remain, wouldn't it? Not that I need something else to put on my list ahead of my P3 and sub receiver. Rick K2XT 73, Ed - KL7UW, WD2XSH/45 == BP40IQ 500 KHz - 10-GHz www.kl7uw.com EME: 144-1.4kw, 432-100w, 1296-testing*, 3400-winter? DUBUS Magazine USA Rep dubus...@hotmail.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] Installed K3EXREF
See < URL:http://www.jrmiller.demon.co.uk/projects/ministd/frqstd.htm > 73, Lyle KK7P I have no financial interest in James' products. I know from decades of working with him that his stuff is meticulously engineered and optimised. LJ > That said, IS there a GPS governed 10 Mhz source to be had out there for > something less than a third world national debt? __ 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] Installed K3EXREF
There have been some homebrew GPS standards in the literature for those who like melting solder. One was in QST back in July '98. A&A engineering is offering circuit boards and has the original QST article on their site (http://www.a-aengineering.com/ ) I certainly agree with David that the K3 needs no apologies for its inherently outstanding frequency stability. The K3EXREF just makes it better :-) Ron AC7AC -Original Message- The K3 is indeed sufficiently accurate for amateur use, but if you already have a 10 MHz Rubidium, Caesium or GPS standard, Rick, then why not couple it up your K3? It's just another refinement and helps to put yours existing frequency standard to good use. 73 de David G4DMP In a recent message, Rick Stealey writes > >Excellent posting by W9AC, a great reference, to be saved. >Now I wonder if it would be possible for someone to enlighten me as to >the need for such extreme accuracy? -- + - - - - - - - - - - - - - - - - + | David M Pratt, Kippax, Leeds. | | Website: http://www.g4dmp.co.uk | + - - - - - - - - - - - - - - - - + __ 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] Installed K3EXREF
While this sounds interesting, has any progress been made for those of us who have the TCXO to be able to program its printed offsets in the firmware and have it act on them? The fields are currently there in the K3 utility but as yet unused, as I understand it. I would be pleased to have this functionality enabled. 73, de Nate >> -- "The optimist proclaims that we live in the best of all possible worlds. The pessimist fears this is true." Ham radio, Linux, bikes, and more: http://www.n0nb.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
Re: [Elecraft] Installed K3EXREF
Jim asked: > What's a GPSDO setup go for including an antenna? > 73 > jim ab3cv You can put together a GPSDO system with 10 MHz output for less than $200. Here's just one example: Ebay item # 290322053618 By buying the items separately, you can sometimes do even better on price. The Trimble thunderbolts are very popular because a lot have been pulled from mobile phone tower sites during upgrades. I use one here to phase-lock my HPSDR system and it works well. Bruce, N1RX __ 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] Installed K3EXREF
I'm guessing this is really useful for EME at UHF. jim ab3cv __ 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] Installed K3EXREF
My reason for wanting one of them is to maintain a stable frequency on VHF and UHF. 73, Tom N5GE On Sun, 20 Mar 2011 14:45:59 +, Rick Stealey wrote: > > >Excellent posting by W9AC, a great reference, to be saved. >Now I wonder if it would be possible for someone to enlighten me as to >the need for such extreme accuracy? Is it because my K3 reads out to 1 Hz >but I can't really believe the absolute accuracy of that number unless I >get a K3EXREF? But if that is the case, my question would still remain, >wouldn't it? >Not that I need something else to put on my list ahead of my P3 and >sub receiver. >Rick K2XT > >__ >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] Installed K3EXREF
The question of 1 Hz accuracy can get multiplied a lot in VHF work. If one is talking about HF, it is hard to see the need. Personally, I *LIKE* the idea of being spot on. It's not a technological justification, but one I might spend a moderate sum to nail. If I was doing VHF or UHF work, I would want it to get the combination of equipment very close. If you are listening to HF SSB and expecting signals to be spot on kilohertz boundaries, there are still many signals out there on equipment over a quarter century old. I helped an older gentleman with a 160 meter antenna problem, and he included a station photo with an email. I was surprised to see that he is STILL using a World War II ARC-5 transmitter as his main transmitter on 160. He uses an old National NC183 as his receiver at MF. AND, he has some recent contest first place in section finishes on 160 to prove that it works. This is perhaps the extreme, but many hams have and use very serviceable older analog rigs without the frequency accuracy, and you will not find them at kilohertz boundaries with 1 Hz accuracy. I would only advise to have a REASON for the accuracy before you start spending the money, even if that reason is just that you WANT to be dead on a kilohertz boundary when you transmit. Nobody is going to throw you off the air because you are 10 Hz off. As the old gentleman proves quite adequately, it ain't the STUFF, it's what you DO, that is all the fun. That said, IS there a GPS governed 10 Mhz source to be had out there for something less than a third world national debt? 73, Guy. On Sun, Mar 20, 2011 at 10:02 AM, wrote: > So if I understand correctly this soon to be option is basically > constantly adjusting the frequency of the K3 to be correct. > > Or in other words a constant adjustment to the reference oscillator. > > This could be a real nice to have, as I have been re-adjusting (zero > beating to WWV) to try and tune my K3 to be spot on. The reason I have > been doing this is that I was thinking I was off frequency but I think > that many radio's out there are off. > > Thanks, now I need even more money. > > Don > KD8NNU > __ 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] Installed K3EXREF
What's a GPSDO setup go for including an antenna? 73 jim ab3cv __ 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] Installed K3EXREF
the need? Just because its there and something the import rigs dont have? Mike AC5P From: Rick Stealey To: elecraft@mailman.qth.net Sent: Sun, March 20, 2011 9:45:59 AM Subject: Re: [Elecraft] Installed K3EXREF Excellent posting by W9AC, a great reference, to be saved. Now I wonder if it would be possible for someone to enlighten me as to the need for such extreme accuracy? Is it because my K3 reads out to 1 Hz but I can't really believe the absolute accuracy of that number unless I get a K3EXREF? But if that is the case, my question would still remain, wouldn't it? Not that I need something else to put on my list ahead of my P3 and sub receiver. Rick K2XT __ 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] Installed K3EXREF
The K3 is indeed sufficiently accurate for amateur use, but if you already have a 10 MHz Rubidium, Caesium or GPS standard, Rick, then why not couple it up your K3? It's just another refinement and helps to put yours existing frequency standard to good use. 73 de David G4DMP In a recent message, Rick Stealey writes > >Excellent posting by W9AC, a great reference, to be saved. >Now I wonder if it would be possible for someone to enlighten me as to >the need for such extreme accuracy? -- + - - - - - - - - - - - - - - - - + | David M Pratt, Kippax, Leeds. | | Website: http://www.g4dmp.co.uk | + - - - - - - - - - - - - - - - - + __ 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] Installed K3EXREF
Excellent posting by W9AC, a great reference, to be saved. Now I wonder if it would be possible for someone to enlighten me as to the need for such extreme accuracy? Is it because my K3 reads out to 1 Hz but I can't really believe the absolute accuracy of that number unless I get a K3EXREF? But if that is the case, my question would still remain, wouldn't it? Not that I need something else to put on my list ahead of my P3 and sub receiver. Rick K2XT __ 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] Installed K3EXREF
So if I understand correctly this soon to be option is basically constantly adjusting the frequency of the K3 to be correct. Or in other words a constant adjustment to the reference oscillator. This could be a real nice to have, as I have been re-adjusting (zero beating to WWV) to try and tune my K3 to be spot on. The reason I have been doing this is that I was thinking I was off frequency but I think that many radio's out there are off. Thanks, now I need even more money. Don KD8NNU On Sat, Mar 19, 2011 at 7:13 PM, Ron D'Eau Claire wrote: > Installing the K3EXREF involves installing a connector/cable assembly > in the > REF. hole in the K3's rear panel and running the cable under the RF > board to > the front panel shield, then up behind the front panel shield. The > other end > plugs into the TMP connector on the KREF3 reference oscillator board > that > sticks through the hole in the shield. > A small pony board plugs into the connector on the component side of > the > KREF3 board, held in place by a screw that passes through it and the > KREF3 > board and into the PEM nut in the shield. > The biggest part of the project is taking the left side off of the K3 > to > install the cable. If you have the K144XV installed, it needs to be > removed. > If you have the KRX3 subreceiver, it can be left in place. You do > *NOT* need > to remove the KRX3 module with all its cables. > Ed's time of 1.5 hrs sounds about right for someone working carefully > and > methodically, doing the job for the first time. There's no soldering, > of > course, but still a fair bit of mechanical disassembly/reassembly. > After doing it several times, I can probably do it in 30 minutes or a > bit > less without rushing. > Ron AC7AC > > -Original Message- > From: elecraft-boun...@mailman.qth.net > [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of David Pratt > Sent: Saturday, March 19, 2011 3:49 PM > To: Edward R. Cole > Cc: Elecraft@mailman.qth.net > Subject: Re: [Elecraft] Installed K3EXREF > > That seems quite a long time to install it, Ted. What's involved? I > have looked for the manual on-line but it does seem to up there yet. > > Any more details would be appreciated; I'd like to order one. > > 73 de David G4DMP > > In a recent message, Edward R. Cole writes >> >> It took me about 1-1/2 hours to install the new EXREF for referencing >> the TCXO to external 10-MHz. I have not installed the new firmware >> or tested it yet...more news, later. > -- > + - - - - - - - - - - - - - - - - + > | David M Pratt, Kippax, Leeds. | > | Website: http://www.g4dmp.co.uk | > + - - - - - - - - - - - - - - - - + > > > __ > 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] Installed K3EXREF
Many thanks to Ed KL7UW, Ron AC7AC and Paul W9CA for your helpful comments on the K3EXREF. I look forward to this product being available in due course and I have my 10 MHz standard poised in readiness. 73 de David G4DMP -- + - - - - - - - - - - - - - - - - + | David M Pratt, Kippax, Leeds. | | Website: http://www.g4dmp.co.uk | + - - - - - - - - - - - - - - - - + __ 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] Installed K3EXREF
On 3/19/2011 9:34 PM, Paul Christensen wrote: At least some AM stations operating with digital subcarriers are GPS locked and can be extremely accurate. WMAL 630 KHz here in the Washington DC area is one example. It's as close to 630 KHz as I can measure (about 10 milli-Hz) and E-mail correspondence with the station's chief engineer confirmed the transmitter frequency is GPS locked. I've measured other local AM stations as far as 16 Hz off - within the FCC's tolerance, but not of much use as a frequency standard. > Commercial AM broadcast station > frequencies are typically only accurate to about +/- 20 Hz although most are > better than that. > > Jack K8ZOA __ 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] Installed K3EXREF
I installed it on Friday in about 30 minutes, but I'm comfortable with my way around the K3. I would think that most users could install it in about an hour or less. Installation is actually very simple with very few parts involved. K3EXREF came with an SMA connector and SMA to BNC between-series adapter. Performance is exactly as promised by Elecraft. Although K3EXREF will not phase lock the K3 to the external frequency source, I'm finding that it stays within 1 Hz on 20m when locked to CHU at 14.670 MHz. I'm also finding that testing for zero-beat to WWV at 10 MHz is not a good idea in my shack, and perhaps yours too. There are many 10 MHz signals being emitted by nearby appliances, LAN routers, security system, Ethernet boards, etc. That common, even frequency is everywhere in a household these days. In much of North America, CHU is an excellent source for testing since it keeps cesium accuracy like WWV but the odd frequency of CHU is a real benefit since the chance for beating against extraneous signals is much smaller than at 10 MHz. Testing at a higher frequency rather than say the MW broadcast band also provides for a reasonably good account of how the K3EXREF performs. After installation, I would also suggest not trying to test zero beat K3EXREF against commercial MW or SW BC stations since their carriers are allowed to deviate much more than the cesium-based time and frequency standards of CHU and WWV. Commercial AM broadcast station frequencies are typically only accurate to about +/- 20 Hz although most are better than that. The K3's 49 MHz oscillator is only adjusted at intervals between 4 and 8 seconds by K3EXREF in order to minimize jitter. The K3 retains its original phase noise performance since the external reference is not used internal to the K3's frequency generating scheme. Think of it this way -- K3EXREF is like lightly touching the 49 MHz oscillator with a feather every few seconds if necessary to keep it within 1 Hz or so. Also, the K3 frequency stays accurate even at the moment of powering up the K3. Kinda' fun to watch the 49 MHz oscillator display change during warm-up as it's being corrected and compared against the external reference. External references: There are three primary types, and all can be purchased for less than USD $150 on the used market. Cesium standards (a fourth type) are also available but are generally much more expensive, complicated, and won't offer any benefit to K3 users since K3EXREF limits resolution and accuracy to about 1 Hz. The first type is the GPS Disciplined Oscillator (GPS-DO). This type of standard locks itself onto the visible GPS satellites orbiting the sky. Requires a GPS antenna and is self-calibrating to the GPS satellites. The GPS-DO's time and frequency averages from the visible satellites, each satellite having it's own on-board cesium-based oscillator. Long-term accuracy is usually good to at least 1 x 10^-11. Extreme accuracy and only a magnitude or two behind cesium. Look for Hewlett-Packard Z3801A, Z3816A, Trimble Thunderbolt, Brandywine, Symmetricon, and Datum models. Short list, but many others available. Rubidium is the next type. No GPS tracking needed. Accuracy commensurate with GPS-DO. No antenna required. Long-term performance is highly dependent on the quality of the optical beam from the rubidium pump lamp. Look for EF Efratom, Datum, Third, is a high quality oven-controlled crystal oscillator (OCXO). Requires periodic calibration. Accuracy good to at least +/- 0.05 ppm and offer the best phase noise performance among the three types of oscillators, but as noted earlier, the excellent phase noise attributes of the OCXO will not be carried over to the K3. A shack reference oscillator is good for use with other equipment too (e.g., frequency counter). Although a bit lossy, I currectly use a Mini-Circuits passive three-way splitter, but one can purchase a distribution amp to feed many pieces of equipment from a single oscillator. Unlike the splitter, a DA offers unity gain and very high port isolation. Finally, be mindful that most GPS-DO and rubidium units use internal switch-mode DC-DC converters. Switching noise was bad enough on two of my units that I decided to gut the converters and used an outboard triple-output linear supply. The Trimble Thunderbolts that have been retired from the cellular industry require an external triple-output supply. If choosing this model, get a linear type and avoid the headaches. Paul, W9AC __ 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] Installed K3EXREF
Field Test. 73, Eric WA6HHQ _..._ On 3/19/2011 4:19 PM, Roger de Valle wrote: > Is the K3EXEREF production or still in test? I see no mention of it on > the Elecraft WEB site, I have 10Mhz, just nowhere to plug it. > > Roger VK3ADA. > > On 20/03/2011 10:13, Ron D'Eau Claire wrote: >> Installing the K3EXREF involves installing a connector/cable assembly in the >> REF. hole in the K3's rear panel and running the cable under the RF board to >> the front panel shield, then up behind the front panel shield. The other end >> plugs into the TMP connector on the KREF3 reference oscillator board that >> sticks through the hole in the shield. __ 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] Installed K3EXREF
Is the K3EXEREF production or still in test? I see no mention of it on the Elecraft WEB site, I have 10Mhz, just nowhere to plug it. Roger VK3ADA. On 20/03/2011 10:13, Ron D'Eau Claire wrote: > Installing the K3EXREF involves installing a connector/cable assembly in the > REF. hole in the K3's rear panel and running the cable under the RF board to > the front panel shield, then up behind the front panel shield. The other end > plugs into the TMP connector on the KREF3 reference oscillator board that > sticks through the hole in the shield. -- Roger de Valle Genette Pty Ltd 03 5330 3081 0407 320 121 __ 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] Installed K3EXREF
Installing the K3EXREF involves installing a connector/cable assembly in the REF. hole in the K3's rear panel and running the cable under the RF board to the front panel shield, then up behind the front panel shield. The other end plugs into the TMP connector on the KREF3 reference oscillator board that sticks through the hole in the shield. A small pony board plugs into the connector on the component side of the KREF3 board, held in place by a screw that passes through it and the KREF3 board and into the PEM nut in the shield. The biggest part of the project is taking the left side off of the K3 to install the cable. If you have the K144XV installed, it needs to be removed. If you have the KRX3 subreceiver, it can be left in place. You do *NOT* need to remove the KRX3 module with all its cables. Ed's time of 1.5 hrs sounds about right for someone working carefully and methodically, doing the job for the first time. There's no soldering, of course, but still a fair bit of mechanical disassembly/reassembly. After doing it several times, I can probably do it in 30 minutes or a bit less without rushing. Ron AC7AC -Original Message- From: elecraft-boun...@mailman.qth.net [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of David Pratt Sent: Saturday, March 19, 2011 3:49 PM To: Edward R. Cole Cc: Elecraft@mailman.qth.net Subject: Re: [Elecraft] Installed K3EXREF That seems quite a long time to install it, Ted. What's involved? I have looked for the manual on-line but it does seem to up there yet. Any more details would be appreciated; I'd like to order one. 73 de David G4DMP In a recent message, Edward R. Cole writes > >It took me about 1-1/2 hours to install the new EXREF for referencing >the TCXO to external 10-MHz. I have not installed the new firmware >or tested it yet...more news, later. -- + - - - - - - - - - - - - - - - - + | David M Pratt, Kippax, Leeds. | | Website: http://www.g4dmp.co.uk | + - - - - - - - - - - - - - - - - + __ 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] Installed K3EXREF
That seems quite a long time to install it, Ted. What's involved? I have looked for the manual on-line but it does seem to up there yet. Any more details would be appreciated; I'd like to order one. 73 de David G4DMP In a recent message, Edward R. Cole writes > >It took me about 1-1/2 hours to install the new EXREF for referencing >the TCXO to external 10-MHz. I have not installed the new firmware >or tested it yet...more news, later. -- + - - - - - - - - - - - - - - - - + | David M Pratt, Kippax, Leeds. | | Website: http://www.g4dmp.co.uk | + - - - - - - - - - - - - - - - - + __ 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] Installed K3EXREF
It took me about 1-1/2 hours to install the new EXREF for referencing the TCXO to external 10-MHz. I have not installed the new firmware or tested it yet...more news, later. 73, Ed - KL7UW, WD2XSH/45 == BP40IQ 500 KHz - 10-GHz www.kl7uw.com EME: 144-1.4kw, 432-100w, 1296-testing*, 3400-winter? DUBUS Magazine USA Rep dubus...@hotmail.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
