WTB Trimble ThunderBolt for K3EXREF / QS1R
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I'm looking for a Trimble ThunderBolt Rev E primarily for an external
reference to be used on the NC7J CW Skimmer Server (which I sysop).... for our QS1R SDR. telnet:dxc.nc7j.com Poking around and doing some research, it's clear I missed the opportunity a number of years ago to get one for less than $100. If anyone has one sitting around or an extra they would like to sell, let me know... on eBay I see them going anywhere from around $125 to $250 at times, but the auctions are not showing up on a regular basis. Hit me up off the list here if you have one you would want to sell. I'll put it to good use keeping the skimmer server spots at NC7J spot on. ;) Max NG7M -- M. George ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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Pete, Brian and Bob, thanks for the nice feedback. I looked the RB
solution, but I had not found the Chinese all in one GPSDO. And Pete I'm glad you jumped in, thought I read that the QS1R would lock on a frequency from 10-125. I'll ping you separate off line... I had some other projects I mind for the Thunderbolt, but based on the input here I will do more research. Max NG7M ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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In reply to this post by ng7m
After posting my message about using an external frequency reference for a
K3 and a QS1R, I got some really nice input and feedback from W7AVK, K3KO, N4ZR and NK4I. A big thanks to these gents for sending me input and experience with different solutions. All the input has been very useful this weekend as I have searched around for a single time reference solution for my needs. (everyone is going to be different) I thought this might help others that want to go down this path if they have similar wants / needs. I decided to still go with a Trimble Thunderbolt Rev. E ~2004 manufacture. This isn't going to be the lowest cost solution, but it covers my needs for the following: 1. Provide a very stable 10mhz external reference for my K3... mainly for fun and I might send in some reports to the ARRL FMT etc.. so there goes $$$ for the external freq reference add on for the K3. 2. The main reason I started going down this path was to use the external frequency reference input on the QS1R I run for the NC7J CW Skimmer. NK4I saved me a bunch of time (no pun intended) and pointed out the fact that the direct output on the Trimble TBolt won't work with the QS1R. Pete pointed me to Graham VK3XDK and David VK3HZ's XRef which will provide a 125 MHz reference for the QS1R from the TBolt 10 MHz output http://www.vk3hz.net/XRef/XRef_Home.html#XRef-Vx I exchanged email with David and have a XRef-Vx on the way... some more $$$ for the XRef-Vx shipped. Seriously not bad at all considering it has a TCXO on board that will take over if the Trimble output lock is lost. 3. Use a PPS reference to drive an NTP Stratum 1 server from my house. I get this out of the TBolt and also from most of the other solutions provided, but the TBolt has some other really nice monitoring capabilities. So for the NTP server, I ordered the latest Raspberry PI $50 with a case shipped and I searched high and low for other implementations using a TBolt with Linux / Raspberry PI for a GPS disciplined NTP PSS reference. Google 'time nuts' which I'm sure many on this list are familiar with... and I quickly found KO4BB's Thunderbolt Monitor Kit: http://www.ko4bb.com/Timing/GPSMonitor/kit.php Which will be a nice display for the serial output on the TBolt as it drives the NTP server (and QS1R and K3 when I'm operating) ARound $80 for this kit when Didier gets the next batch ready. This monitor kit also includes a PPS stretcher to increase the 10uS PPS pulse output by the TBolt to ~1mS. So that is my reasoning to stick with a TBolt... they seem to be holding their value if not getting more expensive and there is all the nice work and comparisons that have been done by KE5FX http://www.ke5fx.com/gpscomp.htm along with his Lady Heather software. It's pretty clear that the TBolt can still hold it's own. At the end of the day, do I need all this precision? Not really, but it's obsessive and fun! I get to spend more $$$ and have stuff shipped to me from around the globe and play with ntpd and cool software... provide a better service to the CW Skimmer community and precision time community with the NTP server. Plus I'll give the ARRL FMT a try and have some more fun. Thanks again for all the input off the list by the guys above. Max NG7M On Wed, Apr 1, 2015 at 8:27 AM, M. George <[hidden email]> wrote: > I'm looking for a Trimble ThunderBolt Rev E primarily for an external > reference to be used on the NC7J CW Skimmer Server (which I sysop).... for > our QS1R SDR. telnet:dxc.nc7j.com > > Poking around and doing some research, it's clear I missed the opportunity > a number of years ago to get one for less than $100. > > If anyone has one sitting around or an extra they would like to sell, let > me know... on eBay I see them going anywhere from around $125 to $250 at > times, but the auctions are not showing up on a regular basis. > > Hit me up off the list here if you have one you would want to sell. I'll > put it to good use keeping the skimmer server spots at NC7J spot on. ;) > > Max NG7M > > -- > M. George > -- M. George ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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A follow up to my write up... I should have included more details from
personal emails I received from Dave, G3TJP. Bob W7AVK also mentioned the BG7TBL GPS Disciplined Clock and I totally got my wires crossed and didn't mention G3TJP in my write-up. Sigh.... Apologies to Mr. Lankshear... Dave took some time in a personal email to point out the follow about the BG7TBL which is going for ~144.00 on ebay... it really is a nice package... here are some of Dave's comments (in hindsight, I wonder if this would have been the way to go): G3TJP: "It’s a very neat and small unit, very professionally produced and comes complete with power supply and GPS antenna. I bought one and then a second one as a gift to a good friend. It uses the Morion double oven 10MHz xtal oscillator, or equivalent. The output is a decent sine wave with just enough distortion to give good harmonics at 10MHz intervals up to at least 50MHz, which is as far as I’ve checked. The Morion is actually a 5MHz oscillator that’s doubled to 10MHz, so you have a usable, locked signal at 5MHz also." Dave also mentioned that the seller 'fly-xy' is a decent guy and will ben over backwards to help you as you treat him fairly. i.e. if something needs to be returned or corrected. Plus, this unit is a turnkey package and he also sells a 10mhz distribution amplifier that looks interesting... another BG7TBL design. KE5FX has also reviewed Bob W7AVK's BG7TBL and has a nice comparison write up on his website (KE5FX of Lady Heather fame). The comparison is easy to find on KE5FX's site. Again, thanks to everyone that had input... I tried to mention everyone that pointed me in the right direction off the list and leaving out Dave G3TJP was my mistake. Regards, Max NG7M On Sat, Apr 4, 2015 at 8:59 PM, M. George <[hidden email]> wrote: > After posting my message about using an external frequency reference for a > K3 and a QS1R, I got some really nice input and feedback from W7AVK, K3KO, > N4ZR and NK4I. A big thanks to these gents for sending me input and > experience with different solutions. > > All the input has been very useful this weekend as I have searched around > for a single time reference solution for my needs. (everyone is going to be > different) I thought this might help others that want to go down this path > if they have similar wants / needs. > > I decided to still go with a Trimble Thunderbolt Rev. E ~2004 > manufacture. This isn't going to be the lowest cost solution, but it > covers my needs for the following: > > 1. Provide a very stable 10mhz external reference for my K3... mainly for > fun and I might send in some reports to the ARRL FMT etc.. so there goes > $$$ for the external freq reference add on for the K3. > > 2. The main reason I started going down this path was to use the external > frequency reference input on the QS1R I run for the NC7J CW Skimmer. NK4I > saved me a bunch of time (no pun intended) and pointed out the fact that > the direct output on the Trimble TBolt won't work with the QS1R. Pete > pointed me to Graham VK3XDK and David VK3HZ's XRef which will provide a 125 > MHz reference for the QS1R from the TBolt 10 MHz output > http://www.vk3hz.net/XRef/XRef_Home.html#XRef-Vx I exchanged email with > David and have a XRef-Vx on the way... some more $$$ for the XRef-Vx > shipped. Seriously not bad at all considering it has a TCXO on board that > will take over if the Trimble output lock is lost. > > 3. Use a PPS reference to drive an NTP Stratum 1 server from my house. I > get this out of the TBolt and also from most of the other solutions > provided, but the TBolt has some other really nice monitoring > capabilities. So for the NTP server, I ordered the latest Raspberry PI $50 > with a case shipped and I searched high and low for other implementations > using a TBolt with Linux / Raspberry PI for a GPS disciplined NTP PSS > reference. Google 'time nuts' which I'm sure many on this list are > familiar with... and I quickly found KO4BB's Thunderbolt Monitor Kit: > http://www.ko4bb.com/Timing/GPSMonitor/kit.php Which will be a nice > display for the serial output on the TBolt as it drives the NTP server (and > QS1R and K3 when I'm operating) ARound $80 for this kit when Didier gets > the next batch ready. This monitor kit also includes a PPS stretcher to > increase the 10uS PPS pulse output by the TBolt to ~1mS. > > So that is my reasoning to stick with a TBolt... they seem to be holding > their value if not getting more expensive and there is all the nice work > and comparisons that have been done by KE5FX > http://www.ke5fx.com/gpscomp.htm along with his Lady Heather software. > It's pretty clear that the TBolt can still hold it's own. > > At the end of the day, do I need all this precision? Not really, but it's > obsessive and fun! I get to spend more $$$ and have stuff shipped to me > from around the globe and play with ntpd and cool software... provide a > better service to the CW Skimmer community and precision time community > with the NTP server. Plus I'll give the ARRL FMT a try and have some more > fun. > > Thanks again for all the input off the list by the guys above. > > Max NG7M > > On Wed, Apr 1, 2015 at 8:27 AM, M. George <[hidden email]> > wrote: > >> I'm looking for a Trimble ThunderBolt Rev E primarily for an external >> reference to be used on the NC7J CW Skimmer Server (which I sysop).... for >> our QS1R SDR. telnet:dxc.nc7j.com >> >> Poking around and doing some research, it's clear I missed the >> opportunity a number of years ago to get one for less than $100. >> >> If anyone has one sitting around or an extra they would like to sell, let >> me know... on eBay I see them going anywhere from around $125 to $250 at >> times, but the auctions are not showing up on a regular basis. >> >> Hit me up off the list here if you have one you would want to sell. I'll >> put it to good use keeping the skimmer server spots at NC7J spot on. ;) >> >> Max NG7M >> >> -- >> M. George >> > > > > -- > M. George > -- M. George ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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Max,
I bought one of the BG7TBL GPSDO from the same seller on eBay. I actually was just looking for a 10 MHz distribution amplifier and found that he was selling the GPSDO along with matching Distribution amp for a very good price. There were options of a square wave output version or a sine wave output (which is what I purchased). The 8 output Distribution amp also contains a Morion 10 MHz double oven oscillator as well, which takes over if the input signal from the GPSDO is disconnected. I was not aware the Morion oscillator was doubling the frequency to reach 10 MHz, I have not found any documentation that mentions that anywhere else. The device is marked as 10 MHz. The included 12 V power supplies work fine, however they are wall warts with I think American 2 pin plugs, which need adapters to fit UK mains sockets. You need a fair amount of current for the ovens when they are heating up, so cannot just substitute a 1 amp supply. I opened up both units and the construction is very well done. No schematic or block diagram was supplied, though you can read what some of the chips are, in particular the GPS receiver is an NEO-6M. They may not satisfy the Time Nuts in every way, but they are good enough for for my uses as a stable 10 MHz for locking other oscillators. There is also a serial port (at true RS-232 levels so beware if you try to connect it to something like an Arduino unless you build a level shifter). It outputs the usual GPS NMEA sentences. I do have a another time and frequency standard which is an old HP Z3801A, it is probably better, but for my uses I would not be able to tell the difference. The HP is much larger, requires a 50 Volt supply so not nearly as portable. It also cost a lot more when I bought it on eBay quite a few years ago. 73 David Anderson GM4JJJ > On 6 Apr 2015, at 00:44, M. George <[hidden email]> wrote: > > A follow up to my write up... I should have included more details from > personal emails I received from Dave, G3TJP. Bob W7AVK also mentioned the > BG7TBL GPS Disciplined Clock and I totally got my wires crossed and didn't > mention G3TJP in my write-up. Sigh.... Apologies to Mr. Lankshear... Dave > took some time in a personal email to point out the follow about the BG7TBL > which is going for ~144.00 on ebay... it really is a nice package... here > are some of Dave's comments (in hindsight, I wonder if this would have been > the way to go): > > G3TJP: "It’s a very neat and small unit, very professionally produced and > comes complete with power supply and GPS antenna. I bought one and then a > second one as a gift to a good friend. It uses the Morion double oven > 10MHz xtal oscillator, or equivalent. The output is a decent sine wave > with just enough distortion to give good harmonics at 10MHz intervals up to > at least 50MHz, which is as far as I’ve checked. The Morion is actually a > 5MHz oscillator that’s doubled to 10MHz, so you have a usable, locked > signal at 5MHz also." > > Dave also mentioned that the seller 'fly-xy' is a decent guy and will ben > over backwards to help you as you treat him fairly. i.e. if something > needs to be returned or corrected. Plus, this unit is a turnkey package > and he also sells a 10mhz distribution amplifier that looks interesting... > another BG7TBL design. > > KE5FX has also reviewed Bob W7AVK's BG7TBL and has a nice comparison write > up on his website (KE5FX of Lady Heather fame). The comparison is easy to > find on KE5FX's site. > > Again, thanks to everyone that had input... I tried to mention everyone > that pointed me in the right direction off the list and leaving out Dave > G3TJP was my mistake. > > Regards, Max NG7M > > Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
Re: WTB Trimble ThunderBolt for K3EXREF / QS1R
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In reply to this post by ng7m
A caveat regarding the use of simple "wall wart" 12v PS for supplying a OCXO.
I am using a Morion OCXO as 10-MHz reference for my K3EXREF and for my synthesized A32 PLL in my DEMI 1296 transverter. I got reports of 120-Hz sidebands on my signal (-10dBc) turned out to be due to excessive AC ripple riding on the 12v coming from my wall wart supply that I was using to power the OCXO. Using a scope I measured half a volt ripple on the 12v dc output. Substituting a clean 12v PS eliminated the sidebands. So be careful if you use a wall wart (many rectify with no dc filtering). I had a 17AH battery being charged by the wall wart which I assumed would present some filtering if 12v ran thru the battery to the OCXO. I could have added a large value electrolytic cap to do the filtering but I changed dc source to a well filtered Astron PS. 73, Ed - KL7UW http://www.kl7uw.com "Kits made by KL7UW" Dubus Mag business: [hidden email] ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
Re: WTB Trimble ThunderBolt for K3EXREF / QS1R
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On Tue,4/7/2015 12:31 AM, Edward R Cole wrote:
> A caveat regarding the use of simple "wall wart" 12v PS for supplying > a OCXO. Wall warts, especially those with switching power supplies, are ALWAYS a BAD thing, thanks to the RFI they generate. A GOOD thing -- a LINEAR supply, wall wart or otherwise, float-charging a battery, where the battery voltage is what the equipment needs, and the current from the wall wart is about 30% more than what it takes to run the equipment. No hum, no buzz, no RFI, and you've got a UPS in the form of that battery. ALL of the stuff in my home (with the exception of a TV and associated A/V gear) runs on that kind of charger-battery system. The only noise I hear is from my neighbors. 73, Jim K9YC ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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In reply to this post by ng7m
I have had a similar experience on 3400MHz EME. I used a 12V wallwart to
power my DEMI 10-4 10MHz splitter after my LPRO101 Rb Standard feeding the K3 and the 10MHz locked Xverter. I got complaints from 3 continents that my signals off the moon had 120Hz sidebands! Dave WW2R Message: 4 Date: Mon, 06 Apr 2015 23:31:55 -0800 From: Edward R Cole <[hidden email]> To: [hidden email] Subject: Re: [Elecraft] WTB Trimble ThunderBolt for K3EXREF / QS1R Message-ID: <[hidden email]> Content-Type: text/plain; charset="us-ascii"; format=flowed A caveat regarding the use of simple "wall wart" 12v PS for supplying a OCXO. I am using a Morion OCXO as 10-MHz reference for my K3EXREF and for my synthesized A32 PLL in my DEMI 1296 transverter. I got reports of 120-Hz sidebands on my signal (-10dBc) turned out to be due to excessive AC ripple riding on the 12v coming from my wall wart supply that I was using to power the OCXO. 73, Ed - KL7UW ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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In reply to this post by ng7m
> From: Edward R Cole <[hidden email]>
> To: [hidden email] > Subject: Re: [Elecraft] WTB Trimble ThunderBolt for K3EXREF / QS1R > Message-ID: <[hidden email]> > Content-Type: text/plain; charset="us-ascii"; format=flowed > > A caveat regarding the use of simple "wall wart" 12v PS for supplying > a OCXO. > > I am using a Morion OCXO as 10-MHz reference for my K3EXREF and for my > synthesized A32 PLL in my DEMI 1296 transverter. I got reports of > 120-Hz sidebands on my signal (-10dBc) turned out to be due to > excessive AC ripple riding on the 12v coming from my wall wart supply > that I was using to power the OCXO. > > 73, Ed - KL7UW Things of note re Trimble Thunderbolt's. Your going to somewhat stress a regular "wall-wart", if you use one to run a Thunderbolt, they are quite juicy in their power requirements, and also need multiple DC voltages. + & - 12V, and +5V Check the datasheet at Trimbles site (Google for it.) They run quite warm too, so if you put it in a box, make sure it has enough cooling, but you don't want the temperature to vary too much over time either. In any case, "Wall-Warts" are the scurge of the earth, most are poorly built, many don't conform to all the needed safety and/or EMC regs, many to fail early in life, compared to "regular" PSU's. They are a cheap (and nasty) solution to a simple problem, plus many are as some have found, poorly regulated. Most of the Thunderbolt "Kits from China" come with a suitable wide input range fairly quiet SMPS and ready made power cable for that to plug into the Thunderbolt. Note also, that unless you also obtain suitable software to configure and monitor the TB (Trimble's or "Lady Heather") it's going to be a bit of an uphill struggle to get it all working the first time. Remember too, that the GPS antenna will need a clear view of the sky for the TB to function correctly. "Have Fun!" Dave G0WBX. ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
Re: WTB Trimble ThunderBolt for K3EXREF / QS1R
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Ed & others -
From my experience in using Rubidium and GPS disciplined standards, I feel that a far better bet is to use an MV89A 10MHz Double-oven CXO. It requires only a 12V d.c. supply. I built one into a Hammond die-cast box (with no ventilation) with its own integral linear PSU, regulated with an L78S12CV regulator. On switch-on it draws 34W from the supply mains, which steadily reduces to 9W after about 12 minutes when the oven attains its working temperature. Using a 10-turn 10K pot the frequency can be finely adjusted to within 1/100 of a Hz and it locks the K3 perfectly with the K3EXREF installed. 100% recommended. The MV89A is available on eBay and the datasheet is at http://morion.com.ru/catalog_pdf/MV89-OCXO.pdf 73 de David G4DMP >> A caveat regarding the use of simple "wall wart" 12v PS for supplying >> a OCXO. >> >> I am using a Morion OCXO as 10-MHz reference for my K3EXREF and for my >> synthesized A32 PLL in my DEMI 1296 transverter. I got reports of >> 120-Hz sidebands on my signal (-10dBc) turned out to be due to >> excessive AC ripple riding on the 12v coming from my wall wart supply >> that I was using to power the OCXO. -- + - - - - - - - - - - - - - - - - + | 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:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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Agree. I've got one here. One can set it to Rb and it stays put within
5 milliHz or so. The warm up time to get within the 5 mHz window seems to be about half an hour. Long term stability is pretty incredible. Also they are cheap. Getting rid of it for anybody that's interested. Also a Rb (LPRO-101) unit is available. 73 de Brian/K3KO On 4/10/2015 12:29 PM, David G4DMP wrote: > Ed & others - > >From my experience in using Rubidium and GPS disciplined standards, I > feel that a far better bet is to use an MV89A 10MHz Double-oven CXO. It > requires only a 12V d.c. supply. > > I built one into a Hammond die-cast box (with no ventilation) with its > own integral linear PSU, regulated with an L78S12CV regulator. On > switch-on it draws 34W from the supply mains, which steadily reduces to > 9W after about 12 minutes when the oven attains its working temperature. > > Using a 10-turn 10K pot the frequency can be finely adjusted to within > 1/100 of a Hz and it locks the K3 perfectly with the K3EXREF installed. > > 100% recommended. > > The MV89A is available on eBay and the datasheet is at > http://morion.com.ru/catalog_pdf/MV89-OCXO.pdf > > 73 de David G4DMP > >>> A caveat regarding the use of simple "wall wart" 12v PS for supplying >>> a OCXO. >>> >>> I am using a Morion OCXO as 10-MHz reference for my K3EXREF and for my >>> synthesized A32 PLL in my DEMI 1296 transverter. I got reports of >>> 120-Hz sidebands on my signal (-10dBc) turned out to be due to >>> excessive AC ripple riding on the 12v coming from my wall wart supply >>> that I was using to power the OCXO. ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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Hi folks,
The inexpensive BG7TBL GPSDO units use the same Morion double oven 10 MHz Xtal osc, and in fact the distribution amp they sell also has a Morion osc included. All in a neat box with BNC sockets and ready to plug in your linearly regulated 12 Volts supply or battery. 73 David Anderson GM4JJJ > On 10 Apr 2015, at 15:12, brian <[hidden email]> wrote: > > Agree. I've got one here. One can set it to Rb and it stays put within 5 milliHz or so. > The warm up time to get within the 5 mHz window seems to be about half an hour. > Long term stability is pretty incredible. > > Also they are cheap. > > Getting rid of it for anybody that's interested. > Also a Rb (LPRO-101) unit is available. > > 73 de Brian/K3KO >> On 4/10/2015 12:29 PM, David G4DMP wrote: >> Ed & others - >> >From my experience in using Rubidium and GPS disciplined standards, I >> feel that a far better bet is to use an MV89A 10MHz Double-oven CXO. It >> requires only a 12V d.c. supply. >> >> I built one into a Hammond die-cast box (with no ventilation) with its >> own integral linear PSU, regulated with an L78S12CV regulator. On >> switch-on it draws 34W from the supply mains, which steadily reduces to >> 9W after about 12 minutes when the oven attains its working temperature. >> >> Using a 10-turn 10K pot the frequency can be finely adjusted to within >> 1/100 of a Hz and it locks the K3 perfectly with the K3EXREF installed. >> >> 100% recommended. >> >> The MV89A is available on eBay and the datasheet is at >> http://morion.com.ru/catalog_pdf/MV89-OCXO.pdf >> >> 73 de David G4DMP >> >>>> A caveat regarding the use of simple "wall wart" 12v PS for supplying >>>> a OCXO. >>>> >>>> I am using a Morion OCXO as 10-MHz reference for my K3EXREF and for my >>>> synthesized A32 PLL in my DEMI 1296 transverter. I got reports of >>>> 120-Hz sidebands on my signal (-10dBc) turned out to be due to >>>> excessive AC ripple riding on the 12v coming from my wall wart supply >>>> that I was using to power the OCXO. > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to [hidden email] Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
Re: WTB Trimble ThunderBolt for K3EXREF / QS1R
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In reply to this post by David Pratt
David, G4DMP:
I won't disagree. I guessed you missed my first sentence: "I am using a Morion OCXO as 10-MHz reference..."? The Double-Oven may be more stable at 2xE-12 vs mine 5xE-12 but doubt you will ever measure the difference let alone discern it in actual use (unless you are operating on high freq microwaves). Mine is single-oven, model MV62. I use a LM7805 for the Vf lead using a 10-turn Helipot (think it is 100K). The frequency control input takes very little current. My counter only resolves 1-Hz so I can only guess how close I have it adjusted (but less than a Hz). Actually, I can adjust it by monitoring my 3400-MHz transverter LO which is a PLL referenced to the OCXO. The LO runs at 3255-MHz which is several multiples above 10-MHz, so if it reads exact then the reference is much more accurate than 1-Hz ( depends on the divider ratio in the PLL). I float charge a 17AH battery so the voltage level is regulated by the battery (an the Astron PS). Advantage of the battery is that the OCXO is immune to power outages, so it remains very stable. Long-term stability is about 5xE-8 (28*5/100 = 1.4 Hz per year at 28-MHz) so one should check for drift about every six months. I use my Rubidium as my local frequency reference for this. I only run it for about an hour to be stable for the check. My mw counter is connected to the Rb for ext ref. I bought my Morion for about $45 a few years ago on e-bay. Recently I bought two sine-wave OCXO for $27.99 with free shipping from a Chinese source on e-bay; too two weeks to arrive. 73, Ed - KL7UW At 04:29 AM 4/10/2015, David G4DMP wrote: >Ed & others - > From my experience in using Rubidium and GPS disciplined standards, I >feel that a far better bet is to use an MV89A 10MHz Double-oven CXO. It >requires only a 12V d.c. supply. > >I built one into a Hammond die-cast box (with no ventilation) with its >own integral linear PSU, regulated with an L78S12CV regulator. On >switch-on it draws 34W from the supply mains, which steadily reduces to >9W after about 12 minutes when the oven attains its working temperature. > >Using a 10-turn 10K pot the frequency can be finely adjusted to within >1/100 of a Hz and it locks the K3 perfectly with the K3EXREF installed. > >100% recommended. > >The MV89A is available on eBay and the datasheet is at >http://morion.com.ru/catalog_pdf/MV89-OCXO.pdf > >73 de David G4DMP > > >> A caveat regarding the use of simple "wall wart" 12v PS for supplying > >> a OCXO. > >> > >> I am using a Morion OCXO as 10-MHz reference for my K3EXREF and for my > >> synthesized A32 PLL in my DEMI 1296 transverter. I got reports of > >> 120-Hz sidebands on my signal (-10dBc) turned out to be due to > >> excessive AC ripple riding on the 12v coming from my wall wart supply > >> that I was using to power the OCXO. > >-- > + - - - - - - - - - - - - - - - - + > | David M Pratt, Kippax, Leeds. | > | Website: http://www.g4dmp.co.uk | > + - - - - - - - - - - - - - - - - + 73, Ed - KL7UW http://www.kl7uw.com "Kits made by KL7UW" Dubus Mag business: [hidden email] ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
Re: WTB Trimble ThunderBolt for K3EXREF / QS1R
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In reply to this post by g8kbvdave
I think these posts contain much wisdom. I'd like to add a little to what
Dave has said. >Remember too, that the GPS antenna will need >a clear view of the sky for the TB to function correctly. Many GPS antennas are sold with a pre-attached coax. Most antennas contain a preamp as well. Ever wonder why? The coax supplied by many is very small allowing it to be easily concealed in a car's headliner. In an apartment or basement shack the distance to clear view may beyond the pre-supplied coax. Before you extend that coax take a look at the total attenuation. The GPS frequencies are approximately 1.6 GHz. At 1.6 GHz the attenuation of the OEM coax used by many runs about 1 db per foot. RG174 is 0.35 and RG58 0.2 db per foot. You can also figure about a db per connector. With this kind of attenuation a preamp is essential. Even with a preamp a long run of coax is deadly to GPS. Caveat Emptor. 73, Fred, AE6QL ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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