10 MHz external reference

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10 MHz external reference

Gary Smith-2
I ordered the K3EXREF and thought it was the oscillator itself which
would provide the external signal source to the K3s. I thought this
was all I was going to need but I see now that is not the case.
Looking on the Elecraft order page, they don't sell a reference
source.

What external 10-MHz reference signal source might I find get that is
not terribly expensive that will do the proper job and allow me to
get this working?

Thanks & 73,

Gary
KA1J


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Re: 10 MHz external reference

Udo Langenohl - DK5YA
Gary,

there is a huge amount of sources available, i.e.

http://world.taobao.com/item/42336500072.htm?fromSite=main&spm=a312a.7700824.w4004-11814489530.4.1iUOwV

or

http://www.ebay.ca/itm/10MHZ-OUTPUT-Square-WAVE-GPS-DISCiPLINED-CLOCK-GPSDO-with-Antenna-power-supply-/171813807811

or

http://www.force12inc.com/products/gps-locked-precision-frequency-reference-low-jitter-gps-clock-450-hz-to-800-mhz-output-custom-low-phase-noise-xtal-version.html

and many more.

73 Udo, DK5YA


Am 09.03.2016 um 18:37 schrieb Gary Smith:

> I ordered the K3EXREF and thought it was the oscillator itself which
> would provide the external signal source to the K3s. I thought this
> was all I was going to need but I see now that is not the case.
> Looking on the Elecraft order page, they don't sell a reference
> source.
>
> What external 10-MHz reference signal source might I find get that is
> not terribly expensive that will do the proper job and allow me to
> get this working?
>
> Thanks & 73,
>
> Gary
> KA1J
>
>
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Re: 10 MHz external reference

Kevin Cozens-2
Am 09.03.2016 um 18:37 schrieb Gary Smith:
>> What external 10-MHz reference signal source might I find get that is
>> not terribly expensive that will do the proper job and allow me to
>> get this working?

You can look for a GPS disciplined oscillator (GPSDO), an FE-5680 Rubidium
based oscillator, or look for some of the lesser expensive GPS receiver
modules that have 10MHz outputs.

A GPSDO can be expensive but there are some more affordable ones if you look
around. FE-5680's used to be available around $100US (or less if you got
lucky). Lately the prices seem to have gone up for these devices, and they
tend to be power hungry. There are some GPS receiver modules that have GPS
receiver blocks on them made by companies such as Ublox. Take a look for GPS
receiver devices that are meant to be used as part of a flight control
system for radio controlled aircraft (or what some people call drones).

--
Cheers!

Kevin.

http://www.ve3syb.ca/           |"Nerds make the shiny things that distract
Owner of Elecraft K2 #2172      | the mouth-breathers, and that's why we're
                                 | powerful!"
#include <disclaimer/favourite> |             --Chris Hardwick
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Re: 10 MHz external reference

Gary Smith-2
In reply to this post by Gary Smith-2

Udo & Kevin,

Thanks for the reply. I hadn't researched any of the options, I
thought the K3EXREF was all I needed. Now that I have a better idea
what to look for, I'll find something. I just need to be sure it fits

what the requirements are.

I'm surprised to find almost all the sources are from China. I know
they are trying ever more to make better products but something as
precise as a 10 MHz standard that will be connected to my K3s,
concerns when me buying from an unknown manufacturer. QC is always a
concern. Sure wish there was an affordable kit with the proper
connections that was available.

If anyone has a 10 MHz reference signal source that works fine with
the K3 & is excess to their needs, please contact me off list.

Thanks & 73,

Gary
KA1J

> Am 09.03.2016 um 18:37 schrieb Gary Smith:
> >> What external 10-MHz reference signal source might I find get that is
> >> not terribly expensive that will do the proper job and allow me to
> >> get this working?
>
> You can look for a GPS disciplined oscillator (GPSDO), an FE-5680 Rubidium
> based oscillator, or look for some of the lesser expensive GPS receiver
> modules that have 10MHz outputs.
>
> A GPSDO can be expensive but there are some more affordable ones if you look
> around. FE-5680's used to be available around $100US (or less if you got
> lucky). Lately the prices seem to have gone up for these devices, and they
> tend to be power hungry. There are some GPS receiver modules that have GPS
> receiver blocks on them made by companies such as Ublox. Take a look for GPS
> receiver devices that are meant to be used as part of a flight control
> system for radio controlled aircraft (or what some people call drones).
>
> --
> Cheers!
>
> Kevin.
>
> http://www.ve3syb.ca/           |"Nerds make the shiny things that distract
> Owner of Elecraft K2 #2172      | the mouth-breathers, and that's why we're
>                                  | powerful!"
> #include <disclaimer/favourite> |             --Chris Hardwick
> ______________________________________________________________
> 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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Re: 10 MHz external reference

W Paul Mills

Little more work than a kit, but you may want to look at this.
<http://ve2zaz.net/GPS_Std/GPS_Std.htm>

On 03/09/2016 06:55 PM, Gary Smith wrote:

>
> Udo & Kevin,
>
> Thanks for the reply. I hadn't researched any of the options, I
> thought the K3EXREF was all I needed. Now that I have a better idea
> what to look for, I'll find something. I just need to be sure it fits
>
> what the requirements are.
>
> I'm surprised to find almost all the sources are from China. I know
> they are trying ever more to make better products but something as
> precise as a 10 MHz standard that will be connected to my K3s,
> concerns when me buying from an unknown manufacturer. QC is always a
> concern. Sure wish there was an affordable kit with the proper
> connections that was available.
>
> If anyone has a 10 MHz reference signal source that works fine with
> the K3 & is excess to their needs, please contact me off list.
>
> Thanks & 73,
>
> Gary
> KA1J
> --
/*************************************************
* Amateur Radio Station AC0HY                    *
* W. Paul Mills         SN807                    *
* Assistant EC Alpha-1 ARES Shawnee/Wabunsee, KS *
* President Kaw Valley Amateur Radio Club        *
*************************************************/
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Re: 10 MHz external reference

W1KSZ
You can't beat a surplus Trimble Thunderbolt. Everything in one small box,
the power supply is available on e-Pay as well as the antenna.

Once upon a time they were cheap, like $20 cheap. But the supply is drying
up. They are still a bargain at $125 though.

I bought a few when they were plentiful.

73, Dick, W1KSZ

-----Original Message-----
From: Elecraft [mailto:[hidden email]] On Behalf Of W Paul
Mills
Sent: Wednesday, March 09, 2016 8:14 PM
To: [hidden email]
Subject: Re: [Elecraft] 10 MHz external reference


Little more work than a kit, but you may want to look at this.
<http://ve2zaz.net/GPS_Std/GPS_Std.htm>

On 03/09/2016 06:55 PM, Gary Smith wrote:

>
> Udo & Kevin,
>
> Thanks for the reply. I hadn't researched any of the options, I
> thought the K3EXREF was all I needed. Now that I have a better idea
> what to look for, I'll find something. I just need to be sure it fits
>
> what the requirements are.
>
> I'm surprised to find almost all the sources are from China. I know
> they are trying ever more to make better products but something as
> precise as a 10 MHz standard that will be connected to my K3s,
> concerns when me buying from an unknown manufacturer. QC is always a
> concern. Sure wish there was an affordable kit with the proper
> connections that was available.
>
> If anyone has a 10 MHz reference signal source that works fine with
> the K3 & is excess to their needs, please contact me off list.
>
> Thanks & 73,
>
> Gary
> KA1J
> --
/*************************************************
* Amateur Radio Station AC0HY                    *
* W. Paul Mills         SN807                    *
* Assistant EC Alpha-1 ARES Shawnee/Wabunsee, KS *
* President Kaw Valley Amateur Radio Club        *
*************************************************/
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Re: 10 MHz external reference

HankP
In reply to this post by Kevin Cozens-2
As a casual observer of this thread - does the oscillator have to be
precisely 10 mhz to a zillion decimal places  OR does it just need
to be close to 10 mhz and verrrrrryyyyy stable ?

Years ago hams used to build 10 mhz xtal
oscillators/buffers  - put them in  a thermos bottle - dig a post hole
and bury the thing about 4 feet deep - it was pretty stable
just xtal aging and needed lo noise stable DC.

Hank K7HP
 

----- Original Message -----
Am 09.03.2016 um 18:37 schrieb Gary Smith:
>> What external 10-MHz reference signal source might I find get that is
>> not terribly expensive that will do the proper job and allow me to
>> get this working?

You can look for a GPS disciplined oscillator (GPSDO), an FE-5680 Rubidium
based oscillator, or look for some of the lesser expensive GPS receiver
modules that have 10MHz outputs.

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Re: 10 MHz external reference

Don Wilhelm-4
Hank,

It needs to be 10 MHz and very stable.
If it is not right on 10 MHz, it will still lock, but the K3 frequency
will be off as much as the reference is different than 10 MHz.

73,
Don W3FPR

On 3/9/2016 10:49 PM, HankP wrote:

> As a casual observer of this thread - does the oscillator have to be
> precisely 10 mhz to a zillion decimal places  OR does it just need
> to be close to 10 mhz and verrrrrryyyyy stable ?
>
> Years ago hams used to build 10 mhz xtal
> oscillators/buffers  - put them in  a thermos bottle - dig a post hole
> and bury the thing about 4 feet deep - it was pretty stable
> just xtal aging and needed lo noise stable DC.
>
>

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Re: 10 MHz external reference

Clay Autery
In reply to this post by W Paul Mills
Awwww... mannnnnn!!  Now that I know I can build one fairly easily, I
may have to do that instead of getting the Leo Bodnar Low-Jitter, custom
low phase noise XTAL version...

http://www.force12inc.com/products/gps-locked-precision-frequency-reference-low-jitter-gps-clock-450-hz-to-800-mhz-output-custom-low-phase-noise-xtal-version.html


______________________
Clay Autery, KG5LKV
MONTAC Enterprises
(318) 518-1389

On 3/9/2016 9:13 PM, W Paul Mills wrote:
> Little more work than a kit, but you may want to look at this.
> <http://ve2zaz.net/GPS_Std/GPS_Std.htm>

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Re: 10 MHz external reference

W1KSZ
In reply to this post by HankP
The Trimble Thunderbolt is locked to the GPS system, which derives it's
reference
from Cesium standards initially, but I believe now they have Rubidium
standards
that are locked to a master reference.

Someone who knows more about the GPS system can chime in on this.

In any case, the T-Bolt 10 MHz reference output is about the best you can
get
unless you want to spring for an HP Cesium standard or maybe a Hydrogen
Maser ??

I have two active ones plus one I built using the N1JEZ design. I have a
third
one boxed up with a power supply and distribution amp that I can loan out to

friends.

73, Dick, W1KSZ

-----Original Message-----
From: Elecraft [mailto:[hidden email]] On Behalf Of HankP
Sent: Wednesday, March 09, 2016 8:50 PM
To: [hidden email]
Subject: Re: [Elecraft] 10 MHz external reference

As a casual observer of this thread - does the oscillator have to be
precisely 10 mhz to a zillion decimal places  OR does it just need to be
close to 10 mhz and verrrrrryyyyy stable ?

Years ago hams used to build 10 mhz xtal oscillators/buffers  - put them in
a thermos bottle - dig a post hole and bury the thing about 4 feet deep - it
was pretty stable just xtal aging and needed lo noise stable DC.

Hank K7HP
 

----- Original Message -----
Am 09.03.2016 um 18:37 schrieb Gary Smith:
>> What external 10-MHz reference signal source might I find get that is
>> not terribly expensive that will do the proper job and allow me to
>> get this working?

You can look for a GPS disciplined oscillator (GPSDO), an FE-5680 Rubidium
based oscillator, or look for some of the lesser expensive GPS receiver
modules that have 10MHz outputs.

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Re: 10 MHz external reference

wb4jfi
In reply to this post by Kevin Cozens-2
The Ublox GPS units (like the Neo-6 and NEO-7) are not great for this
application.  Their master oscillators are an oddball frequency (as far as
freq standards go, IIRC 48MHz?).  That doesn't divide evenly to 10MHz, so
there is some jitter component at 10MHz output.  Not what you want for a
reference signal.

I've used a used commercial-grade GPSDO that I found used, and an HP3801A
from ebay, both less than $100.

I've also purchased rubidium-based units, Efratom LPRO-101 from ebay for
about $75 each.

There are several other GPS-based thingies that aren't "disciplined" for
pretty good prices.  The older Trimble units are usually good.  Hams Summers
of QRPLabs.com sells a QLG1 for about $23 that seems to be usable - I think.
I've got one for my QRP Labs beacon.  You might want to look at the specs
for the SKM1 GPS module on his board.

There are many designs for GPS disciplined oscillators, and many inexpensive
GPS receivers out there.  Make sure their 10MHz output is stable.  However,
if you want "portability", or your shack can't easily see the sky, you might
want to check out the various rubidium oscillators instead.  I'm sure you
can find a TON more info on the timenuts forum.

Also be careful with the 10MHz reference signal distribution, it can play
havoc with the 30 Meters band (and 10MHz WWV), especially it it's a ratty
square wave.
73, Terry, N4TLF



-----Original Message-----
From: Kevin Cozens
Sent: Wednesday, March 09, 2016 5:51 PM
To: [hidden email]
Subject: Re: [Elecraft] 10 MHz external reference

Am 09.03.2016 um 18:37 schrieb Gary Smith:
>> What external 10-MHz reference signal source might I find get that is
>> not terribly expensive that will do the proper job and allow me to
>> get this working?

You can look for a GPS disciplined oscillator (GPSDO), an FE-5680 Rubidium
based oscillator, or look for some of the lesser expensive GPS receiver
modules that have 10MHz outputs.

A GPSDO can be expensive but there are some more affordable ones if you look
around. FE-5680's used to be available around $100US (or less if you got
lucky). Lately the prices seem to have gone up for these devices, and they
tend to be power hungry. There are some GPS receiver modules that have GPS
receiver blocks on them made by companies such as Ublox. Take a look for GPS
receiver devices that are meant to be used as part of a flight control
system for radio controlled aircraft (or what some people call drones).

--
Cheers!

Kevin.

http://www.ve3syb.ca/           |"Nerds make the shiny things that distract
Owner of Elecraft K2 #2172      | the mouth-breathers, and that's why we're
                                 | powerful!"
#include <disclaimer/favourite> |             --Chris Hardwick
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Re: 10 MHz external reference

Petr, OK1RP/M0SIS
This post was updated on .
In reply to this post by Gary Smith-2
Hi Gary,

there is several options how to solve the 10MHz ref. source for your K3.
Some of them has been mentioned over here already.
In all cases you can find Pros and Cons...
In fact you need to know what is your own prefference > precision, simplicity, consumption, price etc.

Try to look for some information about the solution using FE-5680A Rubidium standard here:
http://ok1rp.blogspot.ch/2014/07/fe-5680a-rubidium-standard.html

then you can consider the pluses and minuses and compare it with another solutions.

The FE-5680A units are still available on eBay (my own I found for $69 incl. shipping years ago) now at around $100 I guess but these units are heavily used in BTS stations for long time (Base Transceiver Station in Base Station S(ubs)ystem of GSM cellular network)
These units are retired based on pre-calculated life-time and now are available as surplus parts on eBay.
It not means that it will not work but some units will make good job for us for several years and some unit can fail in short term unfortunately. It is hard to estimate or anticipate.

My unit is purchased on eBay in 2013 and it works perfectly but I am always recommending to ask seller how old the offered unit is and focuse on as young as possible piece.

Another "Cons" for somebody (not my case) can be to consuption as these units (depends to type) needs 15V to 18V @ 1.8A peak and 0.7A steady-state.

Even although all what I said can sound bad I can recommend it as more or less cheap and good solution.

More informations you can find on Doug's, VK3UM pages (RIP)
http://www.vk3um.com/Rubidium%20Standard.html

Hope it helps,

73 - Petr, OK1RP
73 - Petr, OK1RP
"Apple & Elecraft freak"
B:http://ok1rp.blogspot.com
MeWe: https://bit.ly/2HGPoDx
MeWe: https://bit.ly/2FmwvDt
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Re: 10 MHz external reference

Edward R Cole
In reply to this post by Gary Smith-2
If you just need a 10-MHz reference then you do not need a GPSDO.  A
simple surplus OCXO (oven controlled xtal oscillator) off e-bay will
suffice.  I bought a one for about $45 initially (Morion).  Since
then I bought two sine-wave OCXO for $25.  You do need to supply very
clean 12v dc for most of these and a stable bias 0-5v for tuning the
OCXO to 10.000,000 MHz.

Short term stability is 5 E-12 which will do fine with the
K3EXREF.  The TCXO is the limiting factor for frequency in the K3 so
really no need for GPS accuracy.  If you are feeding a PLL system
then the GPSDO will be better.

I use a LM7805 to 100K 15 turn pot to supply the tuning bias.  Adding
a medium value electrolytic cap before the OCXO is extra insurance to
eliminate any ac ripple or noise from modulating the OCXO.  One could
also float charge a battery to feed the OCXO which also damps out any
ac.  Why I mention this is I was using a 1.5A RS wall wart charger
initially until I was told I had 120-Hz spurs on my signal.  There
was about 0.3vac ripple from the so-called 12v wall wart.

I could have built or bought a clean low power 12v PS but I just
hooked the OCXO to my 50A Astron PS.  No spurs, now.

To set up the OCXO use a good frequency counter or net the oscillator
to WWV 10-MHz (if you can hear it).  I have a Rubidium source that I
use as my standard and measure with a microwave frequency
counter.  But that is not needed for basic use on HF/6m with the
K3EXREF.  Note that OCXO will drift off frequency about 1-Hz in six
months so regular checking a couple times per year is needed.  GPSDO
does not need this.

73, Ed - KL7UW

Date: Wed, 09 Mar 2016 12:37:04 -0500
From: "Gary Smith" <[hidden email]>
To: [hidden email]
Subject: [Elecraft] 10 MHz external reference
Message-ID: <[hidden email]>
Content-Type: text/plain; charset=US-ASCII

I ordered the K3EXREF and thought it was the oscillator itself which
would provide the external signal source to the K3s. I thought this
was all I was going to need but I see now that is not the case.
Looking on the Elecraft order page, they don't sell a reference
source.

What external 10-MHz reference signal source might I find get that is
not terribly expensive that will do the proper job and allow me to
get this working?

Thanks & 73,

Gary
KA1J

73, Ed - KL7UW
http://www.kl7uw.com
     "Kits made by KL7UW"
Dubus Mag business:
     [hidden email]

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Re: 10 MHz external reference

Petr, OK1RP/M0SIS
In reply to this post by Petr, OK1RP/M0SIS
Gary,

just one more thing...

If you will decline the Rubidium standard solution and you will thinking more about the GPSDO then my own recommendation is for James, G3RUH solution. It is "ready to go" box, very nice built. Not cheap, but no Chinese crapy and it is using new and very clean AXIOM40 OCXO. (no need to solve the distribution amps issue etc.)

http://www.jrmiller.demon.co.uk/projects/ministd/frqstd.htm

More links for your inspiration how it can be solved are here:

http://www.ntms.org/files/n1jez_ntms.pdf
http://www.qsl.net/zl1bpu/MICRO/SIMPLE/SimpleGPS.htm
http://www.g4jnt.com/SimpleGPSDO.pdf

Hope it helps,

73 - Petr, OK1RP
73 - Petr, OK1RP
"Apple & Elecraft freak"
B:http://ok1rp.blogspot.com
MeWe: https://bit.ly/2HGPoDx
MeWe: https://bit.ly/2FmwvDt
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Re: 10 MHz external reference

briancom
In reply to this post by wb4jfi
Terry,
I beg to differ.  I did extensive comparisons of the UBLOX units with my
Rb.  There is also an article by an LA ham concluded the same.

Yes there is jitter, however it's peak amount is fraction of the 1 Hz
step the XREF corrects for.

If you're interested I'll send you a plot of deviations.

73 de Brian/K3KO
On 3/10/2016 5:04 AM, [hidden email] wrote:

> The Ublox GPS units (like the Neo-6 and NEO-7) are not great for this
> application.  Their master oscillators are an oddball frequency (as far
> as freq standards go, IIRC 48MHz?).  That doesn't divide evenly to
> 10MHz, so there is some jitter component at 10MHz output.  Not what you
> want for a reference signal.
>
> I've used a used commercial-grade GPSDO that I found used, and an
> HP3801A from ebay, both less than $100.
>
> I've also purchased rubidium-based units, Efratom LPRO-101 from ebay for
> about $75 each.
>
> There are several other GPS-based thingies that aren't "disciplined" for
> pretty good prices.  The older Trimble units are usually good.  Hams
> Summers of QRPLabs.com sells a QLG1 for about $23 that seems to be
> usable - I think. I've got one for my QRP Labs beacon.  You might want
> to look at the specs for the SKM1 GPS module on his board.
>
> There are many designs for GPS disciplined oscillators, and many
> inexpensive GPS receivers out there.  Make sure their 10MHz output is
> stable.  However, if you want "portability", or your shack can't easily
> see the sky, you might want to check out the various rubidium
> oscillators instead.  I'm sure you can find a TON more info on the
> timenuts forum.
>
> Also be careful with the 10MHz reference signal distribution, it can
> play havoc with the 30 Meters band (and 10MHz WWV), especially it it's a
> ratty square wave.
> 73, Terry, N4TLF
>
>
>
> -----Original Message----- From: Kevin Cozens
> Sent: Wednesday, March 09, 2016 5:51 PM
> To: [hidden email]
> Subject: Re: [Elecraft] 10 MHz external reference
>
> Am 09.03.2016 um 18:37 schrieb Gary Smith:
>>> What external 10-MHz reference signal source might I find get that is
>>> not terribly expensive that will do the proper job and allow me to
>>> get this working?
>
> You can look for a GPS disciplined oscillator (GPSDO), an FE-5680 Rubidium
> based oscillator, or look for some of the lesser expensive GPS receiver
> modules that have 10MHz outputs.
>
> A GPSDO can be expensive but there are some more affordable ones if you
> look
> around. FE-5680's used to be available around $100US (or less if you got
> lucky). Lately the prices seem to have gone up for these devices, and they
> tend to be power hungry. There are some GPS receiver modules that have GPS
> receiver blocks on them made by companies such as Ublox. Take a look for
> GPS
> receiver devices that are meant to be used as part of a flight control
> system for radio controlled aircraft (or what some people call drones).
>
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Re: 10 MHz external reference

Wes (N7WS)
In reply to this post by Gary Smith-2
I haven't used this to frequency lock my K3S or K3, but it is my house standard.

http://www.force12inc.com/products/gps-locked-precision-frequency-reference-low-jitter-gps-clock-450-hz-to-800-mhz-output.html



On 3/9/2016 5:55 PM, Gary Smith wrote:

> Udo & Kevin,
>
> Thanks for the reply. I hadn't researched any of the options, I
> thought the K3EXREF was all I needed. Now that I have a better idea
> what to look for, I'll find something. I just need to be sure it fits
>
> what the requirements are.
>
> I'm surprised to find almost all the sources are from China. I know
> they are trying ever more to make better products but something as
> precise as a 10 MHz standard that will be connected to my K3s,
> concerns when me buying from an unknown manufacturer. QC is always a
> concern. Sure wish there was an affordable kit with the proper
> connections that was available.
>
> If anyone has a 10 MHz reference signal source that works fine with
> the K3 & is excess to their needs, please contact me off list.
>
> Thanks & 73,
>
> Gary
> KA1J
>
>

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Re: 10 MHz external reference

Pete Smith N4ZR
In reply to this post by Gary Smith-2
Take a look at this GPSDO
<http://www.force12inc.com/products/gps-locked-precision-frequency-reference-low-jitter-gps-clock-450-hz-to-800-mhz-output.html>.
Needs 13-15 VDC and a powered GPS antenna, but it is plug and playon any
frequency from 450 KHz to 800 MHz, with software-adjustable output level.

73, Pete N4ZR
Download the new N1MM Logger+ at
<http://N1MM.hamdocs.com>. Check
out the Reverse Beacon Network at
<http://reversebeacon.net>, now
spotting RTTY activity worldwide.
For spots, please use your favorite
"retail" DX cluster.

On 3/9/2016 12:37 PM, Gary Smith wrote:

> I ordered the K3EXREF and thought it was the oscillator itself which
> would provide the external signal source to the K3s. I thought this
> was all I was going to need but I see now that is not the case.
> Looking on the Elecraft order page, they don't sell a reference
> source.
>
> What external 10-MHz reference signal source might I find get that is
> not terribly expensive that will do the proper job and allow me to
> get this working?
>
> Thanks & 73,
>
> Gary
> KA1J
>
>
> ______________________________________________________________
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> Post: mailto:[hidden email]
>
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> Message delivered to [hidden email]
>

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Re: 10 MHz external reference - GPSDO

Gary Smith-2
I appreciate the replies to my question about sourcing a 10 MHz
external reference for my K3s. I didn't realize I needed more than
the K3EXREF to gain this accuracy and thanks to these replies, I now
better understand what will and what will not work. While I would
prefer to be able to buy a satisfactory GPSDO or kit from Elecraft,
it isn't an option at this time and not knowing if one is on the
Horizon, I must look elsewhere to find one.

What makes it a more difficult choice is understanding what values
are sufficient and what is excess; some of these devices are in the 4
figures and some used are less than $40. I was about to buy a $40
used TCVCXO but learned they need to be recalibrated to maintain
their precision and I having no equipment to do this, one of the more
expensive options apparently is a better solution.

Apparently the low cost GPSDO are an affordable way to go for long
term accuracy but which one to get? Some apparently have jitter from
poorly isolated interference due to the proximity of their 1pps
Square wave functions but is that jitter something to affect their
function as a frequency standard for the K3/K3s, I have no idea. Is
there an advantage in accuracy by using the GPSDO linked below over
the BG7TBL versions from China? $226 & needing antenna and power
supply for low jitter vs $150 for everything but with higher jitter?
Is a square wave output as useful as a sine wave, both are available
in the BG7TBL versions. For an external reference function with the
radio, what is excess? I have no idea.

Apparently the components in the BG7TBL versions change due to their
supply of surplus components; the versions are the manufacturing
date, and not all work identically because of this. But does it
matter, is the least desirable GPSDO still adequate to do this job
properly? Engineering is not my field and there's a lot to sift
through in reading peoples discussions and opinions when most of the
comments are not directed to effectiveness with the K3/K3s.

There are other options available but apparently the prices have gone
up recently and some once viable options are now not available or
highly priced, even when used. If Elecraft is not going to make an
option available for purchase, what would probably be helpful would
be a listing here or on someone's page, of what kind of affordable
units are ideal for the 10 MHz reference source and what is
un-necessary overkill.

Thanks again for the replies, its always fun to learn new things.

73,

Gary
KA1J


> Take a look at this GPSDO
> <http://www.force12inc.com/products/gps-locked-precision-frequency-reference-low-jitter-gps-clock-450-hz-to-800-mhz-output.html>.
> Needs 13-15 VDC and a powered GPS antenna, but it is plug and playon any
> frequency from 450 KHz to 800 MHz, with software-adjustable output level.
>
> 73, Pete N4ZR
> Download the new N1MM Logger+ at
> <http://N1MM.hamdocs.com>. Check
> out the Reverse Beacon Network at
> <http://reversebeacon.net>, now
> spotting RTTY activity worldwide.
> For spots, please use your favorite
> "retail" DX cluster.
>
> On 3/9/2016 12:37 PM, Gary Smith wrote:
> > I ordered the K3EXREF and thought it was the oscillator itself which
> > would provide the external signal source to the K3s. I thought this
> > was all I was going to need but I see now that is not the case.
> > Looking on the Elecraft order page, they don't sell a reference
> > source.
> >
> > What external 10-MHz reference signal source might I find get that is
> > not terribly expensive that will do the proper job and allow me to
> > get this working?
> >
> > Thanks & 73,
> >
> > Gary
> > KA1J

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Re: 10 MHz external reference - GPSDO

GM4JJJ
Hi Gary,

Because the K3 only -frequency- locks the frequency to within about 2Hz you won't notice any difference between them. Similarly because the K3 TCXO isn't -phase- locked to the external reference any phase noise on the reference won't affect low phase noise of the synthesiser in the K3.

So buying a kilobuck reference isn't going to gain you anything at all.

The BG7TBL or the Leo Bodnar unit would be my choice. (I have both here and a Z3801A) . The Leo Bodnar being a nice low power consumption unit, and a lot more versatile than just a 10 MHz GPSDO. It has many other uses around the shack, covering up to 800 MHz.


73 from David GM4JJJ

> On 11 Mar 2016, at 12:53, Gary Smith <[hidden email]> wrote:
>
> I appreciate the replies to my question about sourcing a 10 MHz
> external reference for my K3s. I didn't realize I needed more than
> the K3EXREF to gain this accuracy and thanks to these replies, I now
> better understand what will and what will not work. While I would
> prefer to be able to buy a satisfactory GPSDO or kit from Elecraft,
> it isn't an option at this time and not knowing if one is on the
> Horizon, I must look elsewhere to find one.
>
> What makes it a more difficult choice is understanding what values
> are sufficient and what is excess; some of these devices are in the 4
> figures and some used are less than $40. I was about to buy a $40
> used TCVCXO but learned they need to be recalibrated to maintain
> their precision and I having no equipment to do this, one of the more
> expensive options apparently is a better solution.
>
> Apparently the low cost GPSDO are an affordable way to go for long
> term accuracy but which one to get? Some apparently have jitter from
> poorly isolated interference due to the proximity of their 1pps
> Square wave functions but is that jitter something to affect their
> function as a frequency standard for the K3/K3s, I have no idea. Is
> there an advantage in accuracy by using the GPSDO linked below over
> the BG7TBL versions from China? $226 & needing antenna and power
> supply for low jitter vs $150 for everything but with higher jitter?
> Is a square wave output as useful as a sine wave, both are available
> in the BG7TBL versions. For an external reference function with the
> radio, what is excess? I have no idea.
>
> Apparently the components in the BG7TBL versions change due to their
> supply of surplus components; the versions are the manufacturing
> date, and not all work identically because of this. But does it
> matter, is the least desirable GPSDO still adequate to do this job
> properly? Engineering is not my field and there's a lot to sift
> through in reading peoples discussions and opinions when most of the
> comments are not directed to effectiveness with the K3/K3s.
>
> There are other options available but apparently the prices have gone
> up recently and some once viable options are now not available or
> highly priced, even when used. If Elecraft is not going to make an
> option available for purchase, what would probably be helpful would
> be a listing here or on someone's page, of what kind of affordable
> units are ideal for the 10 MHz reference source and what is
> un-necessary overkill.
>
> Thanks again for the replies, its always fun to learn new things.
>
> 73,
>
> Gary
> KA1J
>
>
>> Take a look at this GPSDO
>> <http://www.force12inc.com/products/gps-locked-precision-frequency-reference-low-jitter-gps-clock-450-hz-to-800-mhz-output.html>.
>> Needs 13-15 VDC and a powered GPS antenna, but it is plug and playon any
>> frequency from 450 KHz to 800 MHz, with software-adjustable output level.
>>
>> 73, Pete N4ZR
>> Download the new N1MM Logger+ at
>> <http://N1MM.hamdocs.com>. Check
>> out the Reverse Beacon Network at
>> <http://reversebeacon.net>, now
>> spotting RTTY activity worldwide.
>> For spots, please use your favorite
>> "retail" DX cluster.
>>
>>> On 3/9/2016 12:37 PM, Gary Smith wrote:
>>> I ordered the K3EXREF and thought it was the oscillator itself which
>>> would provide the external signal source to the K3s. I thought this
>>> was all I was going to need but I see now that is not the case.
>>> Looking on the Elecraft order page, they don't sell a reference
>>> source.
>>>
>>> What external 10-MHz reference signal source might I find get that is
>>> not terribly expensive that will do the proper job and allow me to
>>> get this working?
>>>
>>> Thanks & 73,
>>>
>>> Gary
>>> KA1J
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
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> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
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Re: 10 MHz external reference - GPSDO

GM4JJJ
You may want to have a look at this for some background on real world frequency stability, and remember that the K3 isn't phase locked to the external reference and is only going to be within 2Hz.

https://www.febo.com/pages/stability/

73 from David GM4JJJ

>
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