[Elecraft] 10 MHz external reference

[brian]

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, wb4jfi at knology.net 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: elecraft at mailman.qth.net
> 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).
>