Cheap ref osc to lock K3

[alsopb]

LA3ZA used a UBLOX NEO-7 GPS unit to lock his K3.
This $20 unit including complete development board can be obtained here.
http://www.ebay.co.uk/itm/301199083821

It's tiny, has a patch antenna (although a $10 active antenna works
better) and consumes under 60ma.
It can be powered from +5v or a USB port.  It fits in a 2"x3" box. Once
set up it is stand alone not requiring a computer connection.

There was some question as to whether the jitter of the unit would
disqualify it as a decent ref osc.

A posting on the SpectrumLab group indicated that it seems quite
adequate for K3 disciplining.
[hidden email]

Accuracy within 0.02 to 0.03 Hz of a Rb standard.
Output spectrum seems to indicate that jitter is not a problem for this
purpose.

73 de Brian/K3KO

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[vk2rq]

I bought a module like that. If you set the output frequency to something that divides evenly into 48MHz, then the output is quite stable. Otherwise, if you set it to something else like 10MHz, the jitter is quite obvious on the scope. It is fine for jobs like calibrating a frequency counter or zero-beating a transceiver. You'd probably want to smooth out the jitter though if you want to use it for a K3 reference oscillator.
73, Matt VK2RQ

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On Sat, Oct 3, 2015 at 8:19 AM -0700, "brian" <[hidden email]> wrote:










LA3ZA used a UBLOX NEO-7 GPS unit to lock his K3.
This $20 unit including complete development board can be obtained here.
http://www.ebay.co.uk/itm/301199083821

It's tiny, has a patch antenna (although a $10 active antenna works
better) and consumes under 60ma.
It can be powered from +5v or a USB port.  It fits in a 2"x3" box. Once
set up it is stand alone not requiring a computer connection.

There was some question as to whether the jitter of the unit would
disqualify it as a decent ref osc.

A posting on the SpectrumLab group indicated that it seems quite
adequate for K3 disciplining.
[hidden email]

Accuracy within 0.02 to 0.03 Hz of a Rb standard.
Output spectrum seems to indicate that jitter is not a problem for this
purpose.

73 de Brian/K3KO

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[Sverre Holm (LA3ZA)]

My experience is that the simple GPS-based 10 MHz reference works well with the K3. The K3 is quoted as measuring frequency to 1 Hz accuracy, implying a measurement time of the order of 1 second. That seems to be enough to smooth out the jitter from the Neo-7M.

Of course,  there are better solutions around, but why spend money on something which is unnecessary?

My experience including build instructions was posted on my blog yesterday: http://la3za.blogspot.no/2015/10/just-good-enough-10-mhz-reference.html

vk2rq wrote

I bought a module like that. If you set the output frequency to something that divides evenly into 48MHz, then the output is quite stable. Otherwise, if you set it to something else like 10MHz, the jitter is quite obvious on the scope. It is fine for jobs like calibrating a frequency counter or zero-beating a transceiver. You'd probably want to smooth out the jitter though if you want to use it for a K3 reference oscillator.
73, Matt VK2RQ

[Edward R Cole]

I just bought this GPS for providing accurate time to my computer:
ProGin GPS RECEIVER BU-353 (USB) SiRF STAR III
ebay: 181887610445

Cost me $24 and change including shipping (from Israel).

This is my replacement for Dimension-4 when I pull the internet plug
on my XP computer and switch to my laptop for e-mail/internet using
win-10.  I will then be able to run the XP computer for my ham
applications forever without worrying about security sw, upgrading
drivers, etc.etc.

73, Ed - KL7UW
I'll have to check if it supports frequency reference;  But I run a
OCXO for that so not needed.

From: Matt Maguire <[hidden email]>
To: brian <[hidden email]>,  <[hidden email]>
Subject: Re: [Elecraft] Cheap ref osc to lock K3
Message-ID:
         <[hidden email]>

Content-Type: text/plain; charset=UTF-8

I bought a module like that. If you set the output frequency to
something that divides evenly into 48MHz, then the output is quite
stable. Otherwise, if you set it to something else like 10MHz, the
jitter is quite obvious on the scope. It is fine for jobs like
calibrating a frequency counter or zero-beating a transceiver. You'd
probably want to smooth out the jitter though if you want to use it
for a K3 reference oscillator.
73, Matt VK2RQ



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

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