[NLRS] 10 MHz frequency standards

[Zack Widup]

My Isotemp OCXO's take 15 minutes to warm up. Watching a frequency counter
and a scope with a Lissajous pattern displayed versus another reference,
they climb in frequency for about 10 minutes from a lower frequency than
10.0000000 MHz, overshoot 10.0000000 MHz, then drop slightly in frequency.
They are all completely stable within 15 minutes and I've sat and kept an
eye on the Lissajous pattern for as much as two hours (while doing other
things) and not noticed any drift or change.

While there may be an advantage to keeping them powered up all the time,
when I'm a Rover in the 10 GHz contest it generally takes me 15 minutes to
get set up anyway, so I just unplug them at one location when I'm done and
plug them in at the new site when I get started.

Maybe I'll try running one off the car battery between stops this weekend.

The HP 10811 series OCXO's are supposed to be among the best commonly
available but I don't have one of those. WA1ZMS used a custom-made OCXO with
extremely low phase noise for his 241 GHz record QSO's. I understand that
two of them cost around $2500 each! He also uses a direct-synthesis scheme
instead of a phase-locked VCXO LO running in the VHF region. I want to play
around with a DFS circuit. Garry K3SIW sent me some notes on the scheme he's
using for a DFS LO for 47 GHz.

73, Zack W9SZ


On Wed, Sep 16, 2009 at 11:06 AM, Bruce Richardson <w9fz at w9fz.com> wrote:

>
>
> Hi John:
>
> Take my comments with a grain of salt because I too have
> collected many things over the years (such as the Pyroejoe
> 10mhz gps discipine thing) and still have none of it on the
> air.
>
> My plan is to use a quality 10MHz OCXO.  Undisciplined, just
> mounted and running on my dish. Possibly/probably I'll have
> a dedicated battery for it.  From time-to-time, I'll bring
> that OCXO in the house and trim it to match my GPS standard
> in the house. I have a phase comparator in one of my
> Spectracom WWVB receivers. (What are some of the rest of you
> using for phase comparators on your benches?).  I'll trim
> the OCXO before major events.  That's my plan and as complex
> as I really want to go. And yes, this OCXO will input to the
> A32 board in my 10G xverter.
>
> While the rubes are reasonably priced these days, I like a
> 50-75$ quality OCXO vs 100+ rube. And all rubes expire when
> the tube goes bad (so I'm told).  And I have some of the
> thunderbolts, but I don't want to fiddle with GPS antennas
> and lock up times.
>
> So, those are my thoughts. I look forward to the discussion.
> 73
> Bruce Richardson W9FZ
>
> > -----Original Message-----
> > From: nlrs-bounces at mailman.qth.net
> > [mailto:nlrs-bounces at mailman.qth.net] On Behalf Of
> tosca005 at umn.edu
> > Sent: Wednesday, September 16, 2009 8:11 AM
> > To: NLRS Reflector
> > Subject: [NLRS] 10 MHz frequency standards
> >
> >
> >
> >
> > Which do you think would provide a superior 10 MHz
> frequency
> > standard to
> > lock a 10368 MHz transverter using an Apollo board?
> >   -- rubidium oscillator
> >   -- Thunderbolt GPS disciplined OCXO
> <snip>
>
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