[NLRS] 10 MHz frequency standards

[Zack Widup]

If you intend it for portable operation, I would recommend the rubidium
oscillator. The less you have to fool with, the better. A recent discussion
on the microwave reflector indicates several people (including me) have
noticed occasional small jumps in frequency or phase with GPS-disciplined
OCXO's.
I have been using free-running Isotemp OCXO114 units for a few years now. I
got several on eBay for $20 once upon a time (I think that supply has dried
up). They are very accurate and stable and hold their accuracy. I
check/calibrate them against a GPS-disciplined oscillator every few months
at home but haven't needed to adjust them in over a year. They have great
phase noise specs too. I use them through 10 GHz and will soon try them as
references for an LO on 24 GHz.

Another advantage of these free-running oscillators is that they are
lightweight and only require one supply of about 14 volts. I get that from a
little board I built using an LT1070 switching regulator supply (very stable
over an input range of 9 to 13.6 volts - something to consider when you're
using batteries that are running down).

Another thing you need to consider is the accuracy of what the other guy
uses. I have on occasion found the other guy as much as 5 or 10 kHz off with
whatever LO he's using.

73, Zack W9SZ


On Wed, Sep 16, 2009 at 8:11 AM, <tosca005 at umn.edu> wrote:

>
>
> 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
>
> I've been planning to eventually go the route of the frequency locked
> oscillator for my microwave transverters, and have a kit from Pyrojoseph
> (no longer being sold) to provide a GPS-disciplined 10 MHz oscillator
> source, but with my lack of time to build it up, I started looking around
> for a pre-made oscillator source, and found those two types mentioned
> above. Neither one is ideal for roving use, due to their DC voltage
> requirements (24v for one of them and triple supplies -- +5, -12, +12 for
> the other), but could be pressed into service with some effort.
>
> Ideally, I am looking for BOTH precision and accuracy. It would be really
> nice to tune to 10368.1 MHz and know that I was within 1 KHz of the actual
> frequency so that QSO's wouldn't be lost by failing to tune around far
> enough, as has happened in the past. And it would be really nice to have
> the frequency stay stable from start to finish.
>
> Any thoughts out there?
> 73 de WØJT
>