[time-nuts] Portable standard

[Magnus Danielson]

On 04/06/2011 10:03 AM, WB6BNQ wrote:
> Joe,
>
> Before you worry about batteries and such, you first need to ask what it is that
> you are trying to accomplish.
>
> For instance, if you did not need the really close in low phase noise and really
> short term stability, then perhaps a Rubidium (Rb) oscillator would suit your
> needs.  the Rb has better longer term stability than a crystal oscillator and can
> be left off until it is needed saving on battery requirements.  A decent Rb would
> be up to specs in about 20 minutes and would suffice for most applications as a
> better general frequency reference for portable purposes.
>
> A really high quality crystal oscillator isn't worth a damn unless it is kept
> running constantly and without vibration.  Any banging around is going to
> invalidate it.  The Rb, unless you beat it with a hammer, does not suffer from
> those problems.  Obviously you would like to treat either item with care, but
> things do happen and the Rb would be more rugged the crystal oscillator.

I agree with Bill here. A rubidium is very good bang for the buck in 
this respect. If you only want to do frequency transfer, then a rubidium 
with a lockable multi-turn pot that you adjust at home against a GPS.

Another approach is to have a Thunderbolt and small patch antenna with 
you. About the same money.

Only if you want to carry the phase with you and can't use GPS I would 
say you would need batteries.

Cheers,
Magnus