[time-nuts] Are there any rubidiums programmahttps://mail.google.com/mail/?shva=1#inboxble to 40 MHz?

[Jim Lux]

On 3/25/13 7:17 AM, David Kirkby wrote:
> I'm possibly looking for a 40 MHz source and I know some of the
> rubidiums are programmable. But can any of the affordable ones be
> programmed to work at 40.0 MHz?
>
> I was looking for a source to drive this 144 MHz -> 10 GHz transceiver.
>
> http://www.chris-bartram.co.uk/products.html
>
> The TCXO oscillator is off the board and a separate item, but costs
> £40 and then one ideally wants to lock that to a more precise source.
> The oscillator will lock to an external 10 MHz source, but then one
> needs to buy both a 10 MHz rubidium as well as this 40 MHz TCXO. Hence
> I was wondering if there was a cheaper more compact solution, which
> just used a rubidium, and dispensed with a TCXO.
>

The "two box" solution (10MHz ref + 40 MHz synth,e.g. the SRF040R0L) 
might be best.  A 10 MHz source is more generally useful.

What you really want is a x4 from 10 MHz, *if* your Rb is clean. Some 
sort of pair of doublers or quadrupler might be the ticket. (If the 
Xband converter has a moderately narrow filter on the 40 MHz input, that 
might be pretty easy.. make harmonics, just pick the right one)

  Some Rb sources aren't particularly clean, and the external device 
serves as a "clean up loop" for things outside the loop bandwidth.

Have you asked the mfr if they can work at 10 MHz input?  It might have 
some sort of programmable device inside, and he chose 40 because it's 
what he had. What's inside the box, in other words?