[time-nuts] GPS and Rubidium frequency standards and noise question (newbie).

[Bob Camp]

Hi

If you are trying to do microwave work, phase noise is going to be an issue no matter how you do it.  A lot of the design effort always goes into a low noise oscillator chain in that sort of gear. For HF gear, phase noise may not be quite as big an issue. A lot of rigs pretty much ignore the phase noise of their reference. 

If your radios are not already set up to use a 10 MHz reference, you will need to do some frequency conversion to feed them what they want / need. If that's the case, clean up the phase noise in the conversion process. Normally it's as basic as a crystal oscillator locked up with a narrow band PLL. No need for any fancy OCXO or TCXO, just a home made voltage tunable XO. It's not really even a VCXO, since the tune range can be very narrow. 

Lots of options…

Bob

On Jun 2, 2012, at 5:57 PM, Chris Wilson wrote:

> 
> 
>  I am looking to get a frequency standard for my amateur radio shack,
>  initially for verifying test gear readings, but later as a standard
>  to lock receiver and transmitter oscillators to. I was going to buy
>  a GPS frequency standard but a friend warned me these may have noise
>  issues when I come to use it with an oscillator in RX / TX
>  applications. It's not something I had considered, so what's the
>  score here please? Should I not buy a GPS standard? Thanks. Any
>  links to known safe suitable purchase sources from personal
>  experience welcome, either here or by PM or e-mail. I am in the UK.
> 
> -- 
> Best regards,
> Chris Wilson                          mailto:chris at chriswilson.tv
> 
> 
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