[time-nuts] Rubidiums vs ocxo's vis a vis amateur radio

Mark Spencer mspencer12345 at yahoo.ca
Wed Mar 27 02:26:28 UTC 2013


Just to add to to this, I recently had a partial power outage and one of my better OCXO's (a Datum 1000) lost power for a day or so.  After being powered back up for approx 24 hours the frequency error was well under one part per billion.   This is more than accurate enough for any of my amateur radio activities.   

My approach for portable operation where I was concerned about the OCXO drifting would be to multiply the output of a Rb or Gpsdo up to a suitable frequency so I could quickly confirm that my equipment was on frequency and if needed calculate the actual error.    One of my Gpsdo's conveniently has harmonics extending up to the low Ghz region that i can easily detect with my amateur radio gear without any help. 

This seems easier to me than disciplining an OCXO.

Sent from my iPad

> 
> Message: 5
> Date: Tue, 26 Mar 2013 17:56:43 -0400
> From: Bob Camp <lists at rtty.us>
> To: Discussion of precise time and frequency measurement
>    <time-nuts at febo.com>

> Subject:

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

> Message-ID: <1E2FBFD4-A92B-4543-A0C7-1A0B07C632A5 at rtty.us>
> Content-Type: text/plain; charset=iso-8859-1
> 
> Hi
> 
> All the stability and likely 20 to 30 db better phase noise. Probably 40 to 60 db better spurs / crud. 
> 
> Bob
> 
> On Mar 26, 2013, at 12:31 PM, "Stan, W1LE" <stanw1le at verizon.net> wrote:
> 
>> I should of been clearer, Thanks for your comments.
>> 
>> final configuration is:
>> 
>> OCXO as a 10 MHz reference to the 106.5 MHz PLL then the DB6NT multiplier chain for the LO.
>> 
>> All of the stability I need for a contest weekend.
>> 
>> Stan, W1LE
>> 
>> 
>> On 3/26/2013 1:21 AM, Rex wrote:
>>> Please tell us if I am parsing the content of your message correctly with my inserted comments.
>>> 
>>> On 3/25/2013 9:09 AM, Stan, W1LE wrote:
>>>> Hello Dave,
>>>> 
>>>> The problem I experienced with a Rb at 10 MHz stabilizing a AD6IW PLL at 106.5 MHz
>>>> for a DB6NT 10 GHz G2 transverter,
>>> I assume by "stabilizing" you mean that the rubidium was providing the reference frequency to the PLL.
>>> 
>>>> was the significant microphonics after multiplication.
>>>> The original xtal oscillator did not have microphonics, but would drift.
>>>> 
>>>> My solution was to add a ISO-Temp 10 MHz OCXO as  a reference to the PLL.
>>> By "add" I think you mean replace, as in, the rubidium is no longer used but the OCXO has replaced it as the PLL's reference. If you really meant add, that would imply that somehow the rubidium is disciplining the 10 MHz OCXO.
>>> 
>>>> This provided me with the frequency accuracy and stability
>>>> needed for a weekend of microwave contesting, USB/CW
>>>> 
>>>> My 10 GHz operation is portable and I rove.
>>>> 
>>>> Stan, W1LE    Cape Cod   FN41sr
>>>> 
>>>> 
>>>> 
>>>> On 3/25/2013 10:17 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.
>>>>> 
>>>>> Dave
>>> 
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>> 
>> 



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