[time-nuts] Racal 1992

Ed Palmer ed_palmer at sasktel.net
Thu Aug 27 19:01:48 UTC 2009


Hi Alan,

I have the same info, but it's collected from multiple sources.  I 
haven't seen all of it in one official source.  I'd like to see it and 
I'm sure others would as well.

Ed

Alan Melia wrote:
> Hi Ed I dont know whther it would be of interest but i have a page from a
> cat with the comparative specs for those OXCOs
>
> Alan G3NYK
>
> ----- Original Message -----
> From: "Ed Palmer" <ed_palmer at sasktel.net>
> To: "Time Nuts Mailing List" <time-nuts at febo.com>
> Sent: Thursday, August 27, 2009 6:52 PM
> Subject: Re: [time-nuts] Racal 1992
>
>
>   
>> John Green wrote:
>>     
>>> Ed Palmer wrote:Which timebase does yours have?  I've got option 4E
>>>       
> (similar
>   
>>> to 4B).
>>> Although the timebase appears to be stable, I've noticed that the
>>> counter drifts about 5e-9 during warmup, even when the oscillator has
>>> been on standby for many days.  It takes a couple of hours to settle
>>> down.  Does yours do anything similar?
>>>
>>>
>>>
>>> Ed, Exactly which reference I have seems to be something of a mystery.
>>>       
> The
>   
>>> part number on it is 454879. The part number listed in my manual is
>>>       
> 404386.
>   
>>> My manual makes no reference to optional timebases. The manual I
>>>       
> downloaded
>   
>>> does but doesn't list the part number I have as a choice. Though it is
>>> ovenized, I don't believe it is the best high stability type. It does
>>>       
> look
>   
>>> pretty good in general terms. Retrace is important to me and it seems
>>>       
> pretty
>   
>>> good in this respect. I did try to
>>> get it in sync with the GPSDO and after several minor adjustments and
>>> several hours of observation, I still saw movement. This isn't that
>>> important as I can always use the GPSDO as a standard.
>>> I did find out why it doesn't output a sine wave. There is a nice sine
>>>       
> wave
>   
>>> out of the oscillator itself but that goes through a conditioning
>>>       
> amplifier
>   
>>> and into IC39 which is some kind of 40 pin device. IC39 actually feeds
>>>       
> the
>   
>>> back panel BNC. Why they do this is beyond me but it answers the
>>>       
> question.
>   
>>> I haven't looked at how it behaves coming out of standby yet. I'll let
>>>       
> you
>   
>>> know when I have done that.
>>>
>>>       
>> Yes, they seem to have made a few oscillator substitutions along the
>> way. I'm guessing that they outsourced the oscillators and changed
>> suppliers a few times during the life of the 1991/1992 product. I have
>> two units, one labelled as having 04A and the other having 04E. Pulling
>> info from various manuals, data sheets, and my units, I think the info
>> is as follows:
>>
>> Option Osc. Part # Physical Description - based on my oscillators only
>> 04A 9444* or 11-1710 Approx. cube 5 cm., only one adjustment
>> 04B 9423 Don't know - haven't seen one of these
>> 04E 9462* or 404386 or 454879* Approx 5x5x10cm., two adjustments
>>
>> * these are the markings on my oscillators. The 04E oscillator is
>> actually labelled "9462 454879, Rev. A ERC 87-34". Both of my
>> oscillators are 5 MHz with freq. doubler boards attached to the bottom.
>>
>> IC39 is one of the "Magic happens here" chips in these units. One of my
>> units died shortly after I got it. IC39 didn't let the magic smoke out,
>> but it was running at a temperature of ~90C! IC39 in the other unit was
>> running at ~60C. I decided to put a heat sink on it just in case.
>>
>> Ed
>>     



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