[time-nuts] Racal 9420 OCXO

Robert Atkinson robert8rpi at yahoo.co.uk
Thu Aug 25 16:23:57 UTC 2011


I'm pretty sure Racal made these. They are of consistent design over different models and many years and are unlike any other manufacturers OXCO I've seen. Racal were old school and did prettymuch everything themselves. The did do what appears to be a licence built Sulzer though. The MA-259, see http://www.radiomuseum.org/r/racal_precision_frequency_stan.html

Regards,
Robert G8RPI.


--- On Thu, 25/8/11, Bob Camp <lists at rtty.us> wrote:

From: Bob Camp <lists at rtty.us>
Subject: Re: [time-nuts] Racal 9420 OCXO
To: "'Discussion of precise time and frequency measurement'" <time-nuts at febo.com>
Date: Thursday, 25 August, 2011, 17:01

Hi

Do we know for sure that Racal actually made these OCXO's in house?

My *guess* is that they were made by various companies over the years and
sold to Racal. The "return for service" would have been a return to Racal
and then they forward it to the people who made it...

Bob

-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of paul swed
Sent: Wednesday, August 24, 2011 5:10 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Racal 9420 OCXO

Kind of amazing what time-nuts have in there secret documentation.
Though I do not need this thanks for sharing.
Regards
Paul
WB8TSL

On Wed, Aug 24, 2011 at 4:05 PM, Robert Atkinson
<robert8rpi at yahoo.co.uk>wrote:

> Hi,
> I've attached a copy of the catalogue specification for Racals OCXOs. They
> do have electronic trim as standard. They are used in the 9478 frequency
> standard. The 9478 service manual specfically states that no information
on
> the OCXOs is provided and they must be returned to Racal or appointed
agents
> for repair.
>
> Robert G8RPI
>
> --- On Wed, 24/8/11, GandalfG8 at aol.com <GandalfG8 at aol.com> wrote:
>
> From: GandalfG8 at aol.com <GandalfG8 at aol.com>
> Subject: Re: [time-nuts] Racal 9420 OCXO
> To: time-nuts at febo.com
> Date: Wednesday, 24 August, 2011, 16:03
>
> In a message dated 24/08/2011 00:03:19 GMT Daylight Time,
> danrae at verizon.net writes:
>
> I don't  think Racal released circuit diagrams of any of their ovens.  I
> have  traced out the circuit of the rapid warm up oven found in a lot of
> receivers, the 9442-12 and have fixed those, there is a ceramic cap that
> frequently goes wonky.  The two 9420s I have fixed were just broken
> wires; they seem to have used PVC insulated wire which degrades...  I
> haven't done the homework on those yet.
>
> The 9420s I have do have an  EFC input as well as a stabilised Voltage
> out to feed it, and in the  receivers I have that use it [RA1795] the
> fine setting is done from that,  coarse setting from the top adjustment.
> -------------------------
> Hi Dan
>
> I've taken a further look at the RA1794 manual and see now that it does
> confirm a fine tune pot being available when using the 9420.
> Having opened up this oscillator I find there are  connections to every
pin
> on the B7G connector so will assume until proven  otherwise that it does
> meet the interface spec shown in the 1794 manual.
> I suspect the comments I've seen claiming most do not have the EFC  option
> is more a case that in many installations it isn't used, which  isn't
quite
> the same thing.
>
> Thanks again for your comments.
>
> regards
>
> Nigel
>
>
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