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" <[email protected]> To: "Time Nuts Mailing List" <[email protected]> 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 > > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
