Hamfest find today: HP59309A Clock

[Paul Berger (Canada)]

(08-09-2016 03:17 AM)BobVA Wrote:  

(08-08-2016 04:06 PM)Paul Berger (Canada) Wrote:  They are a nice clock, it looks like it is in good condition. I have two, one is running on the 10MHz from a GPSDO.

Cool! What's the base oscillator? Quartz? I've got a 10 MHz Rb oscillator, but I think I'd have to get a second job to pay my electric bill if I kept that space heater running 24/7.

I ordered a 2.5ppm 10MHz TXCO from a surplus seller. It's in a pretty small (SMD package) so I was thinking of replacing the stock quartz oscillator with it to increase the accuracy.

Unfortunately I don't have any HP-IB gear, so I can only fiddle with the front panel.

The base oscillator is a quartz OXCO, this is the most common type of GPSDO, there is such a thing as Rb based GPSDOs but they are far less common. I have a couple Rb oscillators as well but don't use them a lot.

I hope you don't have many power outages, I think setting date and time from the front panel would get old. You can connect a 9V battery internally but I am not sure how long that would last. I had one of mine connected to a pack of 6 C cells for backup power. There is a BNC connector on the back for external backup power. When using the external connector there is a jumper on the base board near the 9V battery connector that needs to be in place.

You don't necessarily need HP GPIB equipment to talk to the clock, any kind of GPIB host will do, the GPIB interface is a pretty simple minded state machine controlled interface. Manuals for the HP 59309A are available online.



If you are interested in precision time keeping there is a mailing list "time-nuts" that has a lot of very knowledgeable subscribers and lots of information in its archives.

Paul.