I've been able to successfully upgrade my Datum TS2100 to an OCXO from the stock TCXO. I didn't see it in the archives so I thought I'd post my findings. I noticed that the same firmware was used regardless of oscillator configuration so there must either be jumpers or a hidden set of commands. The newer versions of the ET6000 have jumpers to select the oscillator but I couldn't find anything similar on the TS2100. However, in the back of the manual, 8500-0033 Rev K, Appendix I describes how to reconfigure the unit to output GPS instead of UTC for NTP. I'm not interested in that but there are some hints about a hidden menu structure (root eng ee) which allows you to change EEPROM settings. Here's the hidden menu items:
root eng: start net interface timing tools / serial tools / eeprom tools / spi tools / flash tools / display tools / memory tools / intrinsic help Going further into one of them, root eng eeprom: ethernet address board serial number gain default filter constant low filter constant precision set eeprom get eeprom read serial eeprom write serial eeprom tx 16 bits to eeprom location for image info value eeprom_select intrinsic help So that's where the default gain and filter constants are set. You have to jumper across J4 on the PC board to allow EEPROM writes or you get an error. Not sure what the "precision" setting is for (it's currently -19). I don't have the proper OCXO (yet) but I do have an MV89A OCXO that I was able to wire into the circuit temporarily. There is 12V on the board and the 0.5-4.5V EFC range works well with the MV89A. I used a gain of +20 and a filter setting of 0.9994965 based on Jason Rabel's post from 9/26/2010 (note the sign change on the gain). The EFC algorithm had a pretty good overshoot during the first adjustment cycle and took over an hour to completely settle in but eventually the front panel Locked LED turned on. I couldn't find a way to change the starting value for EFC (d/a) value. I *think* an Abracon AOCJY1A-10.000MHz-E-SW part will be pin compatible on the board. Unfortunately nobody has that one in stock and it's a 10 week lead time so I may end up installing one off-board. The MV89A is too tall to fit with the lid on so it's not a long term option. I traced out the two SMA pads on the board and they are for the EFC out and RF in so I could always run them to the back of the unit and put the OCXO outside the unit. -Bob K5RLW _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.