I am about to embark on construction of a GPSDO using the Shera controller and a 05328-20027 HP board based around a 10811-60111 OCXO. GPS is a Jupiter-T.
Given that HP's engineers have done such a good job with the oven and oscillator design, is there anything to be gained by adding extra thermal insulation (lagging)? How much improvement (if any) can be achieved? How much lagging (if any) have people employed. My shack is not air conditioned and the HP board will probably end up in a simple metallic enclosure. Annual temperature extremes range from about 0 to +35 Celcius. My workshop is not very flash and any extra lagging would probably be confined to some bits of foam glued together. The HP board is labelled series 2224. What does this mean? I am yet to measure the VCO sensitivity, but am expecting something around 1x10E-8 per volt. What is a typical value for the 10811-60111? I note that Shera's QST article refers to using the 1 MHz output from a HP5328A. Is there any degradation of performance or increased thermal sensitivity due to the use of a HP marked 7490 (ripple counter) to divide down to 1 MHz? Would use of a synchronous divider or the TVB PIC approach yield a worthwhile improvement? Shera's performance graph shows a reasonably strong diurnal component. I was planning on cutting the PCB track going to the earthed end of the fine adjustment 10k pot and connecting this to the controller. Is there a neater way to achieve this connection? Thanks, Brian VK4GTW _______________________________________________ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts