Thanks for all the info. Agree after my tests on the Tbolt, that is why I will place large mass around it, will keep it close to ambient and move slowly. What is the zero G axis? Presently oven current is 65 mA down from 95 at room temp so I have room to go but I will monitor over ambient changes, presently we have lows in the 60's but it has been as high as 82 in the last week. I try if possible to stay away from any additional heating or cooling, the only exception is on the Rb's where I experiment with small variable speed fans and laptop heat pipes in cooling the base plate to 42 C. Bert In a message dated 1/9/2011 1:42:19 P.M. Eastern Standard Time, [email protected] writes:
>Q) Has anyone experimented with the amount of insulation on a 10811 >oscillator? a) Look inside a double oven 10811 to see one example of what works. >Q) None of the hp/Agilent bench test equipment that uses these >oscillators uses insulation. Perhaps that's a clue. a) It is not much of a clue, considering that a patent & knowledgeable time-nuter can get 10 to 100 + better performance out of them. Look inside a HP Z3801 GPS. >Q) "how far can you go" a) One way is to monitor the Oven current. If it goes to near zero you went too far. I've found a 50% to 75% reduction in heater current from its room temperature value works. A separate issue is if you are cooking the electronics outside of the oven. >Q) too much ... can cause over-heating or instability. a) To see if the oven controller is becoming unstable, Just monitor the Oven current and plot how it resettles after making small changes of a couple volts to the oven voltage or change its case temperature. >Q) What is the preferred orientation of the unit. The Zero G tilt axes. The position that tilting the unit a slight amount in any axes causes the freq to shift in the same direction. comment) What I've found to be very effective is to place a paper towel around the osc and put it in a plastic baggie to keep it from generating any air currents on its own. Then put that inside of an enclosure that does not have holes, and Hold the enclosure's outside temperature constant. I find this technique works great for both Tbolts and 10811's. Easy to get 10 - 100 to one improvement with a little care. IMHO, You do not need, or even want, to raise the case temperature of a Tbolt anymore than absolutely necessary. Just need to keep the Tbolts case temperature from changing very fast (or very far). 1 deg F per hr max works OK for most units, or for the extreme time-nut, go for 0.1 degC per hr max rate of change. To do that, I find mass to be more effective than insulation. (you need some of both) I've gotten the best results using Lady Heather's temperature controller with a small fan blowing air indirectly at the Tbolt's case. ws ********************* _______________________________________________ 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.
