[time-nuts] Maximizing Cs Tube Life

aceamusements at mchsi.com aceamusements at mchsi.com
Sat Jul 11 02:57:35 UTC 2009


 
 I have a similar question I have 2 hp 5071a and I purchased one new in the box never opened and one used.both have been in operation over a year, the new one high perf tube new style tube US4240 started out in storage for two years before I plugged it in for the first time..the pump went right down to .2 -.4ua as normal but as time has gone by it has risen (lineraly) to almost 11.0uA (I think this may not be good). the elect mult volts on this tube started out about 1500 and droped within 6 months to 1150 and has stayed there.

my other used unit has a pump current of 0.0 or 0.2 all the time and a mult of 1430 (stays steady also)been like that for months but the new unit continues to rise(pump current).have tried turning off the cs oven and leaving on the pump but with no avil is this new tube heading twd an early death?
 -------------- Original message from "John Miles" <jmiles at pop.net>: --------------


> 
> >
> > I have a 5061A and 5061B and both have a position on their front
> > panel MODE
> > switch that is CS OFF.  When in this position the CS OVEN is off, the OSC
> > OVEN is on, the ION PUMP is working and there is signal out (10
> > MHz, 5 MHz,
> > 1 MHz, 100 KHz, as appropriate) as measured by the CIRCUIT CHECK meter.
> >
> > Is the 5062C different?  Is there something I am missing here?  I
> > guess I do
> > not understand the need to 'add a switch' unless it is the desire to only
> > run the ION PUMP and the OSC OVEN but not the OSC or anything else.
> 
> Right; there was no CS OFF switch on the 5062C.  You can open the loop, but
> that's it.  I could have run the ion pump supply from the rear panel, but
> that would have taken a separate power supply, and would have left the
> crystal oven cold.
> 
> It sounds like the switch I added does essentially the same thing as the one
> you're talking about.  In your case you could maximize tube life by leaving
> that switch set to CS OFF except when needed.  That doesn't answer the
> question of how long the Cs tube needs in order to meet specs, but
> presumably the manual would...?  I'd be curious to hear the answer myself.
> 
> > The one thing I have noticed is the incredible stability of the crystal
> > oscillators for weeks at a time as compared to my Thunderbolt.
> > On the order
> > of 0.1 Hz at 10 MHz after a week.
> 
> The Thunderbolt should be in that ballpark (being only 1E-8 per week) when
> undisciplined, and of course much better when GPS-locked.  A good OCXO, when
> not locked to anything else, should stay put to the tune of 1E-10 to 5E-10
> per day.
> 
> The HP 10543 oscillator in my 5062C had a bad case of near-constant phase
> jumps, so I have a Wenzel Timekeeper-class unit in there now, plus an x2
> doubler to get 10 MHz out the front panel.  I'm not sure I have the loop
> bandwidth optimized for it yet, but at least it locks up nicely and doesn't
> jump.
> 
> -- john, KE5FX
> 
> 
> 
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.


More information about the time-nuts mailing list