[R-1051] 5 mhz standard

[Jan Skirrow]

This article discusses the technical details of how precision crystals 
behave with temperature changes. I use a Z3801 in my shop to maintain a 
GPS stabilized frequency standard, and that's how I came across this info.

http://www.realhamradio.com/z3801a-turning-point.htm

Note that the temperature controller used in the Z3801 is very similar 
to that used in the R1051 - a bridge circuit with three precision 
resistors and a thermistor.

If you remove power from the R1051 when it isn't in use, the oven will 
be off, obviously. When you try to use the radio, it is likely (at least 
for some of the R1051s I have) that the 5MHz oscillator output will be 
way off frequency. After the oven comes up to temp and stabilizes, the 
crystal 'pops' into its correct operating mode, and all is well. Rather 
than have the oven running all the time, I remove power from my R1051s 
when I'm not using them. But then I need to remember to give them time 
to "warm up" before using again! Of course, if the oven is not working 
at all, or is off the intended temp by much, the crystal may never enter 
the correct mode.

73, Jan - VE7DJX