[time-nuts] GPSDO won't lock: OCXO aged out?

[Scott Newell]

At 01:27 PM 1/12/2021, paul swed wrote:

>Granted at 5V the varicaps may be at minimum. Use a 2K R. That should be
>pretty safe.

Current limited bench supply though 4.7 k and an inline DMM to 
monitor current. Made quick-n-dirty measurements of EFC voltage, EFC 
current, and output frequency.

It looks promising. Dead-bug op-amp, gain of 2, powered by 
unregulated input supply (12-15 VDC)? That should get me enough EFC 
range for a few years, assuming the loop can cope with double the EFC 
sensitivity.

1 V   4 uA     9.999 991 MHz
2 V   9 uA     9.999 992 MHz
3 V   15 uA    9.999 994 MHa
4 V   27 uA    9.999 995 MHz
5 V   41 uA    9.999 996 MHz
6 V   56 uA    9.999 997 MHz
7 V   70 uA    9.999 998 MHz
8 V   85 uA    9.999 999 MHz
9 V   100 uA   10.000 001 MHz
10 V  115 uA   10.000 001 MHz
11 V  129 uA   10.000 002 MHz
12 V  144 uA   10.000 003 MHz
13 V  159 uA   10.000 004 MHz
14 V  173 uA   10.000 005 MHz
15 V  188 uA   10.000 006 MHz
16 V  203 uA   10.000 006 MHz
17 V  217 uA   10.000 007 MHz
18 V  232 uA   10.000 007 MHz
19 V  247 uA   10.000 008 MHz
20 V  261 uA   10.000 008 MHz

-- 
newell  N5TNL