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

[paul swed]

Thats fantastic to see. Yes you have it. Use an opamp to insert an offset
of 6-7V so the DAC itself still uses its normal range of 0-5V. Opamp output
would be 6-11V or something. You just may have the unit for a while longer.
Regards
Paul
WB8TSL

On Tue, Jan 12, 2021 at 8:19 PM Scott Newell <newell+timenuts at n5tnl.com>
wrote:

> 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
>
>
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