[time-nuts] Adjusting HP 5065A frequency

[George Dubovsky]

On Mon, Oct 22, 2012 at 1:00 PM, Tom Van Baak <tvb at leapsecond.com> wrote:

> There's a history to many of the GPSDO products you hear us talk about.
>
> I believe the original TBolt (fancy red case) did have an OCXO but it
> wasn't particularly high quality. Perhaps Bob can shed light on this.
>
> 99% of TBolt's found on the surplus market today, and all the ones in the
> TAPR deal, have a surprisingly good OCXO's. These were customer specials as
> best we can determine, and never described on Trimble's web page. They are
> in the plain brushed golden color aluminum case.
>
> The T'bolts in the gold, brushed aluminum case were provided to Grayson
Electronics, at the time a part of the Allen Group (later Andrew and
Commscope) for use in a receiver for an E911 locator system. The Trimble
p/n was 41562-30 and, as far as I know, the only significant changes are
the value of one Zener to allow the -12 V line to run at -7 V w/o asserting
a fault and the change of the power connector to the "back" side of the
board. Only the board is from Trimble; the sheetmetal and the attached 3dB
coupler were provided by the OEM. Otherwise, I believe it to be the same
unit that was in the red and silver Trimble case being sold at the same
time (the one with the integrated dc-dc converters).

73,

geo - n4ua