[time-nuts] Re: GPSDO replacement recommendation

[ericsp at gmail.com]

I have been doing an analysis of GPSDO's from the usual auction site. These are usually coupled with a crystal I have done the $99.99 TM4313 one and the BG7TBL (2019 version) $150.00. I have started to keep a spread sheet of the Allen variance as well as the Pk-Pk deviation. The analysis has been 100 Samples averaged with gate times of 0.01, .1, 1, 10, and 100 seconds. I have found them to wobble around 20uHz range and up in to the low mHz (>9mHz) If there is a place I can post the Excel document I am happy to do so. 

Testing was done on a HP 53230A with an SRS FS725 as its time base. This is backed up by a GPSDO 1pps -> FS725.
Warm up and settling times are as follows

FS725 - more than a month
HP 53230A - More than 1 Hour (Internal clock not used)
GPSDO under test - 24 Hours or more for stability

I will have videos about this testing on YouTube in a few weeks. 

Eric


-----Original Message-----
From: Wilko Bulte via time-nuts <time-nuts at lists.febo.com> 
Sent: Sunday, April 14, 2024 4:06 PM
To: Discussion of precise time and frequency measurement <time-nuts at lists.febo.com>
Cc: Attila Kinali <attila at kinali.ch>; Wilko Bulte <wkb at xs4all.nl>
Subject: [time-nuts] Re: GPSDO replacement recommendation

hi Atilla,

Assuming you can find one: the Samsung UCCM is form/fit compatible but sports a much more sensitive GPS module. Fast satellite lock with signal levels that made Trimble and Symm. UCCM modules very slow to acquire lock. 

 I happen to own 2 of these Samsungs. Previously also had both a Trimble and a Symm UCCM. The Samsungs were to stay. 

hth,
Wilko

> On 14 Apr 2024, at 15:17, Attila Kinali via time-nuts <time-nuts at lists.febo.com> wrote:
> 
> Moin,
> 
> My house GPSDO (a Trimble UCCM) died recently and I am now looking for 
> a replacement. As I have been a bit out of touch with the current 
> state of affairs regarding GPSDOs, I'd like to ask what the current 
> recommendation for getting a GPSDO is, these days.
> 
> Thanks in advance
> 
>            Attila Kinali
> 
> --
> Science is made up of so many things that appear obvious after they 
> are explained. -- Pardot Kynes 
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