[time-nuts] Re: Oncore UT+

[ghf at hoffmann-hochfrequenz.de]

Am 2022-11-15 12:28, schrieb alan bain via time-nuts:

> A better reference was clearly needed. To convince myself I don't need 
> a
> Caesium standard I decided I needed a GPSDO.  I've been modifying one 
> of
> those Lucent RTFG-u REF-0 boxes following Peter Garde's excellent
> instructions (because it looked fun).  All was going well until i found 
> my
> Motorola Oncore module believed to be a UT+ when bought was in fact a 
> GT+
> and didn't provide some of the T-RAIM messages the HP needs (the GT+ is 
> a
> navigation receiver).
> 
> There's not much info around on these modules (probably because they 
> are
> ancient) - and at the moment no UT+ listed anywhere in the UK for sale; 
> so
> wondering if anyone knows about the differences - are they firmware or
> hardware?  There's a firmware upload option in the WinOncore software - 
> but
> I haven't been able to find any archives of the actual firmware.

I have bought a Ref-0 and a Ref-1 unit from that guy in Florida, maybe 
PyroJoe?
Some people around here did that, too.
The units were still shrink-wrapped, never been on a telecom tower.
The ref-1 units have the GPS-Receiver, the ref-0 units don't. Not even 
an
antenna plug. The ref-1 units were quickly sold out, but nobody wanted
ref-0 w/o GPS. I got a price I could not refuse for the leftover ref-0 
units,
each had a 5 MHz MTI-260 oven as hot spare (so does have the ref-1).
I ended up with abt. 20 ovens. :-) Better deal than those Chinese MV89A
that are removed from their boards with hammer & sickle and best used 
for
5 MHz SC crystals.

I have a back burner project of locking a lot of these MTI-260 slooowly
to the GPS source and Wilkinson-combine the outputs together with the
intent to get 2*2*2* 3dB phase noise improvement. The board for 4
oscillators is still in statu nascendi. Ḿaybe XMESS.

The 10 MHz test point of the ref0 has ugly phase noise.
I made a doubler/distributor for the ref1, directly from the oven.
Nothing special, mostly LM6702 or ad8000 CFB op amps.

<  http://www.hoffmann-hochfrequenz.de/downloads/DoubDist.pdf  >

Please, where is that stuff from Peter Garde?

cheers,
Gerhard   DK4XP





-------------- next part --------------
A non-text attachment was scrubbed...
Name: Auswahl_001.png
Type: image/png
Size: 137592 bytes
Desc: not available
URL: <http://febo.com/pipermail/time-nuts_lists.febo.com/attachments/20221116/4f83a3fc/attachment.png>