[time-nuts] New pics of RFTG-m-Rb, and some comparison details

[Dr Bruce Griffiths]

Bill Hawkins wrote:
> Arrgh! Make that TWO 12.5 volt batteries. 
>
> -----Original Message-----
> From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
> Behalf Of Bill Hawkins
> Sent: Sunday, December 31, 2006 1:15 AM
> To: 'Discussion of precise time and frequency measurement'
> Subject: Re: [time-nuts] New pics of RFTG-m-Rb, and some comparison
> details
>
> Ah, well. I have also received two Lucent KS-24019 L106B, aka RFTG-m-XO
> boxes. The serial numbers indicate 95 and 96 construction.
> The assembly numbers, 55761ASSY103902-001 (55761 is the CAGE number for
> Efratom) have Rev E, S/N 522 and Rev H, S/N 2385.
>
> The Efratom crystal(?) oscillators are 023005-001, dated 95 and 96.
> Google has no hits for that part number.
>
> The GPS receiver has part number 2643686MAB. This gets a few hits from
> vendors that will issue a quote for anything, but will not describe the
> part or its manufacturer.
>
> I made a power cable after tracing the male DB-9. Both drew 600 MA from
> a 12.5 volt battery, started out with No GPS and Fault lights, then the
> No GPS light started blinking. There was no GPS antenna on the TNC
> connector, so I didn't leave them on. The antenna jack supplies +5
> volts.
>
> No signal appeared at the 15 MHz SMA connector, so I hope it is disabled
> until the oscillator is locked. Both of their 10 MHz IN SMA connectors
> still had plastic caps.
>
> I bought these units, and two of their RB cousins, hoping to get rid of
> the HP Z3801 units and the CS standard. They add $30 monthly to the
> electric bill. Now it seems that I was seriously misled, but that's the
> way it goes on the net. I may yet figure out how to discipline the RB
> from the XO.
>
> Anybody know how to divide by 2/3rds without a microprocessor? :-)
>
> Happy New Year (no qualifications)
> Bill Hawkins
>
>
> -----Original Message-----
> From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
> Behalf Of David I. Emery
> Sent: Saturday, December 30, 2006 11:10 PM
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] New pics of RFTG-m-Rb, and some comparison
> details
>
> On Sat, Dec 30, 2006 at 02:24:32PM -0500, John Ackermann N8UR wrote:
>   
>> My RFTG-m-Rb arrived yesterday, so of course it's in pieces on the 
>> bench today.  Photos (along with those of the -XO) are at 
>> http://www.febo.com/time-freq/hardware/Lucent_GPSDO/
>>     
>
> 	My RFTG-m-XO arrived.
>
> 	Seems like they use a version of the UT+ timing receiver
> R5122U1155, which is an 8 channel version of the Motorola Oncore design
> optimized for timing.    This 2002 or so version seems to have been 
> retrofitted to a 1996/97 base design.
>
> 	Apparently have an external antenna power supply on the
> mezzanine board - presumably to allow the 80C188 to read antenna current
> (or maybe it supplies 12 volts instead of 5).
>
> 	
>   
Bill

If you mean multiply the 15MHz output by 2/3 to generate 10MHz, simply 
use asynchronous divide by 3 counter (2 fliplops) to produce a 5MHz 1/3 
duty cycle (or 2/3) output then filter out the 10MHz 2nd harmonic 
component with a bandpass filter. The 3rd Harmonic (15MHz) will 
conveniently be very close to a null (only departure from exact 1/3 duty 
cycle and clock feedthrough from the divider prevent a perfect null).

Bruce