[time-nuts] Re: RFTGm-II (KS-24019) XO Fault but GPS to Rb is OK

k1jos at att.net k1jos at att.net
Mon Nov 1 02:35:50 UTC 2021


Thanks Bob,

I swapped with a known good antenna from my TBolt and still no tracking.  The XO is putting out 5vdc on the antenna jack.  I think I have a spare Motorola UT+ to try and will report back.  

Jerry

-----Original Message-----
From: Bob kb8tq <kb8tq at n1k.org> 
Sent: Sunday, October 31, 2021 9:47 PM
To: Discussion of precise time and frequency measurement <time-nuts at lists.febo.com>
Subject: [time-nuts] Re: RFTGm-II (KS-24019) XO Fault but GPS to Rb is OK

Hi

I think you will find that the list of “visible” sats is coming from the stored almanac and your position (from the hold mode). 
You may have an antenna problem.

Bob

> On Oct 31, 2021, at 7:21 PM, k1jos at att.net wrote:
> 
> Here's a follow-up.. 
> 
> I took out the XO pcb's and powered it up stand-alone.  In the RFTGM 
> software, it shows as Active, Warmup, No Fail code and it is 
> outputting a clean 15MHz sine wave. In GPS - It's showing 8 visible 
> Sats but Zero Tracking SATs and is "Acquiring SATS/Position Hold" .  
> The SAT IDs are listed but Signal Strength and Channel Status are all 
> zero.  Its been powered up for about an hour so far.  Checking XO 
> Voltages, all seems good Control=14.574V, Temp 36.49, Ant Feed 16mA.  The ADC = 0v as I think it
> would be in warm-up mode.   Now hopefully it will acquire and run for a
> while.   
> 
> Jerry
> 
> 
> 
> From: k1jos at att.net <k1jos at att.net>
> Sent: Sunday, October 31, 2021 10:20 AM
> To: 'time-nuts at lists.febo.com' <time-nuts at lists.febo.com>
> Subject: RFTGm-II (KS-24019) XO Fault but GPS to Rb is OK
> 
> I have had a KS-24019 (L108-L109) pair running continuously for 
> several years.  Now have a red LED Fault on the XO unit and the RB unit shows green
> LED On-Line status.   The NO-GPS LEDs are off on both the -XO and -RB units
> but if I disconnect the antenna - they do show Yellow NO_GPS status.   Got
> out my old XP laptop and ran the Lucent software.  The Rb (REF 0) is 
> active and locked to GPS and working fine.  The XO says Unit Failed 
> but the message code for the first 4 hex nibbles which should show 
> alarm status are all zero bits so no failure code is evident.  The 
> last 2 alarm nibbles are 53 representing the # of hours since failure.  
> The GPS time is correct on the Rb but is fixed on the XO at 80-01-06 00:00:00.  The XO checksum shows PASS.
> Based on this the XO GPS is working, locked and sending correct GPS messages
> to Rb.   The XO CPU seems to be working as well so am I correct this seems
> to be a Osc failure?  Besides checking voltages (which I'm not sure 
> what they should be) - any advice how to go about further testing sand repair?
> 
> Thanks in advance
> 
> Jerry NY2KW
> 
> 
> 
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