[time-nuts] Lucent RFTG-m-XO GPSDO

Peter Bell bell.peter at gmail.com
Tue Oct 18 10:56:01 EDT 2011


Thank you - I've downloaded it and it looks very interesting - I guess
I need to dig out my RS232-RS422 converter and have a play.

Regards,

Pete


On Tue, Oct 18, 2011 at 7:35 AM, k4cle at aol.com <k4cle at aol.com> wrote:
> All that's interested, KO4BB now has my RFTGm information on his manuals
> section under GPS Timing.  Please let me know if you have questions about
> it.  73's, Doug, K4CLE
>
> Connected by DROID on Verizon Wireless
>
> -----Original message-----
> From: "Randy D. Hunt" <randy_hunt960 at yahoo.com>
> To: Discussion of precise time and frequency measurement
> <time-nuts at febo.com>
> Sent: Wed, Oct 12, 2011 16:53:04 GMT+00:00
> Subject: Re: [time-nuts] Lucent RFTG-m-XO GPSDO
>
> On 10/11/2011 6:28 PM, Peter Bell wrote:
>>
>> For some reason, the "No GPS" LED is back - although the GPS is
>> tracking 8 satellites in 3D mode and according to the TRAIM status the
>> timing error is below the alarm threshhold (alarm = 1300ns, current =
>> 43ns) - I guess the uinit has it's own standards for the GPS quality,
>> and they are being violated in some way.
>>
>> Still. at ;least I have seen it running with that LED off, which is a
>> positve sign :)
>>
>>
>> On Wed, Oct 12, 2011 at 5:42 AM, k4cle at aol.com<k4cle at aol.com>  wrote:
>>>
>>> If I recall, the firmware in the RFTGm collects about an hours worth of
>
> position info and does an average to establish a self-survey.  The next time
> you cycle power, it will check the new position against the stored one and
> if within 50 feet or so, it will use the stored position.  That's probably
> why it took a while for the LED to extinguish.
>>>
>>> Connected by DROID on Verizon Wireless
>>>
>>> -----Original message-----
>>> From: Peter Bell<bell.peter at gmail.com>
>>> To: Discussion of precise time and frequency
>
> measurement<time-nuts at febo.com>
>>>
>>> Sent: Tue, Oct 11, 2011 12:49:45 GMT+00:00
>>> Subject: Re: [time-nuts] Lucent RFTG-m-XO GPSDO
>>>
>>> The Rx was defective - I just got the new one, hooked it up to my
>>> little test rig anf the antenna, and it happily picked up satellites
>>> and got a position fix.
>>>
>>> Swapped it into the box, and found a TTL level copy of the RX data
>>> stream from the encore on pin 2 of the interface connector, so hooked
>>> that up to a TTL->RS232 converter so I could monitor what was
>>> happening.  It all seemed to be tracking OK, although the "No GPS" LED
>>> was still on, so I just left it and after a couple of hours the LED
>>> went out.
>>>
>>> Next step is getting the Rb working :)
>>>
>>>
>>> On Mon, Oct 10, 2011 at 2:41 AM, k4cle at aol.com<k4cle at aol.com>  wrote:
>>>>
>>>> Hi Peter, yes it sounds like the UT+ is defective if it never gets any
>
> sats.  You can probably find one on eBay.  Someone probably fired RF into
> the receiver front-end and zapped it.  I think the antenna you are using
> should be OK.
>>>>
>>>> I will look for my drawings on this unit and send copies to you.  And I
>
> know I have the software too, just need to find it!
>>>>
>>>> I have read in some of the notes here on time-nuts that people may be
>
> able to use RS232 for communicating with the RFTG units.  But it was
> designed for RS422 and I would suggest you use RS422 for best results.  I
> use a little RS422-4S232 converter which has worked fine for me.
>>>>
>>>> The early units had FRS rubidiums in them.  The LPRO was used in the
>
> newer units.  So, you have the more recent design.
>>>>
>>>> Connected by DROID on Verizon Wireless
>>>>
>>>> -----Original message-----
>>>> From: Peter Bell<bell.peter at gmail.com>
>>>> To: Discussion of precise time and frequency
>
> measurement<time-nuts at febo.com>
>>>>
>>>> Sent: Sun, Oct 9, 2011 05:52:25 GMT+00:00
>>>> Subject: Re: [time-nuts] Lucent RFTG-m-XO GPSDO
>>>>
>>>> On Sun, Oct 9, 2011 at 3:31 AM, k4cle at aol.com<k4cle at aol.com>  wrote:
>>>>>
>>>>> Peter, do you have the software for this unit?  The GPS antenna is
>
> supposed
>>>>>
>>>>> to draw apx. 20 mA at 5 volts in order for the NO GPS LED to turn off.
>>>>>
>
> AT&T
>>>>>
>>>>> (Lucent) used the MicroPulse timing antenna (later sold and now
>
> provided by
>>>>>
>>>>> PCTE).  You are correct in that Efratom used the Motorola UT+ 8 channel
>
> GPS
>>>>>
>>>>> receiver on these units.  The rubidium companion box used the data from
>
> the
>>>>>
>>>>> same receiver (via an interconnect cable between the two units).  Let
>
> me
>>>>>
>>>>> know if you have questions on this unit, Regards, Doug....
>>>>> Connected by DROID on Verizon Wireless
>>>>>
>>>>> -----Original message-----
>>>>> From: Peter Bell<bell.peter at gmail.com>
>>>>> To: time-nuts at febo.com
>>>>> Sent: Fri, Oct 7, 2011 14:13:31 GMT+00:00
>>>>> Subject: [time-nuts] Lucent RFTG-m-XO GPSDO
>>>>>
>>>>> I have been playing with one of these units, and noticed that there
>>>>> has been some discussion on them before on this list, so I wondered if
>>>>> anyone might have any suggestions.
>>>>>
>>>>> Basically, the unit powers up correctly, but the "No GPS" LED never
>>>>> goes off - this obviously could be because it's broken or doesn't like
>>>>> my antenna, but with some of these telecom GPSDOs you have to manually
>>>>> trigger a site survey if you move them to another location. Does
>>>>> anyone know if this Lucent box is like that?
>>>>>
>>>>> Everything else seems to be working - once the "OK" light comes on the
>>>>> 15MHz output is enbled, the "No GPS" LED goes from solid to blinking
>>>>> if you disconnect the antenna - it just doesn't want to get GPS lock.
>>>>>
>>>>> I suppose I could pull the Oncore board (a UT+ according to the label)
>>>>> out of it and test that on it's own - but I thiought I would see if
>>>>> maybe it's a known issue first.
>>>>>
>>>> Hi, Doug
>>>>
>>>> I don't have any documentation at all - just the actual box.  The
>>>> antenna is one that originally came with a Furuno marine GPS, but the
>>>> spec looks plausible (+5V @ 40mA, Internal L1 preamp with 26dB gain -
>>>> and it has worked with several other GPS units without problems.
>>>>
>>>> I just pulled the oncore out, and connected it up outside the box -
>>>> and it doesn't work.  It passes the self test with a response code of
>>>> 0000 (or 8000 with the antenna disconnected / 4000 with a short on the
>>>> antenna socket - so it seems the current consumption is OK) - but no
>>>> matter how long you leave it it still says it's tracking 0 satellites,
>>>> although it happiy generates status reports.
>>>>
>>>> I wonder if this UT+ version is expecially sensitive to the antenna?
>>>> I remember that the oncore VP would work with pretty much anything you
>>>> hooked up to it.  Of course, it's equally possible that the GPS module
>>>> is defective.
>>>>
>>>> I'm tending towards broken - I also got an RTFG-m-RB with this unit,
>>>> and that has a faulty LPRO-101 in it (it's probably fixable - it looks
>>>> like the FET that heats up the Rb cell had gone open circuit) - and
>>>> the two units together only cost me $40 supplied on a "status unkown,
>>>> but likely defective" basis. I should get at least $40 of
>>>> entertainment out of trying to fix them :)
>>>>
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> The 'no gps light' on mine comes on periodically (usually aroundmidnight)
> then goes off after a while.  My antenna is not in the bestlocation, on
> window sill in corner.  But, for the most part, it staysoff most of the
> time. . .
>
> Randy
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