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

EB4APL eb4apl at cembreros.jazztel.es
Sun Oct 9 09:55:17 EDT 2011


My UT+ works ok with common antennas, I tested it with a Trimble 
28367-00 and with a  INPAQ AAF-03B 5V.  Both are quite old garden 
variety GPS antennas intended for car navigators so your problem can be 
in the receiver.
I bought mine from fluke.l and he still have some available on his other 
They are cheap enough to buy one as a spare just in case.  Also you can 
try with another antenna anyway, because the receiver checks only that 
an antenna is connected (that is, the current range is right) but your 
antenna could became defective.


On 09/10/2011 7:52, Peter Bell wrote:
> 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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