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, k4...@aol.com<k4...@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.pe...@gmail.com>
To: Discussion of precise time and frequency measurement<time-nuts@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, k4...@aol.com<k4...@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.pe...@gmail.com>
To: Discussion of precise time and frequency measurement<time-nuts@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, k4...@aol.com<k4...@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.pe...@gmail.com>
To: time-nuts@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 around
midnight) then goes off after a while. My antenna is not in the best
location, on window sill in corner. But, for the most part, it stays
off most of the time. . .
Randy
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