[time-nuts] New NTBW50AA
EB4APL
eb4apl at cembreros.jazztel.es
Tue Sep 10 11:57:55 EDT 2013
Hi,
I have a a small correction to my message, I was talking from memory.
After checking with the real thing I found that 2 commands are needed:
One for turning the yellow LED (Comm fault) off and other for turning
the Green one (Normal) on.
Ignacio EB4APL
On 10/09/2013 13:47, EB4APL wrote:
> Dave,
>
> I have a cousin of your GPSDO, a NTGS50AA whose main differences are
> that in this unit the DB-9 connector and the LEDs are in a separate
> board connected by a flat cable, and that this unit is meant for -48
> volts systems only.
>
> The yellow light indicates that it is not in communication with the
> mainframe for about 30 seconds so it is labeled comm error. There are
> two ways to turn it green:
> - Emulate a small subset of the mainframe protocol with a
> microcontroller and communicate with the board through the 110 pin
> connector in the back. Nothing useful and quite complicated.
> - Ask Mark Sims to include in LH a function to periodically send a
> command to turn the lamp green. I verified with the Trimble-Nortel
> installation tool (GPS_Monitor) that if you tick the box for
> commanding the LED to green, it stays green until the program quits,
> so it is periodically resetting the comm timeout counter. With this
> function the LED would be green as long LH is in communication with
> the box and would turn yellow if the program quits or the
> communication is lost, like when the box is installed in a cell tower.
>
>
> Just an idea,
> Ignacio EB4APL
>
>
> On 10/09/2013 4:31, quartz55 wrote:
>> OK, did a bit more reading. I already understand the difference
>> between accuracy and stability however.
>>
>> I thought ADEV was some sort of measurement of accuracy, but I
>> understand now it is a measure of stability over time. I'm supposing
>> now that I can assume that the best frequency accuracy I can imagine
>> is what is specked in the book for the unit, <.8x10^-10. That should
>> be good enough for me. Although most seem to say the GPSDO units are
>> good for .1Hz at 10GHz which I think would be 10^-13 no?
>>
>> Yeah, I've read through the h...cpp and a lot of it is greek to me,
>> I'm no programmer, but I can pull a bunch of stuff out of it. But it
>> doesn't explain the acronyms or the meanings of them.
>>
>> I've lowered the el mask to 20 and I get plenty of sats now. When it
>> was at 43, lots of times it was down to 2, now it's generally up to
>> 6. I'll see how it does, especially if it rains, and yes the trees
>> really cover the antenna. I am getting 30-40 or more dBc however
>> which is what I had when it was more in the clear. I can move it to
>> the west about 30' on the chimney where my UHF/VHF beams are and it's
>> a lot more open straight up and especially to the south. The
>> position where it is now is just real convenient and it's only maybe
>> 25' from the unit. Plus I didn't have to get up on that part of the
>> roof that's 7 in 12.
>>
>> Yes, I notice the gis for our county seems to have a slightly
>> different co-ordinate system, they don't line up with google or the
>> GPS which seem to agree as far as I can zoom in on our location. I'd
>> say the GPS and google are within a foot or 2.
>>
>> I guess I can just turn off the temp chart if it's not going to
>> report right and stop looking/worrying about it. As long as the
>> green lock light is on. I wonder if I could trick the Nortel unit
>> into thinking it's seeing the CM though, so the top green light would
>> come on instead of the yellow one. But that doesn't matter.
>>
>> Thanks for all your help, I'll hang around for a while.
>>
>> Dave
>> N3DT
>>
>
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