Re: ProgRock not working #progrock

Robin Midgett
 

Great news..at least as far as working on frequency...I've finally had/taken time to build the QLG1 kit & connect it to my ProgRock. Once the QLG1 locked on GPS satellites & the 1PPS started, the ProgRock locked onto the desired frequency of 16.686666 MHz. and so far seems stable. 
Previously, using the Trimble T GPS module and a homebrew 555 based pulse stretcher to give a 116mS long 1PPS, I had a constant 18Hz. frequency discrepancy. In that case I fooled the ProgRock onto the desired frequency by programming register 8 18 Hz. higher than desired & setting register 3=0. Under those conditions the ProgRock would be stable and on frequency over a period of days. I"m still curious to experiment with the Trimble T and see if I can duplicate the reliability that comes with the QLG1, but for now I need to move forward with putting the propagation beacon, which is the basis for the project, on the air.
I'll see how reliable the ProgRock is over the next few days with the QLG1 supplying the 1PPS.
Thanks,
Robin Midgett K4IDC


On Tue, Jul 30, 2019 at 10:38 AM Alan G4ZFQ <alan4alan@...> wrote:
> Is it easy enough for you to check the value of register 2 in your
> ProgRocks when they're on frequency, and then again when they're off
> frequency by whatever error you're seeing?

Robin,

I've never been too bothered about register 2, it's either set for
accuracy if there is no GPS or it sets itself. When setting manually
I've not noticed any non-linearity.
The attached picture taken some time ago shows my Progrock set at
14.996MHz from a cold start. As it starts about 2KHz off I guess
register 2 was about 4KHz away from correct.
As you see it rapidly corrects and settles 2Hz lower than the GPS
derived marker (Neo 7) at 14.996MHz. (Bottom spectrum, RX not quite
accurate) Looks like register 3 is 0?
If I set register 2 I can make it more accurate but if the GPS is
connected it will settle 2Hz low and stay there. I have done more
extended tests to confirm that within a few tenths of Hz.
A restart will then be close to the wanted frequency.
I suspect this test was with a 26MHz TCXO which might explain why the
frequency settles 2Hz low. All my available synth boards are now
non-standard, I cannot repeat this with a standard crystal but it does
show how the control works and that it settles as near as I can see at a
constant frequency.
I'm not sure what GPS I used, possibly a Neo-7, maybe an old Garmin.
I've not got a QLG1.

> I can set reg. 2 to a proper value to give the correct output frequency,
> set reg. 3 to something very high (30),

Why 30? I would think 5 was as much as anybody would want, zero if you
are looking for real precision.
I wish I could help further.

73 Alan G4ZFQ




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