[LinuxPPS] Oncore Refclock interface & thermostat

[Udo van den Heuvel]

Hal V. Engel wrote:
> Oncore modules like the UT+ units I am using have a power consumption of 155mA 
> and can handle antenna loads of up to 80mA (most other Oncore models are 
> lower).  So a typical unit with the antenna load will consume about 175mA to 
> 190mA.   With a higher power consumption antenna amp or if using additional in 
> line amps this could be as high as 235mA (for the Oncore UT+) without 
> exceeding what the module's antenna power circuit can handle.  These numbers 
> are significantly higher than the 60mA power consumption of the Garmin 18LVC 
> but this is in most cases less than 1 watt. 

Could I power them from the 5V / 12V lines of the PSU in my Epia?
(i.e. mount the GPS module there, connect it to an internal serial port 
and make a coaxial antenna input in the case of the Epia.

[...]

Ah:

> If you can mount the GPS module in the computer chassis then there is lots of 
> 5V power available right from one of the internal PSU connectors and the 
> limits of the USB interface become a non-issue.  The only concern I would have 
> is that the inside of a PC chassis is a high RF noise environment and some GPS 
> modules may not handle this very well.  In addition, there are processors that 
> run at frequencies that are close to the L1 GPS frequency of 1.575GHz that 
> could create significant problems.  One example is the Intel Atom operates at 
> at a nominal speed of 1.6GHz and under these conditions you might need 
> additional shielding around the GPS module. 

How to shield? (maybe not so on-topic here...)
But maybe it is if it is gps-related.

> more shielding and higher levels of selectivity than other Oncore models.  The 
> ones you see for sale on ebay and other places are for the most part working 
> pulls from cell sites that are being replaced with newer units like the M12T 
> and M12M Timing Oncores (higher precision and lower power consumption).   

I read about (older) oncores that they have a bug in the binary 
protocol. (somewhere in the ntp source?)
It is some kind of limit in the time that could be represented in the 
chosen procotol. (not nmea)

> One of them arrived DOA but was promptly replaced by the vendor.  At the price 
> he is selling them and with the free shipping on additional units it is worth 
> while to get more than one unit IMO (IE. spares and for additional projects).   
> These are a mix of firmware versions and one of the units I got was version 
> 2.2 and all of the others were version 3.2.  My understanding is that he also 
> has some that are version 3.1.

How much does the firmware matter?

Thanks for the valuable info!

Udo