[time-nuts] Re: Measuring oscillators against GPS - Trimble NetRS

[Skip Withrow]

Hello time-nuts,
Would like to comment on a couple of the points that Tom Wallace made
about measurements with the NetRS.
BTW, all the cheap ones disappeared from eBay in a hurry!  I was going
to pick up another, but think I will wait awhile for the prices to
cool again.

1.  The Trimble part number for the dongle is 48164, but I have
generally found it to be unobtainium.  However, it is VERY easy to
build up.  The NetRS manual is not complete as it does not have the
power connection.

To make the cable you need a female DA-26 connector (L77HDA26S) and
RJ-45 cable.  Power (12-18 volts) goes to Pin-24.  Ground goes to
Pin-6.  Cut off one end of the RJ-45 cable.  Hold the end with the
remaining RJ-45 pointing away from you with the locking clip down.
The pins that you see are numbered 1-8 from left to right.  Pin-1
(Wht/Orn for T-568B) goes to DA-26 Pin-25.  Pin-2 (Orn) goes to DA-26
Pin-16.  Pin-3 (Wht/Grn) goes to DA-26 Pin-26.  Pin-6 (Grn) goes to
DA-26 Pin-17.  That's it!  Plug the RJ-45 into your router and apply
power (and plug the DA-26 into the NetRS).

The NetRS takes awhile to boot up.  Give it time.  Then the lights
operate as in the manual.

2. Amen.

3. Do upgrade if you have a down rev unit.  The surplus Coast Guard
unit that I received was up to date.

4. I found this out the hard way.  Yes, keep clock steering off if you
are measuring an external oscillator.

5. Not true!  The technique that Tom describes is perfectly valid.
HOWEVER, there is a utility on the Trimble website that will convert
in one step.  It is called 'ConvertToRinex' - Trimble RINEX Converter
| Trimble Geospatial.

Have fun,
Skip Withrow