[time-nuts] Trimble Thunderbolt NMEA ?

[Brian Lloyd]

On Mon, Mar 2, 2015 at 5:06 PM, Tim <timt at skybase.net> wrote:

> On 3/03/2015 4:33 AM, Didier Juges wrote:
>
>> Tim,
>>
>> NMEA is normally used for navigation. It would seem unlikely that anyone
>> would want to use a Thunderbolt for navigation. Can you elaborate on what
>> you are trying yo do?
>>
>>
>>  Hi Didier,
>
> I' building a multi frequency beacon based on QRP-labs U3 beacon kit. It
> has the ability to discipline its oscillator with a PPS input and, using
> NMEA input, set and maintain time and location for exact control of WSPR
> and OPERA modes of operation.
>
> As it currently only accepts NMEA input I was wondering there was a way to
> get NMEA out of a thunderbolt. I've lodged an RFE with the developer to add
> TSIP support to the U3, but I don't think that's going to happen anytime
> soon.
>
> I'd rather use the Thunderbolt as the time and PPS source since its way
> more accurate than the LEA-M8FGPS module that optionally comes with the kit.
>

This may be a case where duplication of hardware might be the simplest
solution. Navigation receivers that output 1pps and NMEA data are a
dime-a-dozen now, under $50. Go look at what is available from the likes of
SparkFun or Adafruit. For disciplining the clock in in the computers
running your WSPR and OPERA software even the cheapest receivers greatly
exceed the required timing accuracy. (NTP across the net is sufficient for
these applications.)

What I am doing is using a BeagleBone Black and a Jackson Labs LTE-lite
receiver as my household stratum-1 NTP server and backup 10MHz and 1pps
reference. In the same enclosure I am mounting my Trimble Thunderbolt to
use as my primary 10MHz and 1pps reference. Fan-out of these signals is
accomplished using the TAPR TADD-1 and TADD-3 distribution modules. All of
this is easy to accomplish with a minimum of hardware and software hacking.

I am mounting everything in a 2U rack case into which I plan to incorporate
a battery backup.

By time-nuts standards this is pretty mundane, but still represents a very
credible level of performance from a ham-radio and general timing
point-of-view.

-- 



Brian Lloyd
706 Flightline Drive
Spring Branch, TX 78070
brian at lloyd.aero
+1.210.802-8FLY (1.210.802-8359)