[Elecraft] WTB Trimble ThunderBolt for K3EXREF / QS1R

[M. George]

After posting my message about using an external frequency reference for a
K3 and a QS1R, I got some really nice input and feedback from W7AVK, K3KO,
N4ZR and NK4I. A big thanks to these gents for sending me input and
experience with different solutions.

All the input has been very useful this weekend as I have searched around
for a single time reference solution for my needs. (everyone is going to be
different)  I thought this might help others that want to go down this path
if they have similar wants / needs.

I decided to still go with a Trimble Thunderbolt Rev. E ~2004 manufacture.
This isn't going to be the lowest cost solution, but it covers my needs for
the following:

1. Provide a very stable 10mhz external reference for my K3... mainly for
fun and I might send in some reports to the ARRL FMT etc..  so there goes
$$$ for the external freq reference add on for the K3.

2. The main reason I started going down this path was to use the external
frequency reference input on the QS1R I run for the NC7J CW Skimmer.  NK4I
saved me a bunch of time (no pun intended) and pointed out the fact that
the direct output on the Trimble TBolt won't work with the QS1R.  Pete
pointed me to Graham VK3XDK and David VK3HZ's XRef which will provide a 125
MHz reference for the QS1R from the TBolt 10 MHz output
http://www.vk3hz.net/XRef/XRef_Home.html#XRef-Vx  I exchanged email with
David and have a XRef-Vx on the way... some more $$$ for the XRef-Vx
shipped.  Seriously not bad at all considering it has a TCXO on board that
will take over if the Trimble output lock is lost.

3. Use a PPS reference to drive an NTP Stratum 1 server from my house.  I
get this out of the TBolt and also from most of the other solutions
provided, but the TBolt has some other really nice monitoring
capabilities.  So for the NTP server, I ordered the latest Raspberry PI $50
with a case shipped and I searched high and low for other implementations
using a TBolt with Linux / Raspberry PI for a GPS disciplined NTP PSS
reference.  Google 'time nuts' which I'm sure many on this list are
familiar with... and I quickly found KO4BB's Thunderbolt Monitor Kit:
http://www.ko4bb.com/Timing/GPSMonitor/kit.php  Which will be a nice
display for the serial output on the TBolt as it drives the NTP server (and
QS1R and K3 when I'm operating) ARound $80 for this kit when Didier gets
the next batch ready.  This monitor kit also includes a PPS stretcher to
increase the 10uS PPS pulse output by the TBolt to ~1mS.

So that is my reasoning to stick with a TBolt...  they seem to be holding
their value if not getting more expensive and there is all the nice work
and comparisons that have been done by KE5FX
http://www.ke5fx.com/gpscomp.htm along with his Lady Heather software.
It's pretty clear that the TBolt can still hold it's own.

At the end of the day, do I need all this precision?  Not really, but it's
obsessive and fun!  I get to spend more $$$ and have stuff shipped to me
from around the globe and play with ntpd and cool software... provide a
better service to the CW Skimmer community and precision time community
with the NTP server.  Plus I'll give the ARRL FMT a try and have some more
fun.

Thanks again for all the input off the list by the guys above.

Max NG7M

On Wed, Apr 1, 2015 at 8:27 AM, M. George <m.matthew.george at gmail.com>
wrote:

> I'm looking for a Trimble ThunderBolt Rev E primarily for an external
> reference to be used on the NC7J CW Skimmer Server (which I sysop).... for
> our QS1R SDR.  telnet:dxc.nc7j.com
>
> Poking around and doing some research, it's clear I missed the opportunity
> a number of years ago to get one for less than $100.
>
> If anyone has one sitting around or an extra they would like to sell, let
> me know... on eBay I see them going anywhere from around $125 to $250 at
> times, but the auctions are not showing up on a regular basis.
>
> Hit me up off the list here if you have one you would want to sell.  I'll
> put it to good use keeping the skimmer server spots at NC7J spot on. ;)
>
> Max NG7M
>
> --
> M. George
>



-- 
M. George