GPS locking beacons

[VK3JUG]

I have our new 2m beacon (144.438MHz) running quite happily, but now it's time to add the a GPS. What's around thats gives a 10Mhz ref. out? i see the Uniblox LEA6T do, any others that are cheap and readily available surplus?
PeterN
VK3JUG
Mildura

[VK3WRE]

I have a Jackson Labs LTE-LITE running most of the 3RGI beacons, 2m to be added shortly.
The unit is available on an evaluation board and would need a distribution amp on the output.
check out the link http://www.ebay.com/itm/LTE-Lite-GPSDO- ... 1504585820
The evaluation kit comes with every thing needed to get it running with the exception of a distribution system.
works well.

cheers
Ralph VK3WRE

[VK5KK]

Hi Ralph & Peter

I can second the Jackson labs LTE-Lite (eval board) as an option.

I have a 20 MHz version of LTE-Lite (first ones made available) installed in the 10 GHz gear (wrked VK6DZ last nite with!). Reprogrammed the ADF4360 PLL (2.5 Ghz) for 20 Mhz ref, in theory should have better noise performance @ 10 Ghz as a side benefit. With the on board SMD TCXO quite stable (but must be installed with thermal insulation though) and minimal jitter on 10368. Accuracy better than equipment measuring! I have ordered a DIP package 20 Mhz TCXO to upgrade the boards thermal response, $20 item from multiple chinese vendors.

BTW: Peter if your not aware, Alan VK3XPD has a $200 grant available via the WIA for GPS locking of beacons, Alan can be contacted via his email is alandevlin@bigpond.com

Cheers

David VK5KK

[VK3JUG]

Have been looking at this module, i have some of the "non T" versions, very sensitive receivers, for time pulse applications. No TXCO but half the price and size (25x35mm board with ant.) Will be using XDK's 10MHz distribution board to feed multiple beacons. The 2m beacon exciter is an XDK board. Have registered the clubs beacons with Alan, was a good motivator to upgrade.

http://www.ebay.com.au/itm/261298777057 ... 1693wt_948
http://www.ebay.com.au/itm/261577078446 ... 1807wt_886

[VK1DJA]

On the LEA-6T, it would be worthwhile checking out discussion, etc, on the timenuts forum. Google "timenuts ublox". There is also some good information through the Ublox site. This cuts into some heavy stuff. I chickened out and bought a PicoSync on eBay that was usefully cheaper than a Thunderbolt.

One point on the LEA-6T is that jitter and phase noise are lower if you generate an 8 MHz signal rather than 10 MHz, another is that you need to consider whether the short-term accuracy of the generated reference signal is OK for your use.

Dave

[VK3HZ]

Hi Peter,

The direct output from the LEA-6T would not be good enough as a 10 MHz source for the reasons already stated. You'd need to use it to lock a 10 MHz (preferably) OCXO or TCXO to get a clean enough and stable enough signal.

The LTE-Lite is probably the choice at the moment. They (Jackson Labs) produce 3 versions with different "native" frequencies (10, 19.2 and 20 MHz from memory). The 19.2 seems to be the only one available in their eBay store at the moment, but I believe new batches of the others are in the works. All of them can be configured to output 10 MHz and can be used to lock a 10 MHz (O/T)CXO with minimal external components. There have been extensive discussions on time-nuts about using the LTE-Lite as a reference.

If you have deeper pockets, Jackson Labs also make other excellent GPS References like the Firefly.

If you want to delve into the dark world of eBay, I recently got a FEI Picosync for someone. There's little information on them, but the unit worked well. Only problem was the (24V) power lead came with red and black wires attached - red to negative Fortunately the unit survived the brief reverse voltage incident!

Regards,
Dave
VK3HZ

[VK4UH]

Very Interesting
Today I observed that my 10 MHz "Trimble Thunderbolt" based GPSDO was showing a MINOR ALARM state

This turned out to be a "LEAP SECOND PENDING" notification!

I had heard on the ABC news that a leap second was about to be added.

KJ VK4UH Brisbane

[VK2ZRH]

And don't forget the WIA Grants Scheme program supporting GPS locking of VK beacons: http://www.wia.org.au/members/grantscheme/gpsbeacon/

[VK4CLG]

Very Interesting
Today I observed that my 10 MHz "Trimble Thunderbolt" based GPSDO was showing a MINOR ALARM state

This turned out to be a "LEAP SECOND PENDING" notification!

I had heard on the ABC news that a leap second was about to be added.

KJ VK4UH Brisbane

Thanks for that KJ. I noticed that on my thunderbolt display this morning as well. I had no idea what is was. I'm guessing it just changes by itself at 00:00 UTC.

Robert
VK4LHD

[VK3ALB]

From the text of last week's WIA broadcast.



The International Earth Rotation and Reference Systems Service (IERS) has
announced at the Paris Observatory, in a bulletin addressed to the
"authorities responsible for the measurement and distribution of time" that
it will be giving us "more time."

The bulletin advises authorities an extra second will be introduced to
Coordinated Universal Time (UTC) during the final minute, of the final day of
June. That means that right after the clock hits "23h 59m 59s," it will
strike "23h 59m 60s" UTC.

Another way to think about it:
Instead of the about 86,400 seconds we normally experience in a day, we're
getting 86,401.

This "leap second" system started in 1972, so our clocks stay in sync with
how long it takes the Earth to rotate on its axis. "Leap seconds ensure that,
on average, the Sun continues to be overhead on the Greenwich meridian at
noon to within about one [second]."

IERS already has added 25 leap seconds to Coordinated Universal Time -- most
recently in June 2012.

Leap seconds can only be added in June and December.

http://www.ibtimes.com/extra-leap-secon ... 30-1774068

(International Business Times)

[VK4GHZ]

This turned out to be a "LEAP SECOND PENDING" notification!

Leap seconds are very exciting events!
All the Timenuts will be frothing at the mouth.

In case anyone missed it, here's the last one.
(And no prizes for guessing when this occurred)



Posted as a heads up as to how long that annoying Minor Alarm is going to be hanging around for!

From the text of...

But we have interwebs video this centrury, OM!

[VK3ALB]

But we also have the interwebby advice from a number of sources not including your new fangled video contraption OM.

Try this one

http://tycho.usno.navy.mil/leapsec.html

and the official source

http://hpiers.obspm.fr/iers/bul/bulc/bulletinc.dat

[VK4GHZ]

An entertaining, yet informative, look at leap seconds that might engage any Gen X or Gen Ys out there.
It's slow to start, but hang in there!



... and I didn't know that the ITU were considering dumping the leap second.