[time-nuts] 10MHz LTE-Lite

paul swed paulswedb at gmail.com
Sat Nov 22 11:42:59 EST 2014

Ok give it a week for the magic to wear off.Then its time to hack.
I am sort of headed into that mode.
The system draws what I would technically call squat for power. Hmm wonder
how thats measured VA watts??
Locks pretty darn fast and recovers pretty fast. But you do always go
through the survey. Not really a negative.
It does produce a relatively stable output. But you can see it slip as
compared to the likes of the Z3801 or 3811. This tends to be due to drafts.
Its quite sensitive.
So following best practices two thick socks are on top of it now.

So to the hacking/curiosity.
I will group my interests in several areas (No particular sequence);

   - A good enough reference to replace my cheap-y $25 Telco RB reference.
   - Adding the various buffers to have useful signals.
   - Trying to keep the support power consumption down to match the LTE.
   - The curiosity of adding a oven 10 Mhz oscillator. I have a PTI and
   - Battery back up a real question given the lockup time of the unit.

The buffering and dividing will come first and may have to be 74 HC or HCT
to get the 20 to 10 Mhz. Its unfortunate because 74 AC would allow
everything to run on 3.3V. May just wait and order some AC chips and do it

Then LPF the output 10 Mhz to a sine wave and hit a transistor buffer.
The buffer will be the biggest power pig of all. They always are.

I always seem to need various ticks. The 1 PPS will be adapted to RS232 and
RS 485 using buffers/converters. Simple 1 chip wonders.
The output only data feed could also be RS232 and there is a spare
transmitter in the max chip I would use. These can be wired on a board or
for almost nothing ordered from ebay these days with shipping delays.

The oven is really a curiosity. I have a 20 MHz unit. I think that by
changing the 3 zero ohm Rs on the system I can shift to 10 Mhz and directly
replace the 20 Mhz TCO. If thats not true then the typical oven has to be
doubled to 20 and then converted to a clean 3V digital signal. This thread
already has some hints on the EFC voltage.

Lastly Battery backup. By the time I get to here I will have decided if its
even worth the effort. Batteries are a pain in the .... But is nice in that
the system just runs. Having an oven absolutely takes a 1-2 watt solution
to a 30 watt total solution. Essentially what my RB consumes today when you
look at the wasted energy in the transformers and such. I am using an HP
battery system that drove RB and CS references circa 1980. So not very
efficient. But sure does work.

Someplace sooner then later a box for it all. Drafts do upset the TCXO. It
may need to be a highly customized temporary box. These boxes are available
at most supermarkets. Ask for cardboard.

So there you have it my 10 cents worth of musings on the direction I am

On Sat, Nov 22, 2014 at 10:37 AM, Jim Sanford <wb4gcs at wb4gcs.org> wrote:

> Said:
> Just ordered a second 10 MHz board for my rover station....
> 73,
> Jim
> wb4gcs at amsat.org
> On 11/20/2014 3:32 PM, S. Jackson via time-nuts wrote:
>> Hello everyone,
>>   after what must have been the longest thread in T-nuts history its
>> almost
>> all quiet today. I am going to take advantage of that and  announce some
>> good news:
>>   Its a miracle: the 10MHz DIP-14 TCXOs for the LTE-Lite came in weeks
>> ahead
>> of schedule from the factory! And they work very well.
>>   We will thus be shipping out the 10MHz LTE-Lite eval boards in the  next
>> couple of working days. There are still a number left for sale on Ebay
>> (search for "LTE Lite GPSDO"), so if you were hesitant to get one due to
>> the  long
>> lead-time, then now is your chance.
>>   Also, after being in time nuts hands for almost a week I am surprised
>> there are very few mails, questions, or comments about the 20MHz boards,
>> and we
>> have received almost no feedback on Ebay :( I hope that is a good  sign.
>>   Bye,
>> Said
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