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
  10811
• 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
right.

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
headed.
Reagards
Paul
WB8TSL

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

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Hi Paul, Jim, David,

Let me address all your emails:

Glad you got your boards. $50 in overseas additional charges from your
post office sucks!

Some hints for experimenting from what I have learned:

You definitely want to build a 50 Ohms buffer for the 10MHz boards and the
synthesized outputs on all boards; on the 20MHz boards on the Tcxo output
it's optional.

The biggest problem is building a suitable 3.3V or 5V power supply. I
built a buffer using two NC7SZ04 chips receiving the input in parallel with
a 1M terminating resistor to ground. Then using a 100 Ohms series resistor
on both outputs to get ~55 Ohms equivalent impedance, and combining the two
R's to drive the 50 Ohms inputs through a 100nF cap for DC blocking. You
can use a 74AC04 just as well. I tried a standard high quality 3-pin
regulator and got very bad AM noise modulation due to the large noise on
the rail. Then I used a very low noise LDO from LT and that solved the
problem and the output is now very clean and drives 50 Ohms inputs with
ease.

you can grab the very low noise 3.0V rail output from the eval board to
power the buffers (see the schematics in the user manual) but loading that
creates a bit of heat on the LTE-Lite which will affect stability a tiny
bit.

On the power consumption, you can see we go through a linear regulator to
get 3.3V from 5V USB/EXT power. This is very inefficient. For best power
consumption you want to use a very high efficiency buck regulator to
generate the 3.3V from your battery. This means you loose the USB interface
though as that chip runs from 5V and has an internal LDO.

On the zero Ohms R2/R3 resistors, check the schematics - these allow you
to power the DIP-14 Tcxo from either the digital 3.3V rail, or the
low-noise 3.0V rail (default). The software will auto-detect if you attach
a 10MHz or 20MHz Tcxo, no configuration is needed.

On drafts, yes that is the number one cause of phase drifts. We put the
board into an ESD bag, and put some thin ESD padding material on top. That
prevents drafts, and following the EFC curve you can see the unit still
reacts slowly to the AC or heaters kicking on. That's normal, and that's
why we discipline to GPS.. In our setup the units have typically less than
20ns standard deviation on the RF and 1PPS outputs. The raw gps 1PPS output
on the header is even better on average, but has the sawooth error on it.
The sawtooth error correction value is in the PSTI NMEA message for those
that want to use the raw gps 1PPS output and correct the sawtooth
externally. This chip has a very high rate internal system frequency that
results in very low residual sawtooth error.

On the auto survey process - this is disabled when using 3D mobile mode by
shorting pins 1 and 3 on the 3-pin header as described in the "read me
first". But be aware that changing that header with power applied results
in flash memory corruption, and thus a very bad day. That's why we did not
solder the header - to avoid any accidents..

Bye,
Said

Sent from my iPad

On Nov 22, 2014, at 8:42, paul swed paulswedb@gmail.com wrote:

wonder

drafts.

HCT

it

and

directly

thread

its

that

you

It

available

some

next

to

boards,

sign.

https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts

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On Dec 7, 2014, at 1:32 AM, Orin Eman orin.eman@gmail.com wrote:

Hi Said,

It's a little while since you sent this, but I just finished some testing
with the LTE Lite.

I already had a Trimble Thunderbolt and also have an HP 5335A with OCXO.
The 5335A has shown the Trimble O/P 10 MHz +/- 0.03 Hz for the last few
years (displayed frequency on the 5335A has drifted down by about 0.04 Hz).

So, I set up the LTE Lite (10MHz TCXO version) with its antenna about 6'
from that used by the Trimble.  After letting it settle down, it looked
good.  I was using the high impedance input of the 5335A (aside: if set for
DC coupling, the 5335A would read 20MHz from the ringing.  I only have
about 18" of RG-188 after the pigtail supplied with the LTE Lite).

Today, I made up a buffer using a 74AC04 and LT1763-3.3 LDO regulator
supplied with 5V from a bench supply.  Two inverters each into 100 ohms
then 0.1uF DC block as suggested.  I connected this to the LTE Lite instead
of directly to the 5335A with the 5335A set to 50 ohms and the 5335A read
0.5Hz low!  It settled down to the original reading after a while.  I
looked at the signal from the buffer using a 50 ohm pass-through terminator
and the signal looked nice and square.

A few hours later I went back and it still looked good.  I decided to look
at the input to the buffer on a TDS-210 'scope with a 10X probe.  There is
now perhaps 6" of coax to the buffer which has 1 Mohm in parallel.  The
signal is about 5V pk-pk, but the ringing dies down quickly.  BUT, the
5335A was displaying a few hundredths of a Hz higher than 10MHz, whereas it
was a few hundredths below before!  When I removed the probe, it went a few
hundredths of a Hz below where it was originally and gradually recovered.

So, in addition to temperature, the LTE-Lite eval board with 10MHz TCXO
appears to be sensitive to load as well as temperature, such that just a
10X oscilloscope probe will affect the output.  Normally, you probably
wouldn't notice this, but I switched the loads while it was running.
Certainly, once put in an enclosure, the 74AC04 buffer would be permanently
connected and I'd assume any effect noticed above would be during the
warmup of the LTE-Lite and wouldn't really be noticed.

I'm sure I forgot some detail or other in the above description.  I
couldn't find a DIP 74AC04 so I made a PCB for an SMT 784AC04 using MG
Chemicals 1/32" positive-resist PCB and Eagle for the design; 1206 100 ohm
series resistors and 1206 0.1uF ceramic DC blocking capacitors.  I laid it
out for SMA sockets that you could wire RG-316 or similar directly instead.
I used a 6" MMCX to RG-316 pigtail from the LTE-Lite to my buffer.  I
mounted one SMA socket on the outputs which is what I used to connect to
the HP 5335A.  The LT1763 has a 1uF 35V tantalum on the input and 10 uF 30V
tantalum on the output (they are what I had in the parts bin, or I'd have
used smaller ceramic parts).  I tweaked the design for hand soldering
with no solder mask (i.e. 20 mil clearances and top layer restrictions
around most components to keep the ground fill away).

Orin.

On Sat, Nov 22, 2014 at 9:44 AM, Said Jackson via time-nuts <
time-nuts@febo.com> wrote:

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and follow the instructions there.

Hi Said,

It's a little while since you sent this, but I just finished some testing
with the LTE Lite.

I already had a Trimble Thunderbolt and also have an HP 5335A with OCXO.
The 5335A has shown the Trimble O/P 10 MHz +/- 0.03 Hz for the last few
years (displayed frequency on the 5335A has drifted down by about 0.04 Hz).

So, I set up the LTE Lite (10MHz TCXO version) with its antenna about 6'
from that used by the Trimble.  After letting it settle down, it looked
good.  I was using the high impedance input of the 5335A (aside: if set for
DC coupling, the 5335A would read 20MHz from the ringing.  I only have
about 18" of RG-188 after the pigtail supplied with the LTE Lite).

Today, I made up a buffer using a 74AC04 and LT1763-3.3 LDO regulator
supplied with 5V from a bench supply.  Two inverters each into 100 ohms
then 0.1uF DC block as suggested.  I connected this to the LTE Lite instead
of directly to the 5335A with the 5335A set to 50 ohms and the 5335A read
0.5Hz low!  It settled down to the original reading after a while.  I
looked at the signal from the buffer using a 50 ohm pass-through terminator
and the signal looked nice and square.

A few hours later I went back and it still looked good.  I decided to look
at the input to the buffer on a TDS-210 'scope with a 10X probe.  There is
now perhaps 6" of coax to the buffer which has 1 Mohm in parallel.  The
signal is about 5V pk-pk, but the ringing dies down quickly.  BUT, the
5335A was displaying a few hundredths of a Hz higher than 10MHz, whereas it
was a few hundredths below before!  When I removed the probe, it went a few
hundredths of a Hz below where it was originally and gradually recovered.

So, in addition to temperature, the LTE-Lite eval board with 10MHz TCXO
appears to be sensitive to load as well as temperature, such that just a
10X oscilloscope probe will affect the output.  Normally, you probably
wouldn't notice this, but I switched the loads while it was running.
Certainly, once put in an enclosure, the 74AC04 buffer would be permanently
connected and I'd assume any effect noticed above would be during the
warmup of the LTE-Lite and wouldn't really be noticed.

I'm sure I forgot some detail or other in the above description.  I
couldn't find a DIP 74AC04 so I made a PCB for an SMT 784AC04 using MG
Chemicals 1/32" positive-resist PCB and Eagle for the design; 1206 100 ohm
series resistors and 1206 0.1uF ceramic DC blocking capacitors.  I laid it
out for SMA sockets that you could wire RG-316 or similar directly instead.
I used a 6" MMCX to RG-316 pigtail from the LTE-Lite to my buffer.  I
mounted one SMA socket on the outputs which is what I used to connect to
the HP 5335A.  The LT1763 has a 1uF 35V tantalum on the input and 10 uF 30V
tantalum on the output (they are what I had in the parts bin, or I'd have
used smaller ceramic parts).  I tweaked the design for hand soldering
with no solder mask (i.e. 20 mil clearances and top layer restrictions
around most components to keep the ground fill away).

Orin.

On Sat, Nov 22, 2014 at 9:44 AM, Said Jackson via time-nuts <
time-nuts@febo.com> wrote:

the

with

resistor

two

that

interface

attach

That

than

output

by

not

reference.

or

be

solution

HP

wrote:

Ebay

surprised

time-nuts mailing list -- time-nuts@febo.com
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https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

Hi Said,

It's a little while since you sent this, but I just finished some testing
with the LTE Lite.

I already had a Trimble Thunderbolt and also have an HP 5335A with OCXO.
The 5335A has shown the Trimble O/P 10 MHz +/- 0.03 Hz for the last few
years (displayed frequency on the 5335A has drifted down by about 0.04 Hz).

So, I set up the LTE Lite (10MHz TCXO version) with its antenna about 6'
from that used by the Trimble.  After letting it settle down, it looked
good.  I was using the high impedance input of the 5335A (aside: if set for
DC coupling, the 5335A would read 20MHz from the ringing.  I only have
about 18" of RG-188 after the pigtail supplied with the LTE Lite).

Today, I made up a buffer using a 74AC04 and LT1763-3.3 LDO regulator
supplied with 5V from a bench supply.  Two inverters each into 100 ohms
then 0.1uF DC block as suggested.  I connected this to the LTE Lite instead
of directly to the 5335A with the 5335A set to 50 ohms and the 5335A read
0.5Hz low!  It settled down to the original reading after a while.  I
looked at the signal from the buffer using a 50 ohm pass-through terminator
and the signal looked nice and square.

A few hours later I went back and it still looked good.  I decided to look
at the input to the buffer on a TDS-210 'scope with a 10X probe.  There is
now perhaps 6" of coax to the buffer which has 1 Mohm in parallel.  The
signal is about 5V pk-pk, but the ringing dies down quickly.  BUT, the
5335A was displaying a few hundredths of a Hz higher than 10MHz, whereas it
was a few hundredths below before!  When I removed the probe, it went a few
hundredths of a Hz below where it was originally and gradually recovered.

So, in addition to temperature, the LTE-Lite eval board with 10MHz TCXO
appears to be sensitive to load as well as temperature, such that just a
10X oscilloscope probe will affect the output.  Normally, you probably
wouldn't notice this, but I switched the loads while it was running.
Certainly, once put in an enclosure, the 74AC04 buffer would be permanently
connected and I'd assume any effect noticed above would be during the
warmup of the LTE-Lite and wouldn't really be noticed.

I'm sure I forgot some detail or other in the above description.  I
couldn't find a DIP 74AC04 so I made a PCB for an SMT 784AC04 using MG
Chemicals 1/32" positive-resist PCB and Eagle for the design; 1206 100 ohm
series resistors and 1206 0.1uF ceramic DC blocking capacitors.  I laid it
out for SMA sockets that you could wire RG-316 or similar directly instead.
I used a 6" MMCX to RG-316 pigtail from the LTE-Lite to my buffer.  I
mounted one SMA socket on the outputs which is what I used to connect to
the HP 5335A.  The LT1763 has a 1uF 35V tantalum on the input and 10 uF 30V
tantalum on the output (they are what I had in the parts bin, or I'd have
used smaller ceramic parts).  I tweaked the design for hand soldering
with no solder mask (i.e. 20 mil clearances and top layer restrictions
around most components to keep the ground fill away).

Orin.

On Sat, Nov 22, 2014 at 9:44 AM, Said Jackson via time-nuts <
time-nuts@febo.com> wrote: