[time-nuts] New Member + Basic Questions

paul swed paulswedb at gmail.com
Sun Jan 10 15:55:36 EST 2016


Nathan,
Bob shared a link for the Lucent units and a great amount of detail has
been shared on Time-nuts about them. They will do what you want. The Ref0
requires a external GPS receiver and another Time-Nuts Arduino. It works
really well and the quality of the ref0 seems to be that of the 1pps
feeding it.
But they also make a no brainer pair that has a ref0 and ref1 that has a
built in GPS receiver. They were $175 but they go all over the place in
price. But it does just work.
Trace-ability is an interesting word around this group. From your
description not sure thats really a need. Accept for the oven oscillator
they all are great and yes even really good oven oscillators are great and
can actually be amazing. Not cheap at all though.
You describe your counter and sig gen they have a resolution of .1Hz so
going further isn't really all that helpful.
Now here is the real issue you face and its far more of an issue then you
expect.
First the generator and oscillator and suddenly you find yourself acquiring
more stuff. Maybe a RB, then a Cesium, distribution amplifiers, better
antennas. Sound familiar? You are doooomed. Back away real fast.
Good luck
Paul
WB8TSL

On Sun, Jan 10, 2016 at 2:42 PM, Bob Camp <kb8tq at n1k.org> wrote:

> Hi
>
> > On Jan 10, 2016, at 1:25 PM, Nathan Johnson <jdownj at gmail.com> wrote:
> >
> > Hello All,
> > I'm a ham radio operator, for just a few years, and electronics nut for
> many
> > more. I have been reading the archives and trying to learn a bit. I am
> wanting
> > to develop an accurate frequency standard for "lab" and radio use. I see
> that I
> > have 3 basic options that are possible on my budget, a decent OCXO-based
> device,
> > a rubidium standard, and a GPSDO. My current uses are to supply accurate
> timing
> > to a signal generator(not yet purchased, HP 8640/8650-something) and a
> frequency
> > counter(Fluke 1953), mostly used in aligning radios.
> > In the near future I am hoping to expand that to a homebrew HF
> > transceiver(probably clocking a DDS chip of some sort), and some higher
> > frequency(possibly up to 10GHz) transverters.
> > So what I have learned so far about each option:
> > -OCXO is probably stable enough for what I am trying to do, but by itself
> > provides no guarantee of absolute accuracy(I'm looking at the microwave
> > operators "weapon of choice", the Isotemp 134-10), has an adjustment pin
> for a
> > tuning voltage, but no idea what an appropriate value is for that voltage
> > without access to a more accurate standard. I will probably build an
> OCXO device
> > of some kind anyway as an interim measure while I earn for the money to
> obtain
> > something better, and to validate a distribution amp within the lab etc.
> > -Rubidium Standard seems like a very nice idea, but it's still not
> traceable in
> > terms of absolute accuracy(although the adjustment range of the available
> > standards appears to be several orders of magnitude better than I am
> likely to
> > need). The available standards are being re-imported from China, with
> unknown
> > hours or life remaining, and in some cases unknown condition. They
> appear to be
> > power hogs. A $200 gamble.
> > -GPSDOs have many options available, and are referenced to primary
> standards.
> > Pretty sure this is where I want to go. I'm looking at Item#
> 231803015799 on the
> > usual auction site, and this seems to be everything I need? I also
> looked at
> > item# 111514491254, but there doesn't seem to be any documentation about
> what's
> > inside.
>
> The first item you reference is a Nortel GPSTM with all the “stuff” to
> make it work other
> than the power supply. If you dig into the archives, there is a *lot* of
> information on them there.
>
> The second item is a Chinese Ham built GPSDO without the antenna. It has
> the nice feature
> of being actively developed. If you can read Chinese, you can tune in to
> the lists that have
> information on it.
>
> Of the two, I’d go for the first one from a US seller that I’ve had good
> luck with.
>
> A somewhat more “do it yourself” option is:
>
>
> http://www.ebay.com/itm/221852021307?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT
>
> combined with a GPS receiver board.  They also are available in a “2 for a
> bit less” form from the same seller.
>
> Each item has it’s plusses and minuses. The third item has a pretty clean
> 15 MHz output for microwave use.
> All of the 10 MHz outputs are a bit dirty noise wise if you decide to
> multiply them up to > 10 GHz. The normal approach
> in that case is to lock up a clean 100 to 150 MHz range VCXO to the GPSDO
> and then multiply the
> VCXO output to microwaves.
>
> All of them are quite adequate to supply a reference to a signal generator
> or a counter. All are good enough
> for normal HF radio use.
>
> Bob
>
>
>
> > Am I missing key points here? Or am I headed on the right path?
> Appriciate any
> > and all input.
> > Nathan KK4REY
> >
> > Sent using CloudMagic Email
> > [
> https://cloudmagic.com/k/d/mailapp?ct=pi&cv=7.4.15&pv=9.1&source=email_footer_2
> ]
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