[time-nuts] New Member + Basic Questions

Don Latham djl at montana.com
Sun Jan 10 19:12:57 EST 2016


I see I am in Really Good Company
Don

Rob Sherwood.
> Paul,
>
> Your last paragraph was a hoot.  A ham friend of mine recently rented a
> storage shed to keep all his spare test equipment and parts units.  Another
> ham friend used to have four storage  units to store all his "stuff". The
> disease is not curable with either time or antibiotics.
>
> My XYL will have to deal with two homes with labs and ham shacks, 7 towers, 13
> yagis, etc. when I am SK.  Need I say more.
>
> Rob
> NC0B
>
> -----Original Message-----
> From: time-nuts [mailto:time-nuts-bounces at febo.com] On Behalf Of paul swed
> Sent: Sunday, January 10, 2016 1:56 PM
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] New Member + Basic Questions
>
>
>
> 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&ssPa
>> geName=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
>> > [
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-- 
Felix qui potuit rerum cognoscere causas.
Lucky is he who has been able to understand the causes of things.
Virgil
-------------------------------
"Noli sinere nothos te opprimere"

Dr. Don Latham, AJ7LL
Six Mile Systems LLC, 17850 Six Mile Road
Huson, MT, 59846
mailing address:  POBox 404
Frenchtown MT 59834-0404

VOX 406-626-4304
CEL 406-241-5093
Skype: buffler2
www.lightningforensics.com
www.sixmilesystems.com





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