[time-nuts] Heathkid - New time-nut needs help...

Steve Rooke sar10538 at gmail.com
Tue Jul 27 14:53:48 UTC 2010


Kia Ora Brice,

On 27/07/2010, Heathkid <heathkid at heathkid.com> wrote:

> Yes, the FEI 5680A's I got are programmable from 1Hz to 20MHz (SMA output /
> currently set to 10MHz) plus has the RS232 for programming and one of those
> pins (besides the Rb lock pin that goes low and I've got a LED on it) has
> the 1pps.  Besides the "C" field potentiometer it also has a 0 to 5V fine
> tune voltage.  The slowest of the three takes only about 4 seconds to
> achieve Rb lock.  Here are the exact units I got (and "flyingbest" is a
> great and honest seller):
> http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=180435915714

Not the cheapest I have seen but at least you have a full kit and they
are the programmable ones. What's the PSU like, how good is the
regulation on it as this will have a factor on how clean the output
is. Monitor the voltage at startup right through to it running stable
and see if it changes. There seems to be no requirement for +5V for
programming the device in the listing you quote but others have
indicated that this needs to be connected to pin 4 of the DB-9. That
being said, the info I have,
http://www.mail-archive.com/time-nuts@febo.com/msg01569.html, does not
show a C field adjustment on pin 8. The SMA connector looks like it
has been retrofitted IMHO so it would be interesting to pop the hood
and look for any mods done by the seller.

> The Thunderbolt I bought from fluke.l as he seems to be the "TBolt seller of
> choice" around here.  I also got the LCD display option (looks like fun to
> see what it's doing when not connected to a PC).

Yes, I'm yet to get one of those LCD displays although there is quite
a discussion thread on these in the archives and you can see the
background to this. Before you put the LCD display on for long term
use, I suggest you run it with Lady Heather to see how it it is
tracking sats and stabilising. The tuning of the PLL constants is the
subject of quite a few threads in the archives so you can learn a lot
from that. Once your happy that it's running fine, connect the LCD
display but I'd run it for a few weeks before you get to that stage as
the ocxo will have been sitting on the shelf cold and you want to see
how that is shaping up (this will take months before the xo really
beds in). You should also keep an eye on it continuing to track sats
as some people have found that their TB's have completely lost the
plot at times. When you first start it up it won't know what the heck
is going on as the location it was last running will be internally
stored and it will be looking for sats in the sky and not seeing them.
You should make sure it does a survey straight away so that sanity is
restored and/or you can enter your exact location of the antenna if
you know that.

I don't know your location but you should make sure that your antenna
is located in a good position where it has a good sight to the south
and look out for multipath reception, trees, buildings, etc. but your
a ham anyway and must be in a good position to fix it up as your doing
QRP.

> Okay, so today... I bought a "real" frequency counter.  After a LOT of
> looking and reading... I chose a HP 5335A.  It has option 10 (Oven
> Oscillator) and 030 (C Channel 1.3 GHz ) plus the HPIB plus math and
> statistics functions standard and includes operating and service manuals on
> CD.  It'll also be calibrated just prior to shipping to me (current Date Due
> 03/19/11) but it will be re-calibrated just for me so at least I know it'll
> work and if there is a problem, I can return it.  :)

Well, that's a nice purchase and I'm sure it will serve you well.

> So, now I have the following (when the rest shows up):
>
> (3) FEI 5680A Programmable Rubidium Frequency Standards w/ 1pps
> (1) Thunderbolt "Complete Kit" w/ LCD display - from fluke.l
> (1) HP 5335A Universal Counter w/ Options 10 (Oven Oscillator) & 030 (C
> Channel 1.3 GHz)

Well, that's a start, or should I say, the slippery slope :) You'll
have a good setup with this and have a decent frequency standard for
your lab equipment. You can program those 5680A's to output directly
on some of the HF bands and have a Rb controlled QRP rig :)

> Hopefully, Stanley got my payment for the PICTIC II boards and I got an
> email back from Bob about getting me on the list for the programmed PICs.

All you need now is a DMTD and you'll be in a good position to things
like ADEV measurements on your sources. As the Rbs are not great at
close-in ADEV, it would be worth while looking for the dual-oven HP
10811.

> That's where I'm at right now.

Well, your doing OK.

73 de Steve ZL3TUV & G8KVD

> 73 Brice KA8MAV
>
>
>
> ----- Original Message -----
> From: "Steve Rooke" <sar10538 at gmail.com>
> To: "Discussion of precise time and frequency measurement"
> <time-nuts at febo.com>
> Sent: Monday, July 26, 2010 7:54 AM
> Subject: Re: [time-nuts] Symmetricom X72
>
>
>> Yes, it's because of the various types that you need to verify exactly
>> what you have. A number of them are made to customer specifications
>> with undocumented option numbers but if you have anything like an
>> option 8 then you have the 1Hz to 20MHz version. Beware that to
>> program the thing you need to provide +5V as well as the +15V to run
>> it. Along with the output options, there are a slew of options on such
>> things as ageing and temperature stability. If you have one from a
>> telecom's cellular tower, it's likely to be of higher spec.
>>
>> Steve
>>
>> On 26/07/2010, Bob Camp <lists at rtty.us> wrote:
>>> Hi
>>>
>>> One issue with the FE's is they often show up as conversions. Various
>>> sellers take the 1 pps version and hack in a 10 MHz output. There is a
>>> lot
>>> of room for error in the conversion process.
>>>
>>> Bob
>>>
>>>
>>>
>>> On Jul 26, 2010, at 7:06 AM, Steve Rooke <sar10538 at gmail.com> wrote:
>>>
>>>> Brice,
>>>>
>>>> On 26/07/2010, Heathkid <heathkid at heathkid.com> wrote:
>>>>> Last night, as suggested by several people on this list... I ordered a
>>>>> Trimble Thunderbolt from Bob Mokia, fluke.l so I should be in pretty
>>>>> good
>>>>> shape there to get started once it arrives.
>>>>
>>>> Sounds like your starting on the long path to time-nuttiness :) Bob
>>>> has supplied a lot of stuff to people on this list and he will look
>>>> after you if anything is amiss.
>>>>
>>>>> The counter I mentioned (it's a DFD4 - modified with the tcxo as the
>>>>> "a"
>>>> ...
>>>>> anyway).  :)  By the way, when I built it, I calibrated it by zero
>>>>> beating
>>>>> against WWV at 10 and 20 MHz.  That was the best way I had at the time
>>>>> and
>>>>> if the DFD4 is now 7 Hz off after all these years... it's not doing so
>>>>> bad
>>>>> (based on it's limitations).
>>>>
>>>> Not bad considering it's a TCXO.
>>>>
>>>>> So... that's what that counter is for and not for what I'm doing now.
>>>>> I'm
>>>>> currently looking for a nice/used HP counter.  Please don't think I'm
>>>>> going
>>>>> to use the DFD4 for measuring my Rb standards.  It's a wonderful
>>>>> counter
>>>>> for
>>>>> what it was designed for and that's it.
>>>>
>>>> Dependant upon what your looking for in a counter, you could broaden
>>>> your choices as there are other useful counters out there that may be
>>>> more affordable but still as good. Try looking for a Racal-Dana 1992,
>>>> preferably with the high stability option timebase (although these
>>>> turn up seperately anyway and are a doddle to fit). It makes a nice
>>>> footprint 1ns counter and can be referenced to your T'Bolt.
>>>>
>>>>> I'm not giving up on the FEI's anytime soon.  I understand now that
>>>>> along
>>>>> with the Trimble Thunderbolt (and a decent counter) I'll be on my way
>>>>> to
>>>>> "getting started".
>>>>
>>>> You'll have to see if those FEI's are the programmable types which can
>>>> be set to produce frequencies up to 20MHz. Do they have jut the D'Sub
>>>> connector or have an RF connector as well. There are different
>>>> variants of these produced by FEI under the same product code.
>>>>
>>>> 73 de Steve ZL3TUV & G8KVD
>>>>
>>>>> 73 Brice KA8MAV
>>>>>
>>>>>
>>>>> ----- Original Message -----
>>>>> From: "Steve Rooke" <sar10538 at gmail.com>
>>>>> To: "Discussion of precise time and frequency measurement"
>>>>> <time-nuts at febo.com>
>>>>> Sent: Sunday, July 25, 2010 8:40 AM
>>>>> Subject: Re: [time-nuts] Symmetricom X72
>>>>>
>>>>>
>>>>>> Excuse my replying to my own posting please.
>>>>>>
>>>>>> This post is really about the DFD1 frequency counter.
>>>>>>
>>>>>> Heathkid: You are comparing a Rb against a frequency counter with a
>>>>>> TCXO that you tweaked yourself to calibrate it against no known
>>>>>> frequency standard. Try running the three FEI-5660s for 24 hours and
>>>>>> then measure the output of each with your frequency counter. Pick the
>>>>>> mean of them and adjust your DFD1 to match that. At least you should
>>>>>> be in a better position than you are now.
>>>>>>
>>>>>> As you built the DFD1 yourself, you should have the schematic and may
>>>>>> be able to engineer in a connection for an external reference. There
>>>>>> is plenty of people here who would be happy to advise you on a
>>>>>> suitable interface if you can attach the part of the circuit where the
>>>>>> TCXO is located. If you do get a T'Both, you would be able to use it
>>>>>> as a reference or, perhaps, build in one of the FEI-5660s as an
>>>>>> internal reference. The limiting factor though is how good is the
>>>>>> circuit used in the DFD1 which will limit it's stability and accuracy.
>>>>>> There are many factors, including input circuit, voltage regulation,
>>>>>> counter stage design, level detection, etc. which have a major impact
>>>>>> here. What I'm getting at is that to write-off a bunch of FEI-5660s
>>>>>> after checking them with such a device as this, is a very poor
>>>>>> decision.
>>>>>>
>>>>>> Maybe you could look at a better counter on fleeBay before you make
>>>>>> further assumptions.
>>>>>>
>>>>>> 73,
>>>>>> Steve
>>>>>>
>>>>>> On 26/07/2010, Steve Rooke <sar10538 at gmail.com> wrote:
>>>>>>> Sage advice Bill!
>>>>>>>
>>>>>>> Heathkid, you don't need another Rb unit when you have 3 perfectly
>>>>>>> decent ones! You really need a standard to calibrate your Rb units
>>>>>>> to,
>>>>>>> a Trimble Thunderbolt is likely to be the cheapest choice for you.
>>>>>>> Bob
>>>>>>> Mokia, fluke.l, on fleeBay sells them separately or as a starter kit
>>>>>>> with everything there to get you going. Once you have this up and
>>>>>>> running for quite some time and see that things are looking stable in
>>>>>>> the Lady Heather application, then you can start to think about
>>>>>>> calibrating the FEI-5680's but only after you have run them in well.
>>>>>>> I
>>>>>>> don't know your counter but does it have an input for an external
>>>>>>> reference source? If so you will be able to use the T'Bolt as an
>>>>>>> external reference for it, providing the required reference is 10MHz.
>>>>>>> If it's not, you can divide down the T'Bolt's output to match. If
>>>>>>> your
>>>>>>> frequency counter has no reference input (apart from throwing it in
>>>>>>> the bin) you should be able to engineer it into the instrument,
>>>>>>> depending on your skill set.
>>>>>>>
>>>>>>> So, first get yourself a frequency standard to work with, IE. a
>>>>>>> T'Bolt
>>>>>>> or the like.
>>>>>>>
>>>>>>> My 2c worth,
>>>>>>> Steve
>>>>>>>
>>>>>>> On 25/07/2010, WB6BNQ <wb6bnq at cox.net> wrote:
>>>>>>>> To Bob and Stan (W1LE),
>>>>>>>> [p.s. But not just to you two alone]
>>>>>>>>
>>>>>>>>
>>>>>>>> Why complicate the answers to Heathkid (now Brice KA8MAV) with a
>>>>>>>> bunch
>>>>>>>> of
>>>>>>>> different directions that should only be decided after one gains
>>>>>>>> enough
>>>>>>>> knowledge and understanding (they are not the same) to properly
>>>>>>>> grasp
>>>>>>>> the
>>>>>>>> subject matter ? ? ? ?
>>>>>>>>
>>>>>>>> Clearly Heathkid needs some guidance.  The form should be to start
>>>>>>>> out
>>>>>>>> with
>>>>>>>> the very basics and get his feet on the ground.  He already has
>>>>>>>> three
>>>>>>>> (3)
>>>>>>>> Rb
>>>>>>>> sources that should keep him busy for quite some time.  However, his
>>>>>>>> counter
>>>>>>>> is really junk from a lab point of view.  Nonetheless, even it can
>>>>>>>> be
>>>>>>>> useful
>>>>>>>> if it is understood how to apply it after understanding its
>>>>>>>> limitations.
>>>>>>>>
>>>>>>>> What Heathkid needs to understand is it is not about equipment.  It
>>>>>>>> is
>>>>>>>> all
>>>>>>>> about how to measure and account for errors and unknowns.  Actually,
>>>>>>>> quite
>>>>>>>> a
>>>>>>>> daunting task depending upon the level of achievement.
>>>>>>>>
>>>>>>>> I agree he needs some kind of external reference and I agree the
>>>>>>>> Trimble
>>>>>>>> Thunderbolt (Tbolt) would be the right item for his true reference.
>>>>>>>> Even
>>>>>>>> the Tbolt has its issues that need to be understood.
>>>>>>>>
>>>>>>>> He will also need a method of comparison.   The oscilloscope is a
>>>>>>>> good
>>>>>>>> start
>>>>>>>> but very tedious.  Here Burt's project would help him a lot when
>>>>>>>> Burt
>>>>>>>> gets
>>>>>>>> it done.  I guess he is close.  I guess, also, the PICTIC II would
>>>>>>>> fit
>>>>>>>> the
>>>>>>>> bill after he understands what it is.
>>>>>>>>
>>>>>>>> Still he needs to understand how to apply and use this stuff.
>>>>>>>> Confusing
>>>>>>>> him
>>>>>>>> with suggesting all of the different Rb sources available is only
>>>>>>>> making
>>>>>>>> him
>>>>>>>> think a better one { relative statement } would be the answer which
>>>>>>>> is
>>>>>>>> not
>>>>>>>> true.  His FEI-5680's are so much better for his particular level,
>>>>>>>> it
>>>>>>>> is
>>>>>>>> not
>>>>>>>> even funny.
>>>>>>>>
>>>>>>>> What has not been asked of him is what are his goals and intentions.
>>>>>>>> If
>>>>>>>> it
>>>>>>>> is to just say you have an atomic frequency reference, then sit the
>>>>>>>> FEI-5680
>>>>>>>> on the coffee table; job done.  One cannot be properly guided if the
>>>>>>>> goals
>>>>>>>> are unknown.
>>>>>>>>
>>>>>>>> Bill....WB6BNQ
>>>>>>>>
>>>>>>>>
>>>>>>>> Bob Camp wrote:
>>>>>>>>
>>>>>>>>> Hi
>>>>>>>>>
>>>>>>>>> The only way to be sure of what's going on is to have several
>>>>>>>>> (hopefully)
>>>>>>>>> accurate references. With at least three you can begin to guess how
>>>>>>>>> good
>>>>>>>>> they are.
>>>>>>>>>
>>>>>>>>> The TBolt is different from the Rb in a couple of regards:
>>>>>>>>>
>>>>>>>>> 1) It's short term stability isn't as good when locked tightly to
>>>>>>>>> the
>>>>>>>>> GPS.
>>>>>>>>> 2) It's long term stability is much better than the Rb when it's
>>>>>>>>> locked.
>>>>>>>>> 3) It's easier to tell what's happening with it if you hook up a PC
>>>>>>>>> and
>>>>>>>>> the Lady Heather (free) program.
>>>>>>>>>
>>>>>>>>> The Rb will need a couple of things to make it play right:
>>>>>>>>>
>>>>>>>>> 1) It's got to have a pretty good heat sink on it. An 8 x 10" piece
>>>>>>>>> of
>>>>>>>>> 1/4" aluminum is a reasonable start
>>>>>>>>> 2) It's got to be run for a while (possibly 24 hours) before it
>>>>>>>>> will
>>>>>>>>> be
>>>>>>>>> stable
>>>>>>>>> 3) You need to watch the lock, and lamp voltages to be sure it's
>>>>>>>>> not
>>>>>>>>> doing
>>>>>>>>> something crazy.
>>>>>>>>>
>>>>>>>>> My recommendation based on cost is the Efratom LPRO for a cheap Rb.
>>>>>>>>> They
>>>>>>>>> are in the ~$60 range and seem to work pretty well.
>>>>>>>>>
>>>>>>>>> Setup wise, I would get a TBolt in addition to the Rb. You need
>>>>>>>>> something
>>>>>>>>> to calibrate the Rb (and your counter TCXO) against. Both are
>>>>>>>>> "secondary"
>>>>>>>>> standards. They (unlike a Cesium) are adjusted to match a known
>>>>>>>>> good
>>>>>>>>> reference.
>>>>>>>>>
>>>>>>>>> Once you have the Rb and the TBolt, next step is up to you. Cesium
>>>>>>>>> is
>>>>>>>>> always an alternative, so's a Hydrogen Maser ....
>>>>>>>>>
>>>>>>>>> Bob
>>>>>>>>>
>>>>>>>>> On Jul 24, 2010, at 3:32 PM, Heathkid wrote:
>>>>>>>>>
>>>>>>>>>> Hello Bob,
>>>>>>>>>>
>>>>>>>>>> What would you recommend?  I already have three FE-5680A Rb
>>>>>>>>>> standards
>>>>>>>>>> (which I'm quickly learning likely aren't worth the powder to blow
>>>>>>>>>> them
>>>>>>>>>> to (*insert your own word here*).  Okay, that was probably my
>>>>>>>>>> first
>>>>>>>>>> mistake (thoughts?).
>>>>>>>>>>
>>>>>>>>>> My frequency counter is one I built from a kit from aade.com that
>>>>>>>>>> has
>>>>>>>>>> the TCXO option (although I had to tweak it myself so I have NO
>>>>>>>>>> idea
>>>>>>>>>> how
>>>>>>>>>> close it is to any accuracy or precision).  I have access to some
>>>>>>>>>> really
>>>>>>>>>> nice HP counters at work so that's my next step is to try one of
>>>>>>>>>> those.
>>>>>>>>>> My DFD4 measured the output of one of my 5680A's to 10.000.007 MHz
>>>>>>>>>> after
>>>>>>>>>> about a 10 minute warm-up.  I don't know which one is off.
>>>>>>>>>> Reading
>>>>>>>>>> the
>>>>>>>>>> specs on the 5680A's before I bought them looked like they were
>>>>>>>>>> pretty
>>>>>>>>>> decent.  I'm learning...
>>>>>>>>>>
>>>>>>>>>> So, what "reasonably priced" Rb standard would you recommend?
>>>>>>>>>>
>>>>>>>>>> Should my next step in this process be a Trimble Thunderbolt?  Am
>>>>>>>>>> I
>>>>>>>>>> starting over?
>>>>>>>>>>
>>>>>>>>>> Thanks...
>>>>>>>>>>
>>>>>>>>>> ----- Original Message ----- From: "Bob Camp" <lists at rtty.us>
>>>>>>>>>> To: "Discussion of precise time and frequency measurement"
>>>>>>>>>> <time-nuts at febo.com>
>>>>>>>>>> Sent: Saturday, July 24, 2010 9:31 AM
>>>>>>>>>> Subject: Re: [time-nuts] Symmetricom X72
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>> Hi
>>>>>>>>>>>
>>>>>>>>>>> At least looking at the spec sheet it's not really very
>>>>>>>>>>> impressive.
>>>>>>>>>>>
>>>>>>>>>>> Bob
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> On Jul 23, 2010, at 11:06 PM, Heathkid wrote:
>>>>>>>>>>>
>>>>>>>>>>>> Hello.  Does anyone have any experience with the Symmetricom
>>>>>>>>>>>> X72?
>>>>>>>>>>>>
>>>>>>>>>>>> Thanks...
>>>>>>>>>>>>
>>>>>>>>>>>> _______________________________________________
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>>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> _______________________________________________
>>>>>>>>>>> time-nuts mailing list -- time-nuts at febo.com
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>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> _______________________________________________
>>>>>>>>>> time-nuts mailing list -- time-nuts at febo.com
>>>>>>>>>> To unsubscribe, go to
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>>>>>>>>>>
>>>>>>>>>
>>>>>>>>> _______________________________________________
>>>>>>>>> time-nuts mailing list -- time-nuts at febo.com
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>>>>>>>>
>>>>>>>> _______________________________________________
>>>>>>>> time-nuts mailing list -- time-nuts at febo.com
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>>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> --
>>>>>>> Steve Rooke - ZL3TUV & G8KVD
>>>>>>> The only reason for time is so that everything doesn't happen at
>>>>>>> once.
>>>>>>> - Einstein
>>>>>>>
>>>>>>
>>>>>>
>>>>>> --
>>>>>> Steve Rooke - ZL3TUV & G8KVD
>>>>>> The only reason for time is so that everything doesn't happen at once.
>>>>>> - Einstein
>>>>>>
>>>>>> _______________________________________________
>>>>>> time-nuts mailing list -- time-nuts at febo.com
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>>>>>> and follow the instructions there.
>>>>>
>>>>>
>>>>> _______________________________________________
>>>>> time-nuts mailing list -- time-nuts at febo.com
>>>>> To unsubscribe, go to
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>>>>> and follow the instructions there.
>>>>>
>>>>
>>>>
>>>> --
>>>> Steve Rooke - ZL3TUV & G8KVD
>>>> The only reason for time is so that everything doesn't happen at once.
>>>> - Einstein
>>>>
>>>> _______________________________________________
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>>>
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>>
>>
>> --
>> Steve Rooke - ZL3TUV & G8KVD
>> The only reason for time is so that everything doesn't happen at once.
>> - Einstein
>>
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-- 
Steve Rooke - ZL3TUV & G8KVD
The only reason for time is so that everything doesn't happen at once.
- Einstein



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