[time-nuts] Loran C back on
Rich and Marcia Putz
rputz at bnin.net
Mon Apr 30 00:26:50 UTC 2012
Hi all;
Receiving Wildwood NJ GRI 8970 here in northern Indiana again today.
FYI
Rich
----- Original Message -----
From: <time-nuts-request at febo.com>
To: <time-nuts at febo.com>
Sent: Sunday, April 29, 2012 8:21 PM
Subject: time-nuts Digest, Vol 93, Issue 152
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> Today's Topics:
>
> 1. Re: Wilkinson TDC (David)
> 2. Re: General Technology Corp model 304b (paul swed)
> 3. Re: Antique Rb Standard - Thanks, Pictures, Parts Request,
> Question (Magnus Danielson)
> 4. Re: General Technology Corp model 304b (Ed Palmer)
> 5. Re: Antique Rb Standard - Thanks, Pictures, Parts Request,
> Question (Cliff Sojourner)
> 6. Re: PICDIV for 1 min pulses (Bob Camp)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Sun, 29 Apr 2012 18:17:10 -0500
> From: David <davidwhess at gmail.com>
> To: Discussion of precise time and frequency measurement
> <time-nuts at febo.com>
> Subject: Re: [time-nuts] Wilkinson TDC
> Message-ID: <mr9rp7lgruccve3eaq954sr1og26575ktl at 4ax.com>
> Content-Type: text/plain; charset=us-ascii
>
> On Mon, 30 Apr 2012 06:51:37 +1200, Bruce Griffiths
> <bruce.griffiths at xtra.co.nz> wrote:
>
>>The circuit for the Tek 2440 is in the manual.
>>However, it isnt that well executed.
>
> I like using the 2440 as an example because the design and theory are
> readily available online. Its execution only had to be good enough
> for 40ps equivalent time sampling and less than 50 measurements per
> second. Unfortunately the self calibration logic is obfuscated inside
> of a Tektronix black box custom ASIC.
>
>>Relying on the overload recovery of an unclamped jfet input opamp limits
>>the recovery time and performance as does the unisolated input
>>capacitance of the opamps used to control the current source transistor
>>emitter currents, the Wavecrest interpolators which incorporate several
>>refinements to improve the transient response of the current sources are
>>far better in this respect.
>
> By unclamped JFET input opamps do you mean U590B and U590C which are
> used to adjust the ramp start to zero volts and operate open loop
> during the measurement? With such a slow measurement rate, that
> feedback loop has at least 20ms to complete settling. I notice that
> they attenuated the open loop gain by a factor of 6. I wonder if that
> was to lower the noise or to add phase margin to the control loop.
>
>>The Wavecrest interpolators also have sub picosecond resolution although
>>their noise is around 3-6ps.
>
> Is there a published schematic and theory for the Wavecrest other than
> the patent? The best information I have found through Google is from
> your own posts here.
>
>>
>>Bruce
>>
>>paul swed wrote:
>>> Do you have an actual circuit?
>>> It looks a lot like the old hp5360 counter interpolator.
>>> Regards
>>> Paul
>>>
>>> On Sun, Apr 29, 2012 at 3:51 AM, Bruce
>>> Griffiths<bruce.griffiths at xtra.co.nz
>>>
>>>> wrote:
>>>>
>>>
>>>> The essentials of a Wikinson TDC can be simplified to the attached
>>>> circuit
>>>> which only requires the addition of a zero crossing comparator to
>>>> monitor
>>>> the voltage across the capacitor C1.
>>>>
>>>> A few refinements to improve the capacitor charging current switching
>>>> transitions and the addition of an upper voltage clamp together with
>>>> the
>>>> use of faster transistors may be useful.
>>>>
>>>> Apart from level shifting to drive the npn and pnp longtailed pairs
>>>> only a
>>>> 2 bit shift register is required for the synchronisers reducing the
>>>> number
>>>> of external (to an FPGA or CPLD) logic packages required.
>>>> The jitter of the count logic etc., isn't critical and can be
>>>> implemented
>>>> in an FPGA or CPLD.
>>>>
>>>> With a 100MHz synchroniser and counter clock a resolution of 10ps can
>>>> be
>>>> achieved with a 1000:1 ratio between charge and discharge currents.
>
>
>
> ------------------------------
>
> Message: 2
> Date: Sun, 29 Apr 2012 19:18:13 -0400
> From: paul swed <paulswedb at gmail.com>
> To: Discussion of precise time and frequency measurement
> <time-nuts at febo.com>
> Subject: Re: [time-nuts] General Technology Corp model 304b
> Message-ID:
> <CAD2JfAi67wi3c9Ea4p+Qcx=daowx-28JNAuw_q5cA_ZY+TDr=Q at mail.gmail.com>
> Content-Type: text/plain; charset=ISO-8859-1
>
> Curious is the manual online?
> Would be interesting to look at.
>
> On Sun, Apr 29, 2012 at 6:33 PM, Ed Palmer <ed_palmer at sasktel.net> wrote:
>
>> Hi Don,
>>
>> On 4/29/2012 2:54 PM, Donald Henderickx wrote:
>>
>>> On 4/29/2012 1:36 PM, Ed Palmer wrote:
>>>
>>> Thank you Ed,Paul,and Marco for the reply's
>>> The foam I was referring to is or was around ceramic base were the
>>> igniter wire goes . Yes my wire also broke loose however I do not want
>>> to
>>> disassemble any more than I have to. I think that just inserting it back
>>> in
>>> to the hole and securing in some way should work. I do not know what the
>>> potential is but I have seen a spark jump at least an eight of an inch.
>>>
>>
>> The igniter wire has to be connected to the base of the lamp. The patent
>> explains it quite well. Just inserting it into the hole in the ceramic
>> is
>> unlikely to work. I don't know what the voltage is, but the capacitor
>> that
>> stores the voltage is rated for 400V.
>>
>> Does the foam look original? It definitely isn't on mine so I wasn't
>> sure
>> if it was supposed to be there or not. The patent describes how the base
>> is the coolest part of the bulb. I don't know if a foam covering is
>> appropriate.
>>
>> Tell me about the lamp voltage test point. My manual has no mention of
>>> it? Were is it located?
>>>
>>
>> All the test points are described on page 5-3 of the manual. The lamp
>> heater test point is the sixth one from the top. Ground is the seventh
>> point.
>>
>> In you first posting I think you mentioned some grounding problems. On
>>> this unit there is a three pin amp connector on the rear on mine the
>>> bottom
>>> pin -20 must be grounded or the unit will not work. The red light will
>>> come
>>> on very bright but nothing else works.I believe you can also ground the
>>> +20
>>> this allows this to work in various ground polarity systems IE telco
>>> systems +ground. Perhaps I am wrong.
>>>
>>
>> Do you mean the 3 pin round connector on the back? That's for an
>> external
>> DC power supply. It has no other function and grounding the bottom pin
>> (which is ground) shouldn't make any difference.
>>
>> Ed
>>
>>
>> I have Hp113,Hp115 that caution you on the ground polarity of the
>> systems
>>> you are installing them in. I think all the -20 floats from chassis
>>> ground
>>> until they get to that rear plug.
>>> Thanks for foam an fiberglass suggestions.
>>>
>>>> Hi Don,
>>>>
>>>> You know that we're going to be swapping many emails, don't you? :-)
>>>>
>>>> On 4/29/2012 11:16 AM, Donald Henderickx wrote:
>>>>
>>>>> After following Ed Palmer's thread on 304b restoration,I was inspired
>>>>> to get my GTC (tracor) 304b ser#279 going. It seems that the failure
>>>>> of
>>>>> this unit was the break down of the foam that was wrapped around the
>>>>> vcxo
>>>>> located inside the control box. The vapors or the moisture the foam
>>>>> collected corroded the steel fasteners and caused the switches to
>>>>> become
>>>>> intermittent.
>>>>>
>>>>
>>>> The foam around my OCXO is still in great shape. Still spongy and
>>>> providing lots of holding force for the OCXO. My unit is serial #449.
>>>>
>>>> The replacement of the foam in the control box is not that much of a
>>>>> problem,what I need help with is what to use around the Rb lamp base.
>>>>> The
>>>>> foam has turned to powder.
>>>>>
>>>>
>>>> Do you mean foam around the back end of the lamp where the wire lead
>>>> comes out or the foam that surrounds the reflector (#16 in the picture
>>>> in
>>>> the patent that describes the lamp (3311775))? My #16 foam is really
>>>> solid.
>>>>
>>>> Should I try Home foam sealant? The cell's ,of this seem about the
>>>> same
>>>>> as the old foam.Will it take the heat?Should I make a fiberglass
>>>>> cocoon to
>>>>> put around the lamp base.
>>>>>
>>>>
>>>> Read the fine print on the can. It may list the maximum temperature
>>>> rating. I'd try a fiberglass cocoon first just because it's easily
>>>> reversible if it doesn't work. When your unit is running is the lamp
>>>> test
>>>> point voltage correct?
>>>>
>>>> Ed
>>>>
>>>> The unit now achieves lock in about an hour. The only other thing I
>>>> did
>>>>> was to replace the caps in the main supply.
>>>>> Any thoughts on the insulation?
>>>>> Don H
>>>>>
>>>>
>> ______________________________**_________________
>> time-nuts mailing list -- time-nuts at febo.com
>> To unsubscribe, go to https://www.febo.com/cgi-bin/**
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>> and follow the instructions there.
>>
>
>
> ------------------------------
>
> Message: 3
> Date: Mon, 30 Apr 2012 01:21:24 +0200
> From: Magnus Danielson <magnus at rubidium.dyndns.org>
> To: time-nuts at febo.com
> Subject: Re: [time-nuts] Antique Rb Standard - Thanks, Pictures, Parts
> Request, Question
> Message-ID: <4F9DCCF4.3090601 at rubidium.dyndns.org>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>
> Hi Ed,
>
> On 04/29/2012 05:46 PM, Ed Palmer wrote:
>> Hi Magnus,
>>
>>>> Second, pictures. If anyone is interested, check out
>>>> http://s701.photobucket.com/albums/ww18/edpalmer42/Tracor%20304-B/ .
>>>
>>> Nice photos. Thanks. GAS building up.
>>
>> What does GAS mean?
>
> Gear Acquisition Syndrome.
>
> GAS is a diagnose which I think no time-nut would admit to. ;-)
>
>>>> that talks about cavities in general, but the calculations don't work.
>>>> I'm guessing that the Rb cell is changing the resonant frequency of the
>>>> cavity.
>>>
>>> The glass pulls the cavity resonance somewhat, yes. A TE111 resonance
>>> mode is typically used, allowing light to enter and leave at the ends
>>> of the cylinder.
>>>
>>> TE011 was used before, but it much larger.
>>>
>>> Todays modern cells use a "loaded" cell (dielectrum added) to move the
>>> resonance frequency down, which allows much smaller physical cells.
>>
>> This unit is TE011 No dielectric, plain brass - not silver-plated, 2.495
>> inch diameter @ room temperature, length tunable from ~0.9 to 1.07
>> inches.
>
> Not surprising, and actually I think I've read that during the day.
>
>>> W.J.Riley "Rubidium Frequency Standard Primer" is a good
>>> starting-point, but following the references should help.
>>>
>>> I think just searching for "TE111 mode rubidium" cranks out a few
>>> interesting things, such as:
>>>
>>> http://dspace.thapar.edu:8080/dspace/bitstream/10266/968/1/Satyendr_Thesis.pdf
>>>
>>>
>> Thanks for that link. I have been searching, but it's like panning for
>> gold - lots of sand and dirt and a very few nuggets of gold.
>
> Indeed. I have a few more hints on where it can be worth panning, as I
> have gathered a few books on the subject.
>
> Reading Riley's book (as I mentioned above) today has given much more
> body to the subject. Learning things quickly. While his book isn't heavy
> on the deep stuff, he summarize it so you get an overview and then gives
> several hundreds of references.
>
> Cheers,
> Magnus
>
>
>
> ------------------------------
>
> Message: 4
> Date: Sun, 29 Apr 2012 17:27:04 -0600
> From: Ed Palmer <ed_palmer at sasktel.net>
> To: Discussion of precise time and frequency measurement
> <time-nuts at febo.com>
> Subject: Re: [time-nuts] General Technology Corp model 304b
> Message-ID: <4F9DCE48.3010705 at sasktel.net>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>
> Yes, there's a partial copy of the manual online. It's missing a few
> schematics, but is otherwise complete.
>
> http://sundry.i2phd.com/ServiceManual_304b.pdf
>
> Ed
>
>
> On 4/29/2012 5:18 PM, paul swed wrote:
>> Curious is the manual online?
>> Would be interesting to look at.
>>
>> On Sun, Apr 29, 2012 at 6:33 PM, Ed Palmer<ed_palmer at sasktel.net> wrote:
>>
>>> Hi Don,
>>>
>>> On 4/29/2012 2:54 PM, Donald Henderickx wrote:
>>>
>>>> On 4/29/2012 1:36 PM, Ed Palmer wrote:
>>>>
>>>> Thank you Ed,Paul,and Marco for the reply's
>>>> The foam I was referring to is or was around ceramic base were the
>>>> igniter wire goes . Yes my wire also broke loose however I do not want
>>>> to
>>>> disassemble any more than I have to. I think that just inserting it
>>>> back in
>>>> to the hole and securing in some way should work. I do not know what
>>>> the
>>>> potential is but I have seen a spark jump at least an eight of an inch.
>>>>
>>> The igniter wire has to be connected to the base of the lamp. The
>>> patent
>>> explains it quite well. Just inserting it into the hole in the ceramic
>>> is
>>> unlikely to work. I don't know what the voltage is, but the capacitor
>>> that
>>> stores the voltage is rated for 400V.
>>>
>>> Does the foam look original? It definitely isn't on mine so I wasn't
>>> sure
>>> if it was supposed to be there or not. The patent describes how the
>>> base
>>> is the coolest part of the bulb. I don't know if a foam covering is
>>> appropriate.
>>>
>>> Tell me about the lamp voltage test point. My manual has no mention of
>>>> it? Were is it located?
>>>>
>>> All the test points are described on page 5-3 of the manual. The lamp
>>> heater test point is the sixth one from the top. Ground is the seventh
>>> point.
>>>
>>> In you first posting I think you mentioned some grounding problems. On
>>>> this unit there is a three pin amp connector on the rear on mine the
>>>> bottom
>>>> pin -20 must be grounded or the unit will not work. The red light will
>>>> come
>>>> on very bright but nothing else works.I believe you can also ground the
>>>> +20
>>>> this allows this to work in various ground polarity systems IE telco
>>>> systems +ground. Perhaps I am wrong.
>>>>
>>> Do you mean the 3 pin round connector on the back? That's for an
>>> external
>>> DC power supply. It has no other function and grounding the bottom pin
>>> (which is ground) shouldn't make any difference.
>>>
>>> Ed
>>>
>>>
>>> I have Hp113,Hp115 that caution you on the ground polarity of the
>>> systems
>>>> you are installing them in. I think all the -20 floats from chassis
>>>> ground
>>>> until they get to that rear plug.
>>>> Thanks for foam an fiberglass suggestions.
>>>>
>>>>> Hi Don,
>>>>>
>>>>> You know that we're going to be swapping many emails, don't you? :-)
>>>>>
>>>>> On 4/29/2012 11:16 AM, Donald Henderickx wrote:
>>>>>
>>>>>> After following Ed Palmer's thread on 304b restoration,I was inspired
>>>>>> to get my GTC (tracor) 304b ser#279 going. It seems that the failure
>>>>>> of
>>>>>> this unit was the break down of the foam that was wrapped around the
>>>>>> vcxo
>>>>>> located inside the control box. The vapors or the moisture the foam
>>>>>> collected corroded the steel fasteners and caused the switches to
>>>>>> become
>>>>>> intermittent.
>>>>>>
>>>>> The foam around my OCXO is still in great shape. Still spongy and
>>>>> providing lots of holding force for the OCXO. My unit is serial #449.
>>>>>
>>>>> The replacement of the foam in the control box is not that much of a
>>>>>> problem,what I need help with is what to use around the Rb lamp base.
>>>>>> The
>>>>>> foam has turned to powder.
>>>>>>
>>>>> Do you mean foam around the back end of the lamp where the wire lead
>>>>> comes out or the foam that surrounds the reflector (#16 in the picture
>>>>> in
>>>>> the patent that describes the lamp (3311775))? My #16 foam is really
>>>>> solid.
>>>>>
>>>>> Should I try Home foam sealant? The cell's ,of this seem about the
>>>>> same
>>>>>> as the old foam.Will it take the heat?Should I make a fiberglass
>>>>>> cocoon to
>>>>>> put around the lamp base.
>>>>>>
>>>>> Read the fine print on the can. It may list the maximum temperature
>>>>> rating. I'd try a fiberglass cocoon first just because it's easily
>>>>> reversible if it doesn't work. When your unit is running is the lamp
>>>>> test
>>>>> point voltage correct?
>>>>>
>>>>> Ed
>>>>>
>>>>> The unit now achieves lock in about an hour. The only other thing I
>>>>> did
>>>>>> was to replace the caps in the main supply.
>>>>>> Any thoughts on the insulation?
>>>>>> Don H
>
>
>
> ------------------------------
>
> Message: 5
> Date: Sun, 29 Apr 2012 16:36:22 -0700
> From: Cliff Sojourner <cls at employees.org>
> To: time-nuts at febo.com
> Subject: Re: [time-nuts] Antique Rb Standard - Thanks, Pictures, Parts
> Request, Question
> Message-ID: <4F9DD076.2070809 at employees.org>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>
> On 2012-04-29 16:21, Magnus Danielson wrote:
>> Hi Ed,
>>
>> On 04/29/2012 05:46 PM, Ed Palmer wrote:
>>> Hi Magnus,
>>>
>>>>> Second, pictures. If anyone is interested, check out
>>>>> http://s701.photobucket.com/albums/ww18/edpalmer42/Tracor%20304-B/ .
>>>>
>>>> Nice photos. Thanks. GAS building up.
>>>
>>> What does GAS mean?
>>
>> Gear Acquisition Syndrome.
>>
>> GAS is a diagnose which I think no time-nut would admit to. ;-)
>
> hey GAS happens to musicians too. the reason I have 12 guitars is
> because I have really held back on buying more. anyways the wife has
> three guitars and 4 keyboards, my daughter has two pianos and three
> flutes and two piccolos.
>
> let's not talk about my radios :)
>
>
>
>
>
> ------------------------------
>
> Message: 6
> Date: Sun, 29 Apr 2012 20:20:54 -0400
> From: Bob Camp <lists at rtty.us>
> To: Discussion of precise time and frequency measurement
> <time-nuts at febo.com>
> Subject: Re: [time-nuts] PICDIV for 1 min pulses
> Message-ID: <C59777C6-8676-4ACA-93C2-CCFC372BC06C at rtty.us>
> Content-Type: text/plain; charset=us-ascii
>
> Hi
>
> The problem is a bit more complex than simply getting a pulse at the
> second / minute. At least back when I last got into this - the pulses need
> to be the proper width. In some cases you need pairs of pulses in the
> right order.
>
> Simple solution - feed the Rb 10 MHz into the clock input on a PIC (or
> what ever) and write some simple code to generate exactly what is needed
> for the specific stepper or escarpment. Since the Rb is a power hog
> there's no advantage to low power in this case. For the 5680's you need
> some outboard "stuff" anyway. Just drop the PIC onto the board with the +5
> regulator and DB-9 connector on it.
>
> Bob
>
> On Apr 28, 2012, at 6:29 PM, Magnus Danielson wrote:
>
>> Fellow time-nuts (and Tom in particular),
>>
>> I am now seeing the effects of the article a few days earlier. At least
>> two friends wants to play around. One of my friends wants to drive a
>> classic clock from a rubidium. I recommended him to take a look at the
>> PICDIV and he kind of liked it.
>>
>> So, he would need a minute pulse and a second pulse. Wouldn't it be sweet
>> if the PICDIV was able to crank out these pulses?
>> As I recall from his brief discussion, there is two styles of
>> clock-drive.
>>
>> I thought that this would be a little inspirational to others, so
>> therefore I toss it to the list than just Tom.
>>
>> Cheers,
>> Magnus
>>
>> _______________________________________________
>> time-nuts mailing list -- time-nuts at febo.com
>> To unsubscribe, go to
>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>> and follow the instructions there.
>
>
>
>
> ------------------------------
>
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> End of time-nuts Digest, Vol 93, Issue 152
> ******************************************
>
>
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