[time-freq] TADD-1 Question

[Matt Osborn]

Thanks for the advice, John,  it's exactly what I was looking for.

The TADD-1 is up and running; everything looks fine.

Thanks for the low cost solution to a high cost problem!  I appreciate
your efforts in designing, implementing and distributing the TADD-1.


On Sat, 14 Apr 2007 17:05:14 -0400, John Ackermann N8UR <jra at febo.com>
wrote:

>Hi Matt --
>
>The most important advice first (for the benefit of others who might
>read this):  Only build the bandpass filter if you know you need it!
>The vast majority of applications don't require it.  The only time it
>might be of value is if you have a source that outputs square waves and
>have a device (like a receiver) that needs a sinewave input; most test
>equipment is quite happy with a non-sine input.
>
>The bandpass filter will result in increased temperature sensitivity,
>because any tuned ciruit is a thermometer!  So, don't install it unless
>you really have a need for it.
>
>The TADD enclosure is designed as a "universal" box for all the TADD
>units.  The TADD-3, which is a digital distribution board designed to
>take one PPS signal and provide multiple outputs, has an option to drive
>serial ports, so the DB-9 cutouts are for that use.
>
>73,
>John
>----
>
>Matt Osborn said the following on 04/14/2007 04:55 PM:
>> No need to ship the part, John, I have a replacement part here. My
>> main concern was to take advantage of the experience of others.
>> 
>> I discovered the enclosure you've made available today while exploring
>> the TAP web site.  I see what appear to be two DB9 holes punched in
>> the back panel.  Are there some expansion options available that I
>> haven't found yet?
>> 
>> I don't think I'll need the bandpass filter as my source is an Isotemp
>> OCXO 10MHz oscillator disciplined with Brooks Shera's board.  While I
>> can build these things, my knowledge level is insufficient to design
>> them.  So what do you think of the bandpass filter?
>> 
>> On Sat, 14 Apr 2007 16:27:31 -0400, John Ackermann N8UR <jra at febo.com>
>> wrote:
>> 
>>> Hi Matt --
>>>
>>> Sorry about the missing part!  If you'd like, I can send you the 0.33uF
>>> tantalum.
>>>
>>> The data sheet for the 78XX series regulators shows the 0.33 cap on the
>>> input, but doesn't specify what type it must be, so I think you're OK
>>> using a ceramic or other non-polarized cap.  We ended up using a
>>> tantalum cap for the production units because it's what we had in stock. :-)
>>>
>>> 73,
>>> John
>>> ----
>>>
>>> Matt Osborn said the following on 04/14/2007 04:08 PM:
>>>> I received my TADD-1 kit this morning and found that capacitor C40
>>>> (.33ufd) was missing.  The silkscreen has this as non-polarized, but
>>>> the documentation says that it is polarized.
>>>>
>>>> From the circuit, it doesn't appear to matter what type of capacitor
>>>> is used but before I plug something in from my junk box, I thought I'd
>>>> better ask why C40 was changed from non-polarized and just what kind
>>>> of polarized capacitor would be best.
>>>>
>>>> Thanks for the help.
>>>>
>>>> -- kc0ukk at msosborn dot com
>>>>
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>>>
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>> 
>> -- kc0ukk at msosborn dot com
>> 
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>
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-- kc0ukk at msosborn dot com