[time-nuts] 5 x 2 x 3 = 30 MHz

[KA2WEU at aol.com]

Yes, all about experience , Ulrich 
 
 
In a message dated 7/19/2015 9:46:17 A.M. Eastern Daylight Time,  
kb8tq at n1k.org writes:

Hi

There are an enormous number of variations on the basic  SC trap. Most of
what drives one to be “best” is the component selection  process. If a 
coil above
X uh simply will not fit, time for a new circuit  ….

Bob

> On Jul 19, 2015, at 12:53 AM, jerry shirᴀr  <radio.n9xr at gmail.com> wrote:
> 
> I am attaching a file  showing the schematic for the trap used in a 
Colpitts
> oscillator which  will look like 58pF at 5MHz and will be inductive at
> 5.5MHz.  So  something like this can be used in place of a pair of one of
> the split  capacitors at ~56pF loading the crystal.
> 
> Jerry N9XR
>  
> On Sat, Jul 18, 2015 at 11:59 AM, Magnus Danielson <
>  magnus at rubidium.dyndns.org> wrote:
> 
>> Dear  Ulrich,
>> 
>> Now you taught me something useful, that the  SC-cut has inherent less
>> noise than AT-cut. Many  thanks.
>> 
>> Indeed, measuring below 1 Hz starts to be  challenging as environmental
>> aspects chimes in. I assume you  ovenize your crystals, to make use of 
the
>> turn-over  point.
>> 
>> Even for ovens, (wind)shielding to reduce  thermal stress turns out to be
>> helpful. Some toss their  oscillators into thermal flasks too. As 
always, a
>> myriad off  issues creep up as you push the noise down and want to verify
>> it.  Thermal mass has proven useful in many ways. There was a nice  paper
>> from NIST where they used water-bottles to stabilize  WWVB.
>> 
>> Cheers,
>> Magnus
>>  
>> On 07/18/2015 11:52 AM, KA2WEU--- via time-nuts  wrote:
>> 
>>> Good morning,
>>>  
>>> the AT Cut is inherently noisier then the SC cut but the SC  has some
>>> spurious resonances  modes. Measurements below 1  Hz are very tricky as 
the
>>> oscillator must be (more or less)  insulated from hum, infrared (heater)
>>> .  Here  I
>>> am still struggling .
>>> 
>>>  Ulrich N1UL
>>> 
>>> 
>>> In a message  dated 7/17/2015 9:59:55 P.M. Eastern Daylight Time,
>>>  n1hac at dartmouth.edu writes:
>>> 
>>> He  doesn't  mention that that crystal is used in New Horizons:
>>>  
http://www.bliley.com/products/crystals-precision-standard/vacuum-sealed/
>>>  
>>> Nice.   I have a similar crystal from  Valpey-Fischer, 5 MHz 5th 
overtone
>>> AT-cut  (as opposed to  your 3rd overtone SC-cut).  I would be 
interested
>>>  in  what you would use for an oscillator circuit.
>>>  
>>> David N1HAC
>>> 
>>> 
>>>  On  7/17/15 4:27 PM, paul swed wrote:
>>>  
>>>> Ulrich,
>>>> Nice picture. What  are  you doing with the crystal? I have several 
older
>>>> crystals  that are  nice but have never done anything with  them.
>>>> Regards
>>>>   Paul
>>>> WB8TSL
>>>> 
>>>> On  Thu, Jul 16, 2015 at 6:02 PM, KA2WEU---  via  time-nuts
>>>> 
>>>  <time-nuts at febo.com
>>> 
>>>>   wrote:
>>>>> 
>>>>> I am working with this  ...... amazing device,  Ulrich N1UL
>>>>>   _______________________________________________
>>>>>  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.
>>>>>  
>>>>>    _______________________________________________
>>>> 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.
>>>> 
>>> 
>>>  _______________________________________________
>>>  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.
>>> 
>>>  _______________________________________________
>>> 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.
>>> 
>>>  _______________________________________________
>> 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.
>> 
> <5MHz  SC trap.png>_______________________________________________
>  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.

_______________________________________________
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.