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

[jerry shirᴀr]

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
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