[time-nuts] End-of-Range: Oscilloquartz OCXO 8600-3

Bob kb8tq kb8tq at n1k.org
Fri Dec 8 16:25:14 EST 2017


Hi

The early HP’s (anything before the 10811 would not have had SC’s in them. 
Depending on this or that they either had AT’s or BT’s. 

Bob

> On Dec 8, 2017, at 4:06 PM, Jeremy Nichols <jn6wfo at gmail.com> wrote:
> 
> My HP-103AR is low (the 1 MHz output reads 0.999 999 200 MHz) with the fine
> frequency adjust turned to maximum. I'm a rank amateur at this but the
> circuit diagram looks like a series-resonant (Pierce) oscillator. Looks
> like I need to replace one of the capacitors inside the oven with a smaller
> value.
> 
> 
> On Fri, Dec 8, 2017 at 12:40 PM Bob kb8tq <kb8tq at n1k.org> wrote:
> 
>> Hi
>> 
>> One basic question - Is the frequency high or low?
>> 
>> Assuming it’s an SC and on the lower turn, frequency low is possible
>> with an off temperature oven. Frequency high is unlikely unless it’s *way*
>> off temperature. How far off turn gives you how much delta F depends on
>> the inflection temperature of the crystal. It matters if it’s a “true
>> SC”or a
>> “modified SC”….. If it is a true SC and running at 80C, that’s about 10
>> degrees
>> below inflection. There will not be a lot of frequency change in that case.
>> 
>> Many (but not all) modern crystal processes tend to age positive. If that
>> is the
>> case on these parts, a frequency high is the likely outcome of “age out of
>> range”.
>> Even with a process that has a known tendency, only about 70% of them go
>> that direction over long periods of time. It’s not a perfect thing ….
>> 
>> Bob
>> 
>>> On Dec 8, 2017, at 2:34 PM, Angus <not.again at btinternet.com> wrote:
>>> 
>>> 
>>> The 8601 that I have was about 2 deg C off turnover when I got it, but
>>> I can't remember what sort or frequency error that caused. The
>>> temperature coefficient was terrible with that error.
>>> 
>>> Angus.
>>> 
>>> 
>>> On Fri, 8 Dec 2017 13:05:14 +0000 (UTC), you wrote:
>>> 
>>>> 
>>>> Gentlemen,
>>>> We have an Oscilloquartz OCXO 8600-3that cannot any longer be adjusted
>> into 5,000,000 Hz.It is about 1 Hz out of 5 MHz and turning
>> coarse/fineadjustment potentiometers cannot bring the frequencyinto its
>> specification.
>>>> Oven temperature is about + 80C accordingto the thermistor and the
>> operating voltageis at 24 VDC.
>>>> Have Googled but the only thing that turns upis datasheets w/o any
>> details.
>>>> Before I take it apart and start lookingfor obviously broken
>> components, isthere anyone that has a CLIP on this unit?
>>>> 73
>>>> 
>>>> Ulf Kylenfall - SM6GXV
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> -- 
> Sent from my iPad 4.
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