[time-nuts] Wenzel VHF PLO Oscillators Off Frequency
kb8tq at n1k.org
Sun Nov 12 20:30:55 EST 2017
If it is a OCVCXO and it pulls > 50 ppm at 80 MHz, it’s got terrible phase noise close in.
That’s true with or without the PLL engaged.
> On Nov 12, 2017, at 7:46 PM, Mark Goldberg <marklgoldberg at gmail.com> wrote:
> Yes, exactly those. With no input, would they be expected to be 4 kHz off?
> The spec for the standard part wants the input to be within 1e-7. I would
> not expect them to be so far off free running.
> I saw 13 MHz on the 500-14273 and stayed away from those.
> Do you know of any part numbers that use 10 MHz in? Wenzel would not tell
> me the exact specs of the 500 series parts available on ebay and only sent
> me the specs for the standard 501-14057 that takes 10 MHz.
> I have a couple 8642As and can generate any frequency I want with decent
> phase noise, locked to my 10 MHz reference. I could try these frequencies
> Do you know what the pll lock output does when the input frequency is off?
> These toggle high for any frequencies I have put in.
> Any other ideas are appreciated.
> On Sun, Nov 12, 2017 at 5:19 PM, John Miles <john at miles.io> wrote:
>> Sounds like he's talking about the small 'bricks' that Wenzel sells with
>> internal PLL-disciplined OCXOs. Some of these expect oddball input
>> frequencies. Just looking at the 80 MHz parts on the shelf around here,
>> 500-14273 wants a 13 MHz input, 500-25010 uses 24.576 MHz, and 500-25009
>> uses 19.2 MHz. So that's probably the issue, if two of them seem to be
>> failing the same way.
>> -- john, KE5FX
>> Miles Design LLC
>>> -----Original Message-----
>>> From: time-nuts [mailto:time-nuts-bounces at febo.com] On Behalf Of Bob
>>> Sent: Sunday, November 12, 2017 2:03 PM
>>> To: Discussion of precise time and frequency measurement
>>> Subject: Re: [time-nuts] Wenzel VHF PLO Oscillators Off Frequency
>>> I guess my point was more that there is not a VCO / PLL combo in an OCXO.
>>> If dropping the supply gets you on frequency, then you have moved things
>>> with that voltage change. 50 PPM is a lot of delta T on any normal OCXO
>>> That strongly suggests there is something wrong in the control circuit.
>>>> On Nov 12, 2017, at 2:52 PM, Mark Goldberg <marklgoldberg at gmail.com>
>>>> The standard oscillator, 501-14057 (
>>>> www.wenzel.com/wp-content/parts/501-14057.pdf) will lock to an
>>> external 10
>>>> MHz reference and this one is marked "80 MHz" and "15V on the label.
>>>> someone swapped the labels. I did try lowering the supply voltage. It
>>>> to 80 MHz at about 11V and still did not lock to the reference. This
>>>> oscillator is specified at 1e-6/year aging. That is way less than it
>> is off
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