[time-nuts] eBay seller has Z3801A upgraded to 58503A

[Said Jackson]

We have a number of these upgraded units from China, ours have the double oven 10811 and they are awesome. Great ADEV and great PN and very little spurs. In fact we use them as house standards for our TimePod and TSC5125A.

They are upgraded to a nice desktop case and the 58503A firmware.

They may need several months to a year (yes, a year!)  or more to fully settle down.

Drawbacks: minor spurs at 60/120Hz etc, and not so great isolation between the two 10MHz outputs.

Our TCXOs are ready to go minutes after power on, very little retrace and warmup required. Thats the big tcxo advantage over Rbs and OCXOs.

Bye,
Said

Sent From iPhone

> On Nov 27, 2014, at 15:34, Bob Camp <kb8tq at n1k.org> wrote:
> 
> Hi
>> On Nov 27, 2014, at 4:55 PM, Dr. David Kirkby (Kirkby Microwave Ltd) <drkirkby at kirkbymicrowave.co.uk> wrote:
>> 
>> There's a seller on eBay selling what he says is Z3801A upgraded to
>> 58503A. One or two things have made me a bit suspicious of that seller
>> - nothing to do with his GPS things. Does anyone know what he does? He
>> also have an 58503A, but that's a couple of hundred $'s more than an
>> upgraded Z3801A.
> 
> Most (if not all) of the eBay 58503’s are repackaged Z3801’s. There is very little difference between the two of them. The 3801 manual sends you off to the 58503 manual for a number of details.
> 
>> 
>> I've been thinking of buying one of the Jackson Labs devices, which is
>> obviously a more modern design, but I'm giving some consideration to
>> buying a used GPSDO with an OCXO, rather than a TCXO. By the time I
>> purchase the TCXO based unit, stick it in a box, build a buffer, add a
>> power supply etc etc, it is not going to work out a lot cheaper than
>> buying a used OCXO device.
> 
> If you can keep it on power all the time, the OCXO is the better way to go. If you want portable / fast turn on the TCXO is the way to go. Once it’s settled in, the OCXO will outperform the TCXO for every spec other than input power and size.
> 
>> 
>> My mind is not made up about this. There are advantages and
>> disadvantages of both.
> 
> The TCXO is very specialized. The OCXO is the solution most go with. 
> 
> Bob
> 
>> 
>> 
>> Dr. David Kirkby Ph.D CEng MIET
>> Kirkby Microwave Ltd
>> Registered office: Stokes Hall Lodge, Burnham Rd, Althorne, Essex, CM3 6DT, UK.
>> Registered in England and Wales, company number 08914892.
>> http://www.kirkbymicrowave.co.uk/
>> Tel: 07910 441670 / +44 7910 441670 (0900 to 2100 GMT only please)
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