[Elecraft] WTB Trimble ThunderBolt for K3EXREF / QS1R

[David G4DMP]

Ed & others -
>From my experience in using Rubidium and GPS disciplined standards, I
feel that a far better bet is to use an MV89A 10MHz Double-oven CXO. It
requires only a 12V d.c. supply.

I built one into a Hammond die-cast box (with no ventilation) with its
own integral linear PSU, regulated with an L78S12CV regulator. On
switch-on it draws 34W from the supply mains, which steadily reduces to
9W after about 12 minutes when the oven attains its working temperature.

Using a 10-turn 10K pot the frequency can be finely adjusted to within
1/100 of a Hz and it locks the K3 perfectly with the K3EXREF installed.

100% recommended.

The MV89A is available on eBay and the datasheet is at
http://morion.com.ru/catalog_pdf/MV89-OCXO.pdf

73 de David G4DMP

>> A caveat regarding the use of simple "wall wart" 12v PS for supplying
>> a OCXO.
>>
>> I am using a Morion OCXO as 10-MHz reference for my K3EXREF and for my
>> synthesized A32 PLL in my DEMI 1296 transverter.  I got reports of
>> 120-Hz sidebands on my signal (-10dBc) turned out to be due to
>> excessive AC ripple riding on the 12v coming from my wall wart supply
>> that I was using to power the OCXO.

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 | David M Pratt, Kippax, Leeds.   |
 | Website: http://www.g4dmp.co.uk |
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