[NLRS] 10GHz LO Query

[Jack Parker]

Excellent, Zack. Thanks for the information!

Jack

On 8/17/20 11:29 AM, Zack Widup wrote:
> Hi Jack,
>
> Anything made by Isotemp should be adequate. They publish or supply 
> their phase noise figures. From my observation, any company that 
> actually supplies phase noise figures has good phase noise 
> characteristics.
>
> For over a decade I have been using three Isotemp OCXO's with no GPS 
> disciplining for all bands through 47 GHz. They have been accurate, 
> stable and low phase noise. I calibrate them at home with a rubidium 
> standard every month or so.
>
> I have been using the KD6OZH low-noise phase-locked VHF VCXO circuit 
> in all microwave transverters through 47 GHz. In the 10 GHz 
> transverter I use a 106.500 MHz crystal and one of Paul's "10 GHz 
> personal beacon" multipliers to get 10224.0 MHz. On the higher bands I 
> use Frequency West bricks to lock the ~100 MHz KD6OZH circuit to the 
> brick.
>
> I would stay away from the ApolLO or DIGILO circuits for 10 GHz and 
> above. Their phase noise is far worse than the KD6OZH circuit. Tom 
> WA1MBA has put together a page about this circuit, including files to 
> have ExpressPCB make the boards for you.
>
> http://www.wa1mba.org/PLLVCXO.htm
>
> 73, Zack W9SZ
>
> On Mon, Aug 17, 2020 at 11:00 AM Jack Parker <vhfplus at gmail.com 
> <mailto:vhfplus at gmail.com>> wrote:
>
>     I would like a bit of input on the subject of a local oscillator
>     for a
>     10GHz transverter.
>
>     I am going to attempt to build one of W1GHZ's 10GHz transverters and
>     will start with the LO chain. My system will use a 144MHz IF and I
>     have
>     Paul's LO board to generate the 1136MHz signal the transverter board
>     requires. I realize the best route to take would be a high stability
>     10MHz reference source or a GPS locking system but prefer to avoid
>     that
>     complexity initially. It appears the next option is an OCXO and
>     therein
>     lies my question.
>
>     What would folks in the group suggest as a place to acquire a
>     sufficiently stable OCXO? The 144MHz IF would require a source at
>     94.666667MHz to drive the LO multiplier board I have presently but
>     that
>     seems an odd frequency for readily available off the shelf
>     components. I
>     had considered the Q5 Signal digiLO but they told me even with the
>     high
>     stability option it would not be stable enough to support digital
>     modes
>     at 10GHz.
>
>     It may well be that digital modes at 3cm will mandate an externally
>     referenced LO source. If that is the case then I will have to be
>     satisfied with analog modes initially.
>
>     I look forward to hearing the group's thoughts on this.
>
>     Jack, K0JP/VE3RUA
>
>
>
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