[time-nuts] How can I generate a very clean 1 W signal @ 116 MHz ?

Will Kimber zl1tao at gmx.com
Mon May 30 20:34:53 EDT 2016


14.5Mhz  doubled is 29.0Mhz right in middle of 28 - 30 Mhz where the 
output will be. Quite likely to give a "birdie"

Will..


On 05/31/2016 07:06 AM, Tim Shoppa wrote:
> OK, it sure sounds like you want to use a commercial signal generator or
> something. But a different take:
>
> 14.5MHz is a standard stocked crystal at Mouser, Digikey, etc. Three stages
> of doublers with simple fundamental-reject filters at each stage get you to
> 116 MHz.
>
> If you want to make it time-nutty, there's the NIST JFET "push-push"
> frequency doubler we've talked about here in the past. I think you'll use
> substantially smaller number of turns on the 116MHz stage than on the
> 14.5MHz end of the transformers.
> http://www.ko4bb.com/~bruce/FrequencyMultipliers.html
>
> Tim N3QE
>
> On Mon, May 30, 2016 at 7:06 AM, Dr. David Kirkby (Kirkby Microwave Ltd) <
> drkirkby at kirkbymicrowave.co.uk> wrote:
>
>> I was thinking about designing a 2 m (144-146 MHz) ->HF (28-30 MHz)
>> transverter, using a 116 MHz local oscillator feeding a level 30 mixer.
>>
>> 116 + 28 = 144
>> 116 + 30 = 146
>>
>> I'm wondering what's the best way to generate 116 MHz with very low phase
>> noise. Phase noise at < 20 kHz offset is particularly important, but 200
>> kHz would be fairly important. Outside that, it does not matter too much.
>>
>> The ability to lock to 10 MHz would be "nice", but certainly not essential,
>> as absolute frequency stability would not be of prime importance. Getting
>> the phase noise as low as possible would be more important. I expect better
>> performance can be achieved if one forgets about locking the signal source
>> to something else, but I may be wrong.
>>
>> An HP 8663A sig gen has <-147 dBc/Hz at 10 kHz offset, but I'd hope its
>> possible to produce something better than is possible in a commercial sig
>> gen that covers up to 2.5 GHz.
>>
>> Dave
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