[hpsdr] Penny Whistle Bias

[David McQuate]

If you do a two-tone test, you can fine-tune both R17 and R11 for 
minimum third-order distortion products.  (Make only very small 
adjustments!)

73,
Dave
WA8YWQ

On 12/22/2012 4:25 PM, Graham / KE9H wrote:
> ***** High Performance Software Defined Radio Discussion List *****
>
> John:
>
> I think you are fine.
> You are plenty close enough.
>
> The quiescent PA currents will walk around about 10 percent
> with heatsink temperature.
>
> --- Graham / KE9H
>
> ==
>
> On 12/22/2012 6:07 PM, John wrote:
>> ***** High Performance Software Defined Radio Discussion List *****
>>
>>
>> Powed my TAPR Penny Whistle kit up today for the first time. 
>> According to the manual the PA bias should be about 20 mA.  Mine is 
>> only 8.23 mA.
>>
>> Is that in the normal range or should I begin looking for an assembly 
>> error?  Both R11 and R17 adjust, but it is hard to set them to an 
>> exact balance.
>>
>> My readings are:
>>   Bias   8.23 mA
>>   R17 set (only)  456.1 mA
>>   R11 set 905.4 mA
>>
>> 73,
>>
>> John  WoGN
>>
>>
>>
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Clear Stream Technologies


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