[hpsdr] cycling of PS

[Warren C. Pratt]

Hi Glen and Bill,

PSDR sends the same commands whether the attenuator is 5-bit of 6-bit -- 
it has no knowledge of that specific in the hardware. However, I recall 
other cases that the 6-bit part did not work correctly.  I remember 
looking at the datasheet one time and thought that the 6-bit part should 
work; however, I recall problems with it.

Here's a test you can run on your board with the 6-bit part. Apply a 
signal well above the noise floor and  of steady amplitude to the 
input.  Now, adjust the S-ATT in 1dB steps.  The S-meter and panadapter 
should show the same amplitude independent of the attenuator setting 
because PowerSDR automatically adjusts those amplitudes for the 
attenuator setting.  If that does not happen, then the 6-bit part is not 
working correctly.

73,

Warren  NR0V


On 8/4/2017 6:12 PM, Bill Diaz wrote:
> ***** High Performance Software Defined Radio Discussion List *****
>
> Glen,
>     What radio model do you have?
> Bill KC9XG
>
> On 8/4/2017 5:43 PM, K4KV wrote:
>> ***** High Performance Software Defined Radio Discussion List *****
>>
>> Bill,
>>
>> I see what is happening, and think I know why it is going wrong.
>>
>> I tried it at 50-100W level, and it works fb with the input 
>> attenuator at 0db.  It also works fb with 12% drive to
>>
>> the amp and 600W out.
>>
>> As soon as I exceed that power level, it goes into a cycling mode.  
>> Up and down flashing all over the place.
>>
>>
>> I had reported, and others have reported that PSDR does not handle my 
>> 6-bit attenuator, but I have a board with
>>
>> a 5-bit attenuator and it works as it should.  When the program 
>> attempts to start raising the attenuator value to
>>
>> reduce the PS input level, who knows what the attenuator is really 
>> doing.  I have seen the attenuator in rx mode
>>
>> jump all over the place, incrementing 1 db at a time.
>>
>> This 6-bit attenuator does not do this in Thetis, and works well.
>>
>> I am going to uncheck the auto-attenuate box and try my own attempt 
>> at limiting the PS input signal for full amp
>>
>> output...
>>
>> 73
>>
>> Glen K4KV