[hpsdr] Mercury SSB Phase Noise Testing Thanks for all the help!

[Ronald Cox]

Phil,
Yes it has been an interesting journey. With the error in the handbook  
equation and the phase noise of the first HP Signal source, it has  
taken about three days to get real SSB Phase noise data.
I have been reading the MDS directly, but to be consistent with the  
process documented in the ARRL Handbook (for non-SDRs), I have been  
adding 3 dB to the number read. I agree that this is a waste of 3 dB,  
and I should do as everyone else does on SDRs. We can do it that way  
and establish it as a best practice for SDRs. No use in complicating  
the process just because that was the way it was always done before.  
It comes down to selecting a method that we all agree to use going  
forward. I will update the process documented, and the sample data to  
incorporate using the direct read method and improve the numbers by 3  
dB.

OK on the IP3 tests. Yes I intend to do them too. I will specify that  
Dither and Random be on.

The journey continues!

Ron, W9KFB
Indianapolis

On Oct 27, 2009, at 1:32 AM, Phil Harman wrote:

> Hi Ron,
>
> Many thanks for your most interesting measurements.  Just one comment
> relating to MDS. With PowerSDR, after calibrating the spectrum  
> display,
> you can read the MDS (in the selected bandwidth) directly from the  
> Average
> S Meter display. There is no need to use a test signal.
>
> In this case MDS = receiver noise floor.
>
> I hope you extend your range of tests to include IP3. I expect you are
> aware of this but, unlike an analogue receiver, with a DDC receiver  
> the
> IP3 varies with signal level. Also  enabling Random and Dither will  
> have a
> significant (beneficial) effect on the IP3 performance.
>
> 73's Phil...VK6APH
>
>
>
>> ***** High Performance Software Defined Radio Discussion List *****
>>
>> All,
>>
>> New and improved charts now show results using the HP 10554A Crystal
>> Oscillator.
>> They are posted at:
>> http://openhpsdr.org/wiki/index.php?title=Receiver_Performance_Tests
>>
>> Please let me know if you see any issues with the tests. Thanks for
>> all the help - everyone...
>>
>> Ron , W9KFB
>> Indianapolis
>> _______________________________________________
>> HPSDR Discussion List
>> To post msg: hpsdr at openhpsdr.org
>> Subscription help:
>> http://lists.openhpsdr.org/listinfo.cgi/hpsdr-openhpsdr.org
>> HPSDR web page: http://openhpsdr.org
>> Archives: http://lists.openhpsdr.org/pipermail/hpsdr-openhpsdr.org/
>>
>>
>
>


 1256630240.0