Re: Newbie material on HF+(more)

Pete Smith <n4zr@...>
 

This is all very well, and I am sure that it is technically correct, but what I am primarily interested in at this moment is measuring my background noise level and tracking what will hopefully be improvements as the power company does its thing. So yes, it's all about SNR, but the question is relating what I see now to what I saw last month or last year using a good hardware receiver.

I am also somewhat averse to being told "you don't know enough", when the documentation so lags the hardware and software development.  I don't have an engineering degree, which makes product-specific documentation all the more important.

73, Pete N4ZR
Check out the Reverse Beacon Network 
at <http://reversebeacon.net>, now 
spotting RTTY activity worldwide. 
For spots, please use your favorite 
"retail" DX cluster.
On 4/6/2018 9:15 AM, prog wrote:

On Fri, Apr 6, 2018 at 05:57 am, Pete Smith wrote:
changing the FFToffset to -93 brought the amplitude of my XG-3 signal source to about the correct value
For those who are late to the party: Don't touch the configuration file until you fully understand what you are doing. What you may think is proper calibration is not proper at all.
There's a very good reason why SDR# uses dBFS and not absolute dBm's. This is mostly related to the nature of modern radios with complex gain distribution, ADCs, DSP, and AGC loops. These are already hard to explain to experienced RF engineers, so I can't blame the end users.
Long story short: Revert these changes and learn how to use dBFS and SNR measurements. SNR is the only thing that should matter to you.

PS: "Q: But X software has dBm. A: What happens when the DSP decides to reduce the gain to increase the SNR?"

Join airspy@groups.io to automatically receive all group messages.