Bandwidth of the s-meter in CW-U mode
Posted: Sun Dec 04, 2022 11:39 am
Hi all,
I am measuring the noise factor of some antenna preamplifiers by sending a calibrated signal into the preamp followed by my RTL SDR and SDR console.
I am using the so-called "gain method".
To use this method, I must measure the gain of the system (preamp + receiver). This is easy thanks to the excellent SDR Console s-meter which gives very stable readings in dB.
The "gain method" requires to measure the noise at the receiver when the antenna input is terminated with a 50 Ohm load.
Again, this is veary easily done with the SDR Console s-meter.
However, the gain method then requires to calculate the noise density per Hz. To do this, I need to know the passband of the receiver .
When I change the passband of the filter in the left panel of SDR Console, the reading on the s-meter does not change. With a wider filter, the s-meter should show an increase. And a decrease with a narrower filter.
So I assume thas SDR console uses a fixed filter to calculate the reading shown on the s-meter.
What is the width of this filter?
I guess it must be around 100 Hz, but I would like to be sure.
Thanks to the developer. Keep up the good job!
I am measuring the noise factor of some antenna preamplifiers by sending a calibrated signal into the preamp followed by my RTL SDR and SDR console.
I am using the so-called "gain method".
To use this method, I must measure the gain of the system (preamp + receiver). This is easy thanks to the excellent SDR Console s-meter which gives very stable readings in dB.
The "gain method" requires to measure the noise at the receiver when the antenna input is terminated with a 50 Ohm load.
Again, this is veary easily done with the SDR Console s-meter.
However, the gain method then requires to calculate the noise density per Hz. To do this, I need to know the passband of the receiver .
When I change the passband of the filter in the left panel of SDR Console, the reading on the s-meter does not change. With a wider filter, the s-meter should show an increase. And a decrease with a narrower filter.
So I assume thas SDR console uses a fixed filter to calculate the reading shown on the s-meter.
What is the width of this filter?
I guess it must be around 100 Hz, but I would like to be sure.
Thanks to the developer. Keep up the good job!