Re: coexist SDRuno 1.41.1 with SDRconsole3.1 with RSPdx?


jdow
 

There is a mute setting. Overload usually means you are transmitting. This prevents feedback. In your case the antenna switch made sufficient signal level change that it looked like you were transmitting. At least that's by guess.

And one important note should be appended here. If you connect the antenna and the receiver noise level goes up 6 dB. If it goes up more than 6 dB you are simply wasting dynamic range.  Add front end attenuation. That's the rule for traditional receivers.

For SDRs you can squeak out a little more dynamic range by performing the no antenna test with a signal generator giving you a fairly weak signal. SDRs are sort of magic. They can interpolate between levels. A big signal can put a signal not making 1/2 ADC step can pop out when another signal at say 3 ADC steps. How many times does it hit 2 vs 3 vs 4? You average and there is your 1/2 level signal.

The final trick is purely subjective although SDRC's SNR meter helps. Select a very weak constant signal, SNR maybe 20 dB with the gain up high. Reduce the gain until the SNR drops a couple dB. You'll be set almost perfectly. Then if you connet an antenna with a whole lot more gain, an attenuator is the appropriate fix on HF. At low HF frequencies you can get a natural noise level equivalent to a  40 dB noise figure receiver.

It is hard to accidentally make a receiver that bad. I have done that, though, for a test. Now I run my apparently deceased ProII with 30 dB of attenuation on all the time when on 75 meters. I get the same SNRs as without the attenuation. And the strong 1590 kHz or so signal a couple miles away does not overload anything.

{^_^}    (ProII is about to become an organ donor - it's RF chassis is still just fine.)

On 20220221 12:57:43, Kurt Hechler wrote:

Hi Simon,

from my understanding is the USBpower sufficent.  See attached files.

Maybe I found the problem.  If I was for example on 40m I have to move RF Gain to round about 18 to see the SSB signals. If I go now to 80m and switch from the short dipole to the LW the Console is in overload and does not show spectrum as well the RX is quiet.  If I now minimize the RF gain to round about 10 the Console comes back.  IF Gain is -45, AGC off.   I do not know such a behavior from the early version. Even with the minimized settings the RX is sometimes switching on/off.  Bay the way SDRuno do not show that behavior.

73
Kurt
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