There are some areas of the UHF band that are off-limits due to DAB images as the RSP2 does not have a DAB rejector, but reception everywhere else is excellent.
Reason: No reason
There is a bit of a problem with scanning the Mil-Air band from with SDRuno. As you have pointed out, the architecture of the RSPs makes them vulnerable to DAB images in areas where there are strong DAB transmissions. The DAB filter implemented in the RSP1A and RSPduo has been effective in mitigating this problem, but it also creates a problem with the software scanner in its current incarnation. As you are probably aware, the software contains gain calibration tables for all RSP models and this allows both signals and the noise floor to be referred back to an equivalent value at the antenna port. When the DAB filter is enabled, it causes a noticeable change in the RF gain between 240 and 300 MHz and this throws out the calibration across that range. Because the filtering is performed after the LNA, the impact on the device NF and hence sensitivity is in fact minimal. The problematic impact of this though is the make setting a single threshold for the scanner for the entire Mil-Air band impossible. This is what we believe is causing the problem for the user above. If you set a threshold high enough to allow scanning across the 250-300 MHz range, it becomes too high for signals above 300 MHz and so the device appears to lack sensitivity because the threshold is set too high for the scanner to be able to lock onto certain signals. Of course you can manually tune to these signals, but many people understandably want to use the scanner.
We have a solution in the pipeline and as was explained to the user above, is scheduled for the next release of the software, but because we are unable to provide an immediate fix, the user in question instead chose to return their device, which is of course their right.
The solution is to use a different set of calibration values for when the DAB (and other) notch filters are enabled and this will keep the overall indicated antenna referred noise floor in-line with what the true NF actually is under all circumstances.
The scanning software is still relatively new and we are still learning about how people might use it and issues that they might have. We are constantly working to improve the software, but unfortunately, these things take time.
Reason: No reason