These SDR receivers are very limited in performance. The max signal they can handle is barely in excess of S9, add the total lack of filtering and an inherently poor antenna (in terms of household noise pickup) and it comes as no surprise as to how poorly it performs.
I have a Nooelec SDR, mine is the type in the extruded aluminium case. To give you some idea of how poor they are at signal handling, on an indoor ground plane antenna mine produces phantom signals from a commercial VHF mobile radio base station on a hill 5 miles away, which will not be running over 25W ERP.
Other than being a low cost means to listen to your own transmission, or to listen to local FM radio stations, these type of receivers are of very limited use and do not come anywhere close to the performance of their more expensive SDR cousins, such as the Microtelecom Perseus, SDRplay RSPdx, etc.
73 Dave