The broadcast band appears to be busy. Being AM you can see the carriers.
I've been listening to a rag chew 80 meters while writing this. I am in the middle of the group it covers about 400 mile radius.
HDSDR is the program I am using. You can download the HDSDR for free and a $6 - $8 dongle is what I'm using. The little antenna that came with the dongle will give some listening but I did unscrew the antenna and put a 7 or 8' piece of wire on the screw and tighten it. I put an alligator clip on the end and clipped it to an AC register.
EDIT:
One thing I should point out is the filter is there ti eliminate image signal from the receiver. Bypassing the filter allows the image which is signal below 24 Mhz to pass and a low pass filter should be added to prevent the former desired signal which is the image in our case.
To more simply state it. The LO and the signal mix to produce a sum and difference of the same frequency. The filter eliminates one signal and you receive the other. Without the filter you receive both signals. It works but you may find an out of band signal coming in strong.