I will listen to 7180 but find it crowded on Sunday afternoon at times. 40 can be bad with AM Carriers. 7.285 is a fairly recognized qrp frequency. I had a 20m qso last Sunday on 14.285 They were in Florida about 1000 miles away. 20 of course is not friendly to those with Bitx40s.
Although technically US Generals can go as low as 7175. On LSB that will put one in violation of the rules.
_Dave_ AD0B