Hi Graham. Sadly this is a subject that comes up a lot. Only the other night on our net we were reminiscing about how in the 60’s and 70’s we could throw up a random wire and hear clear signals from all over. In more recent times this has become impossible, due to all the digital and switch-mode devices we (and our neighbours) have scattered around the house. TV’s, computers, phone chargers, you name it, they all radiate some noise, and cheap stuff from China is terrible.
I’m a radio amateur active on the lower HF bands and any attempt to use a simple wire antenna is defeated by high levels of noise. My solution was to spend some cash on a loop antenna, in my case the Wellbrook 1530*. In a flash my troubles were banished and I could hear signals standing out against a quiet background, even with the loop indoors. Outdoors, mounted at gutter height at the end of the extension things were even better. A cheap rotator from Maplin enabled me to use the loop’s nulls to eradicate the more stubborn noises.
It’s also worth fiddling with the gain slider, as sometimes noise can be the product of overload from strong stations. Also make sure you have the correct IF bandwidth for the mode in use – maybe 6 or 9 kHz for broadcast AM, 2.7 kHz for SSB etc.
*Other loops are available. Even a home-made passive loop using a plastic hula hoop and a few turns of wire can work surprisingly well. Add a wideband amplifier at the ends of the loop and you have a mini Wellbrook.
This forum is no longer the ‘official’ board of SDRPlay, it is run independently. The SDRPlay guys call in only occasionally. The Facebook site is quite busy and there is lots of sage advice over there. Good luck.