the t.bone free solo Handheld 863 MHz

I purchased the solo handheld and expected it to work with the wireless unit TWS 16 PT which I got a some time ago. The handheld will connect and signal transmitted, but the quality is poor, unclear and muddy. I tried using different channels, handheld setting and mixer settings but the sound quality did not improve. I compared it with a wired Shure which was crisp and clear.
The receiver TWS 16 PT does not have the ADL feature and I expect that the handheld would work much with the correct receiver.
The handheld is solid build and appears good quality therefore 4 stars. I though found it somewhat heavy (+400g).