Thanks for the response. I am aware of the occasional beeps and squawks on a mobile or portable. This is different. Even the dispatcher breaks up, however, the mobiles and portables read it perfectly. My BC-796D is sitting right beside the HP with its supplied antenna and I am getting perfect copy on the 796. I can hear the same transmission on both units and the HP is unintelligible yet the 796 is perfect copy. This is consistent.
Thanks for the additional information. I did initially consider the audio decode levels. My BC-796D does have some sort of adjustment to obtain the best sounding audio. It has been working perfectly set at the factory default so I have not touched it in years. I took my outdoor antenna down in order to replace my roof. It was a Radio Shack multiband ground plane. 800 Mhz was only slightly better than the supplied antenna. I mostly used the ground plane for analog VHF and UHF. I suspect that the problem is indeed related to signal multipath and the inability to adjust the audio decode level in the HP. That is really disappointing since the old BC-796D does a much better job. The only reason that I am replacing it is that it cannot be programmed for the Virginia STARS system which is a P25 system, however, the synthesizer apparently can't be tuned to the correct frequency. There is no firmware upgrade since firmware can't make the hardware do something it was not designed to do. At least that is my understanding.