I, too, got a BCD436HP in December to hear Sunnyvale & Santa Clara. After some programming hiccups (service types selection!), I was able to hear what I thought was all the talk groups I wanted. But the audio quality was - as described by others - garbled and distorted. That quality varied somewhat by location and proximity to the cities I was monitoring. I really only use the scanner in my car, and I'm using the antenna that came with the unit.
Even the Web-based streaming sites seem to have at least some of the same distortion. I, too, wondered if the PD/fire units were experiencing poor audio, but I'm not hearing anyone voice frustration on the air.
I'll try a different antenna, as recommended above, but any other ideas for changing settings, etc., would be appreciated.
Sounds like you have the same issue as i do.
Apparently, we are victims of having the same (strong) signal coming to our radios from two different antennas (one from Sunnyvale, one from Santa Clara). The problem, as I understand it, is that digital data comes from two sources but delayed. Digital radio expects a very specific stream of data, and if it comes from multiple places and delayed, it confuses the decoding and it cannot give you intelligible data. The symptoms are garbled speech, cutting in and out, and pops and clicks. You also miss a lot of calls.
The solution (apparently) is to have a highly directional antenna you can point at one of the antenna towers so it will not receive the other antenna. A Yagi design antenna receives signals from one specific direction but not another. This is what we need.
As I understand it, the PD/FD have receivers/antennas such that this multipath reception is not an issue. It's supposed to be very expensive. I have no idea how they achieve it. I'm an electrical engineer, and honestly I think it's a terrible design. But that's another argument.
I have ordered a Yagi antenna and will point it so it will just receive the Santa Clara antenna and not the Sunnyvale one (I live in Santa Clara) and I will let you know what happens.
The downside is you lose reception of other agencies (Milpitas, MV, Los Altos, etc.) but this is the price you pay.
Go digital, go P25, go APCO (sarcasm).