Hmm, I didn't say digital eliminated feedback. You have to go back to the original complaint (someone else) to understand my comments there. They said that at fire scenes and other places where loudspeakers are left on in emergency vehicles that digital sounds really bad when the speaker audio gets back into a fire scene radio.
My contention is that we've ALWAYS had a feedback problem in that regard -- analog or digital -- but the PEOPLE using the radios UNDERSTAND the howling/squealing coming from an analog rig because they've seen it before in PA systems, at conferences, at the local baseball stadium. and they also understand how to avoid it. The people in the same situation today with digital radios have no mental frame of reference on what "feedback" sounds like in digital, so they don't move away from the loudspeaker. Eventually they'll get it. Nate From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Jacob Suter Sent: Wednesday, April 08, 2009 3:47 PM To: Repeater-Builder@yahoogroups.com Subject: RE: [Repeater-Builder] (OT) APCO P25 horror stories anyone? I agree entirely on the RF part of your article. But. Digital modes somehow eliminate feedback? Echo cancelation exists but a great deal of the time it fails miserably. You end up with voice-frequency delayed retransmission in the audio which IMHO is harder to understand 'through' than reasonable (ie - public safety person using lapel mic/HT to talk while inside the car with the car's radio's volume reasonably low) feedback. I personally don't understand the actual need (other than paying the FCC/Congress's bills) for all this nonsense of tightening up tx bandwidth. My scanner says theres a lot less on vhf/uhf than there ever was before as the business users all migrated to cellular. Is the 'real world' trick to just apply for 2 side-by-side 12.5k slots and run your big fat 25khz carrier down the center? ;) JS
