Most if not all P25 radios (both portable and mobile) have the ability to do analog and digital communications from the same radio. While most can receive both analog and digital communications on the same channel if set up for mixed mode use, I am unaware of any that can transmit on both analog and digital on the same channel. All radios only have one vocoder, for P25 that is the DVSI IMBE vocoder. It is the same vocoder used by all the manufacturers and DVSI is the only producer/supplier of the vocoder.
Thus any manufacturers radio set for P25 should work on any other manufacturers system since P25 is a standard. I know from personal experience that Thales/RACAL, motorola and EF Johnson radios all talk to each other when in P25 as I have several of each and enjoy playing with them. (now if I could just get this VHF Quantro up and working) So I would guess that the gentleman from M/A-COM was from marketing and not a technical person and just spewing marketing crap (no offense to those that use M/A-COM) and i would ask to talk to a technical person for any article. It has been recommended by many organizations, including APCO, that when on fire ground (scene), any department that has a digital system should revert back to an analog system for firefighter safety. It still boggles my mind why some department don't follow this recommendation to this day. (yea, I know, it's a recommendation not a regulation) Dan KA8YPY On May 29, 2008, at 9:48 AM, [EMAIL PROTECTED] wrote: > Not wanting to start a flame war, but since I know there are some > P25 gurus on here, I am posting this email exchange between an EDACS > user and their local representative. Its rather self explanatory, I > am looking for comments on the response; specifically, don't P25 > radios have an analog mode? All (constructive) comments welcome. > > > > From: MA/COM REP > To: EDACS USER > Hi, > > Thank you for the article and the opportunity to clarify a couple of > points. The system mentioned in the article is a Motorola system. > > This is just another great benefit of EDACS technology...It is able > to provide both digital AND analog features. For Fire, we plan on > programming all of their radios with an analog on-scene talk-around > group in addition to all the other talkgroups as an added feature in > the event it is preferred in those particularly noisy environments. > > There have been some cases reported like the one in Orlando with P25 > systems, since the systems only offer digital technology and does > not have the capability of using analog. All P25 vendors including > M/A-COM and Motorola are aware of the issue and are looking for ways > to improve the technology. Without getting into all of the > technical reasons, a lot of it has to do with vocoders. P25 > technology in general uses less vocoders and therefore can sometimes > "leave out" some of the audio. EDACS technology has not had a > significant number of complaints from Fire Departments as the > technology uses more vocoders. > > I am trying to find a technical explanation to send to you as well. > But in the meantime, MA/COM shouldn't pose the same problem. > > Please call me if you have any other questions. > > Sincerely, > > > ----- Original Message ----- > From: EDACS USER > To: MA/COM REP > > Subject: FW: Orlando FD Radio Article > > > > I sure hope MA/COM is working on this issue. > > > > _____________________________________________ > From: Concerned Citizen > To: EDACS USER > Subject: Orlando FD Radio Article > > Digital Radio Switch Upsets Firefighters > > POSTED: 8:12 am EDT May 21, 2008 > > UPDATED: 8:49 am EDT May 21, 2008 > > > ORLANDO, Fla. -- The city of Orlando replaced its police and fire > radios, but firefighters said the new multimillion-dollar system > sometimes goes silent. > > During a recent supermarket fire, firefighters were forced to use > their old radios to communicate because the new system was distorted. > > Noise was the problem. Warning bells on firefighters' air packs > cause microphone distortion on digital signals much more than with > analog channels. > > "We keep on the analog tracks so that we have the clarity that we > need. So, like I said, get the bugs worked out in the digital > system," said Fire District Chief Keith Maddox. > > The digital radio channels are also hard to hear when the > firefighters are working next to trucks because the engines have to > be revved to pump water. > > Fire departments nationwide have known about digital signal problems > for over a year, but Orlando's fire department thought that the bugs > had been worked out. > > "With this one, we didn't know the problem was there until recently > for us," said Fire Chief Jim Reynolds. > > So they conducted a test that proved the new channels were too hard > to hear. The big question is, why switch the channels now when the > federal government does not require it for four years? > > Steve Clelland of the firefighters' union said he believes the > Orlando Fire Department should have waited until the bugs got worked > out before switching channels. "It is serving us no purpose > sitting there and us not being able to use it," said Clelland. > > For now, firefighters will stick with the old radio channels when > fighting in noisy conditions until radio makers can create a fix. > > The city spent $6.8 million to convert to the new radio system. City > officials said the money would have been spent regardless of the > current radio signal problem. They added that buying sooner rather > than later saved taxpayers money. > > The national study results on the digital radio problem for > firefighters is due out next month. > > > > Get trade secrets for amazing burgers. Watch "Cooking with Tyler > Florence" on AOL Food. >
