One caution - The 900MHz Motorola GTX series radios have a firmware bug in them and will NOT do tone reverse burst at all. The DCS side of the radio is just fine. This is documented on the GTX pages at repeater-builder.
Since every 900MHz user radio that is in use started out as a commercial 2-way they all have both PL and DPL, so the choice of PL tone or DPL code and the choice of which tone or which code is up to the person who sets up the system. Since the GTX is a popular an entry-level radio you will find a LOT of repeaters use DPL, and for what it's worth in some areas DPL code 411 is considered an "open" code - i.e. if the system uses 411 then it's an open system. As to tone selection criteria, the CTCSS overview article (which also contains some historical info) at repeater-builder has some very cogent points - like you DON'T want to use 136.5 Hz or 131.8 Hz on any channel that you might want to run DPL on in the future. See <http://www.repeater-builder.com/tech-info/ctcss/ctcss-overview.html> There is also a chart of "legal" DPL codes at the end. Too many systems are out there that use nonstandard codes. Mike WA6ILQ At 06:35 AM 02/25/10, you wrote: >I think this comes down to personal preference. I know a lot of >folks who will argue that one or the other is "better" but they both >do what they are supposed to do. Some say there are a lot of falsing >issues with PL and that DPL doesn't false. In actual use, I have >heard both false. Some say there are interference problems with >certain tones. This can be true in some situations. DPL will give >you more choices since there are more DPL codes than PL tones. As >far as I know, any modern radio designed originally for 900 MHz >commercial use will do either well. I personally prefer PL because >there are more after market devices for that format and it is easier >to implement in some situations such as with phase modulated >exciters. But it is still just my personal preference. Your Maxtrac >should handle either format. > > > > > >--- In Repeater-Builder@yahoogroups.com, "kq7dx" <kq...@...> wrote: > > > > Hello to the group, > > I have had a couple of really nice hams try to explain this to me > but I am not getting it. Which is better. Most importantly which is > better in a metropolitan city with lots of RFI and noise on the > bands. Particularly 900mhz. I have seen mostly PL and just a few > DPL listings so I am not sure that it is RFI motivated for the > selection. So which is best for a repeater application. > > The receiver for the repeater will be a 800mhz Maxtrac converted > to 902mhz. > > Thank you for your help, and if this was covered on another post > please let me know. I am on a dial up and it is hard to research. > > 73s > > scott > > > > > > >------------------------------------ > > > >Yahoo! Groups Links > > >
