Tone changes??

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cookandcamera

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Just a quick question. I noticed over the last day that East Lyme PD and Fire changed their PL tones from DCS to CTCSS. Montville PD did the same not too long ago with their main PD channel.

This is a little beyond my knowledge. I am not asking for the exact reason why East Lyme made the change, but why do departments occasionally do this? Likelihood that they will change back/again soon?

Where I am responsible for keeping up on all of this for the newsroom, I like to anticipate changes whenever possible, and when one of our main communities goes dark because of a PL tone, I need to able to keep up without leaving everyone on SEARCH.
 

oilmillcharlie

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Just a quick question. I noticed over the last day that East Lyme PD and Fire changed their PL tones from DCS to CTCSS. Montville PD did the same not too long ago with their main PD channel.

This is a little beyond my knowledge. I am not asking for the exact reason why East Lyme made the change, but why do departments occasionally do this? Likelihood that they will change back/again soon?

Where I am responsible for keeping up on all of this for the newsroom, I like to anticipate changes whenever possible, and when one of our main communities goes dark because of a PL tone, I need to able to keep up without leaving everyone on SEARCH.
What are the new tones???
 

RKG

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I have no idea why the specific actions reported were taken by the specific operators in question. However, it is not in my experience unusual for a department relying on "in house" programmers to select one of the "invalid" DPL values, suffer a bunch of falsing, and then decide that DPL doesn't work and go back to analog PL. The reference specified by a previous poster explains why of the 500-odd possible octal values for DPL, only 83 are considered usable.

A second problem that frequently occurs is that a department will be using different makes or models of subscriber equipment and find that some won't decode the DPL. The problem here is that there has never been any consistency amongst manufacturers -- or, for that matter, among different radio models by the same manufacturer -- as to how voltage swings for the first stroke of a digital value. Again, a department suffers the problem, decides that DPL doesn't work, and reverts to PL. In fact, the problem can be solved (once understood), by programming the renegade subscribers for the "inverse" DPL on receive.
 

PJH

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There is a documented issue between how Kenwood and Motorola does DPL, mostly noted on the PRO series of Motorola radios. At the end of transmissions, they use different timings on the phase shifts to prevent squelch crashes. So, a Kenwood radio on a Motorola repeater using DPL would do this and vice versa. Motorola updated software to allow "non-standard" DPL to be checked to help avoid this.

That, and as Bob said, some people just do dumb things with DPL.

Otherwise, could be simple as a distant station coming in and creating a little havoc.
 

sefrischling

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Tone Changes for East Lyme Fire/Police

I changed over the PL/DPL tones , keeping one radio on what I had and one on what you report as the new ones ... now I hear nothing with either.
 

cookandcamera

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ELPD seems to be on right now with DPL 114, I'll try 156.7 later
Odd. When I stopped hearing ELPD with the DPL tone programmed I put it on search, which is where I came up with 156.7.

I have been hearing chatter on both the PD and FD channels with the PL changes. I could programming 2 channels, one with the DPL and one with CTCSS and see what happens.
 

cookandcamera

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As of this moment I am picking up ELPD's 154.7325 frequency with both DPL 114 and PL 156.7.
?!?!?!? Now I am confused. Guess they are testing to see which works better??? I have not checked the FD dispatch to see if they are transmitting on both PLs for their ops yet. Thought I have heard some chatter on 153.86750 in the past week or two as well. No confirmation on that yet.
 

jaspence

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Tone changes

I have seen systems that use both digital and standard tones. One ham repeater I use does this because many users (900 mhz) like the DPL feature of the commercial radios and the very few that use actual ham radios can still have the more common PL tones.
 

sefrischling

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?!?!?!? Now I am confused. Guess they are testing to see which works better??? I have not checked the FD dispatch to see if they are transmitting on both PLs for their ops yet. Thought I have heard some chatter on 153.86750 in the past week or two as well. No confirmation on that yet.


ELFD is on PL and DPL as well now. All day I have run two transceivers side by side, one on PL and one on DPL, both are picking up ELPD and ELFD. This seems a bit odd, but for the moment it is working.

There has been some random chatter on 153.8675, as I understand it this is because 154.73250 is intended to used for a link from the schools to the cops. All the schools have radios with 154.73250 to contact school security and ELPD in an emergency ... but this channel has become the Law Talk channel which is a problem.
 
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