WRFF247 Posted April 5, 2020 Report Posted April 5, 2020 Please bear with me here, totally new. I've got an MXT400 installed in my Jeep for mostly trail coms. It's repeater capable and there are a few within range of my home, I'd like to get those set up. I know about "turning on" the repeater channels on the radio but am confused about the tones. When a repeater requires a "tone" to activate, is that the CTCSS or the DCS? I don't know the difference between those 2 things. I know that for every channel the radio is programmed for you can set a CTCSS or a DCS code or number. Could someone help to clear that up for me? Quote
WRFN403 Posted April 5, 2020 Report Posted April 5, 2020 I am a newbie also! For all repeaters listing 'tone' frequencies, those have to be CTCSS as DCS is a digital code, not frequency based. For example, there is a repeater near me that lists a tone of 141.3 MHz, which is CTCSS 'tone' 22. I am not sure if the 'tone' is required to use the repeater as my understanding is that 'tones' only filter who you can hear on any given channel, while using no 'tone' allows you to hear all activity on any given channel. Quote
WRFF247 Posted April 5, 2020 Author Report Posted April 5, 2020 I think if a repeater requires a tone, if you don't have that tone assigned to the repeater channel, the repeater won't open or activate to re-broadcast your TX. It will recieve all transmissions on that channel, it just will ignore those not having the correct tone added to the TX. From what I've been able to read, they do this so the repeater doesn't just re-broadcast everything it hears on a channel, only those TX's that are trying to use the repeater. If a repeater is "open" then you don't need to add the tone. If it lists a tone, then you will need to choose accordingly. So in your example, If you have a repeater on say channel 16 and it says it requires a tone of 141.3, you would have to program your radio to add tone #22 to that repeater channel. SO, I think the CTCSS "codes" are for setting up your repeater channels. The DCS digital code is used on non-repeater channels to filter out other users on a particular channel. Lets say you are on channel 8. If you don't assign a DCS code, then you would hear every TX on that channel. If you are in a group and only want to hear the TX's from your group, lets say the are all going to agree to use channel 8 AND code number 132/code 20 (from my Midland MTX40 manual), then your radio would only "open" or hear those transmissions from channel 8, number132/code20. EVERYONE on channel 8 would be able to hear all transmissions if they don't have any codes assigned. It's selective hearing if you will. Not a privacy code by any stretch. Quote
Jones Posted April 5, 2020 Report Posted April 5, 2020 CTCSS and DCS are both considered "Tone Squelch" and do the same thing. One is analog, the other is a digital signal transmitted over analog. Either can be used with repeaters, or simplex to keep from hearing other users on the same channel. Most GMRS and Ham repeaters use CTCSS, however, some use DCS. Note that DCS and CTCSS cannot be used at the same time, but they CAN both be used on a "split-tone" repeater system, where it may for example require DCS-315 to activate the repeater, but the repeater puts out CTCSS of 123.0. Another example would be if the repeater requires CTCSS 88.5 to activate, but outputs CTCSS 162.2. Yet another example would be if the repeater requires a CTCSS tone to activate, but doesn't transmit any tone at all. (CSQ) The Midland Micro-mobile radios cannot work with split-tone repeaters. Quote
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