CTSS Q's

[ntsqd]

As I understand this feature it is primarily used to open repeaters for re-broadcast, but what about simplex from station to station (be they mobile or not)?

Can this be used in the same manner as the "Privacy Codes" on some FRS radios? Could a radio then be programmed to have several to many "channels" on the same freq, but each "channel" to have its own unique Code Tone and a radio monitoring that freq would not hear a transmission because it did not have the correct CT programmed?

 

[mr r2fj]

Do you mean CTCSS? If you do, then yes, it will do exactly what you're asking. Most radios can be programed to filter out everything that does not have the tone it's looking for (that's exactly what the repeaters do you are referring to). So if you happen to be talking on a channel that has a lot of interference this is a great way to rid yourself of it. However, please try to be respectful when using this. Not everyone's radio supports it and you may be walking all over other legitment users of the frequency if you can't hear them. It's not a different channel in any sense of the word. It's exactly the same channel with a special tone that others can use to filter out noise. Privacy Codes and CTCSS are nearly synonymous.

 

[Luke]

Using CTCSS tones in simplex operation will essentially filter out any signal that does not have the tone accompanying it. Mind you this only works if the the 1st and 2nd party have the encoding/decoding option enabled on their respective radios. Anyone else listening without the decode option could hear your transmissions just like any other signal. It is a "privacy code" in the effect that you wont hear anyone else, but will not keep anyone else from listening to you.

 

[Luke]

Mr. r2fj beat me to the punch

 

[ntsqd]

Oh, CTCSS, sorry. No wonder a search turned up zilch.

Drats then, it works the reverse of what I had hoped. It won't stop others, like our competitors, from hearing the conversation without the code.

 

[gary in ohio]

Continuous Tone-Coded Squelch System (CTCSS), Motorola calls it Private Line (PL), other call it guard tones some just say tone but its all the same.

Normally when a radio signal is received the receiver hears the signal and you here it on the radio, with CTCSS in place you need not only a signal plus the tone to hear the other party. Often used on repeaters, not used on simplex in ham radio often but will allow you to monitor a common or busy simplex frequency and only hear the station that is using the same tone.

Please note if you use tone on simplex you still need to monitor the frequency before you transmit so you dont talk over an existing conversation. Contrary to what FRS like to call it, its not a scrambler, it doesn't increase the number of channels and it offers no privacy

 

[mr r2fj]

Oh, CTCSS, sorry. No wonder a search turned up zilch.

Drats then, it works the reverse of what I had hoped. It won't stop others, like our competitors, from hearing the conversation without the code.

No worries, I was pretty sure I knew what you meant, but there's lots of stuff I don't know so I wasn't sure! lol

That's correct. Regardless of the fact that it's called "privacy" by some vendors, it provides no such thing. Also, keep in mind that it is illegal to encrypt your signal in any way over amateur frequencies (save a VERY few exceptions). There's nothing private in this technology unfortunately.