Well, you can use either but I don't think they will work at the same time as others have said the decoders won't like it. Also in a mixed system, some radios looking for dcs and some ctcss, there are some ctcss codes that will respond to some ctcss codes and the other way around also, so you have to be careful of code selection.
Transmitting both at the same time will not cause them to mix however, that is unless you have a very non linear audio system. But the decoder dcs decoder will see a wave of a ctcss tone at times as part of a dcs pulse and will either false or lock out because of it. The reverse can also happen with the ctcss decoder. The repetition rate of both are close to each other and the dcs is transmitted as more of a sin wave than it is a square wave so the decoders have a hard time distinguishing each other. 73 Gary K4FMX > -----Original Message----- > From: [email protected] [mailto:Repeater- > [EMAIL PROTECTED] On Behalf Of Bob M. > Sent: Monday, July 02, 2007 10:25 AM > To: [email protected] > Subject: Re: [Repeater-Builder] ctcss and dcs at same time? > > Both signals are generated by the microprocessor, > which has enough troubles doing just one, hence the > programming restriction that only lets you choose one > or the other. > > They both modulate the VCO. CTCSS is a continuous > sine-wave, DCS is a continuous binary coded > square-wave with varying positive and negative pulse > widths. IF you could generate both, or feed both to > the VCO, at the same time, you'd end up with a mixing > situation, where you would end up with both > fundamental signals plus the sum and difference. The > CTCSS would interfere with the DCS and vice versa. The > sum and difference would also get into the mix. The > poor microprocessor in the receiver, attempting to > locate, lock on, and recognize/decode the signals > would see a constantly changing input and just say > "fuggedaboudit". Even two discrete decoders would have > problems. However a vibrating reed might have some > luck with the CTCSS, but not much you can do about the > DCS as it always requires some complex electronics or > software algorithm to be decoded. > > Nothing says you can't send either signal to the VCO > based on what the receiver is hearing. Just not both > at the same time. > > Bob M. > ====== > --- ku4zs1 <[EMAIL PROTECTED]> wrote: > > > Is it possible to run CTCSS and DCS at the same time > > on a > > transmitter? Aside from the fact that most radios > > will not allow you > > to select both at the same time (I will be using an > > outboard DCS > > encoder and the built in CTCSS encoder). I am not > > sure if they are > > capable of both running at the same time. Thanks. > > > > > > Rusty Coleman > > KU4ZS > > > > __________________________________________________________________________ > __________ > Be a better Heartthrob. Get better relationship answers from someone who > knows. Yahoo! Answers - Check it out. > http://answers.yahoo.com/dir/?link=list&sid=396545433 > > > > > > Yahoo! Groups Links > > >
