At 06:44 PM 7/18/2008, you wrote: >Tom, > >The TIA-recommended standard deviation for CTCSS is 500 Hz on a 16K0F3E or >20K0F3E emission. Most CTCSS decoders can reliably detect tone deviated as >low as 100 Hz. Any deviation greater than 500 Hz can be considered >excessive
I thought that GE recommended 750 Hz for the Mastr II/ExecII/MVP series radios, & that Motorola's spec. was even higher. Perhaps this isn't TIA recommended, but that is what the equipment was designed for. For myself, I strike a compromise & use around 600-700 Hz. The repeater's TX CTCSS can be much lower because most ham rigs do a very good job of decoding noisy signals. In fact, some of them are too good - they false on noise. >The HTX-404 is known for somewhat distorted (raspy) CTCSS tones, and that >may be part of the problem. One HTX-404 I tested had a very "deaf" CTCSS decoder, requiring a minimum of 600 Hz to reliably decode. Don't know if they're all that way or just the one I tried. Bob NO6B
