Dual Tone Radios - Radios that can use different tones for encode and decode for the same memory channel.
Last Updated: 07/30/2013
Commercial radios have long been able to use one CTCSS frequency for tone encode (to the repeater) and a different one for tone decode (for the radio). This functionality adds flexibility for repeater use.
This has not been the case among amateur radios.
The radios that we know of that have this functionality are
Yaesu: FT-857, FT-897, FT-270, FT-277, FT-250, FT-1900, FT-2900 and FT-7900
Kenwood: TH-D72, TH-F6/F7, TH-K2, TM-271, TM-281, and TM-471
Baofeng: UV-5R, UV-F11, UV-B5, UV-B6
Wouxun: KG-UVD1P, KG-UV3D, KG-UV2D, KG-UV6
For the radios listed, access to the two tones is achieved by
1) Set the Offset Direction to Split (even if this is a repeater - just check that the Receive and Transmit frequency are correct).
2) Set Tone Mode to TSql (both the CTCSS and Rx CTCSS columns will become active)
3) Set the correct values for the tone frequencies.
Note: Although many radios use CTCSS and Rx CTCSS in the programmer, the radio us designed to use these two values separately. CTCSS will be associated with Tone Mode of Tone (encode) the value shown will be sent to the repeater. Rx CTCSS will be associated with TSql and this ONE value will be transmitted to the repeater and heard by the radio during tone squelch operataions.
It may appear that you can set these two values independently from the face of the radio. Right... you can. However, the radio will not use them at the same time. The radios in the list were identified through testing with other radios using tones set to specifically measure or trigger toned responses. Through this testing we determined that these radios have that advanced functionality.
Radios lacking dual tone functionality but with dual displays may be able to emulate this function. This could be done by using one channel to transmit with one tone, and listening on another channel which is set to a different tone.