Understanding CHIRP's columns

This document is intended to help users understand the meaning of each column in the channel editor. In most cases, the default value for a column can be used if you don't know what the meaning of the column is.

Users unfamiliar with programming radios are encouraged to enable Hide Unused Fields mode in the View menu. Also, enabling Smart Tone Modes in the same location can be rather helpful for reducing confusion.

Loc

This is the location or "channel number" of the memory. The limits of what can be in this field are defined by your radio.

Frequency

This defines the receive frequency of the channel in Megahertz. If Duplex is set to None, then it is also the transmit frequency of the channel.

Name

This is the alphanumeric label for the memory, as displayed on the front panel. The length and valid characters are defined by what the radio is capable of supporting.

Tone Mode

This sets the mode used to transmit or receive squelch tones (or related selective calling technologies). The following explains what the options means:

  • (None): No tone or code is transmitted, receive squelch is open or carrier-triggered.
  • Tone: A single CTCSS tone is transmitted, receive squelch is open or carrier-triggered. The tone used is that which is set in the Tone column.
  • TSQL: A single CTCSS tone is transmitted, receive squelch is tone-coded to the same tone. The tone used is that which is set in the ToneSql column.
  • DTCS: A single DTCS/DCS code is transmitted, receive squelch is digitally tone-coded to the same code. The code used is that which is set in the DTCS Code column.
  • Cross: A complex arrangement of squelch technologies is in use. See the definition of the Cross Mode column for details.

Tone

This sets the CTCSS tone to be transmitted if the Tone Mode is set to Tone. In Cross mode, it has additional meanings (see description of Cross Mode for more details).

ToneSql

This sets the CTCSS tone to be transmitted and used for receiver squelch if the Tone Mode is set to TSQL. In Cross mode it has additional meanings (see description of Cross Mode for more details).

DTCS Code

This sets the DTCS code to be transmitted and used for receiver squelch if the Tone Mode is set to DTCS. In Cross mode it has additional meanings (see description of Cross Mode for more details).

DTCS Rx Code

This sets the DTCS code to be used for receiver squelch (if the radio supports this capability) and Tone Mode is set to Cross (see description of Cross Mode for more details).

DTCS Pol

This sets the DTCS polarity of the transmitted code and the code used for the receive squelch any time DTCS is used for transmit or receive squelch. The first character pertains to the transmit polarity and the second pertains to receive polarity. The corresponding character is N for normal or R for reversed (aka "inverted") polarity.

Duplex

This sets the duplex mode of the channel. If set to (None) then the transmit and receive frequencies are the same. If set to either +* or *- (plus or minus) then the transmit frequency will be either above or below (respectively) the receive frequency by the value of the Offset field.

If the duplex is set to split then the Offset field should contain the absolute transmit frequency to be used (if the radio supports this capability).

If the duplex is set to off then transmission on this channel will be disabled (if the radio supports this capability).

Note that for simplex channels, this should be set to (None) and repeater channels should have this set to either +,-, or split.

Offset

This sets the amount of difference between the transmit and receive frequencies used for the channel if Duplex is not (None) or off (in which case it is ignored). If the Duplex is set to a shift direction, then the Offset field should be set to the amount (in Megahertz) above or below the receive frequency to shift to find the transmit frequency. If Duplex is set to split then the Offset field should be set to an absolute transmit frequency.

Mode

This controls the transmit and receive mode of the channel. The following lists the common values and their meanings:

  • FM: "Wide" FM for two-way communications (i.e. 5 kHz deviation)
  • NFM: "Narrow" FM for two-way communications (i.e. 2.5 kHz deviation)
  • WFM: "Wide" FM for broadcast communications (i.e. ~100 kHz deviation)
  • AM: "Narrow" AM for two-way communications (i.e. aircraft band in the US)
  • DV: Icom's digital D-STAR mode

Tune Step

The tuning step used to channelize the receive frequency.

Skip

The scan skip mode for the channel. The values and their meanings are:

  • S: Skip this channel during scan
  • P: This channel is a priority

Cross Mode

This field controls the squelch behavior of the channel when the Tone Mode is set to Cross. Each value consists of two technologies separated by an arrow (->). The value to the left of the arrow controls the selective-call method used on transmit, while the one to the right of the arrow controls the receive squelch. The possible values are:

  • Tone: CTCSS tones are used. Transmit tone is taken from the Tone column, receive tone from the ToneSql column.
  • DTCS: DTCS/DCS codes are used. Transmit code is taken from the DTCS Code column, receive code from the DTCS Rx Code column.
  • <blank>: Indicates that no method is used for this, either transmit or receive.

The Cross Mode field allows addressing more commercial modes of squelch operation, such as using different tones or codes for transmit and receive. For example:

  • Tone->Tone: This means use the Tone value for transmit tone, and the ToneSql value for receive squelch
  • Tone->DTCS: This means use the Tone value for transmit tone, and the DTCS Rx Code value for receive squelch
  • DTCS->Tone: This means use the DTCS Code value for transmit code, and the ToneSql value for receive squelch
  • ->Tone: This means do not transmit a Tone or DTCS Code, but use the ToneSql value for receive squelch
  • ->DTCS: This means do not transmit a Tone or DTCS Code, but use the DTCS Rx Code value for receive squelch
  • DTCS->: This means use the DTCS Code value for transmit code, and receive squelch is open or carrier-triggered
  • DTCS->DTCS: This means use the DTCS Code value for transmit code, and the DTCS Rx Code value for receive squelch
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