All ham radio ALE channels are specified by dial (VFO) frequency in USB (Upper Sideband). The standard ALE 8FSK signal always transmits FIXED audio tones. The common ham practice of saying the "offset" is not needed with ALE. The lowest of the ALE 8 tones is 750Hz and the highest tone is 2500Hz. The ALE 8FSK centre is 1625Hz.
If your transceiver is tuned to an ALE channel, you can always decode all the other ALE stations on that channel. Quite simple. Rather than seeing ALE as a digital mode in itself, try to consider ALE as a platform for initiating QSOs or Nets in any mode. Thus, when you have a QSO established on an ALE channel, you now have a common passband for SSB voice, CW, texting, digital voice, images, data ARQ or FEC... using any mode. If you are linking on an ALE VOICE channel, you can continue the QSO in SSB voice (USB standard on all bands). If you are linking on an ALE DATA channel, it is customary to start the QSO with a short AMD of 40 characters or less, that includes only your Name, QTH, and your ALE "platform" (such as PCALE, MARS-ALE, HARDWARE, or MULTIPSK). This initial AMD helps open the possibility to use other modes you have in common, and the QSO may continue with one of them. Keep in mind that if the other station is using a transceiver with built-in ALE commonly known as "HARDWARE" ALE, then you may be limited to the universal AMD text messaging only. They will be reading your AMD message on their transceiver's LCD display. For ham radio ALE, 1500Hz is the standard audio centre for initiating an unknown digital mode during a link. Here are some of the standard modes and offsets that have been in normal use by hams with ALE: SSB Voice: no offset, USB Upper Sideband standard on all bands. ALE AMD: the "universal" ALE standard 8FSK short text messages. DTM or DBM with ARQ: standard 8FSK using PCALE or MARS-ALE software. PSK31 or PSK63: 1500Hz audio centre; ask operator via AMD. Olivia: 1500Hz audio centre, 500Hz/16tone; ask operator via AMD. CW: +700Hz or +1000Hz, ask operator via AMD. Digital Voice: AOR system with USB (Upper Sideband) no offset. Note: Recently, MULTIPSK has introduced an 8FSK "FAE" mode. 73---Bonnie KQ6XA .
