[TVARC] Alphanumeric Characters in FT8 Responses

Sun Jun 9 11:23:07 EDT 2024

George,

Thanks for the info on the characters.  I'm using version 2.6.1 and
wondered if the characters were part of a new release.  WSJT-X V2.7.1 rc2
seems to be a pre-production release that contains the "a#" characters.  I
think they serve as aid to the decoding function by determining a
probability of what it is supposed to be.

This got me to thinking about what the future holds with all the buzz about
AI software.  Today's ham operating has a lot of the computer in the loop.
For example, WSJT-X FT8 operating involves little more than point and click
on a station that the program receives via my rig interface, decodes,
transmits, and logs.  It should be fairly straightforward for an AI program
to learn my operating habits for the mode.  It would look for the best DX
on the band at a given time, find a transmit slot for me, call the station,
etc. My virtual self could operate 24/7 working stations and uploading them
to my logging program.  With the right AI capabilities, I might even be
able to keep K2TE on the air long after I become a member of the SK club,
hi.

73 de Ed

On Sun, Jun 9, 2024 at 3:39 AM James Simpson <kf8j at hamware.com> wrote:

> Do we know what they mean??
>
> Sent from my iPhone
> Jim Simpson, KF8J
> 937-478-0996
>
> On Jun 8, 2024, at 1:15 PM, Jim Shaw <jshaw32163 at gmail.com> wrote:
>
> 
>
> I’ve gotten those, but I don’t have “Enable AP” checked, just “Deep” in
> the Decode menu.
>
>
>
> 73
>
> Jim
>
> AL7BA/8
>
>
>
> Ps I’ll listen for you, Pete.  Where are you starting out on SSB?
>
>
>
> *From:* tvarc-bounces at mailman.qth.net <tvarc-bounces at mailman.qth.net> *On
> Behalf Of *K2PS Pete Stafford
> *Sent:* Saturday, June 8, 2024 13:09
> *To:* k2dm at comcast.net; 'Ed Deichler' <k2te.1nh at gmail.com>; 'villages
> reflector' <TVARC at mailman.qth.net>
> *Subject:* Re: [TVARC] Alphanumeric Characters in FT8 Responses
>
>
>
> I think you’ve got it.  I’ve wondered about the Enable AP choice in the
> WSJT Decode menu.  Now I know!
>
>
>
> Thanks, George.
>
>
>
> 73, Pete, K2PS
>
>
>
> *From:* k2dm at comcast.net <k2dm at comcast.net>
> *Sent:* Saturday, June 8, 2024 10:55 AM
> *To:* K2PS Pete Stafford <psk2ps at gmail.com>; 'Ed Deichler' <
> k2te.1nh at gmail.com>; 'villages reflector' <TVARC at mailman.qth.net>
> *Subject:* Re: [TVARC] Alphanumeric Characters in FT8 Responses
>
>
>
> Could this be it?  From the WSJT-x manual:  (the formatting didn't copy)
>
>
>
> 12. Decoder Notes 12.1. AP Decoding The WSJT-X decoders for FST4, FT4,
> FT8, JT65, and Q65 include procedures that use naturally accumulating
> information during a minimal QSO. This a priori (AP) information increases
> sensitivity of the decoder by up to 4 dB, at the cost of a slightly higher
> rate of false decodes. AP is optional in FT8 and JT65, but is always
> enabled for Q65 and for FT4 and FST4 when decode depth is Normal or Deep.
> For example: when you decide to answer a CQ, you already know your own
> callsign and that of your potential QSO partner. The software therefore
> “knows” what might be expected for at least 57 message bits (28 for each of
> two callsigns, one or more for message type) in the next received message.
> The decoder’s task is thus reduced to determining the remaining 15 bits of
> the message and ensuring that the resulting solution is reliable. AP
> decoding starts by setting AP bits to the hypothesized values, as if they
> had been received correctly. We then determine whether the remaining
> message and parity bits are consistent with the hypothesized AP bits, with
> a specified level of confidence. Successful AP decodes are labeled with an
> end-of-line indicator of the form aP , where P is one of the single-digit
> AP decoding types listed in Table 1. For example, a2 indicates that the
> successful decode used MyCall as hypothetically known information. Type a7
> , used only in FT8 mode, uses information from the previous Rx sequence.
> Table 1. FST4, FT4, and FT8 AP information types aP Message components a1
> CQ ? ? a2 MyCall ? ? a3 MyCall DxCall ? a4 MyCall DxCall RRR a5 MyCall
> DxCall 73 a6 MyCall DxCall RR73 a7 (Call_1 or CQ) Call_2 ? If a codeword is
> found that is judged to have high (but not overwhelmingly high) probability
> of being correct, a ? character is appended when the decoded message is
> displayed. To avoid misleading spots of occasional false decodes, messages
> so marked are not forwarded to PSK Reporter (
> https://pskreporter.info/pskmap.html). Table 2 lists the six possible QSO
> states that are tracked by the WSJT-X auto-sequencer, along with the type
> of AP decoding that would be attempted in each state in FT4 or FT8. The
> FST4 table (not shown) is the same except that it omits the decoding
> attempts for AP types 4 and 5 to save time. Table 2. FT4 and FT8 AP
> decoding types for each QSO state State AP type CALLING STN 2, 3 REPORT 2,
> 3 ROGER_REPORT 3, 4, 5, 6 ROGERS 3, 4, 5, 6 SIGNOFF 3, 1, 2 CALLING CQ 1, 2
> Decoding with a priori information behaves slightly differently in JT65.
> Some details are provided in Tables 3 and 4. Table 3. JT65 AP information
> type
>
>
>
> George K2DM
>
>
> ------------------------------
>
> *From:* tvarc-bounces at mailman.qth.net <tvarc-bounces at mailman.qth.net> on
> behalf of K2PS Pete Stafford <psk2ps at gmail.com>
> *Sent:* Saturday, June 8, 2024 10:41 AM
> *To:* 'Ed Deichler' <k2te.1nh at gmail.com>; 'villages reflector' <
> TVARC at mailman.qth.net>
> *Subject:* Re: [TVARC] Alphanumeric Characters in FT8 Responses
>
>
>
> Yes, and no clue.
>
>
>
> Pete
>
>
>
> *From:* tvarc-bounces at mailman.qth.net <tvarc-bounces at mailman.qth.net> *On
> Behalf Of *Ed Deichler
> *Sent:* Saturday, June 8, 2024 10:07 AM
> *To:* villages reflector <TVARC at mailman.qth.net>
> *Subject:* [TVARC] Alphanumeric Characters in FT8 Responses
>
>
>
> I'm sure many have noticed the "a#" (a2, a3, a7, etc.) characters that
> occur in the response line when working stations in FT8.  I haven't been
> able to find an explanation as to what they mean.
>
>
>
> Anybody have a clue?
>
>
>
> 73 de Ed
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