[RTTY] who understands rtty code, strange thing happening, same characters always dropped

[Joe Subich, W4TV]

 >> A, C, D, E, F, I, J, K, R and U, and 3, 4, 7, 8,

All of these characters either start or stop with a space (I has
seen them listed both ways in code tables and can't track down a
definitive "Bit order" - Chen?).  There are two other "printing"
characters with the same attribute (N and S).

In the FT-920 "space" is FSK line open, mark is FSK line pulled
low (to ground).  I would suspect a problem in the FT-920 ...
perhaps a pull-up issue.

 > Maybe something went nuts in the lookup table which stores the
 > actual code pattern transmitted for each character.

microKEYER does not use a "lookup table" - it implements a UART.
Since the report is the same issue when changing microKEYERs, I
think one can safely eliminate both the software and interface.

I'd suggest bypassing the FSK circuit in the FT-920 and going to
AFSK.  Yaesu's Application Note on Digital modes with the FT-920
has been sent direct to avoid the attachment issues with Mailman.

73,

    ... Joe, W4TV

On 1/7/2011 10:51 AM, Jerry Flanders wrote:
> As a test, I would completely uninstall and reinstall whatever
> program is generating the RTTY  (MMTTY or whatever). Maybe something
> went nuts in the lookup table which stores the actual code pattern
> transmitted for each character.
>
> Or try a different program temporarily.
>
> Jerry W4UK
>
> At 08:06 AM 1/7/2011, you wrote:
>> trying to setup a FT-920 with a microkeyer for FSK use with
>> MMTTY....it's not my rig, so not sure the history, it keys up fine,
>> but sends strange or missing characters, tried it with a different
>> microkeyer, and tried it with power all the way down.....here is
>> whats strange, it always drops the same characters, not matter what,
>> I repeated this test several times this morning. It always misses:
>> A, C, D, E, F, I, J, K, R and U, and 3, 4, 7, 8, and enter....I
>> suspect the keying circuit in the radio, but not sure, I don't
>> believe anyone else has tried FSK with this rig.....any thoughts?
>> _______________________________________________
>> RTTY mailing list
>> RTTY at contesting.com
>> http://lists.contesting.com/mailman/listinfo/rtty
>
> _______________________________________________
> RTTY mailing list
> RTTY at contesting.com
> http://lists.contesting.com/mailman/listinfo/rtty
>