<div dir="auto"><div>The problem may be the use of the wrong hashing algorithm. They are generating max of 22 bit hashes. Too me, that is ancient history. I only use sha256 to generate hashes.<br><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Wed, Mar 6, 2024, 9:48 AM Tim K1DC <<a href="mailto:k1dc.radio@gmail.com">k1dc.radio@gmail.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><u></u>
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<font face="Verdana">In the last few weeks while operating FT8 I've
seen calls from Nigeria (ATNO for me), North Korea (ATNO for most
everyone) and Antarctica that were suspiciously loud and
completely unresponsive to my calls. A quick check of QRZ.com
indicated that there was no info on these calls. I was
experiencing an FT8 'hash collision'.<br>
<br>
The short version of the story is that the FT8 protocol uses a
shortcut (a hash code) to send some callsigns. In some rare-ish
cases it is possible for multiple call signs to have the same hash
code value. For example (this is a made up example), 'PY2PEACE'
could share the same hash code as 'P5AXXX'. So while PY2PEACE is
active on FT8 it may appear in your decode list as P5AXXX. You
start frantically calling P5AXXX with no response. There is a
much longer, and detailed description of the issue here:
<a href="https://bit.ly/49AnNOC" target="_blank" rel="noreferrer">https://bit.ly/49AnNOC</a><br>
<br>
So if you happen to run across a P5 on 10m FT8 and it is not under
the Mother-of-all-pileups you can simply restart your FT8 software
and it will rebuild the hash code table. This will work a lot of
the time, but not always. So do a little research on that
too-good-to-be-true call before you tape down your 'Enable TX'
button.<br>
<br>
73,<br>
Tim - K1DC<br>
</font>
<div>-- <br>
<p style="font-family:Verdana,Geneva,sans-serif;font-size:10px">Courageously
sent from a non-Apple device that <em>includes</em> a headphone
jack.</p>
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<h3>Tim Carter - K1DC (was KC1RET)</h3>
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