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Hi Bob,<br>
<br>
Interesting question. I'm thinking that the only important values
at the high end of the scale are whether the object is in orbit
(999), or going faster than Mach 1 (998). Between Mach 1 and
orbital velocity, whatever it is will be something military (RIP,
Concorde), with the speed of sound being the important dividing
line. How much above Mach 1 the object is going is probably not too
important (unless you are the target), likely unknown with any
precision, and probably too dynamic to track anyway. If you want
another inflection point, perhaps Mach 2 (so, 998 for Mach 2, 997
for Mach 1)? There's probably an exponentially decreasing
population of objects beyond that. But, Mach 1 is the fundamental
dividing line for "fast things" for me. I suppose we'll need to
revisit this if Elon's ICBM-with-passengers concept happens.<br>
<br>
For this purpose, I would propose an average Mach 1 velocity of 750
mi/hr (1,200 km/h). The exact value is both altitude and
temperature dependent, but I'm thinking that once you're in that
territory, you will quickly settle out a good distance on one side
or the other.<br>
<br>
Greg KO6TH<br>
<br>
<br>
<div class="moz-cite-prefix">Byon Garrabrant wrote:<br>
</div>
<blockquote type="cite"
cite="mid:f08cb54d-409b-4488-96e6-ff02b7f1d607@Spark">
<title></title>
<div name="messageBodySection" style="font-size: 14px;
font-family: -apple-system, BlinkMacSystemFont, sans-serif;">As
long as you are defining arbitrary values like this, perhaps
use:
<div><br>
<div>999 = unknown or not applicable speed</div>
<div>998 = faster than 15200 knots</div>
<div>997 = 15200 to 1601 knots</div>
<div>996 = 1600 to 1201 knots</div>
<div>995 = 1200 to 995 knots</div>
<div>994 = 994 knots</div>
</div>
<div><br>
</div>
<div>Byon</div>
</div>
<div name="messageReplySection" style="font-size: 14px;
font-family: -apple-system, BlinkMacSystemFont, sans-serif;"><br>
On Oct 11, 2017, 8:18 AM -0700, Robert Bruninga
<a class="moz-txt-link-rfc2396E" href="mailto:bruninga@usna.edu"><bruninga@usna.edu></a>, wrote:<br>
<blockquote type="cite" style="margin: 5px 5px; padding-left:
10px; border-left: thin solid #1abc9c;">
<div class="WordSection1">
<p class="MsoNormal"><span style="color:#1f497d">My head
hurts trying to read the Mic-E spec as written.</span></p>
<p class="MsoNormal"><span style="color:#1f497d">Also, I
screwed up MPH and KTS in last email…</span></p>
<p class="MsoNormal"><span style="color:#1f497d">So here is
what I am suggesting for the CSE/SPD field:</span></p>
<p class="MsoNormal"><span style="color:#1f497d"> </span></p>
<p class="MsoNormal"><span style="color:#1f497d">999 =
15,200 knots space station</span></p>
<p class="MsoNormal"><span style="color:#1f497d">998 =
1600 knots military mach 2.8</span></p>
<p class="MsoNormal"><span style="color:#1f497d">997 =
1200 knots Concorde</span></p>
<p class="MsoNormal"><span style="color:#1f497d">996 =
996 knots normal speeds down to 0</span></p>
<p class="MsoNormal"><span style="color:#1f497d"> </span></p>
<p class="MsoNormal"><span style="color:#1f497d">So using
this same idea for Mic-E would result in</span></p>
<p class="MsoNormal"><span style="color:#1f497d"> </span></p>
<p class="MsoNormal"><span style="color:#1f497d">789 =
15,200 knots space station</span></p>
<p class="MsoNormal"><span style="color:#1f497d">788 =
1600 knots military mach 2.8</span></p>
<p class="MsoNormal"><span style="color:#1f497d">787 =
1200 knots Concorde</span></p>
<p class="MsoNormal"><span style="color:#1f497d">786 =
996 knots for consistency with above</span></p>
<p class="MsoNormal"><span style="color:#1f497d">785 =
785 knots normal speeds down to 0</span></p>
<p class="MsoNormal"><span style="color:#1f497d"> </span></p>
<p class="MsoNormal"><span style="color:#1f497d">Any
objections? About the only one we will ever use is the
orbital velocity for the space station and for
satellites, but I thought we may as well include a few
more.</span></p>
<p class="MsoNormal"><span style="color:#1f497d"> </span></p>
<p class="MsoNormal"><span style="color:#1f497d">Bob, WB4APR</span></p>
<p class="MsoNormal"><span style="color:#1f497d"> </span></p>
<p class="MsoNormal"><span style="color:#1f497d"> </span></p>
<div>
<div style="border:none;border-top:solid #e1e1e1
1.0pt;padding:3.0pt 0in 0in 0in">
<p class="MsoNormal"><b>From:</b> Robert Bruninga
[mailto:<a href="mailto:bruninga@usna.edu"
moz-do-not-send="true">bruninga@usna.edu</a>]<br>
<b>Sent:</b> Wednesday, October 11, 2017 8:48 AM<br>
<b>To:</b> TAPR APRS Mailing List<br>
<b>Cc:</b> Robert Bruninga<br>
<b>Subject:</b> APRS Speed Spec?</p>
</div>
</div>
<p class="MsoNormal"> </p>
<p class="MsoNormal">Authors,</p>
<p class="MsoNormal">I thought that I had years ago declared
that a speed of 999 would mean Orbital Velocity 17,500 MPH
and that 998 would mean something else for high speed
jets. Maybe mach 3?</p>
<p class="MsoNormal"> </p>
<p class="MsoNormal">Actually I may have defined three
speeds greater than 999 for the last three enetries.</p>
<p class="MsoNormal"> </p>
<p class="MsoNormal">Clearly we need orbital velocity for
the Space station, etc…</p>
<p class="MsoNormal">And Mach 3 for our fighter pilots…</p>
<p class="MsoNormal">And something for the Concord (or its
replacement)…</p>
<p class="MsoNormal">What about Elon Musk’s hypter tube?
But I think it is under 999…</p>
<p class="MsoNormal"> </p>
<p class="MsoNormal">Anyway, is this written down anywhere?</p>
<p class="MsoNormal"> </p>
<p class="MsoNormal">And if not, then here is what I
propose:</p>
<p class="MsoNormal">999 = 17500 MPH space station</p>
<p class="MsoNormal">998 = 1850 MPH military</p>
<p class="MsoNormal">997 = 1350 MPH concord</p>
<p class="MsoNormal">996 = 996 MPH</p>
</div>
</blockquote>
</div>
<br>
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<br>
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</blockquote>
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