<html>
<head>
<style><!--
.hmmessage P
{
margin:0px;
padding:0px
}
body.hmmessage
{
font-size: 10pt;
font-family:Tahoma
}
--></style>
</head>
<body class='hmmessage'><div dir='ltr'>
Steve,<BR>
<BR>
Since you are obviuosly a risk taker and like to stir the pot a bit ;-) and have brought the subject of netting back up again... I thought I thought I would joint you and say I'm surprised that nobody has discussed the issue of the effects of doppler on mobile stations and how it affects the the signal at 10MHZ. and what it will do to all the hours of alignment that people are currently perfoming. See my calcs below.<BR>
<BR>
<TABLE class=calc cellSpacing=1 cellPadding=0 width=300 border=0>
<TBODY>
<TR>
<TD><SMALL><I>Source speed:</I></SMALL></TD>
<TD><INPUT class=infield onblur=calculate(); size=10 value=110 name=ia {95919BE0-C436-4eab-8083-096E94826667}="110"></TD>
<TD><SELECT class=infield onchange=calculate(); name=uia><OPTION value=1:1:0>m/s</OPTION> <OPTION value=0:1:0>--- METRIC ---</OPTION> <OPTION value=100:1:0>cm/s</OPTION> <OPTION value=0.001:1:0 selected>km/s</OPTION> <OPTION value=0:1:0>-- IMPERIAL --</OPTION> <OPTION value=39.37007874:1:0>inches/second</OPTION> <OPTION value=3.280839895:1:0>feet/second</OPTION> <OPTION value=196.8503837:1:0>feet/minute</OPTION> <OPTION value=0:1:0>- RECIPROCAL -</OPTION> <OPTION value=26.8224000006523:-1:0>min/mile</OPTION> <OPTION value=16.6666666666667:-1:0>min/km</OPTION> <OPTION value=83.3333333333333:-1:0>min/5 km</OPTION> <OPTION value=166.666666666667:-1:0>min/10 km</OPTION> <OPTION value=0:1:0>--- OTHER ---</OPTION> <OPTION value=3.6:1:0>km/h</OPTION> <OPTION value=2.236936292:1:0>mph</OPTION> <OPTION value=0.000621371192:1:0>miles/second</OPTION> <OPTION value=1.943844492:1:0>knots</OPTION> <OPTION value=6012.884753:1:0>furl's/f'night</OPTION> <OPTION value=0.0029385836027035:1:0>Mach</OPTION> <OPTION value=3.335640952e-09:1:0>c</OPTION></OPTION></OPTION> (light speed)</OPTION></SELECT></TD></TR>
<TR>
<TD><SMALL><I>Angle á</I></SMALL></TD>
<TD><INPUT class=infield onblur=calculate(); size=10 value=0 name=ib {95919BE0-C436-4eab-8083-096E94826667}="0"></TD>
<TD><SELECT class=infield onchange=calculate(); name=uib><OPTION value=1:1:0 selected>degrees (°)</OPTION> <OPTION value=17.4532925199433:1:0>milliradians</OPTION></OPTION></OPTION></OPTION> <OPTION value=0.0174532925199433:1:0>radians</OPTION> <OPTION value=1.11111111111111:1:0>grad</OPTION> <OPTION value=60:1:0>arcseconds</OPTION></OPTION></OPTION></OPTION> <OPTION value=3600:1:0>arcminutes</OPTION></OPTION></OPTION></OPTION> <OPTION value=0.00277777777777778:1:0>circles</OPTION></SELECT></TD></TR>
<TR>
<TD><SMALL><I>Wave speed:</I></SMALL></TD>
<TD><INPUT class=infield onblur=calculate(); size=10 value=1 name=ic {95919BE0-C436-4eab-8083-096E94826667}="1"></TD>
<TD><SELECT class=infield onchange=calculate(); name=uic><OPTION value=1:1:0>m/s</OPTION> <OPTION value=0:1:0>--- METRIC ---</OPTION> <OPTION value=100:1:0>cm/s</OPTION> <OPTION value=0.001:1:0>km/s</OPTION> <OPTION value=0:1:0>-- IMPERIAL --</OPTION> <OPTION value=39.37007874:1:0>inches/second</OPTION> <OPTION value=3.280839895:1:0>feet/second</OPTION> <OPTION value=196.8503837:1:0>feet/minute</OPTION> <OPTION value=0:1:0>- RECIPROCAL -</OPTION> <OPTION value=26.8224000006523:-1:0>min/mile</OPTION> <OPTION value=16.6666666666667:-1:0>min/km</OPTION> <OPTION value=83.3333333333333:-1:0>min/5 km</OPTION> <OPTION value=166.666666666667:-1:0>min/10 km</OPTION> <OPTION value=0:1:0>--- OTHER ---</OPTION> <OPTION value=3.6:1:0>km/h</OPTION> <OPTION value=2.236936292:1:0>mph</OPTION> <OPTION value=0.000621371192:1:0>miles/second</OPTION> <OPTION value=1.943844492:1:0>knots</OPTION> <OPTION value=6012.884753:1:0>furl's/f'night</OPTION> <OPTION value=0.0029385836027035:1:0>Mach</OPTION> <OPTION value=3.335640952e-09:1:0 selected>c</OPTION></OPTION></OPTION> (light speed)</OPTION></SELECT></TD></TR>
<TR>
<TD><SMALL><I>Emitted frequency:</I></SMALL></TD>
<TD><INPUT class=infield onblur=calculate(); size=10 value=10 name=id {95919BE0-C436-4eab-8083-096E94826667}="10"></TD>
<TD><SELECT class=infield onchange=calculate(); name=uid><OPTION value=1:1:0>Hz (per s)</OPTION> <OPTION value=0:0:0>- FREQENCY -</OPTION> <OPTION value=0.001:1:0>kHz (per ms)</OPTION> <OPTION value=1e-06:1:0 selected>MHz (per ?s)</OPTION> <OPTION value=1e-09:1:0>GHz (per ns)</OPTION> <OPTION value=1e-09:1:0>THz</OPTION> <OPTION value=60:1:0>per minute</OPTION> <OPTION value=3600:1:0>per hour</OPTION> <OPTION value=86400:1:0>per day</OPTION> <OPTION value=604800:1:0>per week</OPTION> <OPTION value=2592000:1:0>per month</OPTION> <OPTION value=31557600:1:0>per year</OPTION> <OPTION value=0:0:0>--- PERIOD ---</OPTION> <OPTION value=1000000000:-1:0>ns</OPTION> <OPTION value=1000000:-1:0>?s</OPTION> <OPTION value=1000:-1:0>ms</OPTION> <OPTION value=1:-1:0>s</OPTION> <OPTION value=0.0166666666667:-1:0>mins</OPTION></OPTION></OPTION></OPTION> <OPTION value=0.000277777777777778:-1:0>hours</OPTION> <OPTION value=1.15740740740741e-05:-1:0>days</OPTION> <OPTION value=1.65349153491535e-06:-1:0>weeks</OPTION> <OPTION value=3.1688087814e-08:-1:0>years</OPTION></SELECT></TD></TR>
<TR>
<TD colSpan=3>
<HR>
</TD></TR>
<TR>
<TD><SMALL><I>Increase in frequency:</I></SMALL></TD>
<TD><INPUT class=outfield readOnly size=10 value=-0.0366786 name=oa {95919BE0-C436-4eab-8083-096E94826667}="-0.0366786"></TD>
<TD><SELECT class=outfield onchange=calculate(); name=uoa><OPTION value=1:1:0 selected>%</OPTION> <OPTION value=0.01:1:0>[fraction]</OPTION></SELECT></TD></TR>
<TR>
<TD><SMALL><I>Detected frequency:</I></SMALL></TD>
<TD><INPUT class=outfield readOnly size=10 value=9.99633e+6 name=ob {95919BE0-C436-4eab-8083-096E94826667}="9.99633e+6"></TD>
<TD><SELECT class=outfield onchange=calculate(); name=uob><OPTION value=1:1:0 selected>Hz (per s)</OPTION> <OPTION value=0:0:0>- FREQENCY -</OPTION> <OPTION value=0.001:1:0>kHz (per ms)</OPTION> <OPTION value=1e-06:1:0>MHz (per ?s)</OPTION> <OPTION value=1e-09:1:0>GHz (per ns)</OPTION> <OPTION value=1e-09:1:0>THz</OPTION> <OPTION value=60:1:0>per minute</OPTION> <OPTION value=3600:1:0>per hour</OPTION> <OPTION value=86400:1:0>per day</OPTION> <OPTION value=604800:1:0>per week</OPTION> <OPTION value=2592000:1:0>per month</OPTION> <OPTION value=31557600:1:0>per year</OPTION> <OPTION value=0:0:0>--- PERIOD ---</OPTION> <OPTION value=1000000000:-1:0>ns</OPTION> <OPTION value=1000000:-1:0>?s</OPTION> <OPTION value=1000:-1:0>ms</OPTION> <OPTION value=1:-1:0>s</OPTION> <OPTION value=0.0166666666667:-1:0>mins</OPTION></OPTION></OPTION></OPTION> <OPTION value=0.000277777777777778:-1:0>hours</OPTION> <OPTION value=1.15740740740741e-05:-1:0>days</OPTION> <OPTION value=1.65349153491535e-06:-1:0>weeks</OPTION> <OPTION value=3.1688087814e-08:-1:0>years</OPTION></SELECT></TD></TR>
<TR>
<TD><SMALL><I><SMALL><I><SMALL><I><SMALL><I><SMALL><I><SMALL><I><SMALL><I><SMALL><I>Muscial</I></SMALL></I></SMALL></I></SMALL></I></SMALL></I></SMALL></I></SMALL></I></SMALL> interval:</I></SMALL></TD>
<TD><INPUT class=outfield readOnly size=10 value=-0.00317554 name=oc {95919BE0-C436-4eab-8083-096E94826667}="-0.00317554"></TD>
<TD><SELECT class=outfield onchange=calculate(); name=uoc><OPTION value=1:1:0>semitones</OPTION> <OPTION value=100:1:0>cents</OPTION> <OPTION value=2:1:0>quarter-tones</OPTION> <OPTION value=0.5:1:0 selected>tones</OPTION> <OPTION value=0.142857142857143:1:0>perfect 5ths</OPTION> <OPTION value=0.0833333333333333:1:0>octaves</OPTION></SELECT></TD></TR>
<TR>
<TD></TD>
<TD><INPUT class=calculate onclick="return calculate()" type=button value=Calculate! name=go></TD></TR></TBODY></TABLE><BR>
<BR>
<A href="http://www.calctool.org/CALC/phys/default/doppler"></A> <BR>
<BR>
Realising this potentual problem, I reflected back to when I was young, my Platoon Sgt said, never come to me with a problem that you dont have a solution for. So in memory of Sgt Zima ( he really didnt like me much) I thought about this for awhile and the only way to be sure your on frequency exactly netted to the igate is to drive constantly at right angles to the each Igate: see below my calcs <BR>
<BR>
<TABLE class=calc cellSpacing=1 cellPadding=0 width=300 border=0>
<TBODY>
<TR>
<TD><SMALL><I>Source speed:</I></SMALL></TD>
<TD><INPUT class=infield onblur=calculate(); size=10 value=110 name=ia {95919BE0-C436-4eab-8083-096E94826667}="110"></TD>
<TD><SELECT class=infield onchange=calculate(); name=uia><OPTION value=1:1:0>m/s</OPTION> <OPTION value=0:1:0>--- METRIC ---</OPTION> <OPTION value=100:1:0>cm/s</OPTION> <OPTION value=0.001:1:0 selected>km/s</OPTION> <OPTION value=0:1:0>-- IMPERIAL --</OPTION> <OPTION value=39.37007874:1:0>inches/second</OPTION> <OPTION value=3.280839895:1:0>feet/second</OPTION> <OPTION value=196.8503837:1:0>feet/minute</OPTION> <OPTION value=0:1:0>- RECIPROCAL -</OPTION> <OPTION value=26.8224000006523:-1:0>min/mile</OPTION> <OPTION value=16.6666666666667:-1:0>min/km</OPTION> <OPTION value=83.3333333333333:-1:0>min/5 km</OPTION> <OPTION value=166.666666666667:-1:0>min/10 km</OPTION> <OPTION value=0:1:0>--- OTHER ---</OPTION> <OPTION value=3.6:1:0>km/h</OPTION> <OPTION value=2.236936292:1:0>mph</OPTION> <OPTION value=0.000621371192:1:0>miles/second</OPTION> <OPTION value=1.943844492:1:0>knots</OPTION> <OPTION value=6012.884753:1:0>furl's/f'night</OPTION> <OPTION value=0.0029385836027035:1:0>Mach</OPTION> <OPTION value=3.335640952e-09:1:0>c</OPTION></OPTION></OPTION> (light speed)</OPTION></SELECT></TD></TR>
<TR>
<TD><SMALL><I>Angle á</I></SMALL></TD>
<TD><INPUT class=infield onblur=calculate(); size=10 value=90 name=ib {95919BE0-C436-4eab-8083-096E94826667}="90"></TD>
<TD><SELECT class=infield onchange=calculate(); name=uib><OPTION value=1:1:0 selected>degrees (°)</OPTION> <OPTION value=17.4532925199433:1:0>milliradians</OPTION></OPTION></OPTION></OPTION> <OPTION value=0.0174532925199433:1:0>radians</OPTION> <OPTION value=1.11111111111111:1:0>grad</OPTION> <OPTION value=60:1:0>arcseconds</OPTION></OPTION></OPTION></OPTION> <OPTION value=3600:1:0>arcminutes</OPTION></OPTION></OPTION></OPTION> <OPTION value=0.00277777777777778:1:0>circles</OPTION></SELECT></TD></TR>
<TR>
<TD><SMALL><I>Wave speed:</I></SMALL></TD>
<TD><INPUT class=infield onblur=calculate(); size=10 value=1 name=ic {95919BE0-C436-4eab-8083-096E94826667}="1"></TD>
<TD><SELECT class=infield onchange=calculate(); name=uic><OPTION value=1:1:0>m/s</OPTION> <OPTION value=0:1:0>--- METRIC ---</OPTION> <OPTION value=100:1:0>cm/s</OPTION> <OPTION value=0.001:1:0>km/s</OPTION> <OPTION value=0:1:0>-- IMPERIAL --</OPTION> <OPTION value=39.37007874:1:0>inches/second</OPTION> <OPTION value=3.280839895:1:0>feet/second</OPTION> <OPTION value=196.8503837:1:0>feet/minute</OPTION> <OPTION value=0:1:0>- RECIPROCAL -</OPTION> <OPTION value=26.8224000006523:-1:0>min/mile</OPTION> <OPTION value=16.6666666666667:-1:0>min/km</OPTION> <OPTION value=83.3333333333333:-1:0>min/5 km</OPTION> <OPTION value=166.666666666667:-1:0>min/10 km</OPTION> <OPTION value=0:1:0>--- OTHER ---</OPTION> <OPTION value=3.6:1:0>km/h</OPTION> <OPTION value=2.236936292:1:0>mph</OPTION> <OPTION value=0.000621371192:1:0>miles/second</OPTION> <OPTION value=1.943844492:1:0>knots</OPTION> <OPTION value=6012.884753:1:0>furl's/f'night</OPTION> <OPTION value=0.0029385836027035:1:0>Mach</OPTION> <OPTION value=3.335640952e-09:1:0 selected>c</OPTION></OPTION></OPTION> (light speed)</OPTION></SELECT></TD></TR>
<TR>
<TD><SMALL><I>Emitted frequency:</I></SMALL></TD>
<TD><INPUT class=infield onblur=calculate(); size=10 value=10 name=id {95919BE0-C436-4eab-8083-096E94826667}="10"></TD>
<TD><SELECT class=infield onchange=calculate(); name=uid><OPTION value=1:1:0>Hz (per s)</OPTION> <OPTION value=0:0:0>- FREQENCY -</OPTION> <OPTION value=0.001:1:0>kHz (per ms)</OPTION> <OPTION value=1e-06:1:0 selected>MHz (per ?s)</OPTION> <OPTION value=1e-09:1:0>GHz (per ns)</OPTION> <OPTION value=1e-09:1:0>THz</OPTION> <OPTION value=60:1:0>per minute</OPTION> <OPTION value=3600:1:0>per hour</OPTION> <OPTION value=86400:1:0>per day</OPTION> <OPTION value=604800:1:0>per week</OPTION> <OPTION value=2592000:1:0>per month</OPTION> <OPTION value=31557600:1:0>per year</OPTION> <OPTION value=0:0:0>--- PERIOD ---</OPTION> <OPTION value=1000000000:-1:0>ns</OPTION> <OPTION value=1000000:-1:0>?s</OPTION> <OPTION value=1000:-1:0>ms</OPTION> <OPTION value=1:-1:0>s</OPTION> <OPTION value=0.0166666666667:-1:0>mins</OPTION></OPTION></OPTION></OPTION> <OPTION value=0.000277777777777778:-1:0>hours</OPTION> <OPTION value=1.15740740740741e-05:-1:0>days</OPTION> <OPTION value=1.65349153491535e-06:-1:0>weeks</OPTION> <OPTION value=3.1688087814e-08:-1:0>years</OPTION></SELECT></TD></TR>
<TR>
<TD colSpan=3>
<HR>
</TD></TR>
<TR>
<TD><SMALL><I>Increase in frequency:</I></SMALL></TD>
<TD><INPUT class=outfield readOnly size=10 value=0.00000 name=oa {95919BE0-C436-4eab-8083-096E94826667}="0.00000"></TD>
<TD><SELECT class=outfield onchange=calculate(); name=uoa><OPTION value=1:1:0 selected>%</OPTION> <OPTION value=0.01:1:0>[fraction]</OPTION></SELECT></TD></TR>
<TR>
<TD><SMALL><I>Detected frequency:</I></SMALL></TD>
<TD><INPUT class=outfield readOnly size=10 value=1.00000e+7 name=ob {95919BE0-C436-4eab-8083-096E94826667}="1.00000e+7"></TD>
<TD><SELECT class=outfield onchange=calculate(); name=uob><OPTION value=1:1:0 selected>Hz (per s)</OPTION> <OPTION value=0:0:0>- FREQENCY -</OPTION> <OPTION value=0.001:1:0>kHz (per ms)</OPTION> <OPTION value=1e-06:1:0>MHz (per ?s)</OPTION> <OPTION value=1e-09:1:0>GHz (per ns)</OPTION> <OPTION value=1e-09:1:0>THz</OPTION> <OPTION value=60:1:0>per minute</OPTION> <OPTION value=3600:1:0>per hour</OPTION> <OPTION value=86400:1:0>per day</OPTION> <OPTION value=604800:1:0>per week</OPTION> <OPTION value=2592000:1:0>per month</OPTION> <OPTION value=31557600:1:0>per year</OPTION> <OPTION value=0:0:0>--- PERIOD ---</OPTION> <OPTION value=1000000000:-1:0>ns</OPTION> <OPTION value=1000000:-1:0>?s</OPTION> <OPTION value=1000:-1:0>ms</OPTION> <OPTION value=1:-1:0>s</OPTION> <OPTION value=0.0166666666667:-1:0>mins</OPTION></OPTION></OPTION></OPTION> <OPTION value=0.000277777777777778:-1:0>hours</OPTION> <OPTION value=1.15740740740741e-05:-1:0>days</OPTION> <OPTION value=1.65349153491535e-06:-1:0>weeks</OPTION> <OPTION value=3.1688087814e-08:-1:0>years</OPTION></SELECT></TD></TR>
<TR>
<TD><SMALL><I><SMALL><I><SMALL><I><SMALL><I><SMALL><I><SMALL><I><SMALL><I><SMALL><I>Muscial</I></SMALL></I></SMALL></I></SMALL></I></SMALL></I></SMALL></I></SMALL></I></SMALL> interval:</I></SMALL></TD>
<TD><INPUT class=outfield readOnly size=10 value=0.00000 name=oc {95919BE0-C436-4eab-8083-096E94826667}="0.00000"></TD>
<TD><SELECT class=outfield onchange=calculate(); name=uoc><OPTION value=1:1:0>semitones</OPTION> <OPTION value=100:1:0>cents</OPTION> <OPTION value=2:1:0>quarter-tones</OPTION> <OPTION value=0.5:1:0 selected>tones</OPTION> <OPTION value=0.142857142857143:1:0>perfect 5ths</OPTION> <OPTION value=0.0833333333333333:1:0>octaves</OPTION></SELECT></TD></TR>
<TR>
<TD></TD>
<TD><INPUT class=calculate onclick="return calculate()" type=button value=Calculate! name=go></TD>
<TD vAlign=bottom>
<DIV class=grayed>Add <A href="http://www.calctool.org/CALC/FAV"><IMG alt="login to add" src="http://www.calctool.org/ct/add.png" border=0></A></DIV></TD></TR></TBODY></TABLE>
<SCRIPT type=text/javascript><!--
// --></SCRIPT>
<BR>
<BR>
Problem solved.. but wait..then I realised, as they ( Igates) are scattered throughout the world, I fear that we will be <STRONG><U>forever going around in circles </U></STRONG>trying to net, as the propagation shifts from one gate to another... I did come up with another idea.... that is never leave home ( zero velocity), but that would defeat the purpose of HF mobile APRS.. <BR>
<BR>
Then the solution came to me, you net while you drive as then it is all relative.. I think its the only way to be sure..thoughts anyone?<BR>
<BR>
on a more serious, but none the less more fun aspect of Doppler and radio...have you ever tried 70cm SSB mobile....<A href="http://www.calctool.org/CALC/phys/default/doppler">http://www.calctool.org/CALC/phys/default/doppler</A> try it yourself... its fun you do get a little doppler sometimes, dependant on speed and Alpha ( angle of incidence), 1.2 GHZ is even more fun to net as you drive..<BR>
<BR>
BTW the PSK31 kit usage is a stroke of genius, pity they are no more..!!<BR>
<BR>
Regards<BR>
<BR>
Peter<BR>
<BR>
<BR> <BR>
<DIV>
> Date: Wed, 6 Jul 2011 18:13:52 +1000<BR>> From: stevez@tpg.com.au<BR>> To: ozaprs@aprs.net.au<BR>> Subject: Re: [OZAPRS] Homebrew HF APRS transmitter<BR>> <BR>> I heard you at around 10:00 this morning. Only one packet so far though.<BR>> <BR>> What a great idea in pushing a PSK31 kit into use for HF APRS. Not <BR>> enough of this sort of thing going on I reckon!<BR>> <BR>> Steve (VK2ZSZ-4 RX only HF I-Gate, "netted" with WWVH only - oops, <BR>> shouldn't start that one up again! ;-).<BR>> <BR>> </DIV> </div></body>
</html>