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<div class="moz-cite-prefix">On 11/11/2017 1:28 PM, Ron VE8RT wrote:<br>
</div>
<blockquote type="cite"
cite="mid:20171111112819.b8e7db37c7ef423866339439@yknwt.ca">
<pre wrap="">Hi Stephen,
up until this summer I though the same about HF propagation.
Having been asked to monitor the WSPR (1/2 W) station on board the
CG3EXP Polar Princess expedition through the northwest passage I've
changed my mind. On 40M some nights, running my own 5W WSPR station I
was being heard in VK ZL and other countries in the south pacific.
Most days, even through some of the roughest solar conditions my
station was tracking the Polar Princess in the high arctic. Rather
than being concerned whether southern stations could hear an HF Igate,
I though it might provide a service to stations inside of the auroral
oval.
There has been ever increasing research and recreacreational boat
and ship traffic through the northwest passage. I was wondering if a
Sgate may be of use to those plying the airctic ocean who might not
otherwise be able to use a satellie digital repeater because the
satellite itself is out of sight of a ground Sgate. Perhaps that
doesn't happen, maybe with a low enough inclination on their orbit they
never track far enough over the poles to be out of sight of Sgates.
Those were my thoughts.
Ron VE8RT
</pre>
</blockquote>
<br>
HF---<br>
<br>
The only band with significant HF APRS activity is 30 meters. 40
would be substantially different, since it is open more of the time,
and supports significant NVIS activity (There is next to no NVIS
behavior on 30 meters. When mobile, I simply DON'T HEAR my home
station at all, until I am around 300 miles away due to the skip
distance on 30M.) However, you would be on-your-own on 40 meters,
without the diversity receive capability that has existed on 30
meters for decades due to the two dozen or so igates around North
America (including mine) running 24/7. <br>
<br>
Satellite--<br>
<br>
The most severe problem that far north will not be lack of igates,
but rather lack of accessible satellites. Except for the handful
of polar-orbit satellites, most satellites are inclined orbits that
don't take them anywhere near far enough north or south to be useful
in the Arctic/Antarctic regions. <br>
<br>
For example, consider the ISS digipeater. (By far the easiest to
hear and use, due to it's relatively high transmit power and low
orbital height.) The ISS orbit inclination is such that it's
sub-satellite point is never more than a few miles north of the
US-Canada border. The farthest north it can ever be directly
overhead (i.e. longest time) is Vancouver BC or Calgary, AB. At
your location, the highest it will ever be above the southern
horizon is about 15 degrees. <br>
<br>
The image below, captured from my iPad Mini from an app called
HamSatHD shows this. I set the ground station location ("Home") to
the 62 degs N / 114 degs W coords you gave me. Then I wound the
data/time back and forth to yield a pass nearly due south of you
(i.e. nearest possible). Note the two range circles (ISS footprint
and the Home station's horizon at the station's elevation) are
distorted into asymmetric ellipses that far north due to the
Mercator-projection word map used. (Near the equator, you get
nearly perfect circles...) <br>
<br>
The most important take-away is the polar sky-view map in the
upper-right corner that shows the satellite track in the sky as seen
from your location. Note how short and close to the horizon it
is. At least you wouldn't need any exotic satellite-type
antenna that elevates above the horizon. Any common high-gain base
station collinear that squishes the radiation pattern at the horizon
is all you would need. This kind of pass might be OK for
"Hello-CALLsign-Signal Report-Goodbye" contest-type exchange, but it
won't be long enough to exchange any useful amount of information.<br>
<br>
<img src="cid:part1.DE172524.57C40929@aol.com" alt=""><br>
<br>
<hr size="2" width="100%">Stephen H. Smith wa8lmf (at) aol.com <br>
Skype: WA8LMF<br>
EchoLink: Node # 14400 [Think bottom of the 2-meter band]<br>
Home Page: <a class="moz-txt-link-freetext" href="http://wa8lmf.net">http://wa8lmf.net</a><br>
<br>
Live Off-The-Air APRS Activity Maps<br>
<a class="moz-txt-link-rfc2396E" href="http://wa8lmf.net/map"><http://wa8lmf.net/map></a><br>
<br>
Long-Range APRS on 30 Meters HF <br>
<a class="moz-txt-link-rfc2396E" href="http://wa8lmf.net/aprs/HF_APRS_Notes.htm"><http://wa8lmf.net/aprs/HF_APRS_Notes.htm></a><br>
<br>
<br>
<br>
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