<html>
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
</head>
<body bgcolor="#FFFFFF" text="#000000">
<br>
<div class="moz-forward-container"><br>
<br>
-------- Original Message --------
<table class="moz-email-headers-table" cellpadding="0"
cellspacing="0" border="0">
<tbody>
<tr>
<th align="RIGHT" nowrap="nowrap" valign="BASELINE">Subject:
</th>
<td>Re: [VHF] SDR Play [ NEW SDR RECEIVER. 2 GHz, 8MHz
bandwidth under $300 USD ]</td>
</tr>
<tr>
<th align="RIGHT" nowrap="nowrap" valign="BASELINE">Date: </th>
<td>Mon, 08 Sep 2014 12:55:34 -0600</td>
</tr>
<tr>
<th align="RIGHT" nowrap="nowrap" valign="BASELINE">From: </th>
<td>Patrick Dyer <a class="moz-txt-link-rfc2396E" href="mailto:pjdyer@swbell.net"><pjdyer@swbell.net></a></td>
</tr>
<tr>
<th align="RIGHT" nowrap="nowrap" valign="BASELINE">To: </th>
<td><a class="moz-txt-link-abbreviated" href="mailto:vhf@w6yx.stanford.edu">vhf@w6yx.stanford.edu</a> <a class="moz-txt-link-rfc2396E" href="mailto:vhf@w6yx.stanford.edu"><vhf@w6yx.stanford.edu></a></td>
</tr>
</tbody>
</table>
<br>
<br>
<pre>That 8-MHz bandwidth would be more than enough to reveal what is going
on with Es propagation of an entire 6-MHz wide DTV signal as was
tantalizingly suggested in this:
<a class="moz-txt-link-freetext" href="http://www.youtube.com/watch?v=NVam6bmJ7p8">http://www.youtube.com/watch?v=NVam6bmJ7p8</a> from KOTA-DT-2 Rapid City, SD
in June 2013 using a USB dongle with SDR# (max 2-MHz display). Similar
results were seen later while KSNV-DT-2 Las Vegas, NV was coming thru so
it's not a KOTA artifact of some sort. (Though, due to the awkward
complexity of my hardware/software setup, I've not made any subsequent
combination videos.)
No one had really expected that there would be those drifting
undulations/ripples across the (virtually flat) emissions of a DTV
channel vs something of a wedge-shaped (or even cliff-like) profile as
the MUF was approached. K6MIO/KH6 has been working on some simulations
to explain that behavior.
Such a view of an 6-MHz NTSC (analog) channel would be less-revealing as
those energy peaks are concentrated near the audio and video carriers
(and, to a lesser extent, the color burst subcarrier) with lots of
"near-empty" space in between. It's been a long-observed fact that Es
MUFs are often "sharp" enough to preclude any audio in spite of a very
intense, clean video being resolved on a kinescope (some examples of
which are on my YouTube page, <a class="moz-txt-link-freetext" href="http://www.qsl.net/wa5iyx/YouTube.htm">http://www.qsl.net/wa5iyx/YouTube.htm</a>)
while at other times the audio will be present even with relatively weak
and snowy video.
More details of NTSC vs DTV Es propagation are at
<a class="moz-txt-link-freetext" href="http://www.qsl.net/wa5iyx/lovesavd.htm">http://www.qsl.net/wa5iyx/lovesavd.htm</a>
73, Pat - WA5IYX
<a class="moz-txt-link-freetext" href="http://www.qsl.net/wa5iyx/index.html">http://www.qsl.net/wa5iyx/index.html</a>
------
Submissions: <a class="moz-txt-link-abbreviated" href="mailto:vhf@w6yx.stanford.edu">vhf@w6yx.stanford.edu</a>
Subscription/removal requests: <a class="moz-txt-link-abbreviated" href="mailto:vhf-request@w6yx.stanford.edu">vhf-request@w6yx.stanford.edu</a>
Human list administrator: <a class="moz-txt-link-abbreviated" href="mailto:vhf-approval@w6yx.stanford.edu">vhf-approval@w6yx.stanford.edu</a>
List rules and information: <a class="moz-txt-link-freetext" href="http://www-w6yx.stanford.edu/vhf/">http://www-w6yx.stanford.edu/vhf/</a>
</pre>
<br>
</div>
<br>
</body>
</html>