<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
</head>
<body text="#000000" bgcolor="#FFFFFF">
<p><br>
</p>
<p>Hi Stephen!</p>
<p><br>
</p>
<div class="moz-cite-prefix">
</div>
<blockquote type="cite"
cite="mid:mailman.3.1559563203.13181.mythtv-users@mythtv.org">
<blockquote type="cite" style="color: #000000;">
<pre class="moz-quote-pre" wrap=""> --------1600
Antenna ---- 4x -----1600
--------2500
----------------------------------1609
(If the diagram gets clobbered the antenna feeds to the 4x splitter.?
The four tuners feed from the 4x splitter.)
'4x' is a 4-way signal splitter.
The 1600 and 2250 tuners are inside the old Backend (BE1); the 1609 is
inside the new Backend (BE3). The signal strength to the 1609 should be
the same as what is going to the 1600 and 2250. What happens inside the
tuner card with single, dual and quad tuner devices is another level.
</pre>
</blockquote>
<pre class="moz-quote-pre" wrap="">OK, so each of those cards is getting a little less than one quarter
of the signal from the aerial. On the 2250 card, that is then split
again so that each of its tuners is getting only less than 1/8 of the
aerial signal. So those tuners would be the ones most likely to be
affected by pixellation or total loss of signal when the aerial signal
is degraded.</pre>
</blockquote>
<p> </p>
<dl>
<dd>
<table width="627" cellspacing="0" cellpadding="4">
<colgroup><col width="617"> </colgroup><tbody>
<tr>
<td style="border: 1px solid #000000; padding: 0.04in"
width="617" valign="top">
<p><font face="moz-fixed"><font style="font-size: 9pt"
size="2">Yes; there is a pole-mounted antenna
amplifier to compensate some for the signal
losses. Had tied without the amp – the 1600 and
2250 tuners were not happy.. And the pixelation
issues I have with the old Backend do not appear
to have been due to AGC overloading of the amp
circuitry – two simultaneous recordings on
different tuners did not cut out concurrently.
Also with the way the new Backend with the 1609
quad-tuner is connected in via the 4x splitter it
is getting the same signal as the old BE with the
old tuners. The old BE can have a <pbbt!>
recording and the new BE can have no/minimal
issues.</font></font></p>
</td>
</tr>
</tbody>
</table>
</dd>
</dl>
<p>
<style type="text/css">td p { margin-bottom: 0in; }pre.cjk { font-family: "Courier New", monospace; }p { margin-bottom: 0.1in; line-height: 115%; }a:link { }</style></p>
<p><br>
</p>
<blockquote type="cite"
cite="mid:mailman.3.1559563203.13181.mythtv-users@mythtv.org">
<pre class="moz-quote-pre" wrap="">In the 1609, if the speculation is right, there is a low noise
amplifier (LNA) on its aerial connection, which boosts the level to a
bit over 4 times the input level, and then feeds a 4 way splitter so
that each of the 4 tuners gets the same level as the input - a bit
less than one quarter of the aerial signal. The LNA and splitter seem
to be on-silicon, and are likely high quality, with very little loss
of signal quality compared to the normal sort of aerial amplifier and
splitter that are available retail for aerial systems. It is not
unlikely that the LNA actually adjusts its amplification level to
match the requirements of the tuners, so that each of the 4 tuners is
getting an optimum signal level, no matter what the input aerial
signal level is. The net result is that all 4 tuners work very well.</pre>
</blockquote>
<p> </p>
<dl>
<dd>
<table width="626" cellspacing="0" cellpadding="4">
<colgroup><col width="616"> </colgroup><tbody>
<tr>
<td style="border: 1px solid #000000; padding: 0.04in"
width="616" valign="top">
<p><font face="moz-fixed"><font style="font-size: 9pt"
size="2">Certainly
appears so in my unscientific tests! ...I will
have to test if the
pre-amp is still needed after removing the 4x
splitter.</font></font></p>
<style type="text/css">td p { margin-bottom: 0in; }p { margin-bottom: 0.1in; line-height: 115%; }a:link { }</style>
<p>
<style type="text/css">td p { margin-bottom: 0in; }p { margin-bottom: 0.1in; line-height: 115%; }a:link { }</style></p>
</td>
</tr>
</tbody>
</table>
</dd>
</dl>
<p>
<style type="text/css">td p { margin-bottom: 0in; }pre.cjk { font-family: "Courier New", monospace; }p { margin-bottom: 0.1in; line-height: 115%; }a:link { }</style></p>
<p><br>
</p>
<p><br>
</p>
<p><br>
</p>
<blockquote type="cite"
cite="mid:mailman.3.1559563203.13181.mythtv-users@mythtv.org">
<pre class="moz-quote-pre" wrap="">By the way, people who were used to the old analogue TV usually have
the wrong idea about pixellation. They think of it as degraded
picture, which was a gradual thing in the analogue system, ranging
from present but not visible except to a trained eye, through nasty
but still watchable, all the way to completely unwatchable (but the
audio was usually still hearable). But in the digital system,
pixellation is really loss of signal for short periods, not degraded
signal. </pre>
</blockquote>
<p> </p>
<dl>
<dd>
<table width="623" cellspacing="0" cellpadding="4">
<colgroup><col width="613"> </colgroup><tbody>
<tr>
<td style="border: 1px solid #000000; padding: 0.04in"
width="613" valign="top">
<p><font face="moz-fixed"><font style="font-size: 9pt"
size="2">Yes: half-know the analog signal’s
fluctuations and drop outs were better tolerated
by the human brain as a more natural rise and fall
as opposed to a digital signal’s square wave
rise/fall. The brain was able to sort of fill-in
the missing/erroneous analog signal. And of course
the faulty digital data gets displayed as
odd-coloured squares, again not found in nature.
You gave the technical explanation, which did fill
in some of my ‘pixelated’ learning. <g></font></font></p>
</td>
</tr>
</tbody>
</table>
</dd>
</dl>
<p>
<style type="text/css">td p { margin-bottom: 0in; }pre.cjk { font-family: "Courier New", monospace; }p { margin-bottom: 0.1in; line-height: 115%; }a:link { }</style></p>
<p><br>
</p>
<p><br>
</p>
<blockquote type="cite"
cite="mid:mailman.3.1559563203.13181.mythtv-users@mythtv.org">
<pre class="moz-quote-pre" wrap="">
The difference in signal level between 100% reception and no reception
at all (no valid packets received) is actually quite small. And all
the digital signals have been carefully designed to be resistant to
the usually problems that plagued analogue signals. For example,
analogue ghosting, caused by receiving the same signal via multiple
different paths and hence at slightly different times, is virtually
completely eliminated by the way DVB and ATSC signals are broadcast -
the ghost signal(s) are simply ignored.</pre>
</blockquote>
<p> </p>
<dl>
<dd>
<table width="623" cellspacing="0" cellpadding="4">
<colgroup><col width="613"> </colgroup><tbody>
<tr>
<td style="border: 1px solid #000000; padding: 0.04in"
width="613" valign="top">
<p>Yes, digital does provide a sharp picture when the
Propagation Gods allow! </p>
<p><br>
</p>
<p>Thanks again!</p>
<p>Barry </p>
</td>
</tr>
</tbody>
</table>
</dd>
</dl>
<p style="margin-bottom: 0in; line-height: 100%"><br>
</p>
<p style="margin-bottom: 0in; line-height: 100%"><br>
</p>
<p style="margin-bottom: 0in; line-height: 100%"><br>
</p>
<p>
<style type="text/css">td p { margin-bottom: 0in; }pre.cjk { font-family: "Courier New", monospace; }p { margin-bottom: 0.1in; line-height: 115%; }a:link { }</style></p>
<p><br>
</p>
</body>
</html>