<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<meta content="text/html; charset=ISO-8859-1"
http-equiv="Content-Type">
<title></title>
</head>
<body bgcolor="#ffffff" text="#000000">
Unless a filter is specifically designed (an absorptive filter) it
becomes highly reflective outside the pass-band. <br>
Even in the pass-band, the reflection may be high enough at some
frequencies that it's a poor mixer termination,<br>
especially if you're hoping for really good intermod performance.<br>
<br>
Dave<br>
wa8ywq<br>
<br>
On 9/10/2010 9:10 AM, Anthony Taylor wrote:
<blockquote cite="mid:13505.27121.qm@web120007.mail.ne1.yahoo.com"
type="cite">
<pre wrap="">***** High Performance Software Defined Radio Discussion List *****
</pre>
<br>
<fieldset class="mimeAttachmentHeader"></fieldset>
<br>
<table border="0" cellpadding="0" cellspacing="0">
<tbody>
<tr>
<td style="font: inherit;" valign="top">Shel,<br>
<br>
The diode mixer is already looking at 50 ohms across the
entire IF range as it's terminated into a suitable LPF,
adding a BPF may have some merit, however, if you provide
an additional MMIC after the mixer (12db-3dB for the BPF
loss) you are looking at adding about 9dB this would cause
the ADC to overload, trying to do gain optimisation at the
second IF after this will not help.<br>
<br>
BTW the RLP-50+ loss across it's passband is less than
2dB, the LTC 6400-20 provides over 20dB of gain so you are
looking at atleast 18dB of gain before the ADC.<br>
<br>
73s,<br>
<br>
Tony<br>
</td>
</tr>
</tbody>
</table>
<br>
<pre wrap="">
<fieldset class="mimeAttachmentHeader"></fieldset>
_______________________________________________
HPSDR Discussion List
To post msg: <a class="moz-txt-link-abbreviated" href="mailto:hpsdr@openhpsdr.org">hpsdr@openhpsdr.org</a>
Subscription help: <a class="moz-txt-link-freetext" href="http://lists.openhpsdr.org/listinfo.cgi/hpsdr-openhpsdr.org">http://lists.openhpsdr.org/listinfo.cgi/hpsdr-openhpsdr.org</a>
HPSDR web page: <a class="moz-txt-link-freetext" href="http://openhpsdr.org">http://openhpsdr.org</a>
Archives: <a class="moz-txt-link-freetext" href="http://lists.openhpsdr.org/pipermail/hpsdr-openhpsdr.org/">http://lists.openhpsdr.org/pipermail/hpsdr-openhpsdr.org/</a></pre>
</blockquote>
<br>
</body>
</html>