<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
</head>
<body text="#000000" bgcolor="#FFFFFF">
<div class="moz-cite-prefix">On 6/24/2019 11:05 AM, Michelle
Thompson via Ground-Station wrote:<br>
</div>
<blockquote type="cite"
cite="mid:CACvjz2XBOzNuhKFLj3vbJxPFYH1OOdPgYDNUAbJVkAVKWaxp0Q@mail.gmail.com">LimeSDR
has posted a front end amplifier.<br>
</blockquote>
The specifications on their webpage are very limited. P1dB is a
useful figure of merit for xmit amplifiers but is of no value for
receive amplifiers. What we really need to see is IP3 -- this is the
third order intercept point. That tells you how your receiver will
behave when there are two or more signals within the passband of the
front end filter. Also there is no mention of Noise Figure. This is
important for all bands above 100MHz (not important for HF and most
6m operation).<br>
<br>
In the case of mw hambands, a high IP3 is needed for our bands that
are shared with other services. It is not important for 10GHz except
during the Fall N.A. contest when there are many people sharing a
hilltop or operating in nearby locations.<br>
<br>
73,<br>
Jeffrey WA6KBL<br>
<br>
<p><br>
</p>
</body>
</html>