Fw: RE: [HBR] THE BEST receiver

[windy10605 at juno.com]

Yep, that brings up another point ....mixers. I've seen many articles on
how much better Pullen mixers are from a noise standpoint. I think this
is basically because it's made up from 2 triodes which would make it more
quiet ....HOWEVER, the gain you see is much less than that of a
Pentode/Pentagrid and by the time you add another stage to equal the
gain, the total noise introduced may be back to the same level ??

73 Kees K5BCQ

--------- Forwarded message ----------
From: "Ian Wilson" <ianmwilson at earthlink.net>
To: "'HBR Receiver List'" <hbr at mailman.qth.net>
Date: Fri, 29 Jul 2005 07:25:51 -0700
Subject: RE: [HBR] THE BEST receiver
Message-ID: <001001c59449$738ed0b0$6902a8c0 at trabucoian>

Tubes, like all other physical parts, generate thermal noise.
Additionally, multigrid tubes like pentagrids generate 'partition' noise
(caused by the random division of the electron flow between candidate
targets).

73, ian K3IMW

> 
> Tubes generate NO internal noise, as ALL "PN" junctions do, thus tubes
ARE
> quieter in the noise-floor department.
> 


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