Stewart,
That's a good question. Certainly lower RF output will generate less
heat. One issue that would need to be determined is whether the 2M
module has any operating mode which would result in a full output
spike which would likely destroy 0 dBm input circuit
components. This has been documented for many non-Elecraft radios.
But let's assume you can turn power to 0.1w at minimum (that is
currently indicated on the KX3 PWR control). That would be 100mw or
+20 dBm level. That can be attenuated to 0 dBm using a chip 50-ohm
load or 20-dB attenuator (which I would be sure was rated for 3w -
just in case). Design of transverter IF connections could either be
common Rx/Tx or separate (preferred). If common, the transverter
will have some sort of IF T/R control so load/atten. could be
inserted on the Tx side. Inserting 20-dB attenuation on receive
would affect receive sensitivity and possibly system NF. The circuit
using a 50-ohm load would couple low power via a 10pF capacitor. You
might need to have an adjustable drive level pot following this (make
it an L-pad).
With operation at this level frequency drift characteristics will
likely by the same for Rx and Tx. I can test this concept when I get
the 2M module for testing on my bench.
73, Ed - KL7UW
------------------
Date: Wed, 9 Apr 2014 08:24:57 +0100
From: "stew...@g3ysx.org.uk" <stew...@g3ysx.org.uk>
To: Dave <d...@g0dja.co.uk>
Cc: "<elecraft@mailman.qth.net>" <elecraft@mailman.qth.net>
Subject: Re: [Elecraft] KX3-2M module?
Message-ID: <967726d0-0801-494f-9816-88c484d22...@g3ysx.org.uk>
Content-Type: text/plain; charset=us-ascii
When driving a transverter presumably you will be running at 0dbm
rather than at 5W. I wonder if the KX3 still experience thermal drift
due to PA heating at very low power?
Stewart/G3YSX
Sent from my iPad
73, Ed - KL7UW
http://www.kl7uw.com
"Kits made by KL7UW"
Dubus Mag business:
dubus...@gmail.com
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