[Elecraft] KX3 and Digital Modea

[Edward R Cole]

Ron the problem is that digital modes run "key-down" for long periods 
of time.  No radio (except an Alpha amp is designed to do that).  As 
Lyle states it is a thermal issue and not a digital design issue.

Either run less power to keep from overheating or consider installing 
a bigger heat sink.  I opted for the bigger heat sink from VE7FMN 
(link on my KX3 webpage.  It was easy to install (a couple bolts 
using a allen wrench which he can supply).

I have tested running 5w on 6m for extended time and difficult to 
reach overtemp with the new heat sink.
http://www.kl7uw.com/KX3.htm
Testing duplicated running JT65 which is key-down about 50-seconds 
followed by 70-seconds in receive.  If you are running psk31 you may 
have to limit the time you send text in one period. WSPR is the most 
demanding with 2-min key-down Tx periods.  I have not run the KX3 in 
WSPR as I usually use my K3/10 which may have different heat sink 
characteristics.

73, Ed - KL7UW
---------------------
From: KM4VX <roncerra at earthlink.net>
To: elecraft at mailman.qth.net
Subject: [Elecraft] KX3 and Digital Modea
Message-ID: <1437398899812-7605122.post at n2.nabble.com>
Content-Type: text/plain; charset=us-ascii

I am on my second KX3, having sold the first one and then  find myself
missing it.  However, I now find the KX3 routinely overheats in digital
modes. Specifically, at just 5 watts on WSPR with transmission time of 2
minutes (as regulated by WSPR software) the KX3 overheats "HI TEMP" at a
minute and a half, resulting in a safety shutdown of the rig. This radio has
a wonderful built-in digital capability, but digital appears beyond the
rig's ability, save CW which is my main digital interest anyway.  I would
like to use the KX3 occasionally on PSK, JT65 and WSPR without the absurdity
of having to buy an after-market heat sink to replace a factory installed
heat sink. There is no guarantee the after-market one is superior, and it
shouldn't be necessary since a radio with a digital capability should not
need some after-market accessory to enable the advertised digital mode. I
wonder if anyone has found a firmware or software answer to the over heating
problem. The overheating problem happens regularly in digital modes and I
believe comments about the KX3 working correctly in digital are simply
incorrect. This is not an antenna issue and not an SWR issue. Thanks Ron
KM4VX



73, Ed - KL7UW
http://www.kl7uw.com
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