[Elecraft] KX2 Heatsink

[Howard Hoyt]

Hi Kev,

The issue is related to the fact that Elecraft, as do virtually all 
amateur radio manufacturers rate power output with 50% duty cycle SSB/CW 
modes only.  As is stated in the KX3 specifications and here copied from 
the KX2 manual:

/"80-17 meters, 10 W PEP max (+/- 1 dB); 12 and 10 meters, 8 W PEP max 
(+/- 1 dB).//
//Recommended transmit duty cycle: 50%, all modes. (If power amplifier 
temperature or//
//current drain is too high, power will automatically be reduced.)//
//NOTE: When using over 5 W in SSB, DATA-A and AFSK-A modes, the//
//recommended supply voltage is 12 V or higher to minimize transmit 
intermodulation//
//products. Higher power with lower voltages should be used only when 
necessary."/

I believe many or most of the requests we have had to make an 
aftermarket heatsink have come from hams using these rigs in digital 
modes such as JT and desire full-power operation, which Elecraft does 
not explicitly endorse, but which is possible with additional cooling.  
Elecraft designs and specifies operation of their rigs very 
conservatively compared to many other manufacturers, and the KX2 and KX3 
specifications are spot on.
Also as is stated in the specification, the KX2 internal battery, at 
10-11V depending on state of charge is considered adequate for 5W or 
less, and we have supplied many Kx33 14V supplies to KX2 owners who want 
to use the rig at 10W power when AC power is available.

I conclude many of these KX2 rigs are being used in digital modes from 
fixed location AC power, not from batteries.  I can't blame the hams who 
do this, the KX2 is a fantastically full-featured rig for fixed 
operation, I have used it at home to check into local 10M SSB nets 
driving a KPA500 and no one was the wiser compared to my K3.

Cheers,
Howie - WA4PSC


On 5/14/2017 4:01 PM, elecraft-request at mailman.qth.net wrote:

>>It seems odd to me that an issue like this would go unmentioned
>> and unaddressed by Elecraft.
>>
>>73,
>>Kev K4VD