[Elecraft] K3 - Power cable voltage drop

[Edward R Cole]

In my current station layout the rack-mounted Astron-50M is separated 
from the radio shelf, so I need a 15-foot run of cable.  The Astron 
runs 14.2 vdc.  I have 13.69 v at the main power strip (handles 10ga 
wiring).  The primary dc power cable is No. 6 welding cable (more 
flexible than std No. 6) so I have a BUSS30 fuse at the main power 
strip.  The Astron is capable of 50 amps if the main cable were to 
short (cable is rated for a over 200A for welding).

I use the std power cord that came with my K3/10 and see 13.3v 
displayed by the K3 in transmit with 10w RF output.  The K3/10 does 
not draw a lot of current.  I drive a KXPA100 which has 5-foot 
Elecraft power cable (looks like No.12).  I get 100w on all bands 
with about 5w drive (only 6m requires 8w drive for 80w output).

I have not measured the voltage at the power-pole connector when in 
transmit but should be approx 13.5v based on current draw of 20 A.

I run several high power solid-state amplifiers that draw up to 50A 
at 50v so paying attention to dc voltage drop in dc wiring is quite important.

73, Ed - KL7UW
   http://www.kl7uw.com
Dubus-NA Business mail:
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