[Elecraft] Power Cord Questions

[Fred Townsend]

Lee: Please see answers inline.

-----Original Message-----
From: elecraft-bounces at mailman.qth.net
[mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Lee Buller
Sent: Friday, March 09, 2012 6:38 PM
To: Elecraft Reflector
Subject: [Elecraft] Power Cord Questions


I am rebuilding the power cord from my RM35M to the K3.

Questions.....

1.  Do you need fuses to be in both the positive and negative lead?  Or,
since I am a "fixed" station, can I get away with one fuse in the positive
lead?  
Currently, I have both leads fused.

There are arguments that support fusing the ground lead but I do not buy
them. The national electrical code says never to fuse a ground. While are
rigs are not covered by the NEC I still do not see a reason to fuse ground.

2.  What length should the power cord be....considering that there will be
some power consumption (voltage drop) in the line which is longer than
shorter?  My current length is over 6 feet.

Shorter is obviously better but the K3 will compensate for voltage drop. I
cut mine to fit with a little extra for service.

3.  Should the fuse(s) be mounted at the radio or at the power supply?  
Currently, mine are right at the power supply.

Assuming some disaster will befall your cable, fuses should be at the power
supply. Having said that, I put mine where they are accessible and cool.
Cool because the ambient temperature will affect the current they blow at.

It is a good idea to put a clamp-on choke around the power leads. Again with
a good antenna system you don't need the choke but it help the RF out of the
shack when things are less than optimal. They are cheap and easy to install
so why not.

Fred, AE6QL.

The reason why I am rebuilding the power cord is that I am getting somewhat
of a voltage drop on key down.  According to the K3, the voltage is at 13.8
but goes to 11 volts at key down at 100 watts....around 21 to 22 amps.  So,
I suspect something might a tad glitchy in the power cord.  Maybe I just
need to reinstall the Anderson Power Poles.

Comments?

Lee - K0WA




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