[Elecraft] KX3 fuses

[Fred Jensen]

Well ... yes, best to fuse the + conductor. However, be aware that 
inline fuse holders [and their fuses] are not zero ohm superconducting 
devices.  The best ones seem to be the automotive blade-type [Rig 
Runners use them] with a wide contact surface and wiping action on 
insertion and removal. K<mumbles> [actually, most radios] do not like 
low supply voltages, it increases the IMD among other things.  So after 
installing the fuse, you should adjust your power supply voltage to make 
sure it's not sagging under load from the additional resistance.

In the case of a mobile installation, you should fuse BOTH conductors.  
Should the connection from the battery to vehicle frame become 
disconnected or high resistance, starting current return will be through 
your radio equipment's chassis and return conductor.  I've never heard 
of this actually happening but then there's a reason aircraft connectors 
are made so things can't be cross connected.

I witnessed a real event where cross connection happened, however with 
apologies to Pierre Fermat, the story is too long to fit in this email.

73,
Fred ["Skip"] K6DGW
Sparks NV DM09dn
Washoe County

On 10/15/2019 2:19 PM, Don Wilhelm wrote:
> Terry,
>
> The KX3 has internal protection, but a fused power lead (only 
> necessary in the positive lead) provides additional protection. That 
> is important IMHO when powered by an external battery - there is a lot 
> of energy in a battery, and if the wire is pinched and shorts, it will 
> spew molten metal.
>
> Fuse close to the power source, NOT the radio end of the power cable.
>
> 73,
> Don W3FPR
>
> On 10/15/2019 12:54 PM, Terry Basom wrote:
>> I was looking at my power leads and realaized I had no fuses in the 
>> lines.
>> The factory power lead as well had no fuses. I'm about to change that 
>> with
>> inline fuses.
>>
>> I would appreciate any comments..