http://elecraft.85.s1.nabble.com/RF-on-power-to-K3-question-tp7254202p7256358.html
wire is cancelled by the field from the other wire. Remember, in any
... Joe, W4TV
> Don, a spike is not a concern with choke for RF in the range of a few
> millihenrys such as you created winding a few turns through the ferrite
> core, but a larger value choke such as is often used for suppressing
> generator hash and noise on a d-c line can do damage.
>
> What happens is that whenever current flows through the choke a magnetic
> field is created around the windings. When the current stops, that magnetic
> field collapses producing a pulse in the winding. With small value chokes,
> such as the choke you made winding the wire through the ferrite core, the
> pulse is very tiny and of no concern.
> But that pulse can be as high as several hundred volts with larger value
> chokes, even working from a 13V supply. That would be plenty to do serious
> damage to the K3 and most other 13V electronics you may have on the circuit.
>
>
> Batteries are typically lousy conductors at RF. Putting a capacitor across
> the d-c line provides a low-impedance path for any RF on the line. That
> capacitor is usually built into any good rig, and the K3 is no exception. It
> has both a capacitor across the line and an RF choke in series with the
> power line where it enters the rig.
>
> 73,
>
> Ron AC7AC
>
> -----Original Message-----
>
> I am asking the question simply because I was warned by another ham to
> consider the possibility of a power spike on the feed to the K3 with the
> choke by another ham. He was not fully sure and suggested that I post
> the question to the folks who might really know the answer.
>
> Plus if it is good practice to put a CAP across the batteries for the
> way I am doing my power to help with a clean signal, clean power and
> better battery life I want use good practice.
>
> If I had not been prompted by the ham who suggested a CAP I would have
> never asked the question.
>
> Power is an SGC power cube good for 500w. Antennas are a 2 WL loop for
> 160m and a dipole and the shack is on the second floor.
>
> Maybe the answer to the question is so obvious that it just shows my
> total ignorance. Hey but I do learn slowly at times :-). Example I now
> work split and if you remember those posts from me on that topic I think
> everyone wanted to hit me in the head with a baseball bat.
>
> Like I indicated right now everything is working real good and I have no
> problems, but I dont want to be in the process of creating new ones.
>
> Cheers
> Don
>
>
> ______________________________________________________________
> Elecraft mailing list
> Home:
http://mailman.qth.net/mailman/listinfo/elecraft> Help:
http://mailman.qth.net/mmfaq.htm> Post: mailto:
[hidden email]
>
> This list hosted by:
http://www.qsl.net> Please help support this email list:
http://www.qsl.net/donate.html>