[RFI] Ferrite Question...

[Al K0VM via RFI]

If there is rf on the outside of the feed line then the feedline is a 
part of the antenna SYSTEM and a part of the impedance presented to the 
radio.  If there is rf on the feedline then adding a ferrite snapped on 
around the feedline will change antenna SYSTEM and thus the impedance 
presented to the radio.  The change may or may not be beneficial to the 
radio and/or radiation efficiency.

If the feed line is not a part of the antenna system ( no currents on 
the outside of the feed line ) then other things are more predictable.


AL, K0VM

On 6/20/2014 2:26 PM, David Cole wrote:
> Hi,
> I should have asked a different question...  Any idea why the rig is
> getting warmer than if no ferrite's...
>
> Here is some more information...
>
> A fellow wrote me off list asking for more info...
>
> Antenna is on roof, and AC wiring is I am sure in attack area.  About
> three feet of coax between the tuner and radio.  He is running 30 watts,
> no grounds, all bonds are via coax, one ground to tuner.  No balun on
> the OCF...
>
> I get that the OCF makes things very unbalanced, (he has no balun on
> it), and I get that a single ferrite won't correct this, (he did no
> winding), but why might the rig get warm?  I thought I had a handle on
> how this stuff was working, but for the life of me, I can't imagine why
> the rig gets warm...  It always sees a 1:1 because he is tuning it the
> feedline to 1:1 as it feeds the rig...
>
>
>