[TowerTalk] antenna choices for K4XS

[Bry Carling]

How many watts do you then suppose is being dissipated in a trap on your average tribander running at 1500watts out?

Just a typical number. Take the worst case scenario. Empiricist that I am, I would bet it's less than 10 watts per trap, and hardly significant. You would need to be losing at least 50-100 W per trap to even be able to notice any difference on the receiving end using instruments, let alone with the human ear.

Don't burn your fingers on those traps :)

Best regards - Brian Carling
AF4K Crystals Co.
117 Sterling Pine St.
Sanford, FL 32773

Tel: +USA 321-262-5471




> On Apr 14, 2015, at 1:16 PM, Doug Smith <doug at w7kf.com> wrote:
> 
> Losses in an inductor are related to both the Q of the inductor and the current flowing through it.  
> 
> Simplistically, one could think of it as:  P(loss)  =  I^2 * R.
> 
> So, given the same Q, in a high voltage, low current scenario (like the RF tank coil in your amp) the losses will be less than in a higher current, lower voltage scenario (antenna trap).
> 
> Inductors in antenna traps are usually low Q affairs due to the physical constraints imposed upon them.  Thus, higher losses even without any operational faults such as you describe.  And, they’re usually in a fairly high current area of the antenna.  Again, resulting in higher losses..
> 
> I have an inductor in an L-network that, on 80 meters, has 17 amps flowing through it.  You can bet your last dollar I have taken every step possible to make sure the Q of that inductor is as high as I can make it.  (Huge, silver plated, enclosure is non-conductive, etc.)  That inductor is MUCH larger than the tank coil in the amp driving it.  But it has much more ability to make heat than the inductor in the tank circuit, due to the nature of the circuit it is in.  It has many more amps flowing through it even though the amount of power is the same (1.5 KW).
> 
> 73,
> Doug, W7KF
>  http://www.w7kf.com
> 
> 
>> On Apr 14, 2015, at 10:32 AM, Bry Carling AF4K <bcarling at cfl.rr.com> wrote:
>> 
>> Then there would also be the issue of your RF tank coil in a linear amplifier being similarly 
>> "metal enclosed."  Somehow I am not seeing your point.
>