[ARC5] " ARC-5 " Transmitter Antenna Matching.

[Marty Reynolds]

Well we're getting there

All this biz about spectral ephemera is like getting lost on paint
pigments w/o picking a color

I got interested in the 1:4 broadband xfrmr 2 yr.s back w. NO success.
Reason was no reactrance cancellation

An antenna exhibits

     an impedance of    Z=R+jX

Power is only disipated in R, X leads to swr & big unwanted voltages.
Job 1 in 'conjugate match' is getting rid of X.

Next the R.  A swinging link is like a tapped inductor.  It WILL allow
provide a 50 ohm match.  Will.  The math is difficult but tenable.

And on (D S) big degree, my mentor on this is a PhD EE/Electromag &
I'm an Physics type.

Same Xc cancellation works fine iw. BC-230, TCS, GRC-9... into 50
ohm transmission lines for which thery were never designed.

One thing.  If you use more Xc than needed, you can compensate with the
loading coil (int'l Xl).  This is actually mentioned in a 1950 ART13a book
& the series cap was an accsy.

It ya think that smidge of int'l Xl will help harmonic supression, there's
your shining path.  I could say this's like believing in Santa, but I've
stopped
saying that since Polar Express.


   Marty


> Mike Hanz wrote:
>
>> Let's be clear on this.  An unun is */not/* required to get a command
>> transmitter on the air.  The series cap /*is*/ generally a requirement,
>> however - either Marty's receiver variable or the fixed cap that Dave
>> suggested.
>
> I agree. The series capacitor IS REQUIRED to resonate the inductor in the
> set.
> This series resonance maximizes the current through the radiation
> resistance
> (i.e.: radiated power)
>
> The only real purpose of adding a transformer would be to raise the
> resistive
> part of the output Z from the 5 to 20 ohm range to roughly 50 ohms to
> match the
> input to a 50 ohm antenna or antenna/tuner combo. There is NO NEED to
> modify the
> Tx.
>
> -John
>