[Amps] amp with push-pull output and magnetic coupling to the antenna

[Mike Waters]

>
> From: gdaught6 at stanford.edu
> To: amps at contesting.com
> Date: Fri, 28 Jan 2011 09:12:52 -0800
> Subject: Re: [Amps] amp with push-pull output and magnetic coupling to the
> antenna
> Gene May wrote...
>
> ...As I recall, the inductance of the swinging link (and therefore, the
> physical size)
> varies quite a bit from 160m - 10m.  This necessitates having different
> plug-in tank
> coil assemblies for different bands, or a monstrous rotating turret/switch.
>  The same
> would likely be required for the cathode circuit components.  This is not
> to say it
> can't be done, but it sounds to me like a real challenge to accomplish.
>

You might want to look at a link that does not swing, but instead has a
series capacitor.

That's what I've used for years in my balanced antenna tuner. The links are
pretty much the same IIRC, but I have to switch different values of series
capacitance in or out, depending on what band I'm on.

It uses four B&W plug-in coils with fixed links for 80 through 10. The photo
at http://www.w0btu.com/files/antenna/W0BTUBalancedTuner.jpg shows the 10/15
meter plug-in coil (which originally used a swinging link), but the three
other plug-in coil assemblies have fixed links. You might find some floating
around on eBay or one of the forums for sale. You'll also need the base(s)
with the sockets; they use oversize banana plugs.

I would love to build a 160 through 20 P-P amplifier with a couple of
833C's, but it's just too complex for me right now.

73, Mike
www.w0btu.com