[ARC5] Balanced antenna coupling...

[Kenneth G. Gordon]

On 25 Dec 2014 at 20:39, AKLDGUY . wrote:

> 
> Hi Kenneth
> Sorry for the delayed reply (been out all afternoon).

No sweat: we've been traveling all day anyway. ;-)

> > You might consider making that an inverted-vee dipole,
> 
> Nope, there are tenants on the next floor above me. The 5 foot fence around my
> property is the practical height limit.

Oh, yuck. You're VERY "Antenna Challenged" !!! Gee...
 
> > However, if you make the link tunable by adding a fairly high capacitance
> > tuning cap in series with the coil to ground, it will make it considerably
> > quicker to set up for a particular frequency or band.
> 
> Very good suggestion.
> 
> > You may wish to make the link coil adjustable for inductance, less inductance
> > for higher frequencies.
> 
> Nope, it's too much like hard work to make something like that, especially if
> the much easier link tuning cap suggestion above is already implemented.

Yes. I never had to "adjust" my link-coil's inductance either: the "series" cap 
to ground did everything I needed it to. Adjusting that link is a real PITA (Pain 
In The A**) anyway.

> > Actually, if you diagram the entire link-coupling system, including the coax
> > and the final tank Pi-network circuit, you will find that it is actually two
> > parallel-tuned circuits that only LOOK series tuned where two of the tuning
> > capacitors in the link circuit (the Pi-network loading cap and the
> >link-tuning  cap) are in series across the link coil, with the
> >center-connection of those two  capacitors grounded.
> 
> But the BC-230 doesn't have a pi-network output. It has a parallel tuned, series
> fed tuned circuit with an antenna coil wound over the top. The antenna picks off
> from a movable tap. I see your point though.

Well then, using that "series-tuned" link coil works exceptionally well with 
circuits like yours. I use the the link capacitor as the loading capacitor, and 
the final tank capacitor as the plate tuning cap. The action is very similar to 
the use of a modern pi-net. Dip with the final tank tuning cap and load with 
the link cap. Works like gangbusters.

>The aim is to have
> fun and play with the BC-230.

Well, believe me, I envy you. I have more or less lusted after those or the 
RU/GF set. They look like they would be very serious fun.

Merry Christmas, Neil

Ken W7EKB