[Heathkit] AT-1 Question

Fri, 23 Jan 2004 07:27:23 -0500

Why not convert it to Pi coupling - you can change it back if you want to
sell it original later.
----- Original Message ----- 
From: "Mark S Graalman" <[email protected]>
To: <[email protected]>
Cc: <[email protected]>; <[email protected]>
Sent: Friday, January 23, 2004 5:32 AM
Subject: Re: [Heathkit] AT-1 Question


>   Some experiments here indicate the link coupling, if done
> rather loosely  such as at the cold end of the tank provides about
> 20 dB at the second harmonic. A far cry from a pi-network, but
> if the link output is run into an 50 ohm I/O output filter then
> the performance is pretty good. So you could preserve the AT-1 by
> just running it into a 50 ohm I/O pi network, or even better a half wave
> filter. But you'd have to build a filter for each band you intend to
> operate.
>  I've built critical coupled link outputs feeding half wave filters here
> while prototyping no-tune amplifiers and 60-65 dB at the second
> harmonic was obtainable without much trouble.
>
> Mark  WB8JKR
>
>
> On Thu, 22 Jan 2004 23:03:06 -0500 Garey Barrell <[email protected]>
> writes:
> > Joe -
> >
> > The link coupled output does NOT have the harmonic suppression
> > provided by a
> > Pi-Net.  I used to have typical numbers, but long forgotten!  :-)
> >
> > That said, it is pretty difficult to match anything but a resonant
> > antenna with
> > link coupling, so you usually end up with an antenna tuner anyway!
> > The Heath
> > AC-1 was offered by Heath to address this need, but it cost half as
> > much as the
> > transmitter, so most (poor!) hams just kludged something together.
> > With the
> > result that the AC-1 is even more scarce today than the AT-1.  The
> > AC-1 included
> > a low pass filter AND and LC matching network AND a neon "output
> > indicator".
> >
> > 73, Garey - K4OAH
> > Atlanta
> >
> >
> >
> > [email protected] wrote:
> >
> > > It appear the AT-1 has a link coupled output.  What is the
> > harmonic
> > > suppression characteristics compared to a pi-section output?
> > >
> > > Thanks,
> > > Joe
> > >
> > >
> >
> >
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>
>
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