[Amps] CB amp directly coupled via cap to antenna

[Fuqua, Bill L]

The q of a halfwave dipole is about 10. Due to losses in a mobile mounted vertical the Q will be much less due to radiation resistance and ground losses due to the poor coupling to ground. However, the antenna is also resonant to odd harmonics. This makes it an effective radiator on other frequencies which is not desirable. 

73
Bill wa4lav
 

________________________________________
From: amps-bounces at contesting.com [amps-bounces at contesting.com] On Behalf Of Bill, W6WRT [dezrat1242 at yahoo.com]
Sent: Thursday, April 08, 2010 6:49 PM
To: amps
Subject: Re: [Amps] CB amp directly coupled via cap to antenna

ORIGINAL MESSAGE:

On Thu, 08 Apr 2010 17:09:08 -0400, Ron Youvan
<ka4inm at tampabay.rr.com> wrote:

>   By adjusting the antenna length to be resonate at the exciter's frequency the antenna
>is that "tank circuit," it's just lossy by the radiation resistance.  A variable coupling
>capacitor is not necessary.

REPLY:

Upon further consideration, if the antenna impedance matched the
tube's plate load impedance, wouldn't the Q be just one? I think you
still need the simple LC tank circuit for the flywheel effect.

73, Bill W6WRT
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