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Re: [Amps] CB amp directly coupled via cap to antenna

To: "TexasRF@aol.com" <TexasRF@aol.com>, "dezrat1242@yahoo.com" <dezrat1242@yahoo.com>, "amps@contesting.com" <amps@contesting.com>
Subject: Re: [Amps] CB amp directly coupled via cap to antenna
From: "Fuqua, Bill L" <wlfuqu00@uky.edu>
Date: Thu, 8 Apr 2010 11:56:24 -0400
List-post: <amps@contesting.com">mailto:amps@contesting.com>
I see some interesting applications for this type of antenna. 
You can have a 80 meter transmitter that will transmit on 80,40,20,15,10 meters 
and lots of other frequencies at the same time.
Field strength measurements would be improved by making use of all these 
harmonics. 
Hi Hi 
73
Bill wa4lav

________________________________________
From: amps-bounces@contesting.com [amps-bounces@contesting.com] On Behalf Of 
TexasRF@aol.com [TexasRF@aol.com]
Sent: Thursday, April 08, 2010 11:31 AM
To: dezrat1242@yahoo.com; amps@contesting.com
Subject: Re: [Amps] CB amp directly coupled via cap to antenna

With the shunt C from tube anode to ground there would not be a case for 50
 +j0 right at the tube.

Also, with tube in the discussion the plate load impedance would be a bit
higher than 50 ohms anyway.

Agreed?

Now, your vertical idea has some interesting possibilities: By choosing the
 length carefully, one can set the R of the vertical to match the plate
load  impedance. You are still left with the need to reconcile the reactance
that  remains. Since the tube will be capacitive, perhaps there would be a
happy  coincidence of antenna R +j to handle the match, maybe somewhere around
3/4 wave  length?. If not, careful selection of the coupling C would surely
make it all  possible.

73,
Gerald K5GW





In a message dated 4/8/2010 10:06:13 A.M. Central Daylight Time,
dezrat1242@yahoo.com writes:

ORIGINAL  MESSAGE:

On Thu, 8 Apr 2010 08:29:25 EDT, TexasRF@aol.com  wrote:

>
>We all know there HAS to be some kind of matching to  get significant
power
>transfer.

REPLY:

If the  antenna impedance is the same or nearly so as the plate load
impedance, no  matching network is necessary. A half wave vertical has
very high impedance  and might be just the ticket. Pun intended.

73, Bill  W6WRT
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