[Amps] CB amp directly coupled via cap to antenna

[Carl]

Jo Jennings built an amp in the 60's that ran a mess of sweep tubes at 2KW 
PEP input. The output tank was a .01 cap. It was even published in QST.

Carl
KM1H


----- Original Message ----- 
From: "Fuqua, Bill L" <wlfuqu00 at uky.edu>
To: <TexasRF at aol.com>; <dezrat1242 at yahoo.com>; <amps at contesting.com>
Sent: Thursday, April 08, 2010 11:56 AM
Subject: Re: [Amps] CB amp directly coupled via cap to antenna


>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 at contesting.com [amps-bounces at contesting.com] On Behalf 
> Of TexasRF at aol.com [TexasRF at aol.com]
> Sent: Thursday, April 08, 2010 11:31 AM
> To: dezrat1242 at yahoo.com; amps at 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 at yahoo.com writes:
>
> ORIGINAL  MESSAGE:
>
> On Thu, 8 Apr 2010 08:29:25 EDT, TexasRF at 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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