The z presented to the rig's input by the amp in the GG varies with tuning.
So if you are tuning up the amp's tank, how does that also not show up as an
unmatched condition triggering the LDG to auto tune?
73/jeff/ac0c
www.ac0c.com
--------------------------------------------------
From: "Alek Petkovic" <vk6apk@bigpond.com>
Sent: Sunday, August 29, 2010 8:04 AM
To: "Fuqua, Bill L" <wlfuqu00@uky.edu>; "jeff millar" <jeff@wa1hco.net>;
<Amps@contesting.com>
Subject: Re: [Amps] Using automatic tuner for Amp input
> G'day Bill,
>
> I just did a few calcs. We are gonna use the LDG 100AMP tuner in a gs35B
> amp.
>
> Let's assume it's 100 ohms. We need a cap whose Xc on 3.5MHz = 25 ohms. Xc
> =
> 1/2.pi.f.C, So C = 1820pF.
>
> Forgive me mate but that sounds like a bloody big capacitor to have
> sitting on the input at 10m.
>
> Even with 50 Ohm tube input impedance, we are looking at 900pF sitting
> there.
>
> Did I do something wrong or is this all ok?
>
> Thanks and 73,
> Alek.
>
>
>
> At 02:15 AM 29/08/2010, Fuqua, Bill L wrote:
>>You can make it work as long as you shunt the input of the amplifier
>>with a capacitor with a reactance of 1/4 or less of the input
>>impedance. This will provide the charge storage needed to smooth out
>>the sinusoidal wave from and the antenna tuner will still match the
>>impedance. I prefer a Q of 10 or better myself but if you chose 1/4
>>for 80 meters you will have a Q of 4 on 80 meters and on 10 meters
>>it will be 32 with out switching capacitors.
>>
>>73
>>Bill wa4lav
>>
>>________________________________________
>>From: amps-bounces@contesting.com [amps-bounces@contesting.com] On
>>Behalf Of jeff millar [jeff@wa1hco.net]
>>Sent: Saturday, August 28, 2010 11:31 AM
>>To: Amps@contesting.com
>>Subject: [Amps] Using automatic tuner for Amp input
>>
>>What do people think of the amplifier by Bill W4NFR shown in the
>>latest QEX? It
>>uses an LDG tuner on the amplifier input instead of a set of
>>filter/matching
>>networks for each band. It seems like an innovative design.
>>
>>jeff, wa1hco
>>_______________________________________________
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>
>
> http://www.qrz.com/db/vk6apk
> http://www.qrz.com/db/vk6ap
>
>
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