Lucky you, I had to give up all those fancy toys when I retired! Thanks for
that info.
So whats a good broadband 1.8-30MHz input for a 400 Ohm load, Input C 30pf,
and Class AB2 with 35ma Ig and how much drive power is needed for 350 Peak
RF Volts at the grid?
Carl
KM1H
----- Original Message -----
From: "pfizenmayer" <pfizenmayer@q.com>
To: "Carl" <km1h@jeremy.mv.com>; "Vic K2VCO" <k2vco.vic@gmail.com>;
<amps@contesting.com>
Sent: Friday, August 10, 2012 3:19 PM
Subject: Re: [Amps] 4CX1500B
> Just for hell of it since I was set up -- I built that network in Genesys
> and let it
> optimize for what Rload and Cload was optimum 2 to 29.75 mHz.
>
> First looked at network using 50 ohms R load and let Cload optimize - and
> was less than 2:1 SWR from 2 to 29.75mHz with C load 154 pfd.
>
> Then let it optimize Both R load and Cload and it came up with R load 43
> ohms , Cload 160 pfd SWR less than 1.6:1 from 2 - 28.25 mHz and 2.3:1 at
> 29.75.
>
> FWIW - if you set R load at 50 ohms and leave the inductors at the given
> values , then let the C values optimize , you get better than 1.2:1 SWR
> 2 - 29.75 mHz -- C input(was 120) 71.5 pfd , C2 (was 250) 136 pfd
> and tube is 60 pfd.
>
> As a common sense test I normally always put 10 to 20 nhy lead inductance
> in the shunt caps (total of one half to one inch of lead length) - but 10
> or 20 nhy did not degrade response - slight change in caps values of a
> pfd or two which is expected.
>
>
> Hank K7HP
>
>
>
> =====
> ----- Original Message -----
> From: "Carl" <km1h@jeremy.mv.com>
> To: "Vic K2VCO" <k2vco.vic@gmail.com>; <amps@contesting.com>
> Sent: Thursday, August 09, 2012 1:42 PM
> Subject: [Amps] 4CX1500B
>
>
>> You can also give the YU1AW circuit a try where he came up with a 160-10
>> broadband input for a tetrode not named.
>>
>> It is a 120pf input cap to ground, a series 345nH coil, 250pf cap to
>> ground and a series 308nH coil. I have the coil dimensions if needed. The
>> terminating resistor is 50 Ohms.
>>
>> Disclaimer: I havent tried or analyzed it.
>>
>> Carl
>> KM1H
>>
>>
>>
>
>
>
> -----
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