[Amps] 4CX1500B

[Carl]

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 at q.com>
To: "Carl" <km1h at jeremy.mv.com>; "Vic K2VCO" <k2vco.vic at gmail.com>; 
<amps at 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 at jeremy.mv.com>
> To: "Vic K2VCO" <k2vco.vic at gmail.com>; <amps at 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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