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Re: [Amps] Stripline design

To: Carl <>
Subject: Re: [Amps] Stripline design
From: Roger <>
Date: Sun, 15 Nov 2009 23:42:59 -0500
List-post: <">>

Carl wrote:
> QST and HRM had some theory/construction articles mostly by Eimac 
> engineers.
> Ive done some stripline myself but prefer a single 3CX1000A7 and 8877 
> which I use on 144 and 222.  I remember a dual 4CX1000A article for 2M 
> that worked well.
> These days the only 2 x 3CX800 design Im aware of is K1FO's Lunar Link 
> products.
That's one of the reasons I'd like to learn a bit of strip line theory 
as I only have dimensions for a single 3 CX-800 that I could replace 
with a single 4CX-1500 for legal limit. What I don't know is how going 
from 800 to a 1000 watts pep to the legal limit, or running a pair of 
tubes might change the dimensions of the strip line. I'd rather not go 
with the "cut-and-try" approach. Of course there is always the 
possibility of a single GU-84B/4CX2500, or the GU-73B that take 
reasonable voltages and currents on the filament, plate, screen, and 
grid with what appear to be pretty good gain characteristics. OTOH 
spares might be a bit hard come by in the future.  The GS35 as I 
understand takes more drive and a step start, but no screen circuit 
requirements...they're cheap too. 

OTOH I do have a pair of new 4CX-1500s on the way and already have some 
spare pulls.

The ARRL amp handbook uses a pair of the 3CX-800s in parallel for 
6-meters and Push Pull for 2-meters. It appears I could use the 
4CX-1500s in that design with little change except for the power 
supply.  OTOH the dual band controls make the front panel a bit less 
than elegant in layout.<:-)) 

When I finish I want to end up with the legal limit amp(s) on both 6 and 
2 with no time limit, key down for any mode.


Roger (K8RI)
> Carl
> KM1H
> ----- Original Message ----- From: "Roger" <>
> Cc: <>
> Sent: Sunday, November 15, 2009 10:04 PM
> Subject: [Amps] Stripline design
>> I'm looking at building a 2-meter amp using a stripline with a pair of
>> 3-CX800's or 4CX-800's, but I've not found any real data on the design
>> (dimensions) of the actual strip line.  Another possibility is building
>> the 6 'n 2 amp in the ARRL classic amp design handbook. I also have a
>> Henry 2002A using a single 3CX-800 with a strip line.
>> Unlike using the tube characteristics and designing a standard Pi or
>> Pi-L network for a given Q, I've found no information on strip lines in
>> any of the hand books.  Yes, there were a couple of amps using one and
>> the dimensions were given, but if the design information was there I
>> missed it.
>> The only thing I found on the net were the download sites that appear
>> free until you give them your information and then they want you to
>> pay.  I'd probably sign up if they told me the charges up front.
>> 73
>> Roger (K8RI)
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