Hi guys:
I think I have on the machine a piece of software that can help calculate a
strip line. If anybody's interested contact me.
73:
Alex 4Z5KS
-----Original Message-----
From: amps-bounces@contesting.com [mailto:amps-bounces@contesting.com] On
Behalf Of jeff millar
Sent: Monday, November 16, 2009 8:56 AM
To: Roger
Cc: amps@contesting.com
Subject: Re: [Amps] Stripline design
Roger...
The best place for design examples of 2 meter amplifiers is
http://www.nd2x.net/base-1.html It's aimed at amps using the Russian tubes
but the designs work with any tube having a similar size and plate
capacitance.
My personal favorite is the PA3CSG half wave line approach because it uses
very few specialized components and doesn't run high circulating current
through any capacitors or joints in metal pieces, but it does result in a
physically large amplifier.
http://www.nd2x.net/PA3CSG-2.html
Assuming you use capacitive flappers for tuning power output coupling, it's
very easy to design a stripline by cut and try. The strip line is designed
to be physically large with a lot of surface area for current carrying. Some
people talk about making it be a certain impedance, but that's totally not a
factor. Wide lines have lower inductance and have to be longer, that's all.
To set the line length, uses an impedance bridge on the output port, or
couple a grid dipper into the cavity with the cover mostly on and adjust
length with tune and load flappers at mid range.
The W6PO design uses two quarter wave lines on each side, presumably to
balance currents, but that doesn't seem necessary on 2M.
jeff, wa1hco
Roger wrote:
> 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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