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Author Topic: improving a cheap amp - beginner level  (Read 736 times)

2E0DED

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improving a cheap amp - beginner level
« on: November 05, 2018, 10:53:12 PM »

I own a zetagi vhf 2m amp, its a B40. nothing wrong with it at all, powers into a dummy load no issues.
so as a newbie beginner i want to do several things with this amp.

first up i  want to know how it works, so i am looking for pdf and web pages on how an amp work, not this exact make and model but general low power amps, what are  the basics?

next is how to test it, i own a few test items of kit but not a full spectrum analyser or scope, so how do you test and or fault find an amp with  a dmm? and what other items ( cheap beginners evel) can you suggest for the get on the shack bench?

last question is what to build to improve its performance. i am thinking something to clean the signal or to control its pattern, filters perhaps or some other items. all designs i want have to be home built and therefore simple. its an educational item not a ground breaking design
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G3RZP

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RE: improving a cheap amp - beginner level
« Reply #1 on: November 12, 2018, 06:06:20 AM »

Get the RSGB Radio Communication Handbook. Plus get the latest ARRL Handbook.
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W9GB

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RE: improving a cheap amp - beginner level
« Reply #2 on: November 14, 2018, 04:36:58 AM »

Jim Klitzing, W6PQL is retired engineer (Hewlett-Packard-Packard) who designs VHF/UHF RF amplifiers
with current NXP/Phillips or Freescale/Motorola components.
Jim covers the basics, with an emphasis on the Practical - design to build.
https://www.w6pql.com
Jim sells a number of modules/components for the DIY radio amateur builder.

80-watt VHF (2-meter) amplifier
Toshiba has discontinued the S-AV36, but still available.
https://www.w6pql.com/2_meter_80w_all_mode_amplifier.htm

IF you wish to “dive deeper” ,
THEN the Motorola Application Notes written by Helge O. Granberg, K7ES/OH2ZE (SK, 1996).
Helge was a Finnish-American radio amateur, long-time Motorola engineer and ARRL
Technical Advisor.  In Finland, he is equivalent to the “Art Collins” of that radio era.

Radio Frequency Transistors
Principles and Practical Applications
, 2nd edition (2001)
Norman Dye, Helge Granberg, Larry Leighton
https://books.google.com/books/about/Radio_Frequency_Transistors.html?id=iKbJNksGgQIC&printsec=frontcover&source=kp_read_button

Donna Vigneri, KF7SJF posted this rememberance of Helge Granberg,
as Motorola’s RF Division (now Freescale, NXP) was designing new 21st century RF components.
https://community.nxp.com/thread/313550
« Last Edit: November 14, 2018, 04:53:50 AM by W9GB »
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2E0DED

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RE: improving a cheap amp - beginner level
« Reply #3 on: November 14, 2018, 11:41:57 AM »

many thanks both.
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