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THE AM BULLETIN BOARD => Technical Forum => Topic started by: Tom WA3KLR on December 20, 2005, 10:54:16 AM



Title: Class E System Power Supply and PWM Deck Started
Post by: Tom WA3KLR on December 20, 2005, 10:54:16 AM
I’m starting to build the power supply/pulse width modulator deck for my Class E transmitter system.

The cabinet was my homebrew 68B09 Forth language-dedicated computer in its first life, completed 12/24/82.  Two 8” floppies.   Remember them ? – hi. 
10 ½” rack panel, box is 21” deep.  I stripped out everything except the switches, fuse holders, fan, r.f.i. line filter, line cord and pushbuttons.  See photo below.

I mounted the 3 kVA toroidal power transformer vertically to the left wall.  Bridge rectifier mounted on the right wall.  I’m doing testing of various power supply configurations. See photo below.

The front panel is 1/8” aluminum.  The Variac is the only new item to get mounted to the panel.  I will make two 0.050” aluminum plates to set in the floppy openings.  All of the meter movements, switches, pots, jacks, and LEDs will be mounted on those plates. 

All for now, happy holidays guys.


Title: Re: Class E System Power Supply and PWM Deck Started
Post by: steve_qix on December 21, 2005, 10:52:25 AM
Nice!

How many FETs are you going to use in the RF amp (and on what band(s))?

Balanced design (better!) ?

Talk later and Regards,

Steve


Title: Re: Class E System Power Supply and PWM Deck Started
Post by: K1JJ on December 21, 2005, 12:08:59 PM
Nice start, Tom!

You got the grunt work done - now fun, fun, joy joy with the RF deck!

Post em as you do em.

73,

T


Title: Re: Class E System Power Supply and PWM Deck Started
Post by: Tom WA3KLR on December 21, 2005, 06:07:46 PM
Hi Steve and Tom,

I am planning to try to get away with just 3 FETs in the PA.  It will be a while before I get to the PA though.  I’m doing the complete PS/PWM first.  It includes temperature monitoring/over-current/over-voltage protection, keying sequencer, and CW waveform generator.

The PAs will be single-ended, single-band decks.  That's the plan.  We'll play it by ear though. 

160 meters is first!  I also plan to build 75 and 40 meter decks.

I have been making posts on the Class E Forum also, with a link to my posts here on the AM Forum.
AMfone - Dedicated to Amplitude Modulation on the Amateur Radio Bands