114 lines
5.7 KiB
Plaintext
114 lines
5.7 KiB
Plaintext
25-200MHz / 8-45W AMP
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*****************************************************************************
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--------------------O input
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| D1 __ |
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*-------|>|---- --)|--
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| R2 -- | C1 | R1
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*---/\/\/-----*----------|-/\/\/---
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| ^ | |
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| C2 | R3 | |
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*--)|-*----/\/\/----*----- |
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| | |
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| / |
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| \ |
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| / R4 |
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| \ |
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| | g |
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| Q1 ----- |
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| ----- |
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| s| ^ |d L1 |
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*-------------------|_| |-*-(()((-*
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| < C3 L2 | |
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*-----)|---*-------(()((--| C5 |
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| | --)|--*
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| | > output | C6 |
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| --|(----O -----)|--*
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| C4 |-----| |
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-------------------- --- |
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- +12-24V
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*****************************************************************************
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SchemAsciit(r) (skem-as-kit) Symbols Key
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========================================
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> g
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-|(- = trimmer capacitor -----
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----- = RF power transistor
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-|(- = capacitor | ^ | g)ate s)ource d)rain
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s|_| |d
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-/\/\/- = resistor
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* = connection point
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-(()((- = coil
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__ --|-- = jump (not connected)
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-|>|--- = Zener diode ___
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-- _ = ground
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Component Listing
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=================
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R1 - 2.5K ohm L1 - 5 turns, #18 varnished,
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R2 - 20K ohm trimmer potentiometer 5/16" inside diameter
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R3 - 68 ohm
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R4 - 10 ohm L2 - 3 turns, #18 varnished,
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C1 - 220pF Tantalum, 35 volt 5/16" inside diameter
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C4 - 16-100pF trimmer capacitor
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C2,C6 - 4.7uF Tantalum, 35 volt D1 - 1N5230 (4.7V Zener diode)
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C3 - 8-50pF trimmer capacitor
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C5 - .1uF ceramic disc capacitor, 50 volt Q1 - (see chart)
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Transistor Data (input --> output watts at 100MHz, 24 and 12 volts)
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===============
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PART # IN OUT IN OUT
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------ ---- --- ---- ----
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MRF134 - 0.4W --> 8W || 0.6W --> 3.5W
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MRF136 - 0.4W --> 19W || 0.6W --> 8.5W
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MRF137 - 1.0W --> 45W || 1.0W --> 17W
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MRF138 - 1.5W --> 45W || 1.5W --> 15W
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[24V] [12V]
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* ASSEMBLY: Watch it with static around the TMOS transistor. It is VERY
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sensitive. If there's any static voltage difference between the drain or
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gate and the source, you can toast it! Keep it in the static-proof bag in
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which it was shipped until you're ready to install it as the LAST component.
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Then solder the source tabs first, then the gate (opposite diagonal tab) and
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drain (diagonal) tabs. (See diagram:)
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S /\ __ D
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\ \___/ /
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/====\/MRF\/====\
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| O | 137 | O | <--- mounting flange
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\====/\___/\====/
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/ / \ \
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G \/ \/ S
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Mount the TMOS flange to a metal box with some heatsink compound. Ground your
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PCB to the same cabinet.
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* TESTING: Connect the output to a dummy load which can handle the power level
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you'll be generating. Set the trimpot at mid-range and apply your 12 or 24V.
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At this point, the power transistor shouldn't get warm until you turn the pot
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up more. If it does start to warm up, turn the pot down a bit until the temp.
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remains the same or lowers. DO NOT adjust past this point. Now feed your RF
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signal to the amp's input. Use C3 (tuning) and C4 (load) to adjust for max.
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output. You may also have to readjust R2 for the best reading. Keep and eye
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on the meter for sudden jumps in output - this shouldn't happen.
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* TROUBLESHOOTING: If tuning is erratic, the amp is probably going into self-
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oscillation which can be caused by insufficient grounding, bypassing of the
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power supply leads, too long of input or output wires, or too high a bias.
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* PARTS: Contact "RF Parts" at 619-744-0728 for the transistor you choose. Ask
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'em for their latest flyer, too. It's free. Your local electronics supplier
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other than Smack Shack ought to have everything else you'll need (at least mine
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does!). If not, try "Mouser Electronics" at 800-346-6873 and get their free
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catalog, too.
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Well, I tried... :) If there's some discrepancy about this lousy schematic
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representation, or anything else for that matter, E-Mail me at:
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cdimick@esunix.sim.es.com
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I'll try to clear things up for you. It works like a charm for me, albeit a
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little hot. Good luck! (BTW - The complete plans including schematic, PCB
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layout, and detailed assembly instructions are available from Panaxis Prod.
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P.O. Box 130, Paradise, CA 95969. No copyright was listed on the plans, so
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I copied what little I could tolerate for you folks.)
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