Ramsey Electronics QRP CW POWER AMPLIFIER KIT QAMP30 manual

QAMP- 30 • 1 Ramsey Electronics Model No. Q A MP30 Need a little extra boost for yo ur QRP rig? Believe it or not, 20 watts is only about an ‘S’ unit below a 100 watt rig! This nifty little amp will add some “punch” to any QRP tra nsmitter. • W orks gr eat with Ram sey Q RP rigs o r an y other 1 -2 watt transmitte rs • Built-in T/R re[...]

QAMP- 30 • 2 RA M SEY T RA NSMIT TE R KIT S • FM100B Professi onal FM Ste reo Transmi tter • FM25B S ynthesized Stereo FM Transmitter • MR6 Model Rocket Tr acking Transmi tter • TV6 Tele vision Transmi tter R AMSEY RE CEI VER KI TS • FR1 FM Broa dcast Receiver • A R1 A ir craft Band Rece iver • SR2 Shortw av e Recei ver • SC1 Shor[...]

QAMP- 30 • 3 Ramsey Publication No. MQAMP30 Price $5.00 TABLE OF CONTENTS Introduction to the QAMP30 ........... 4 How it works ........... .............. .......... 4 Parts list .............. ............. .......... .... 5 Tips and notes ........... ............. ....... 6 QAMP30 assembly instructions ..... 6 Initial testing ..... ......... ..[...]

QAMP- 30 • 4 IN TRO DU C TIO N The Ra msey QAMP ser ies of QRP power ampl ifiers are co mpact 1 0 to 20 watt RF amplifiers for QRP C W transmitters. These amplifiers are m ade to be driven by transmitters in the ½ to 2 w att ran ge. Built-i n to the power amplifier is a sensitive T-R relay which w ill switch the unit in and out of the antenna li[...]

QAMP- 30 • 5 PARTS LIST F O R THE Q AMP30 QRP POWER A MPLIFIER CAPA CITORS:  1 100 t o 220 µ f elect rolytic ca pacitor [ C1]  1 10 µ f elect r oly tic capaci tor [C2]  4 .1 µf disc capacito r (marked . 1 or 104) [C3,8, 10,13]  2 330 ρ f disc capac ito r (marked 33 0 or 331) [C4,7]  2 560 ρ f disc capac ito r (marked 56 0 or 5[...]

QAMP- 30 • 6 "THE RAMSE Y LEARN-AS-YOU-BUI LD ASSEMBLY STRATEG Y" Take a look at the parts layout diagra m. There is quite a lot to the construction of the QAMP30. It's easier than it seems once you get going, especially after you have installe d a fe w of the "land m ark" compo nents. Once these "landmark" comp[...]

QAMP- 30 • 7 • If helpf ul, gently bend the pa rt’s wire lead s or tabs to hold it in place, with the body of the part snugly against the top side (component side) of the PC board. • Solder a ll wires or pi ns of the pa rt, whether t he 2 wires of a resistor or the 3 or 4 wires of a transistor. • Trim all excess wires extending beyond eac[...]

QAMP- 30 • 8  16. Install diode D4, 1N40 02 style black epoxy diode. Check positioning of the banded end.  17. Install jumper JMP2. Use a piece of scrap com ponent lead wire bent into a "staple" shape and inserted into the board like a component. Jumpers act as electronic "bridges" carrying sign al s over PC board circui[...]

QAMP- 30 • 9 These last four parts (R8, 9 and C11,12) form parasit ic suppression net works across each transistor to suppress any tendency for high frequency oscill ation in the pow er amplifier.  32. Install C3, anot her .1 µf disc ca pacitor (m arked .1 or 104). Both of these capacitors by p ass the center tap of the ferrite transformers t[...]

QAMP-30 • 10 W e're al m ost finished. All w e need to do now is install a f ew remaining parts that have to be handmade - for that "old-w or ld craf tsmanship" touch ! W e'll prepare all those parts now f or f urt her assembly . W e give you plen t y of enameled w i re, but if you mess up, y ou c an get a whole 50' spool[...]

QAMP-30 • 11 amount of w ire cut fo r this task is the proper amount. If you have too little or too much, then you have not w ound th e core correctl y. Tin ea ch end with solder as before. Tin all the w a y up to the core body. Th is winding is the primary of transformer T2.  44. Cut o ff another length of wi re, 8 inches long. W ind 1 turn t[...]

QAMP-30 • 12  47. Locate the smaller trans forme r (T2) and in stall it snugly on the PC board.  48. Install the larger tra nsformer (T1) into the indicated location on the PC board.  49. Install L1, a 15 turn to roid inductor wo und previ ously. If desired, a sm all dab of hot melt glue, bathtub sea ler, or caulk may be used to secur e [...]

QAMP-30 • 13  3. Connect a dummy load t o J1, the amplifier RF output. In a pinch, a light bu lb ma y be us ed - see the section, "Ver ifying RF Po wer Output."  4. Temporarily insta ll a jumper f rom the collector o f Q3 to ground.  5. Apply power to the am plifier but do not tu rn on the transmitter. Measur e the current dr a[...]

QAMP-30 • 14 VE RI FYI NG TR ANS MI T TER RF OU TP U T The most important thing to know is whether yo ur transm itter is delivering some measurable and reassuring level of RF pow er. Th en you can continue on to adding the QRP amplifier and checking out the whole set-up. Ideally , you have a small RF wattmeter, already inserted in the antenna lin[...]

QAMP-30 • 15 Amateur radio magaz ines and hand books provide a varie ty of circuits for RF wattm eters an d relati ve field -strength indicat ors, in cluding me thods of using your VOM as an indicating device. CQ magazine for March 1990 offers an article by KB4ZGC on how to make a highly accurate ye t inexpensive dumm y load and wattmeter capable[...]

QAMP-30 • 16 If you he ar an AC hum on the transmitted signal, usual causes are RF getting back into the power suppl y or a b ad VSW R on the antenn a. These short checks in no way de tail an y and all problems that can rear their ugly he ad, but should get you on the way to solving m ost errors. W e'd li k e to be able to fo resee a problem[...]

QAMP-30 • 17 W hile we believe that th e R ams ey enclosure an d kno b option is a f ine value for finishing off y our Ramsey kit, we are happy to g ive you a coup le of additional suggestions and our reasons for them. If y our f irst goal is economy and rugged portability, you will find t hat the circuit board can be mounted nicely in a standard[...]

QAMP-30 • 18[...]

QAMP-30 • 19 Amateur radio magazines and handbooks provide a variety of circuits for RF wattmeters and rela tive field-strength indicato rs, including methods of using your VOM as an indicating device. CQ magazine for March 19 90 off ers an article by The Ramsey Kit Warranty Please read carefully BEFORE calling or writing in about your kit. Most [...]

QAMP-30 • 20 Q AMP30 20 WATT LINEAR AMPLIFIER Quick Referen ce Page Guide Introduction to the QAMP-30 .......... 4 How it works .............. .......... ........... 4 Parts list ........... ............. ............. ..... 5 QAMP-30 assembly instructions .... . 6 Initial testing ..... .. ............. .......... ... 12 Verifying RF output powe [...]