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Ramsey Electronics QAMP40 - page 1
QAMP-40 • 1 Ramsey Electronics Model No. QAMP40 Need a little extra boost for your QRP rig? Believe it or not, 20 watts is only about an ‘S’ unit below a 100 watt ri g! This nifty little amp will add some “punch” to any QRP transmitter. • Works great with Ramsey QRP rig s or any other 1-2 watt transmitters • Built-in T/R relay automat ...
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Ramsey Electronics QAMP40 - page 2
QAMP-40 • 2 P A RTI A L LIST OF A V A IL ABLE KITS RA M SEY T RA N SMIT TE R K ITS • FM10, FM25B FM Stereo Transmi tters • FM100 Super Pro FM Transm itter • MR6 Model Rocket Tracking Transmitter • A M1, AM25 AM Transmitter s RAMSE Y RECEIV ER KITS • FR1 FM Broadcast Receiver • A R1 A ircraft Band Recei ver • SR2 Shortwave Receiver ? ...
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Ramsey Electronics QAMP40 - page 3
QAMP-40 • 3 Ramsey Publication No. MQAMP40 Price $5.00 TABLE OF CONTENTS Introduction to the QAMP40 ........... 4 How it works ............... .................... 4 Parts list .... ....................... .............. 5 Tips and notes .... ........................... 6 QAMP40 assembly instructions . .... 6 Initial testing ..... ............ .. ...
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Ramsey Electronics QAMP40 - page 4
QAMP-40 • 4 INTR ODU CTIO N The Ram sey QAMP series of QRP power ampl ifiers are com pact 10 to 20 watt RF amplifiers for QRP CW transmitters. These amplifiers are made to be driven by transmitters in the ½ to 2 watt range. Built-in to the power amplifier is a sensitive T-R relay which w ill switch the unit in and out of the antenna line. W hen ...
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Ramsey Electronics QAMP40 - page 5
QAMP-40 • 5 PARTS LIST FOR THE QA MP40 QRP POWER AMPLIFIER CAPACIT O RS: 1 100 to 220 µ f electroly tic capacito r [C1] 1 10 µf el ectroly tic cap acitor [C2] 4 .1 µf disc ca pacitor (mar ked .1 or 104) [C3 ,8,10,13] 2 560 ρ f disc capacito r (mar ked 560 or 561) [C4,7] 2 330 ρ f disc capacito r (mar ked 330 or 331) [C5,6 ...
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Ramsey Electronics QAMP40 - page 6
QAMP-40 • 6 "THE RAMSEY LEARN-AS-YOU-BUILD ASSEMBLY STRATEGY" Take a look at the part s layout diagram . There is quite a lot to the construc tion of the QAMP40. It's easier than it seems once y ou get going, especially after you have installed a few of the "landmark" components. Once these "landmark" components ...
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Ramsey Electronics QAMP40 - page 7
QAMP-40 • 7 • Insert the part, oriented correctly, into its correct holes in the PC board. If helpful, gently bend the part’s wire leads or tabs to hold it in place, with the bod y of th e part snugly against the top side (component side) of the PC board. • Solder all wires o r pins of the part, whether the 2 wires of a resistor or the 3 or ...
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Ramsey Electronics QAMP40 - page 8
QAMP-40 • 8 16. In stall diode D4, 1N4002 style blac k epoxy diod e. Check positioning of the banded end. 17. Install jumper JMP2. Use a piece of scrap componen t lead wire bent into a "staple" shape and inserted into the board like a component. Jumpers act as electronic "bri dges" carrying signals over PC board circui ...
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Ramsey Electronics QAMP40 - page 9
QAMP-40 • 9 30. Install C12, another .001 µf disc capacitor (marked .001 or 102). 31. Install C8, .1µf disc capacitor (marked .1 or 104). These last four part s (R8,9 and C11, 12) form parasitic suppress ion networks across each transistor to suppress any tendency for high frequency oscillation in the power amplifier. 32. Install C3 ...
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Ramsey Electronics QAMP40 - page 10
QAMP-40 • 10 We're almost finished. All we need to do now is install a few remaining parts that have to be handmade - for that "old-world craftsmanship" touch ! We 'll pre pare all those part s now for fu rther assem bly . We gi ve y ou plen ty of ename led wire, but if you mess up, yo u can get a w hole 50 ' spool of it ...
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Ramsey Electronics QAMP40 - page 11
QAMP-40 • 11 Tin each end w ith solder as before. Tin all the way up to the core body. This winding is the primary of transformer T2. 44. Cut off another length of wire , 8 inches long. Wind 1 turn through the core, loop out 1 inch, twist together and run o ne more turn through the core, continuing on in the same direction as before. Tin each end ...
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Ramsey Electronics QAMP40 - page 12
QAMP-40 • 12 47. Locate the smaller transformer (T2) and install it snugly on the PC board. 48. Install the larger transformer (T1) into the indicated location on the PC board. 49. Install L1, a 19 turn toroid inductor wound previously. If desired, a small dab of hot melt glue, bathtub sealer, or caulk may be used to se cure the toroi ...
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Ramsey Electronics QAMP40 - page 13
QAMP-40 • 13 3. Connect a dummy load to J1, the amplifier RF output. In a pinch, a light bulb m ay be used - see the section, "Ve rifying RF Power Output." 4. Temporarily install a jumper from the collector of Q3 to ground . 5. Apply power to the amplifier but do not turn on the transmitter. Measure the current draw n b y th ...
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Ramsey Electronics QAMP40 - page 14
QAMP-40 • 14 VERIFYING TRANSMITTER RF OU TPUT The most important thing to know is wh ether your transmitter is delivering some meas urable and reassuri ng level of RF pow e r. Then y ou can continue on to adding the QRP a mplifier and checking out the w h ole set-up . Ideally, yo u have a small RF w attmeter, already inserted in the antenna line ...
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Ramsey Electronics QAMP40 - page 15
QAMP-40 • 15 KB4ZGC on how to make a highly accurate yet inexpensive dummy load and wattmeter capable of showing 1/10 -watt differences in RF power. If y ou use a wattmeter characterized for the HF frequency region, it will not give accurate results at the much higher t w o meter fr equencies, although it will be quite adequate for go/no-go testi ...
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Ramsey Electronics QAMP40 - page 16
QAMP-40 • 16 check are the bias circuitry and RF path through the relay. The amplifier should draw about ¼ amp with no signal applied. If you see m ore than that, recheck the bias setting (see the secti on "INITIAL TESTS"). If you hear an AC hum on the transmitted signal, usual causes are RF getting back into the powe r supply or a bad ...
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Ramsey Electronics QAMP40 - page 17
QAMP-40 • 17 case and hardw are set w i ll give your unit that nice finished look and increase its resale value. These sturdy black instrument cases a r e supplied w ith n eatly lettered front and rear panels, switch knobs, rubber feet and mounting screws. While we believe that the Ramsey enclosure and knob option is a fine value for finishing of ...
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Ramsey Electronics QAMP40 - page 18
QAMP-40 • 18 ...
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Ramsey Electronics QAMP40 - page 19
QAMP-40 • 19 The Ramsey Kit Warra nty Please read carefully BEFORE calling or writing in about your kit. Most problems can be solve d without contacting the factory . Notice that thi s is not a "fine print" w ar ranty. W e w ant you to unders tand your righ ts and ours too ! All Ramsey kits w ill work if assembl ed properly . The very f ...
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Ramsey Electronics QAMP40 - page 20
QAMP-40 • 20 Q A MP40 20 WATT LINEAR AMPLIFIER Quick Re ference Page Gu ide Introduction to the QAMP40 .......... .4 How it works ........................... ........4 Parts list ................. ........................ .5 Tips and notes ........... ..................... 6 QAMP40 assembly instructions ...... 6 Initial testing .... . ........... ...
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