Qamp20 • 1 ramsey electronics model no. Qamp20 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 rig! This nifty little amp will add some “punch” to any qrp transmitter. • works great with ramsey qrp rigs or any other 1-2 watt transmit...
Qamp20 • 2 ramsey transmitter kits • fm10a, fm25b fm stereo transmitters • tv6 television transmitter • cube tv transmitters ramsey receiver kits • fr1 fm broadcast receiver • ar1 aircraft band receiver • sr2 shortwave receiver • aa7 active antenna • sc1 shortwave converter ramsey hobby kits • sg7 p...
Qamp20 • 3 ramsey publication no. Mqamp20 price $5.00 table of contents introduction to the qamp20 ........... 4 how it works ................................... 4 parts list ......................................... 5 learn as you build ......................... 6 qamp20 assembly instructions ........
Qamp20 • 4 introduction the ramsey qamp series of qrp power amplifiers are compact 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 will switch the unit...
Qamp20 • 5 parts list for the qamp20 qrp power amplifier capacitors: 1 100 to 220 µf electrolytic capacitor [c1] 1 10 µf electrolytic capacitor [c2] 4 .1 µf disc capacitors (marked .1 or 104) [c3,8,10,13] 2 180 ρf disc capacitors (marked 180 or 181) [c4,7] 2 330 ρf disc capacitors (marked 330 or 331...
Qamp20 • 6 required, not supplied: ramsey case, knob and panel set, ramsey part no. Cqrp matching input and output cables to existing qrp transmitter 12 volt dc power supply 3 amp rating proper dummy load or resonant antenna "the ramsey learn-as-you-build assembly strategy" take a look at the parts ...
Qamp20 • 7 in all the following instruction steps, our word "install" means to do the following: • 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 body of the part snugly against the to...
Qamp20 • 8 15. Install q3 and q4, 2n3904 npn transistors, observing proper orientation of the flat side. These two transistors amplify the signal diode's output to a level high enough to close relay k1. 16. Install diode d4, 1n4002 style black epoxy diode. Check positioning of the banded end. 17. In...
Qamp20 • 9 these last four parts (r8,9 and c11,12) form parasitic suppression networks across each transistor to suppress any tendency for high frequency oscillation in the power amplifier. 32. Install c3, another .1 µf disc capacitor (marked .1 or 104). Both of these capacitors bypass the center ta...
Qamp20 • 10 41. Winding l1 and l3 toroid rf coils (two identical units ): locate 2 of the donut shaped yellow toroid cores provided in the kit. Cut 8" of the enameled magnet wire and, following the drawing, thread the wire through the core 12 times - not 11, not 13; it must be 12 times through the c...
Qamp20 • 11 through the core, continuing on in the same direction as before. Tin each end with solder all the way up to the core body. This winding is the 2 turn center-tapped secondary of t2. 45. Winding t1: locate the remaining larger 2-hole ferrite core. Cut off a 10 inch length of the enameled m...
Qamp20 • 12 50. Install l2, the 14 turn toroid inductor - you marked it special, remember? 51. Install l3, the remaining 12 turn toroid inductor. This completes the assembly of your qrp power amplifier. Now's a good time to give your masterpiece a good going over, being especially alert for any: • b...
Qamp20 • 13 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 drawn by the amplifier and slowly rotate the bias pot, r4, clockwise until you reach a reading of ¼ amp. Do not allow the current to...
Qamp20 • 14 ideally, you have a small rf wattmeter, already inserted in the antenna line, capable of accurately measuring low output power in watts. And it cost you less than what you paid for the transmitter kit. Right? In the words of wayne from "wayne's world"... Not! So here are a few other idea...
Qamp20 • 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 you use a wattmeter characterized for the hf frequency region, it will not give accurate results at the much higher two meter frequencies, although it...
Qamp20 • 16 if you hear an ac hum on the transmitted signal, usual causes are rf getting back into the power supply or a bad vswr on the antenna. These short checks in no way detail any and all problems that can rear their ugly head, but should get you on the way to solving most errors. We'd like to...
Qamp20 • 17 while we believe that the ramsey enclosure and knob option is a fine value for finishing off your ramsey kit, we are happy to give you a couple of additional suggestions and our reasons for them. If your first goal is economy and rugged portability, you will find that the circuit board c...
Qamp20 • 18.
Qamp20 • 19 the ramsey kit warranty please read carefully before calling or writing in about your kit. Most problems can be solved without contacting the factory. Notice that this is not a "fine print" warranty. We want you to understand your rights and ours too! All ramsey kits will work if assembl...
Qamp20 • 20 qamp20 20 watt linear amplifier quick reference page guide how it works ................................... 4 parts list .......................................... 5 learn as you build .......................... 6 qamp20 assembly instructions ..... 7 initial testing ..... ..................
