Qrp-40 • 1 40 meter (7mhz) cw transmitter ramsey electronics model no. Qrp40 the ramsey qrp-40 is an amazing performer that will work the world on about a watt! Folks of all ages have successfully built and enjoyed this easy, fun kit. • ideal for portable or travel fun • vcxo design allows up to 5 k...
Qrp-40 • 2 partial list of available kits ramsey transmitter kits • fm10a fm stereo transmitter • fm100b professional fm stereo transmitter • fm25b synthesized fm stereo transmitter • am25 synthesized am transmitter • am1 am transmitter ramsey receiver kits • fr1 fm broadcast receiver • ar1 aircraft...
Qrp-40 • 3 qrp40 40 meter cw transmitter kit ramsey publication no. Qrp40 price $5.00 table of contents introduction to the qrp40 ............. 4 understanding power levels ......... 5 circuit description .......................... 7 simplified block diagram ............... 8 parts list ...............
Qrp-40 • 4 introduction: most "qrp" transmitters are one-of-a-kind experimental circuits which take some patience and fine-tuning to get clean keying and satisfactory performance. Most qrp building projects presume either unlimited radio junkboxes with all the right coils and capacitors, or that you...
Qrp-40 • 5 if you're studying this manual before deciding to try this ramsey "qrp" transmitter project, perhaps the following discussion will be helpful to you. The purpose of this manual is to help you construct this ramsey electronics 4- stage, variable-frequency cw transmitter efficiently and suc...
Qrp-40 • 6 s9+10 db. 1000 watts output s9 100 watts output s8 25 watts output s7 6.25 watts output s6 1.56 watts output s5 .39 watts output we can see that it becomes easy to play games with such numbers. For example, an rst of 439 is a legitimate report which permits reasonably effective communicat...
Qrp-40 • 7 while these figures also can be used to show how nice it is to have a power amplifier and beam antenna, they indeed serve to show that reasonable signal levels indeed are achievable with low power and a dipole antenna. "qrp" enthusiasts have their own rituals, jargon, strategies, qrp oper...
Qrp-40 • 8 l6,c17 and c18 form a low pass filter (butterworth) to match the output of q3 to the antenna and reduce harmonics to acceptable levels as specified by the fcc. When the keying line is closed, q4 conducts +12vdc to the oscillator stage, applies a positive bias to the base of q2 through r8,...
Qrp-40 • 9 parts supplied with qrp40 transmitter kit: capacitors: 2 47 pf capacitor (c6,c2) 1 330 pf capacitor (marked 330 or 331) (c3) 1 470 pf capacitor(marked470 or 471) (c17) 1 820 pf capacitor (marked 820 or 821) (c18) 11 .01 uf capacitors (marked .01 or 103 or 10 nf) (c1,4,5,7,8,9,10,13,14,15,...
Qrp-40 • 10
Qrp-40 • 11 qrp40 parts layout diagram:.
Qrp-40 • 12 "learn-as-you-build" transmitter assembly strategy: as you can see in examining the circuit board and components, there is a bit more to this transmitter kit than soldering a few parts and putting a signal on the air. So that you don't spend extra time "troubleshooting" instead of gettin...
Qrp-40 • 13 5. Insert and solder r1, the 10k tuning potentiometer. 6. Insert and solder s1, pushbutton switch. Carefully select, insert and solder the following components in the order given in the following steps. Check off each step as completed. 7. C16, 100 to 220 uf electrolytic. Electrolytic ca...
Qrp-40 • 14 20. Install c15, .01 uf (marked .01 or 103 or 10 nf). So far, here's what we've accomplished. First, we've got over a third of all the parts soldered onto the board, which should make you happy, and you should be used to locating the correct component holes with increasing ease by seeing...
Qrp-40 • 15 30. Install r6, 470 ohms (yellow-violet-brown). With the above components installed correctly, the three holes for q1 should be clearly apparent. Make sure q1 is correctly identified as a 2n3904. 31. Install q1, 2n3904. Orient its flat side correctly. 32. Install c5, .01 uf 33. Install r...
Qrp-40 • 16 crystal oscillator testing: connect a key, keyer or momentary switch to j3. Connect +12vdc to power connector j4. Note that the center connection is the positive (+) side. Tune a nearby receiver to the anticipated crystal frequency. Make sure that s1 is set to the correct crystal positio...
Qrp-40 • 17 45. Install l3, 3.9 uh inductor (marked lq396 or orange-gold-white bands). 46. Install c14, .01 uf (marked .01 or 103 or 10 nf). 47. Install c9, .01 uf (marked .01 or 103 or 10 nf). 48. Install d1, 1n4002 (large black epoxy body), notice placement of banded end. 49. Install l4, 100 uh in...
Qrp-40 • 18 capability for casual operating. For maximum rf output power, use a supply of 14 to 15 volts dc. The easiest method is to place two fresh "d cells" in series with your power source, if a full 13.6-15 volts dc is not available. If your supply voltage is in the 11-12 volt range, you can ex...
Qrp-40 • 19 please remember, though, that a flashlight bulb does not present the proper load impedance to the transmitter output, so theoretical calculations based on the bulb`s rating can only be approximate. For example, the pr-4 at full brilliance presents only an 8.2 ohm load to the transmitter....
Qrp-40 • 20 this transmitter is an ideal travel companion to the growing number of portable shortwave broadcast receivers which feature digitally synthesized tuning, memories and other features, provided that a bfo for cw-ssb reception is one of the features. In most cases, transmitter keying can be...
Qrp-40 • 21 final considerations: our earlier discussion of how a watt of rf output can indeed offer satisfying communications has several presuppositions: 1. A resonant antenna (dipole or quarter-wave vertical) 2. Good quality coaxial feedline and connectors 3. An effective earth ground we cannot e...
Qrp-40 • 22.
Qrp-40 • 23 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...
Qrp-40 • 24 40 meter cw transmitter kit quick reference page guide introduction to the qrp40 ..............4 understanding power levels ...........5 circuit description ...........................7 parts list ..........................................9 schematic diagram ......................10 part...
