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40 METER (7MHz)
CW TRANSMITTER
Ramsey Electronics Model No.
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 KHz of tuning about the crystal
frequency
•
Front panel switching of TWO channels and includes a crystal for
7.040 MHz, the International QRP frequency
•
Excellent and clean keying waveform
•
Built-in antenna T-R switch
•
Operates on 12 - 15 volts DC at 1/4 amp current
•
Appoximately 1 Watt RF power
•
Clear, concise step-by-step instructions carefully guide you to a
finished kit that not only works - but you'll also learn too!
•
Proven design that has won many of awards for operators around
the country!
•
Add our case and knob set for a finished 'Pro' look. Cases match all
Ramsey products
QRP-40 • 1
QRP40
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Summary of Contents for Ramsey Electronics QRP40
- Page 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. •...
- Page 2 RAMSEY MINI-KITS Many other kits are available for hobby, school, scouts and just plain FUN. New kits are always under development. Write or call for our free Ramsey catalog. 40 METER CW TRANSMITTER KIT INSTRUCTION MANUAL Ramsey Electronics publication No. QRP40 Revision 1.3 First printing: January 1995 COPYRIGHT 1994 by Ramsey Electronics, Inc.
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Page 3: Table Of Contents
KIT ASSEMBLY AND INSTRUCTION MANUAL FOR QRP40 40 METER CW TRANSMITTER KIT TABLE OF CONTENTS Introduction to the QRP40 ..... 4 Understanding Power Levels ..5 Circuit Description ......7 Simplified Block Diagram ....8 Parts List ........9 Schematic Diagram ...... 10 Parts Layout Diagram .... -
Page 4: Introduction To The Qrp40
"QRP" refers to transmitter powers under 5 watts. In our manuals for the Ramsey Amateur Band receivers for the 80 and 40 meter bands, which tend to be of interest to many beginners because of... -
Page 5: Understanding Power Levels
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 successfully, not necessarily to "sell"... - Page 6 S9+10 db. 1000 watts output 100 watts output 25 watts output 6.25 watts output 1.56 watts output .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 communication.
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Page 7: Circuit Description
"milliwatt" world ARE setting records with "milliwatt" tests. With the world record set in 1970 between Alaska and Oregon on ONE microwatt, think about it this way: your Ramsey QRP transmitter is almost one million times more powerful than the transmitter used in that historic test! WHO SHOULD USE A "QRP"... -
Page 8: Block Diagram
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, and +12VDC through choke L4 to the anode of D1, which permits RF to pass through D1 to the filter network while applying negative bias to D2 which blocks RF from passing to the... -
Page 9: Parts List
PARTS SUPPLIED WITH QRP40 TRANSMITTER KIT: CAPACITORS: 47 pf capacitor (C6,C2) 330 pf capacitor (marked 330 or 331) (C3) 470 pf capacitor(marked470 or 471) (C17) 820 pf capacitor (marked 820 or 821) (C18) 11 .01 uf capacitors (marked .01 or 103 or 10 nf) -
Page 10: Schematic Diagram
QRP-40 • 10... -
Page 11: Parts Layout Diagram
QRP40 PARTS LAYOUT DIAGRAM: QRP-40 • 11... -
Page 12: Assembly Instructions
The assembly sequence will follow the circuit flow from key jack to antenna as faithfully as is practical, as part of Ramsey's "Learn-As-You-Build" kit assembly philosophy. - Page 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 capacitors are polarized, which means there is a right and a wrong way to install them! Generally, the Negative ( - ) side is indicated on the capacitor, while the Positive ( + ) is shown on the PC board.
- Page 14 The PC board used in your kit is common to all the QRP transmitters in the Ramsey Kit line. This means that there are some component locations on the PC board that may not be used on your kit. Please be aware of this and install your parts carefully.
- Page 15 HALFTIME SUGGESTION It won't be too much longer before your Ramsey transmitter is ready for testing and on-the-air operation. It is common for experimental projects to give disappointing results because of inefficient "haywire" hookups as soon as they are completed.
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Page 16: Crystal Oscillator Testing
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 position. Keying J3 should result in a crisp, clean oscillator signal in your receiver. -
Page 17: Initial Tests
"halftime" instructions, NOW is the time to make proper preparations for testing and using your transmitter. As we suggest in all Ramsey Electronics kit projects, now might also be an excellent time to take a break and then come back to re-check your connections, or have a friend go over them. - Page 18 Saying the same thing one more way, we assume you already know that accurate, commercially built RF wattmeters cost much more than what you paid for this Ramsey transmitter kit. Since this solid-state transmitter does not require tuning or adjustments, a periodic power output check-up should suffice.
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Page 19: Maximizing Rf Power Output
You're on your own, that's what experimenting is all about! TRANS-RECEIVE OPERATION: If you plan to use this transmitter with a Ramsey HR-series direct conversion receiver for portable operation, it will be necessary to work out a receiver muting and keying sidetone circuit. - Page 20 OTHER ENCLOSURE RECOMMENDATIONS: While we believe that the Ramsey enclosure and knob option is a fine value for finishing off your Ramsey receiver or transmitter, we are happy to give you a couple of additional suggestions and our reasons for them.
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Page 21: Troubleshooting Guide
However, you also will be interested to know that test QSO's, including DX, were made with this Ramsey transmitter using both a mobile whip antenna and simple dipole on the balcony of a condo building. -
Page 22: Ramsey Kit Warranty
QRP-40 • 22... -
Page 23: Ramsey Kit Warranty
But on rare occasions a sour component can slip through. All our kit parts carry the Ramsey Electronics Warranty that they are free from defects for a full ninety (90) days from the date of purchase. - Page 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 Parts layout diagram .....11 Assembly instructions ....12 Initial tests ........17 Troubleshooting guide ....21 Ramsey kit warranty .....22...