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QRP and Home Brews presentation at the 2008 W.V.A.R.A. HAMFEST March 8, 2008. John Swez KC9JPZ. URL for download of this Presentation newton.indstate.edu/swez. This talk consists of four parts. An introduction to QRP An introduction to the speaker
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So Now You're HF-ActiveReply by WA0ZZG on January 18, 2007 Mail this to a friend! Last winter, on a night that was below zero, I was tuning around 40 meters on a little QRP CW rig. Found a slow station, not very strong, calling CQ. I went back to him. Talked for about 45 minutes to a older gentleman from Atlanta. I felt good about making the contact with only four watts, so I told him how much power I was running. He completely deflated my balloon by coming back and telling me "that’s OK I am running one half watt." Dave WA0ZZG
To be classified as QRP your power level must not exceed 5 watts output when transmitting a CW signal.
“Borrowed From” New Jersey QRP Club http://www.njqrp.org/whyqrp/2.htm
K.I.S.S. Use a simple dipole up in the tree
Reference: Same article as previous slide
Look! If you only got a few watts, make sure it gets up into the sky!
Most QRP QSOs are CW QSOs (we will talk about QRP Math later
"Welcome to the realm of QRP, a place where less RF power is more fun for the operator! In general, QRP operators use equipment that weighs less, takes up less space, costs less and is less dependent on ac power than the typical ham station of 50 watts or more. In return, QRP enthusiasts get freedom - freedom to carry a complete station, with accessories and antenna, in a briefcase.
A typical QRP station is small enough to take along on vacation in a car full of family, by air or backpacking. Your QRP station can operate from batteries for long periods when the power fails, or indefinitely from unusual power sources such as private hydroelectric, wind or solar power systems.
Freedom is gratifying, but better still is the sense of accomplishment that comes from operating equipment you built yourself. You may best love the feeling when that first CQ from your home-built transmitter is answered - or the way a smile steals onto your face when that 1-KW station gives your 1-W transmitter a 599 report."
- Dave Sumner, K1ZZ -
"What motivates the low-power (QRP) amateur operator? This question does not have a simple answer. A vast number of QRPers are "turned on" by the relative simplicity of most home-made QRP equipment. Simple gear is not only easy to construct and operate, but it is fairly inexpensive to build. This has a special appeal to those who lack technical backgrounds and have yet to develop their skills. Furthermore, many of published QRP circuits may be assembled on a PC (printed circuit) board that is available by mail from one or more PC-board vendors. The parts-placement guide for a given project is generally published in the related article. Guesswork is thus eliminated for the most part.”
“Other amateurs have the ability to design their own circuits. QRP equipment offers a short-term exercise in the workshop because many of the projects are simple. This enables an experimenter to try new circuits in an evening or within a couple of days. He can try new ideas and obtain fast results1. He may continue to work with his new circuit until it is perfected at which time a final model can be built, housed in a cabinet and used in his station.” 1 I (KC9JPZ) recommend Experimental Methods in RF Design-- by Wes Hayward, W7ZOI, Rick Campbell, KK7B, and Bob Larkin, W7PUA published by ARRL It makes designing a snap.
From VE6BPR’s Home Page http://www.qsl.net/ve6bpr/ About QRPer’s
“Other QRPers are captured by the nostalgia that takes them back to the early days of Amateur Radio, when hams, through necessity, used only a few watts of RF power for communicating. In other words, they had to do things the hard way. Each successful QSO was logged as an achievement! Pride accompanied home-made gear and the ability to be heard at great distances. In general, QRPers are a special breed of friendly operators. You have much to gain by getting involved in this growing movement." - Doug DeMaw, W1FB -
In 1954 I was licensed as W3HUK. I received a conditional class license since in those days you had to go to a city with an FCC examiner. My written and 13 wpm code test was given to me from my cousin W3OAQ. My equipment consisted of a Hallicrafters SX28A receiver (Super Sky-Rider) and a Heathkit DX 35 transmitter. Although my 6146 final amplifier was capable of 65 Watts I usually ran 50 Watts input to the final stage.
I built the Heathkit DX 35 as a kit by saving a lot of hard earned chores money while living on a farm in Union Dale, PA. I first built a power supply from scratch as my first practice in soldering. I remember the first time I turned it on “the plates glowed red”. My cousin when immediately upon seeing this told me to “shut it off!” He later discovered a blown out Pi network capacitor because I had selected too low of a voltage! Hi Hi! I did better with the DX-35. I assembled the whole thing but it did not work. No RF output. But the only mistake I made was applying too much soldering heat to the RG-58U coax feed to the amphenol output connected on the rear of the chassis. Not bad for a farm boy!
ARRL Field Day circa 195?
Hallicrafters SX-28A Super Skyrider
"All stations shall only use the minimum power required for effective communications."
My Dad’s farm was located in Northeastern Pennsylvania to the east of Elk Mountain in Union Dale, PA. Our elevation was about 1,500 ft on the east slope. Thus I had a clear shot facing New Jersey and New York City. My 80 meter and 40 meter dipoles and my 50 Watts would blow “cool kilowatters” transmitting from apartment buildings in New York City “right out of the sky”.
I was at my usual Tuesday night auction at the Shadow Auction Barn (1517 Maple Ave., Terre Haute) about two years ago. I had just gotten there. There were two auctions going on in the “back room”. A young friend (Andrew) yelled out to me when I got there. “Hey Doc! They’re auctioning off a radio right now!” I looked around to my right and saw the auctioneer holding up a Drake R8 Communications Receiver. I held up my hand and got it for $3. The R8 Speaker went next. I had to pay $5 for that!
I took it home, hooked a short wire to it, and plugged it in. Low and behold the LCD screen lit up and noise came out of the speaker. It worked! I got a manual off the Web. The next day I found out there was not one thing wrong with this receiver. Drake R8’s go on eBay for about $500 (if you can find one!).
After a year or so of listening to it and especially the HAM bands, my code came back and I was hooked again.
I was licensed as KC9JPZ in Summer of 2006. In fact,I took my General Class exam at W.V.A.R.A. 2006 Field Day
I did quite a bit of Ham Radio between the time of 1954 (8th grade) and High School. I established many contacts. I think I remember almost getting my WAS and having quite a bit of DXing for my DXCC. My pride and joy was my QSL card from Eritrea (a small country just north of Ethiopia). Unfortunately, after high school I entered Penn State University and really did not lose interest in Ham Radio but lost all my time for it. Later in life I was busy earning a living. Eventually I lost my license.
After my resurgence back into Ham Radio, I thought “why not do it again” but this time make it more exciting and “QRP it.” Although I did buy an ICOM 718 during the Fort Wayne Hamfest last year (which can be adjusted to low power) as my main rig, my QRP endeavors would be left to kit building and dragging my Drake R8 occasionally into the field camping with a good deep cycle battery.
In my “younger days” I worked a lot of the 40 meter band. I then chose to purchase the Ramsey QRP 40 meter transmitter because “The kit looked attractive”.
Go to http://www.qsl.net/miqrpclub/links.html the “chain locker” of the Michigan QRP Club (to see a list of clubs and kit suppliers for QRP)
QRP isn't just about using low power, it's about using simple equipment (and simple antennas.
Graph again courtesy of New Jersey QRP Club
http://www.njqrp.org/ and http://www.njqrp.org/whyqrp/whyqrp.htm (why QRP?)
http://home.stny.rr.com/wa2ntk/qrp_1.htm W2NTK circuits
Picture from Ramsey Home Page
Manual at: http://www.ramseyelectronics.com/downloads/manuals/QRP40.pdf
Transistor circuit, oscillator, RF amp chain, and clean keying stage
RF output approx 1 Watt (.75W for QRP-20)
Pi-network output for good matching and harmonic suppression
Provision for two internal crystals, front panel switching
VCXO tuning, frequency can be tuned approx 7kHz around xtal freq.
(3.22 kHz with our rig)
Ramsey QRP40 transmitter Block Diagram
54.3 Ohm Attenuator Used to Measure RF output of Ramsey QRP40c Transmitter
Scope Settings: 0.1 uS per division X and 2 V/division (Y) 1 division = 1 cm using a Tektronix 2205 Scope
V p-p output voltage versus Input voltage to transmitterusing 54.3 ohm termination and RG-58c (50 ohm impedance) cable to oscilloscope
Ramsey 40 meter QRP rig
RF power calculated as V(p-p)2/(8*53.4)
From 2007 RF Experimenters Handbook
At 12.54 V input current drain is 0.34 amps
FFT Signal Analysis of QRP 40c Ramsey Transmitter using a A-M Systems Model 3800 Digital Oscilloscope with Rectangular Math
Two repeat experiments at 13.69 Volts input. The rightmost peak represents the 14.08 MHz first harmonic and the fundamental is noted by the vertical dotted line.
The average of the two experiments show that the first harmonic is 32.6 dB down
Solution courtesy of Mathematica 4.0
10 k tuning pot = 7040.631 kHz Max CW and 7037.217 Max CCW. Range = 3.414 kHz
Input to QRP Rig
Xtal osc pot at max CW
1Actually 15 volts can be tested with the QRP 40 within specs but I chose not to go this high
Faraday Shield eliminates electrostatic noise
Varactor diode tuning – one wire connection 500’
Low noise high gain FET preamplifier circuit
Rugged antenna enclosure constructed from PVC pipe
Directional properties of antenna helps to “null” overpowering stationsRamsey Electronics SM100 Signal Magnet Noise Reduction Antenna
Top: Antenna Assembly
Bottom: Control Assembly
An external PVC tube covers the foil covered ferrite rod (not shown for simplicity)
Aluminum Foil Covering
PVC Antenna Assembly
Signal level S10
Signal Level S10
Signal Level S8
Signal Level S7
http://www.qsl.net/miqrpclub/ Michigan QRP Club
http://www.qrpworld.com/ QRP World.com
http://www.netwalk.com/%7Efsv/CWguide.htm A Beginner’s Guide to Making CW Contacts
http://home.c2i.net/hamradio/anifram.html Ham Radio Animation Clip Art