DICKSON COUNTY AMATEUR RADIO CLUB RADIO SIGNALS WC4DC http://www.qsl.net/dicksonarc/ Monitoring: 146.57, 145.01 (24/7) Repeaters: 147.375 + PL 146.2 White Bluff 442.225 + PL 123.0 White Bluff 145.330 PL 114.8 Cumberland Furnace Issue 46 MARCH 2015 Dickson, TN Editor NA4C Dickson County ARC Monthly Meetings Second Monday Each Month 7:00 p.m. at Dickson County EOC Dickson County ARC Monthly Meeting Programs All programs subject to change March 9, 2015 Program J Pole antenna constuction Jerry, KG4HDZ DICKSON COUNTY ARC VE TESTING SESSIONS Dickson County EOC 7:00 p.m. Walk in s Welcome VE Testing Dates 2015: January 29 th March 19 th May 21 st July 23 rd September 24 th
FROM THE DESK OF THE PRESIDENT Afternoon All, I have got the Club down to participate in the Community Preparedness Fair again this year. The date is March 28th from 10 am until 2 pm. We will have the same spot we did last year.(helps to get your name in early) This gives us plenty of time to get our thoughts together on what we want to do this year. I will have it on the agenda next month to talk about it. Stay warm, Warren W4WJV Thanks, Jerry Lewis \ud83d\ude8d kg4hdz Dickson County EC SPRING FESTIVLE 4-29, 30, 5-1, 2. 29, 30, 1 usually 5 pm- 10pm 5-2 usually 8 am- 10 pm Full-wave Rectifier Barry, N4KKT The half-wave rectifier chopped off half our signal. A full-wave rectifier does more clever trick: it flips the - half of the signal up into the + range. When used in a power supply, the full-wave rectifier allows us to convert almost all the incoming AC power to DC. The full-wave rectifier is also the heart of the circuitry that allows sensors to attach to the RCX in either polarity. A full-wave rectifier uses a diode bridge, made of four diodes, like this:
At first, this may look just as confusing as the one-way streets of Boston. The thing to realize is that the diodes work in pairs. As the voltage of the signal flips back and forth, the diodes shepard the current to always flow in the same direction for the output. Here's what the circuit looks like to the signal as it alternates: So, if we feed our AC signal into a full wave rectifier, we'll see both halves of the wave above 0 Volts. Since the signal passes through two diodes, the voltage out will be lower by two diode drops, or 1.2 Volts. AC Wave In: AC Wave Out (Full-Wave Rectified): If we're interested in using the full-wave rectifier as a DC power supply, we'll add a
smoothing capacitor to the output of the diode bridge. A Word about Lists tufts university web site By Charles M. Seay - KN4HL I just read a book I bought on Amazon with some great ideas that the amateur radio experimenter or operator should consider. These ideas I will share come from the book, Record Keeping for the Radio Experimenter by James McClanahan, W4JBM. Each of us should make a folder for each piece of equipment we Purchase, whether new or used from a friend or at a Hamfest. You should place a number on the folder and a corresponding number on the equipment. In this folder should placed the schematic, and or operating manual for that piece of equipment, after using the equipment, a memo on the operating characteristics, such as power output on each band, and any other peculiarity you may have noticed. This will give you a baseline for future reference. If parts are needed, the part numbers and values should be noted. If parts are ordered, the place ordered from with address should be noted. Be sure you note the original price paid, where purchased and from whom, and lastly, the date. If you build or buy a new antenna and have a Antenna Analyzer,
you should connect the antenna to the analyzer and take SWR readings on each band the antenna is designed for, with SWR readings on frequencies in the lower, middle, and high end of the band. This will give you a baseline about the antennas performance for future reference. I have a bad habit of placing an antenna in operation and never checking its performance again as long as it loads. By checking the performance every 6 months to a year against the original figures, you can determine any change in performance. Connections and solder joints corrode or break and you would never know unless you check performance against a baseline. There are many great ideas listed in this book and it takes time to build a folder, which can be done the old fashion (Paper way) or on a computer and saved to a thumb drive. Notes written down and help jog your memory in the future. These folder will help your estate get top dollar for the equipment when you are an SK. The future owner will greatly appreciate your effort too. This is a book of great ideas which was $.99 on a Kindle from Amazon.
WANTED OR FOR SALE WANTED ROHN 25' TOWER John, N4GRW, 615-426-3175 lp14255@yahoo.com SALE Ten-Tec Scout with 10-20-30-40-80 meter modules and 705 Ten-Tec desk mike. $450 call Larry B. K4LFB 615-332-4288 SALE VIBROPLEX KEY $50.00 Vollie, NA4C From February 1990 QST, p. 43 Why QRP? Low-power operation is more popular than ever before. Why not join in the fun? By Kenny A. Chaffin, WBOE Why would anyone except a masochist want to operate with less than 5 W output? What possible attraction could there be? Perhaps it's for the same reason anyone would operate an amateur station in this age of global telephone systems and satellite TV. Maybe it's for the challenge of doing something a little different. Maybe it's for the thrill. But I can tell you, there's nothing quite like having a QSO with a Japanese, Russian, or rare DX station while running less power than a kid's nightlight! The QRP Q signal was created to mean "Shall I reduce power?" but has since been adopted by the enthusiasts of low-power operation as their banner. QRP has come to mean 5 W or less output for CW, or 10 W PEP output or less for SSB. Most amateur organizations and contests embrace these as the official QRP limits. Many of the same amateur activities that take place in the rest of Amateur Radio's domain are alive and well within the QRP community. These activities include constructing
home-brew equipment, operating QRP stations, experimenting, DX chasing, and contesting. You Can Build It The QRP arena is one of the few places where the average home-brewer still can make a decent showing. In this age of multistage, integrated circuit, super-sophisticated all-mode transceivers, QRP operation stands out as a home-brewer's dream. How many hams can hope to duplicate the operation of the latest HF transceiver on their workbench? Probably none. If, however, we change the rules by restricting the power output, it is certainly possible for nearly anyone with the ability to obtain a ham license to build a 5W transmitter. QRP transmitting equipment is simple and physically small. The same can't always be said for the receiver, however. A QRP receiver must do the same job as any other receiver, while usually in a smaller box. It is certainly possible to build an adequate QRP receiver by using minimal circuitry and integrated circuits-but it's not easy to duplicate a top-of-the-line commercial receiver in a matchbox. If you are interested in home-brewing, but haven't actually done much, I would suggest the QRP transmitters as a good first project. QRP transmitters usually consist of a few transistors, and for HF work, the layout is not particularly critical. Probably the toughest part is finding or building the coils and chokes. Even the coils are not a big deal once you've wound a few. Schematics and kits are readily available. They make it easy to get started. After you've put together a kit or two, it'll be a piece of cake to move on to "bigger and better" projects. If you do start with a QRP transmitter, you can simplify the circuit even further by opting for crystal control. It may not be as restrictive as you think. A fair amount of QRP operation takes place on dedicated QRP frequencies-making it easy to pick the crystal you need. By adding a trimmer capacitor across the crystal you can "pull" the resonant frequency slightly to the lower side of the crystal frequency (This is, in effect, a simple VXO circuit.) The crystal can be pulled from about 3 khz on 80 meters to 10 khz on 15 meters, depending on the crystal type and other factors. Antennas Once you have a working transmitter, you'll need a suitable antenna. Which brings us to the question: What kind of antennas do QRP stations use? You may think that following the lead of low-power, simple transmitter and receivers, QRP antennas should be small and simple. This is definitely not the case. A QRP antenna system should be as efficient as possible. Many transmission lines attentuate the signal considerably before it reaches
the antenna. If you have 5 W of RF output and a poor feed line, you could end up with only a couple of watts at the antenna! You should approach your QRP feed line as if it were being used for UHF or satellite work. You want to get as much power to the antenna as possible. Using a lossy feed line at kw power levels is tolerable; at QRP levels, however, the loss of every milliwatt becomes more critical. The antenna itself is also important. For best results you need the best antenna you can put up -- it's as simple as that -- a high-gain Yagi if possible, up high and clear. It's just as though you were chasing the farthest DX. My antenna is a vertical, which is probably one of the worst choices. But it's the best I can do considering aesthetics, ordinances, and neighborly relations. Even with my vertical I've worked Japan and many Soviet stations using only 5 W output. FUTURE EVENTS TO BE THINKING ABOUT Club Annual Spring and officer elections May 2015 Location and time to be announced Field Day 2015 Fourth Rainy Week End in June Further specifics to be announced soon.