The tenna dipper a low power antenna analyzer and atu tuning aid by kd1jv using just a few mw of output power, this circuit is used to find the 50 ohm resonance frequency of antennas or can be used to adjust an antenna tuning unit for 50 ohm match, without generating qrm. One section the larger one for a superhet capacitor is in parallel with the antenna coil, and the other is between the. This preselectortuner is made by just selectable inductors and an air variable capacitor. The super sloper has been cut and carefully tuned to be resonant on the swl bands of 4149 meters, 31 meters, 2225meters, 1619 meters, and 11 meters. H rolling inductor and 500 pf capacitor are sufficient to match from 10 to 80 meters. Shortwave radio enthusiasts, ham radio operators and others can use this to monitor solar conditions that impact radio propagation.
The windom antenna this antenna is basically a random wire but with the leadin mounted away from the end closest to the receiver some 36% of the overall length of the wire. I have not measured the capacitance but i suspect both sections together give a maximum of 300 to 400pf. The combination can be made to work efficiently at all frequencies between 500 and 6800 khz. The mfj956 preselectorantenna tuner greatly improves reception from. This is old video, but still fills the void for antenna building here on this channel. This is a big upgrade from a simple dipole or a vertical made from coax. Jul 29, 2016 if you look at a picture of the first antenna, used by heinrich hertz, you will see it looks like a capacitor. It is designed to match a high impedance antenna, so it could not match the medium impedance 150 ohms wire to the 30 and 31 meter bands very well at all. Oct 27, 2015 that is, indeed, a brilliant and simple mod. A i wrote the following explanation about why not to assume that an antenna tuner is necessary, or even useful for good reception. Sdr software defined radio dongle in the following post and tutorial is a clone of the sdrplay rsp1 sdr. It has two plates separated by about a metre and a wire linking them together.
For regular swl work in the 330 mhz range, the coil should be about 100 or 120. Antenna tuning unit via medium wave eeweb community. Please dont hesitate to download my simple computer program mde. Mhz if coil has a built in capacitor at the base, remove it. Inexpensive and simple mono or multiband hf ham radio. I called the manufacturer and he said it the program doesnt work well with 5 so use internet explorer or download and install 3. I use it on a super small radio and it gets stations in from about 100 miles away. To be honest, pretty much any chunk of wire will do as an antenna for most. Download the qrpswl homebuilder pdf archive mafiadoc. About radio 64 magnetic loop antenna capacitor tuner youtube. The windom antenna is almost as old as the random wire. In fact, you will likely enjoy it more by building your own simple equipment, and then making contacts with it. Shortwave radio enthusiasts acknowledge the thrill the romance, in a way of. Bills simple sony srf59 passive loop antenna modification.
B the so called tuner is an altogether different device, having the design capability and intent on adjusting the antenna impedance as seen by the in putout puts of a transceiver. Its purpose is to make the antenna system look like a purely resistive load usually 50 ohms for the vast majority of ham radio transceivers or receivers. Youll need a good antenna to do that, which is where this homebrew loop antenna for the shortwave radio bands shines. If i had to run an indoor apartment antenna for swl, it would likely be backtoback helicals, horizontal, centerfed dipole. Homebrewing antenna tuners category is a curation of 85 web resources on, balanced antenna tuner, qrp random wire tuner, icom tuner connector. The variable capacitor can be any 0500 pf capacitor, preferably with a 14. Efswl antenna par electronics filters for the commercial. The medium wave 5301700 broadcast band crystal radio or one tube radio is set up by opening the two brass link switches between the capacitor gangs. Simple hfwire antenna wewillexploretypical varia2onsofthewiredipole highfrequencyhf antenna typicalamateurradio transmiing antenna. A horizontal loop antenna for shortwave listening and. The answer is to download a special version of the kiwi software from the. Sure you can get into specially tuned antennas of all sorts of designs, but a long wire works amazingly well. While there may be some value in the use of an atu for swl ing, it is very limited. The best general advice is to use as much wire as you can for a listeningonly shortwave receiver.
The reactance of the active antenna goes with the reactance produced by the capacitor or the inductor, which will then lead to the resonance of. The capacitor is a variable capacitor from a receiver. Loops without an external tuning capacitor are only resonant at one frequency. The par electronics efswl is an endfed short wave antenna optimally designed for mhz reception. Personally, i use a slightly different antenna system for shortwave listening, where the antenna is placed much further away from the house. Antenna tuner 2 tuned very sharply on the 40 and 41 meter bands. The variable capacitor can be any 0500 pf capacitor, preferably with a 14 shaft that you can put a convenient knob on. If you use a pisection coupler, your antenna can be as short as 30 feet or as long as 100 feet. Most all portable shortwave radios will have a telescoping antenna as well as one built inside mainly for am radio band reception. Actually determining necessary capacitor values and breakdown voltages for tuner capacitors takes several steps. The antenna construction of a longwire antenna is simple. Grayhat had done research prior to purchase and believed it not to be a clone, but only using the same chipset as the rsp1 hence the compatibility with sdruno. Capacitor c2 combines the function of matching capacitor for ra i rs with the function of phase correction for an inductive antenna. Dj5il amateur radio station the magic sounds of radio.
There are many differences between transmit and receive antennas. The best part of this antenna is that when transmitting, the antenna loads well at every harmonic the 3. Jul 07, 2015 a slightly more complicated but ultimately more versatile antenna, which can be constructed in perilous times without any commercial supplies other than a swr meter, is a nonresonant horizontal dipole antenna with a very simple lnetwork antenna tuner. Variable capacitors are often used in lc circuits to set the resonance frequency, e. If you look at a picture of the first antenna, used by heinrich hertz, you will see it looks like a capacitor. Some radios usually the higher priced models will have an external antenna jack, usually a 3. For now swl s would be very well advised to read this white paper. For both versions, hooking up the required network, power and antenna connections. Not different from any other impedance matching circuit. For those too lazy to build this or too much money to care.
A bulletin board chat with jeff ka1ogm ive been using an off the shelf roller inductor tuner with its internal balun for output to balanced line for quite a while, now. So, using the example shown in fig 3 of a ten metre wire, the leadin would be 3. Figure 11 illustrates the application of parallel phase correction. Look for a bigger capacitor with wider plate spacing for your antenna tuner unless its strictly a qrp tuner. Great little gadget for boosting signal that actually works by sp bisbee florida really does boost signal, maybe twice as good as antenna alone.
This menu provides a link to my webmasters page and some basic. Figure out what the extremes of tuning impedance you want to support with your tuner. One connection to your radios antenna or antenna jack to the length of wire. I use a wifi antenna adapter to receive internet on my. Jul 10, 2016 this is old video, but still fills the void for antenna building here on this channel.
Nov 25, 2012 this is one of probably three videos that relate to a slow motion drive mechanism that ive made for use with my homemade magnetic loop antenna. Antenna tuner, matching network, matchbox, transmatch, antenna tuning unit atu, antenna coupler, and feedline coupler are all equivalent names for a device connected between a radio transmitter and its antenna, to improve power transfer between them by matching the specified load impedance of the radio to the combined input impedance of the feedline and the antenna. Introduction i keep getting email asking me for an antenna tuner atu or astu for the hf bands. Current stock status at these ham radio outlet locations. Jan 31, 2019 the best general advice is to use as much wire as you can for a listeningonly shortwave receiver. Mfj1778 g5rv wire antenna 8010 meters authorized dealer. Why antenna tuners arent necessarily useful for shortwave listening by daniel a.
For general shortwave listening this antenna tuner will work very well with a straight wire of up to 50 or even 75 feet in length. If you just remember and adhere to the following rules of safety. For now swls would be very well advised to read this white paper. Although computers may be the most important outworking of electronics in the modern world, wireless communications isnt far behind. A generator of very high frequency ac is inserted at the middle of the wire. The srf59 inductively couples to the loop antenna, so no soldering is needed. The qrpswl homebuilder web site is referred to as the popcorn site by. Although it does not use tuning diodes, a 40 meter band vfo schematic has.
An antenna tuner or swl preselector will considerably improve sn ratio, particularly on indoor antennas. Some users simply want to install an ethernet cable between the kiwi and a. Another idea is to use parallel phase correction for an inductive antenna together with series phase correction. Thanks rgood123 sometimes simple approach is the best one. Old school am receivers are so simple a beginner can build one and its the only mode that can be.
This is one of probably three videos that relate to a slow motion drive mechanism that ive made for use with my homemade magnetic loop antenna. When the circuit unit is combined with the active antenna, the tuning of antenna is done by modifying the capacitor or the inductor. Simple antenna for better shortwave radio reception. Shortwave antenna plans and links category is a curation of 54 web resources on, echelonlog beverages, hula loop antenna, slinky and loaded beverages. Albeit the very simple design, it is very effective as a prelector on lw, mw and sw up to 7mhz. The par electronics ef swl is an endfed short wave antenna optimally designed for mhz reception.
This technology is a far cry from tuning the sw bands with a homebrew or. A slightly more complicated but ultimately more versatile antenna, which can be constructed in perilous times without any commercial supplies other than a swr meter, is a nonresonant horizontal dipole antenna with a very simple lnetwork antenna tuner. Click here to view on ebay this partner link can support the swling post spread the radio love this entry was posted in accessories, antennas, news, vintage radio and tagged mario filippi n2hun, panasonic rf2200, rd9820, rf2200 on april 29, 2020 by thomas. N0hr propfire addons for firefox thunderbird addons. Popcorn connotes the essential theme of the web site. Ham radio a simple magnetic loop modification with a big. How to apply principles of capacitors and inductors to a. New indoor passive loop antenna for shortwave the swling. An inexpensive way to begin is to build your own antenna tuner. Commercially sold antenna tuners are usually fancier, using pi or t networks. Rating is available when the video has been rented. I have tried quite a few combinations before with folded dipole, center fed, simple long wire single with 1. An antenna tuner coupler is a more correct term is an impedance matching device which minimizes mismatch loss maximizes power transfer. This preselector tuner is made by just selectable inductors and an air variable capacitor.
A variable capacitor is a capacitor whose capacitance may be intentionally and repeatedly changed mechanically or electronically. First of all let me say that i do not believe in them, although i have built a few for one reason or another. Each band has its own antenna wire section and acts as an individual antenna. The signal is inductively coupled to the nearby crystal set detector. By connecting an antenna and ground, this device becomes an antenna tuner. A matching principle the first approach was to make use of a principle described by the writer in amateur radio, december 1985. The transmatch, or ham radio antenna tuner, is a variable impedance matching device. A horizontal loop antenna for shortwave listening and amateur. To increase the range of the tuning of the loop i included a switch to allow either one or. The reactance of the active antenna goes with the reactance produced by the capacitor or the inductor, which will then lead to the resonance of the circuit together with the active antenna. Posted in radio hackstagged air variable capacitor, antenna tuner, capacitor, coil. With 5, it wont allow me to open the program that i use to do that.
Why antenna tuners arent necessarily useful for shortwave. Referring to figure 1, a network is made up in two sections, an antenna phasing section which cancels any antenna reactive component and an impedance matching section often called an l match which transforms the remaining resistive component to a value equal to rs. The qrpswl homebuilder web site is referred to as the popcorn site by many. Beyond, using wideband non resonant antennas, if there are intermodulations say at 14mhz because of large signals at 6 and 7 9 mhz, the filter is unable to. I use a wifi antenna adapter to receive internet on my boat. The outside antenna ground wire was soldered to the large copper ground plane. The separation of the plates and the wire are crucial in order to obtain radiation. Small loop antenna for hf listening va3stls weblog. Homebrew loop antenna brings the shortwave world to you. Essentially, it is the same as a parallel tuner, except, you use a ganged capacitor, such as a dual 365 pf capacitor some are still around, or even a superhet variable capacitor with an antenna and an oscillator section. If the tuner is mounted in a metal box install the components at a proper distance, 5 cm or more from the metal parts. How to build a cheap antenna tuner for a ham radio our. A great thing about ham radio is that you can spend literally as much or as little as you can afford and still enjoy the hobby. The other antenna sections are made from multiwire cable, which is weather sealed for years of dependable service.
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