# Folded Dipole Attic Antenna

The resource is currently listed in dxzone. As the ends appear to be folded back, the antenna is called a folded dipole antenna. I soldered two nine foot sections of 16 AGW o. Good rig with a built in antenna tuner--but the internal tuner will NOT tune end fed or open wire. Thinking of a folded dipole but I am so green I need some advice. Find great deals on eBay for ham dipole. Set them up so they look like a "T" and play with location (and rotation) in the room. Nevertheless, I installed a dipole cut roughly to resonate on 40m but because it is folded in M-shape, it does not resonate on that frequency, but can be used with a tuner as multiband doublet antenna. I'm getting ready to put antenna up in attic. (The Greek letter \lambda is commonly used to represent wavelength. Attic antennas •Many types of antenna can be mounted in the attic IF you don’t have Radiant Barrier (Tech Shield). Given the all-or-nothing reception of a digital TV signal, I can't make any meaningful comparison. Also adjust angle of each antenna. This antenna is commonly used. Reinventing the tape dipole via eHam; Shortened Folded Dipoles via eHam; Six Band HF Center-Loaded Off Center Fed Dipole; The Terminated Tilted Folded Dipole (T2FD) The Folded Dipole Antenna; Understanding Antennas for the Non-Technical Ham (PDF) The Vactrol for MW and LW DXing; VE7SL -PA0RDT E Probe Antenna - Blog Notes; MFJ Antenna Talk series. DX your antenna outperforms the attic dipole. I have an 80m OCF Dipole (aka Windom) hung from the peak of my roof at about 25ft and a ladder line fed 40m Doublet folded around in my attic at about the same height. Any reuse or redistribution of the contents of this website are strictly forbidden without authorization from MFJ Enterprises, Inc. 40-10M antennas in an Antenna Restricted Community Over a period of several months prior to the completion of my attic antenna suite I operated with a borrowed AEA Isoloop antenna. A-l Example of Antenna Pole Siting 35 Fig. com in 3 categories. Loft & Attic antennas for restricted spaces - M. If you are in a neighborhood with moderately strong signals, an attic antenna might work. So the measurements are based on a 40 meter 1/2 wave dipole. > > This *is* resistively loaded. The antenna pictured at the top of my FAQ page is the 2 meter Slim Jim antenna. Again run your dipole as far away from metal as possible. COVER SHEET ALPHA DELTA MULTI-BAND DIPOLES Models DX-CC, DX-DD, DX-EE, DX-LB, DX-LB Plus Power ratings, MAX output (Assuming SWR at the FEED POINT, not tuner, is 2:1 or less). The transmitter is located at 100 degrees almost due east to you. A dipole in the attic of your home is a good idea if you have enough space in your attic to place one. It is designed for extreme conditions and comes with fully assembled for convenient installation. With Folded Dipole Antennas, I've always used a "tuner" to be on the safe side. B&W makes a "Folded Dipole", 7-30mhz, 45 feet long - with supposed flat swr? Like $245. I needed an antenna system capable of the lower HF bands. It’s easy to build your own CB radio base station antenna with a piece of 50 ohm coax cable (such as RG 58) and 20-30 feet of wire (any gauge). What I came up with was a trapped end fed folded dipole. The only time the entire antenna is truly visible is when the sun is just over the horizon and the antenna is wet with very fine dew drops. As with all trap dipoles, this one has less-than-ideal bandwidth due to the load- ing effect of the traps. If we feed the antenna with 450 ohm ladder-line, we can install a 4:1 or 6:1 balun at the shack and obtain a pretty good match to our 50 ohm transmitters. 798MHz, the maximum antenna height will be very long around 3 meters. All information, images, and documents on this website are the sole property of MFJ Enterprises, Inc. The input impedance of the folded dipole is higher than that for a regular dipole, as will be shown in the next section. It is all weather rated at 1 KW PEP SSB /CW. However, you can hang a wire folded dipole in the attic by tying cord to the two ends and nailing the cord to roof beams. Figure 19 illustrates how the folded dipole will be positioned around the boom. Some have suggested antennas like an end fed or dipole fed with open wire--good ideas--BUT--you will need an external antenna tuner. Thus, I have decided that my first antenna will be a 20m half-wave, center-fed dipole installed in the attic/crawl space of my home. Shop outdoor and attic TV antennas, amplifiers, rotors, and mounts. This antenna is commonly used. I just hope the leaves don't absorb all the signal. But you are wasting your time installing an attic antenna in a poor-signal neighborhood. It is simple to make and cost can be nearly nothing. No-Tuner Shortened Folded Dipoles. I prefer a 160-meter inverted V to a horizontal dipole at heights less than 100 feet. Rabbit eras give some directional gain, thus rotate the antenna for best signal to noise. 3 to provide a multi-band antenna. Loft and Attic antennas for restricted places. The antenna comes fully assembled and pretuned so no measuring or cutting is required. ca2 fm fm dipole reflector. The antenna has therefore proved itself to be a very acceptable all-rounder, but is, of course, no substitute for an HF beam. I decided to install an 40 meter dipole in my attic space which is about 25 by 45 feet, and about 25 feet up from the ground. It performs best if it is isolated from the mast. Also included is an in-line balun which cures the occasional “RF hot” problem when operating from a portable location with a poor (or no) ground system. 5 dB NF, a power supply for powering the preamplifier and rotating the antenna with an infrared remote controller. com in 3 categories. folded dipoles are identical - only the feedpoint impedance is affected by the "folding" process, and only the pattern is being modelled here. This is the main problem and why an air-gap is the preferred method, even though you can get a folded-braid dipole resonant with trimming. Within the limits of my artistic skills I have depicted a folded dipole. Delta Fed Dipole Antenna 13 18. This picks up VHF, UHF and FM signal. As prcguy mentions, a braid folded back down over it's own covering is not ideal since the jacket doesn't make for a very good rf insulator (and also not the best conductor either, but that's what we'll use). A dipole antenna is the simplest, usually the least expensive and most popular type of radio antenna used in ham radio and radio communications and has been around longer than you can remember. The half-wave ham radio dipole is also the most common antenna used by amateur radio operators throughout the world. Folded Dipole Antenna. The primary reason for using a balun at the feed point of a dipole antenna is to prevent RF currents from flowing on the outside of the shield of the coax feeding the antenna. However, the folded dipole approach to matching has some disadvantages: The use of twin lead adds to the weight of the antenna; A shorting link has to be placed at a position along the folded dipole, determined by the differential-mode velocity-factor of the cable. A Stealthy Homebrew Vertical Dipole Using Mobile CB Antennas. The DBJ-1: A VHF-UHF Dual-Band J-Pole Searching for an inexpensive, high-performance dual-band base antenna for VHF and UHF? Build a simple antenna that uses a single feed line for less than$10. My attic antenna is a Folded Dipole for 20 m, that I use with a 4:1 balun made with an Amidon T200-2 core. From an antenna theory perspective, if you've bent the wire it isn't a dipole antenna any more. But you are wasting your time installing an attic antenna in a poor-signal neighborhood. I have been trying out more antennas and I believe the answer is NO - I have not found an indoor FM antenna significantly better than the Terk FM+. It exhibits an impedance of 300 ohms whereas a half wave dipole is 75 ohms and I'm certain someone will be alert enough to ask "why 75 ohms, if figure 3 above is 50 ohms?". Actually, the distance between lower and upper conductor is approx. When I got up there, I found an attic fan blocking my way to half the length. This antenna is similar in construction to the 2-meter OFC sleeve dipole I built over 8 years ago, but it is a simple center-fed dipole. A dipole that is ½ λ high has a characteristic feed impedance of 75 ohms. Here are the comments from an email from VE6BP concerning his success with the Lattin 5 Band Antenna years ago. A television antenna, or TV aerial, is an antenna specifically designed for the reception of over-the-air broadcast television signals, which are transmitted at frequencies from about 47 to 250 MHz in the VHF band, and 470 to 960 MHz in the UHF band in different countries. Includes Omnidirectional Vertical Dipole for FM Band, but see OMNIDIRECTIONAL album for more info. Page 5 MFJ-1775 Rotatable Mini-Dipole Instruction Manual Step-By-Step Procedure 1) Set up saw horses or other stable supports (plastic trash cans, chairs, folding tables, etc. I have it in my attic and works pretty good expecially down at the low end of the band for which it is tuned and where those more interesting stations that have lower power. An Attic Coaxial-Cable Trap Dipole for 10, 15, 20, 30, 40, and 80 Meters John DeGood, NU3E [email protected] 5, ), when the antenna is fed in the center as shown in Figure 1. The Channel Master Deep Fringe Masterpiece 100-Mile Range Outdoor Antenna is compact and lightweight. Folded monopole antenna is an old and well known design but not so common used. Alpha Delta tests antennas, in the clear (no surrounding objects), at a height of 35 ft. It has some gain and is omni directional to boot. Both antennas are similar in that they use a J style matching system consisting of a 1/4 wave stub, but the difference between the two is that the Slim Jim is a half wave folded dipole antenna. Lower frequencies will pass the trap effectively making the antenna bigger. 5-Band, 1/2 wave rotatable dipole for 40/20/15/10/6 meters. The folded dipole antenna. First, I must say that setting up a base radio (11 meter) and accompanying antenna is a new hobby for me. In the first couple hours of having it up I was able to hear stations I could not hear before. " - BNC Ground Plane Kit "Definitely a big improvement over the dipole that came with the receiver. MFJ recommends the antenna be mounted at least 20-feet off the ground. The folded dipole antenna consists of a basic dipole, but with an added conductor connecting the two ends together. That means putting up an antenna that gives a decent signal over a wide range of frequencies. and CATV headends use 300 Ω folded dipole antennas to receive off-the-air signals, 75 Ω coax makes a convenient 4:1 balun transformer for these as well as possessing low attenuation. Attic Antenna-- From NU3E -- An Attic Coaxial-Cable Trap Dipole for 10, 15, 20, 40, and 80 Meters; Duplexer (Diplexer) HF + 6m / Horizontal Antennas above Real Ground ; Inverted L Antennas By Arnie Coro(CO2KK). For an 80-10 meter OCF dipole antenna, divide the ½ wavelength standard of 468 by the lowest operating frequency of 3. I searched the internet and books high and low to no avail. The problem with these is that they are simply too inefficient. This is the main problem and why an air-gap is the preferred method, even though you can get a folded-braid dipole resonant with trimming. Here are the comments from an email from VE6BP concerning his success with the Lattin 5 Band Antenna years ago. A simple corner reflector is not a good antenna for TV unless you only have one channel. Antenna performance and 2:1 VSWR bandwidth is site dependent and varies with height above ground and surrounding objects. Since installing the antenna in April 2013, I have worked 76 countries (including India twice) and 49 states as of December 2013. If you can get a bit more wire up in your attic than I am able to hang, the open loop might perform as a folded dipole on 80 meters or lower. Nevertheless, as K2DFW points out, it still remains one of the easiest skywires to install and adjust. The folded dipole antenna. Not sure that you can still buy them, but they were commonly available from the 1950s - 80s. I don't claim to have invented these designs, but I see that there aren't many quick, makeshift antenna tutorials here. I decided to install an 40 meter dipole in my attic space which is about 25 by 45 feet, and about 25 feet up from the ground. I estimate that this dipole cost me a grand total of £35 (£20 for the speaker wire itself), not bad going for a multi-band HF antenna!. The DBJ-1: A VHF-UHF Dual-Band J-Pole Searching for an inexpensive, high-performance dual-band base antenna for VHF and UHF? Build a simple antenna that uses a single feed line for less than \$10. This magnetic loop antenna covers the HF band from 10-30 Mhz. Note 688). Here we have collected some links to building instructions for 11m antennas on the Internet. As with all trap dipoles, this one has less-than-ideal bandwidth due to the load- ing effect of the traps. The dipole antenna is a simple antenna consisting of two rods or wires of exactly the same type and length, which serve as the conductive elements for the electrical energy. There are places, that we mentioned earlier, that won't allow antennas, towers or antenna poles to be constructed. The only mod I did was to add wing nuts to make it a no tools easy-up. Dipoles antennas are easy to build and can be very effective when placed half a wavelenth or more above ground. Or, the simple folded dipole antenna is another option. The antenna elements are secured to the frame using zip ties. The random length all band dipole represents some clear advantages in cost and operational flexibility within the limitations of the average Australian suburban block. Magnetic loop antennas are compact and can be moved around as needed. Detailed information for the do it yourself TV antenna installer. Just plug a coax feeder into the SO-239 socket. Chameleon Antenna has been a pioneer at rethinking and redesigning portable antenna systems since almost a decade! Pushing the limits of design and manufacturing with cutting edge technology, Chameleon Antenna are known to design, manufacture and distribute products worldwide that are versatile, dependable and built to last!. I have a very small attic, but at 34' long I thought I could hang a dipole antenna. A dipole design for the 20-meter band is an efficient and inexpensive antenna for the novice and veteran ham enthusiast alike. But, I suspect you may already have that antenna. Don't get. I have been trying out more antennas and I believe the answer is NO - I have not found an indoor FM antenna significantly better than the Terk FM+. half wave dipole antenna calculator. Find the cheap Hf Dipole, Find the best Hf Dipole deals, Sourcing the right Hf Dipole supplier can be time-consuming and difficult. The attic was in a 5 story building, long enough for a 160m dipole. The small antenna I recommend is the Winegard HD7694P. Wire Antennas. I have yet another question on the never ending quest to get an antenna to fit in my attic. Alpha Delta tests antennas, in the clear (no surrounding objects), at a height of 35 ft. Dipole bandwidth is a function of frequency, diameter, material and the antenna ' s environment. The HD Stacker TV antenna is considered to be one of the best HD TV antennas for weak/rural signal areas on the market today. The Dipole Antenna by N4UJW. The maximum radiation for an inverted V-antenna is at its center. MY IDEAS ON AN IN-THE-ATTIC T2FD ANTENNA : Old Idea - Terminated 'Tilted' Folded Dipole (T2FD) [ Twisted -Not- Tilted ] New Idea - Terminated "Twisted" Folded Dipole (T2FD) [ Twisted / Flat-not-Tilted / In-the-Attic ] First Build the Terminated Tilted Folded Dipole (T2FD) as Big as you Can to get down to your "Lowest Desired. My dad had an old Shakespeare CB antenna but it’s made for a drill-in mount. This antenna is a good performer and I was able to work and confirm about 125 countries on multiple bands with it. Engineered for maximum performance with a 14 Gage wire to our coaxial mono band double bazookas of RG11. A dipole in the attic of your home is a good idea if you have enough space in your attic to place one. Other antennas like the dipoles should be a good match for 50 ohm or 75 ohm line depending on how high and clear the mounting is. MFJ recommends the antenna be mounted at least 20-feet off the ground. For an 80-10 meter OCF dipole antenna, divide the ½ wavelength standard of 468 by the lowest operating frequency of 3. It got us on the air but absolutely sucked when compared to simple outside antennas. DX Engineering is your #1 source for wire antennas. There are places, that we mentioned earlier, that won't allow antennas, towers or antenna poles to be constructed. Thanks, Jim. This link is listed in our web site directory since Wednesday May 15 2013, and till today "Attic T2FD SWL antenna" has been followed for a total of 1838. ) However, the radiating elements are made of two parallel wires that are connected at the ends, and the feedpoint is at the centre of one of the two wires. I'll post the complete design and variations (including templates, BOM, etc) - possibly as an article - when I am done. The reflector is made from poster board and aluminum foil. A-2 Dipole Adjustment Required to Change Resonant Frequency 43 Fig. The High power magnetic loop handles 100W PEP easily. A folded dipole, made from a larger diameter, has an impedance of 300 Ohms (so it requires a balun), but also has a much greater bandwidth. basic guidelines on how to create an outdoor antenna (you can send links the most suitable type of antenna that can receive 70 MHz tv station frequency. It is all weather rated at 2KW PEP Input, 1 KW PEP. Antenna performance and 2:1 VSWR bandwidth is site dependent and varies with height above ground and surrounding objects. folded dipole would also work on 80 meters, but manyhours01 poundingout COwithoutan answer (theonlycrystalIownedwas3720 kHz)convinced me Iwas wrong about folded dipoles. Thanks David for the insulators – first to comment below & i’ll send you an insulator in the mail. Figure 19 illustrates how the folded dipole will be positioned around the boom. If you want to put this thing outdoors, do not use brass, as it gets brittle. This antenna is a good performer and I was able to work and confirm about 125 countries on multiple bands with it. The Godar was clearly the worse. Antennex -- The Ham Antenna Magazine -- all about antennas -- on line Attic Antenna-- From NU3E -- An Attic Coaxial-Cable Trap Dipole for 10, 15, 20, 40, and 80 Meters All-band Wire Antenna - From Joe Tyburczy, WB1GFH BackPack Antennas-- From HFpack, The HF Portable Group. This antenna, like nearly all antennas, works best when in the clear. I estimate that this dipole cost me a grand total of £35 (£20 for the speaker wire itself), not bad going for a multi-band HF antenna!. In production since early 2004; No tuner or counterpoise required, uses just one wire!. These are dipoles made from two helically wound mobile whips mounted back to back. This is the price paid for multiband coverage and physical short- ening. Note the spelling of CobWebb vs CobWeb – The original G3TPW was designed by Steve Webb, hence the spelling. A simple balanced wire dipole antenna has a limited bandwidth which is not adequate for covering the entire FM band. It is all weather rated at 1 KW PEP SSB /CW. The Infamous Attic Dipole. My dad and I experimented with attic antennas when winter storm damaged our inverted Vs for the lower bands. Page 5 MFJ-1775 Rotatable Mini-Dipole Instruction Manual Step-By-Step Procedure 1) Set up saw horses or other stable supports (plastic trash cans, chairs, folding tables, etc. 1, 14 & 21 Mhz Bands; An Attic Coaxial-Cable Trap Dipole for 10, 15, 20, 30, 40, and 80 Meters A coaxial-cable trap dipole antenna installed in the attic provides a surprisingly effective solution to HF operation on the 10, 15, 20, 30, 40, and 80 meter amateur bands at a QTH with restrictive covenants that prohibit outside antennas. The tilted terminated folded dipole (T2FD) antenna is a good match for these requirements. The cheap "folded dipoles" made of 300-ohm twinlead that are included with most receivers and tuners, are a good place to start. Barker & Williamson HF broadband antennas feature operation over the band without need for a tuner. Yagi Calculator is a Windows program that also runs well on Linux, Ubuntu 8. See more ideas about Ham radio antenna, Communication and Dipole antenna. A television antenna, or TV aerial, is an antenna specifically designed for the reception of over-the-air broadcast television signals, which are transmitted at frequencies from about 47 to 250 MHz in the VHF band, and 470 to 960 MHz in the UHF band in different countries. Folded Dipole. The folded dipole antenna is probably only ever seen as a TV antenna. The O-shaped antenna is more properly called a “folded dipole” or “loop dipole. It is similar to a halfwave dipole antenna. Typically, the width d of the folded dipole antenna is much smaller than the length L. Here are the comments from an email from VE6BP concerning his success with the Lattin 5 Band Antenna years ago. Figure 19 illustrates how the folded dipole will be positioned around the boom. Tuning the antenna indoors mounted in my attic was another story. multiband hf dipole antenna. 10 of 300 ohm twin lead to build. If ISS or MIR is (was) greater than 5-10 deg. Dipole Types Sloper Has 3dB to 6dB of directivity toward slope Inverted-V Single high mount, internal angle should be >90 degrees Bent Good attic antenna Keep center section straight Remainder of element can bend or curve to fit 28. Re: Antenna in the attic? Fit whatever antenna you can into it, your more likely to get interferance from other devices and possibly cause TVI or the like. The goal here is to put up a cheap, easy, and quick 2-meter antenna that is simple and unobtrusive, but works. An omnidirectional FM antenna in the attic works quite well. This standing wave consists of both current and voltage that are 90 degrees out of phase. This antenna was built to replace an old dipole antenna that was no longer serviceable. net Abstract A coaxial-cable trap dipole antenna installed in the attic provides a surprisingly effective solution to HF operation on the 10, 15, 20, 30, 40, and 80 meter amateur bands at a QTH with restrictive covenants that prohibit outside antennas. A dipole design for the 20-meter band is an efficient and inexpensive antenna for the novice and veteran ham enthusiast alike. Folded monopole antenna is an old and well known design but not so common used. Folded dipoles are also 1/2 wavelength long. 00 from Walmart. Its best to do this with the antenna in the position that it will be used. Below is one example of how to build and mount a 40 meter loaded dipole using basic materials. A folded dipole, made from a larger diameter, has an impedance of 300 Ohms (so it requires a balun), but also has a much greater bandwidth. If you are in a neighborhood with moderately strong signals, an attic antenna might work. Think of it as a fullwave dipole that has fat ends to increase the bandwidth, the way that whiskers increase the bandwidth in the bowtie antenna. The half-wave ham radio dipole is also the most common antenna used by amateur radio operators throughout the world. it's a 67' dipole. com article by John Reisenauer (KL7JR) titled Simple and Inexpensive Dipole and V Antenna Mount. 6 m) off-center fed dipole antenna for the 20 m and 40 m bands designed for those who need to conceal an antenna. Let's Keep It Simple - Adjusting the Novice Antenna. Yes, this is a balanced antenna, and coax is unbalanced, but I still recommend you solder the coax directly to the antenna. When an antenna that is one half wave length long has RF energy applied to it at its resonant frequency a standing wave develops on it. This makes the 2 Meter Slim Jim antenna a great solution for repeater sites, data and packet stations, APRS, and even every day. multiband hf dipole antenna. Folded Dipole Antenna. Folded monopole antenna is an old and well known design but not so common used. BTW the Antennas Direct VHF Kit (VHF addon component for your antenna - for all Clearstreams in fact) is also a pair of rabbit ears. The Barker & Williamson Broadband Folded Dipole Antenna is designed for continuous frequency operation over its specified range. be Half of the Dipole… just clip on a ¼ wave long wire to the ground side of the BNC and you have a more effective antenna ! For 2 meters this wire is about 19 ½ inches long. This input is ideal for use with a VHF FM folded dipole antenna which can be made up very simply. Barker & Williamson continuous coverage folded dipoles offers operation over large parts of the HF band without need for an antenna tuner. net is a Web site dedicated to ham radio (amateur radio). From an antenna theory perspective, if you've bent the wire it isn't a dipole antenna any more. Did some slight adjustments to the length and we're now all set to compare the vertical dipole I'm currently using and the horizontal dipole in the attic. Page 5 MFJ-1775 Rotatable Mini-Dipole Instruction Manual Step-By-Step Procedure 1) Set up saw horses or other stable supports (plastic trash cans, chairs, folding tables, etc. Wire Antennas. This link is listed in our web site directory since Wednesday May 15 2013, and till today "Attic T2FD SWL antenna" has been followed for a total of 1838. I tried the Godar, the Tune trapper, a Radio shack folded dipole, and a single-wire antenna that came with my receiver. As the ends appear to be folded back, the antenna is called a folded dipole antenna. Stealth antennas for the loft Fig 4. The attic. Folded dipole, by definition, has a feed point impedance 4 x simple dipole, around 300 Ohms, give a take a brick. Manually trimming and tuning the elements to resonant frequencies on the bands they are cut for. The folded dipole antenna has a wider bandwidth than the common dipole, although at the expense of a little constructional complexity. Figure 2––This EZNEC plot shows the difference in the radiation patterns between a vertical half-wave radiator operated at its fundamental. It exhibits an impedance of 300 ohms whereas a half wave dipole is 75 ohms and I'm certain someone will be alert enough to ask "why 75 ohms, if figure 3 above is 50 ohms?". That means putting up an antenna that gives a decent signal over a wide range of frequencies. A folded dipole, made from a. If you have any length of attic you could build a dipole 88 foot long (44 foot on each side) ladderline if possible and run that to a tuner like an Icom Ah-4. Geometriy is not that critical. Drill 1/16 inch dia. It's common to use omnidirectional antennas for FM. Because our folded-dipole's bend diameter is 37 mm, and because the boom diameter is 18 mm, the required standoff height is 9. Both antennas are similar in that they use a J style matching system consisting of a 1/4 wave stub, but the difference between the two is that the Slim Jim is a half wave folded dipole antenna. > > This *is* resistively loaded. I was thinking about folding the dipole antenna in one half of attic. All information, images, and documents on this website are the sole property of MFJ Enterprises, Inc. Dipoles are relatively easy to construct and are pretty cheap compared to commercially available antennas and in some instances a simple dipole can outperform other ‘compromise antennas’. Drill four 1/4 inch dia. Many hams' first choice of antenna is a half-wave dipole. Written By: Scott Wolfington The following article is based on a HamUniverse. Any reuse or redistribution of the contents of this website are strictly forbidden without authorization from MFJ Enterprises, Inc. A lewyears later I took an old conical TV antenna. There are two important points to consider: first, dipoles being a balanced antenna, a balun is required to mate them up with unbalanced coaxial cable; second, whereas a standard dipole with two ¼λ lengths of conductor has an impedance of ~73Ω at resonance, a folded dipole is around 300Ω at resonance. The Barker & Williamson Broadband Folded Dipole Antenna is designed for continuous frequency operation over its specified range. The one-wavelength perimeter loop antenna behaves like a folded dipole antenna, with an impedance that is higher than that of a half-wavelength dipole antenna. I spent many years as an avid contester and DX-chaser … Continue reading Moxons in the Attic (Part 1) →. Thanks, Jim. The HD Stacker TV antenna is considered to be one of the best HD TV antennas for weak/rural signal areas on the market today. 67 feet long at 60 meters), the T2FD provides signal gain, wide frequency coverage, and exceptionally low noise characteristics. Overall length is 40 ft. Also commercial multiband or shortened dipoles work well. Loft & Attic antennas for restricted spaces - M. Antenna was originally a 66 foot (22+44 feet) horizontal with 25 feet of 450 ohm LL vertical. 80/40 Meter Attic Antena I live in a tightly packed urban neighborhood without much room for antennas. Multiband Tuned Doublet Antenna 14 21. There are places, that we mentioned earlier, that won't allow antennas, towers or antenna poles to be constructed. A Hawaii-based Amateur Radio Antenna Blog focusing on the theory, design, and use of homemade antennas. Bow-Tie Dipole Antenna 14 20. Shop for 2 Meter Antennas here. To study folded dipole configurations, an antenna model was designed based on: 1) a calculated resonant Length (velocity corrected), 2) a bend Ratio, 3) the vertical Length of the bend. " - BNC Ground Plane Kit "Definitely a big improvement over the dipole that came with the receiver. Later generation of the Windom are more correctly called off-center-fed dipoles (or in abbreviated form, OCF dipole antennas). After a couple of minutes, the SWR suddenly went off the scale. feed line and tuner analysis!! EH antenna: the E-H and CFA antennas. Resources listed under T2FD category belongs to Antennas main collection, and get reviewed and rated by amateur radio operators. Look on the sites I mentioned, maybe you can build a dipole, or folded dipole antenna, these work well. This antenna covers 65 kHz of 160 meters, 75 kHz of 80 meters and the entire 40-meter band with SWRs under 2:1. Home-built antenna experiments on CB Radio 5 August, 1992. You’ll be happy to have purchased any of our fine dipole antennas for your radio station. A Hawaii-based Amateur Radio Antenna Blog focusing on the theory, design, and use of homemade antennas. ANTENNAS and antenna related topics. Louis Vertical (SLV) offers portable enthusiasts an easy-to-build, easy-to-use antenna. If you are in a neighborhood with moderately strong signals, an attic antenna might work. It exhibits an impedance of 300 ohms whereas a half wave dipole is 75 ohms and I'm certain someone will be alert enough to ask "why 75 ohms, if figure 3 above is 50 ohms?". BTW the Antennas Direct VHF Kit (VHF addon component for your antenna - for all Clearstreams in fact) is also a pair of rabbit ears. The basic format for the folded dipole aerial is shown below. This is the price paid for multiband coverage and physical short- ening. If the attic area is not large enough to accommodate an almost full-size dipole, simply erect as much of the antenna as possible in a straight line, then bend the ends of the dipole up, down, or sideways from the main portion of the system. A simple balanced wire dipole antenna has a limited bandwidth which is not adequate for covering the entire FM band. The other option is using the spiral dipole as a directional antenna with the same -2 dB dB gain for the signal it provides -25 dB on interference signal, there is a good chance you will not hear it at all. Written By: Scott Wolfington The following article is based on a HamUniverse. The Barker & Williamson Broadband Folded Dipole Antenna is designed for continuous frequency operation over its specified range. These are dipoles made from two helically wound mobile whips mounted back to back. Broadband Folded Dipole Antennas. CQ 15 – ITU 28 – Loc. The antenna design is from a Tilted Terminated Folded Dipole (T2FD). Re: Antenna in the attic? Fit whatever antenna you can into it, your more likely to get interferance from other devices and possibly cause TVI or the like. Also adjust angle of each antenna. Compact Multi-Band Rotatable Dipole Antenna Array Dr. The Barker & Williamson Broadband Folded Dipole Antenna is designed for continuous frequency operation over its specified range. Wire Antennas. Most people don't have a lot of success with attic antennas, and I think it's because all of the nails in the rafters, roofing, etc. I built the dipole and did some testing using my K3's built-in SWR meter. It’s easy to build your own CB radio base station antenna with a piece of 50 ohm coax cable (such as RG 58) and 20-30 feet of wire (any gauge). 23-26 step-by-step tutorial on constructing dipoles for any one of the hf bands from 1. MFJ recommends the antenna be mounted at least 20-feet off the ground. -160 meters (1. Please try again later. Other designs will follow. With twice the gain of a standard J-Pole antenna, the 2 meter Slim Jim antenna is a J-Pole on steroids! The Slim is an end-fed folded dipole antenna that has a gain of 6 dbi and a nice low RF take off angle. This magnetic loop antenna covers the HF band from 10-30 Mhz. Hi Everyone! Thanks for all the past help. A basic or folded dipole antenna picks up equally well in front of or behind its poles, but poorly at each end. net Article: Fan Dipole -- How Long to Make Them - N3JBH provides a list of measurements and links for antenna builders. above the horizon, they are full scale at this qth My turnstile is a bit different in that I have "folded dipoles" for the elements using 300 ohm twinlead. In this case, the Customer Care team will remove your account from auto-renewal to ensure you are not charged for an additional year and you can continue to use the subscription until the end of your subscription term. Part 1 shows the antenna placement in the attic and basic construction. My 3G modem Huawei E1550 is in the attic with the wifi router. Thanks, Jim. Other designs will follow. The exact results will depend on what specifically you did. I recommend using not less than 18 gauge for most antennas. DX Engineering is your #1 source for wire antennas. You can buy outdoor antennas made for FM, but TV antennas work very well — and there are a lot of old ones available, thanks to cable and satellite. As with all trap dipoles, this one has less-than-ideal bandwidth due to the load- ing effect of the traps. Resources listed under T2FD category belongs to Antennas main collection, and get reviewed and rated by amateur radio operators. The Dipole. The basic format for the folded dipole aerial is shown below. Originally Posted by SFischer1 The VHF Lo/Hi antenna in the attic is tied up with string and is pointed in the correct direction towards Sutro in San The Official AVS Antenna and Related Hardware Topic!. Antenna was originally a 66 foot (22+44 feet) horizontal with 25 feet of 450 ohm LL vertical.