160m Ocf Dipole Measurements

Attempt #1 for an 80/40/20/10 didn't work as I can't actually fit the entire 40m odd long aerial on the property without bending the ends, and besides the wire snapped while I was trying to get it up somewhere so I gave up in frustration. 8 MHz) is exceptionally broad. My Windom has the same 133ft overall length of a traditional dipole. Loop Skywire (average height of about 35 feet) 80/40 Loaded Dipole (inverted V, center at 21 feet, ends at 5 feet) 80/40 Resonant End Fed (sloper, loaded end at 25 feet, feedpoint at 3 feet) Test Procedure. Each dipole kit contains a glass-filled Budwig HQ-1 centre insulator, two Budwig HQ-2 glass-filled end insulators, #14AWG insulated 168-strand copper wire, and 50 feet of solar. > INFO presented SWR Chart; Diagram of a suggested > Inverted "V" Antenna Set-up; and Pictures. These are basically similar but vary in small details. A dipole’s impedance varies according to its height above the ground. One is called The Carolina Windom and another is called the Buckmaster OCF Dipole. As an option , a self guying kit allows you to place the rotary dipole DXBeam at the top of mast (regardless of the height required for guying). As already mentioned it is fed at the 1/3 point. Degrees of a Loading Coil. This end cannot be raised. Dipole resonance is lower in frequency (dipole too long). This becomes most severe with a 160M (250’ long) dipole because it is so close to the ground relative to the wavelength. I've ran a 160M OCF, 80M OCF, 20/10M Fan all kinds of stuff. Last year on Field Day I was able to use an OCF dipole for the first time, and I enjoyed the quick bandswitching it allowed, so I thought I'd try and find a good OCF. Design Parameters. OCF Dipole antenna BALUN 4:1 BL-41W-2K for OCF / Windom antenna with insulators. This antenna performs well on Transmit as well as on Receive on 160m, 80m, and 40m. 3 Material Description 6 2. In the first two columns, the antenna's height above ground is given in wavelengths and in feet. Buckmaster 7-Band 300 Watt OCF Dipole Antenna (Click for larger image) Our 7-Band antennas cover 80, 40, 20, 17, 12, 10, and 6 meters , with no tuner required! Wire antennas are a great simple way to work 40M and 80M rather than a noisy vertical antenna that requires horizontal radials. The picture above on the left shows the classical Dipole, which is usually fed with 50 Ohm coax, through a 1:1 balun. Tuning is carried out in the same way that you would tune a standard 40 meter dipole. Elecraft K3 & 100w. The Center-Loaded Off-Center-Fed Dipole Antenna (CL-OCFD) In order not to tease your curiosity any further, you will find an EZNEC -calculated VSWR-graph of the antenna below. Simply stated, you want as much of your signal going up as possible and ten to fifteen foot height has shown to function very well. 40m - 80m - 160m Short Dipole Antenna. Around 120 feet would be optimum for very local communications and a couple hundred feet or more would be better if you wanted a general purpose antenna for working close in and far out. I have a question about a 160 meter dipole. This paper describes a multi-band DX antenna for the 160m-40m amateur radio bands with low visibility but great performance for long distance communication. 80-10 Meter W7FG True Ladder Line Open Wire Fed Dipole 125' Dipole 100' Feedline $138. 1 Antenna Description 5 1. 10m Beacon —1/4-wave vertical at 15 feet with 3 wire radials. OFF Center Fed/Loaded HF Antennas VE3KL •Searching for the elusive 40,30,20 m Short Antenna •Small, no bulky traps, minimum of components •Leads to a general design approach for a broad class. I have 1 coax into my station RAT-PAK antenna selector, from an outside relay box for my 6 antennas (actually 7, since one is a fan dipole for 160/75). Classical dipole design with multiple elements that allows two band operation. The 160m Reduced Half Sloper is for 160m operation when space is limited. Whoa! Holy Cow! You found W0HC’s ham radio web page. Made to last. Wire Antennas. Building an amateur radio antenna for 160 meters is a challenge. 95 from Ham Radio. Desiring a multiple band wire antenna and not wanting to gather all of the piece parts. Each dipole kit contains a glass-filled Budwig HQ-1 centre insulator, two Budwig HQ-2 glass-filled end insulators, #14AWG insulated 168-strand copper wire, and 50 feet of solar. The antenna is ideal for local communications within 1000-2000 km of your location or for DX depending on how high the antenna is mounted and in what configuration. I hung it in an Inverted V config with the apex hanging at approximately 70 feet and the long end (180ft) running to the south and the short end (90ft) running to the north. Dipole packages consist of two end insulators, one center insulator with an SO-239 and eye bolt on it, and the proper amount of wire needed. 2EØZEH has built a 40-m OCF dipole and would like to add an extension for 80-m. Spiderbeam 160m Vertical Model 160-18-4WTH 2 160-18-4WTH Manual, Ver. 5 / 10 = 14. 12m —I use the OCF. OCF-8010E-3K OCF antenna (Windom) This is OCF Dipole antenna also known as Windom antenna fed at 19% of one end(19/81% ratio). The basic formula for determining the length of a center fed, half-wave wire Dipole or Inverted Vee antenna is:. I have in place an OCF dipole for 160 meters. I was very much in the dark on what to expect in the relationship between the off center fed (ocf) and a regular dipole. Wintertime is the perfect time for exploring the "Top Band. His basic design starting point was the half size G5RV, to which he added inductors on each leg. Anyway, after calculating the dimensions, I put up this OCF > dipole using insulated #14 wire I got from the Wireman at the Orlando > Hamcation. I put a 160m full-wave sky loop at about 75 feet and it works pretty good. This paper describes a multi-band DX antenna for the 160m-40m amateur radio bands with low visibility but great performance for long distance communication. height AGL Usable NVIS service occurs from 6 to 24 feet above ground with energy directed upward. Background. An antenna tuner with a built in balun matches the feed-line impedance to the 50-Ω coax to your radio. Construction details are the same as the 7 and 4-Band antennas, the 8-Band just has more wire so it can work 160M. One is called The Carolina Windom and another is called the Buckmaster OCF Dipole. High horizontally polarized dipole at least 70-100 feet high easily provides 6 dB of ground gain - for free! 4-Square array of phased 33 foot verticals with 30-60 radials good performance if high horizontal Yagis and quads aren't feasible at least 50-70 feet away from all nearby towers and antennas. Using that measurement and more carefully considering how the dipole connected into the balun, my updated length was 60 feet, 3 inches, or 60. Only the OCF series antennas come through with baluns installed. The ideal height for a dipole is half a wavelength above the ground, and therefore of course depends on the frequency. 7 MHz) and 10M (28. It utilizes an internal 9:1 UnUn and a BNC female antenna connector. I put a 160m full-wave sky loop at about 75 feet and it works pretty good. They are designed to give you years of trouble-free service! Find Buckmaster OCF Dipole Antennas DX-OCF-160 and get Free Standard Shipping on orders over $99 at DX Engineering!. Due to a very steep hill in the back yard, the long side of the dipole has to run up the side of the hill. The height above ground will affect the feed point impedance and the transformation ratio of the balun. 99 Carolina Windom 160M - 10M Dipole Antenna. With 10 metres being open most days world-wide,. off-center-fed or (ocf) dipoles! Off-Center-Fed Dipole usual practice is to feed a ½ wave dipole in the center where the feed point impedance is low and makes a suitable match to coaxial cables. So you could make an off-center fed folding 80m dipole that will also be resonant on 160m. Rick Sagers (W7YC) and David McAnally (WD5M) have been working on an Offset Center Fed (OCF) Dipole antenna project the past few weeks. 60 meter antenna. The repeater project is going ok. Battle Creek Special - 160-80-40 Meters - Vertical - by PI4CC Contest Club. Dipole Antennas - the Effect of Height Above Ground I frequently hear the question: how high should my dipole be? Or alternatively, will my dipole work well at this or that height? Unfortunately, these questions can not be answered without first stating what you want the dipole to actually DO, i. The 220 ft W8JI multi-band dipole is based on the design guidelines presented in this reference on page 7. 6 MHz, take 468 / 3. He said my signal was "considerably stronger" on the OCF dipole than the end-fed. Lower dipole and cut off 3" from each leg. The 160m Reduced Half Sloper is for 160m operation when space is limited. My K9AY RX Antenna. It Will Handle The Legal Limit, 1500 Watts Of Power. W3 Division W3TS 42 35 77 20 1540 x2 3080 60 foot high tee using 80/40m fan dipole K3MSB 38 32 70 21 1470 x2 2940 Inv-L for TX/RX and BOG for RX N3QE 32 27 59 15 885 x2 1770 130 foot wide Marconi T up 80 feet. On the other hand, an OCF dipole is an ungrounded dipole antenna fed with twin-conductor line, either coaxial or open wire parallel conductors. The optimum height for 160m antennas for any purpose is almost always a lot higher than anyone can actually install them. Falcon Antenna Products Newest 160 Thru 6 Meter Off Center Fed Windom Style Dipole Base Station Antenna With A Built in 14 Gauge 4:1 Balun. I put a 160m full-wave sky loop at about 75 feet and it works pretty good. One is called The Carolina Windom and another is called the Buckmaster OCF Dipole. The MMANA-GAL model of the K1POO antenna at 8m height shows that the antenna has a more complex lobe structure as the frequency increases. how you plan to operate with it. Background. The ideal height for a dipole is half a wavelength above the ground, and therefore of course depends on the frequency. You get an amazing (up to) 11. Study of the Off Centre Fed Dipole Antenna - G8ODE Short Long Feed point The Off Centre Fed Half-wave Dipole The Off-Centre Fed Half-Wave Dipole, more commonly referred to as the OCFD, is very popular because it offers good performance as a multi-band antenna using an antenna matching unit in conjunction with a 4:1 or 6:1 current balun. So it may be necessary to prune helix height after deliberately making it too long. Another antenna added from the antenna plan is a 160 meter ¼ wavelength inverted L. This video shows the difference in gain between my OCF dipole at 52 feet and my 160 meter dipole at 45 feet. The Windom (or OCF Dipole if you prefer), offers a true multi-band, experience without much use of a tuner. height AGL Usable NVIS service occurs from 6 to 24 feet above ground with energy directed upward. Using that measurement and more carefully considering how the dipole connected into the balun, my updated length was 60 feet, 3 inches, or 60. Apparently, OCF dipole designs had so far been a compromise between these three bands. 80 and 160m. The possible exception is between 20 and 200 miles. Try To Fit A Resonant Dipole First • Well behaved pattern • Inherently has gain in horizontal plane • Vertical pattern depends on height • For most QTHs - Higher is better on 40, 80, 160 - Height not as important on 20-10 • Directivity tends to reduce noise • Easy to feed with coax - Chokes can minimize receive noise, RFI. After cutting the coax pieces, I simply connected them together and set off to the antenna's location for installation and measurement. I have been doing a study for a couple of years now on the off center fed dipole. Building an amateur radio antenna for 160 meters is a challenge. Understanding And Building The OCF Dipole by Ron Bertrand. Engineered for maximum performance with a 14 Gage wire to our coaxial mono band double bazookas of RG11. Wire Antennas. I've ran a 160M OCF, 80M OCF, 20/10M Fan all kinds of stuff. During the current lull in solar activity, operation on the 160 meter ham band has become more popular. The height of the antenna above ground (J) was varied from 8' down to 1. I had a dipole for awhile but the background noise is considerably lower with the sky loop than it was with the dipole, and I can hear stations with the sky loop that aren't copyable with the dipole. The bazooka worked well but was a single band antenna and I would replace it after any 160M contest with either a Carolina Windom or a 80M delta loop. com FREE DELIVERY possible on eligible purchases. The following PDF files maybe of interest to you then, these are some of the better performing Multi-Band HF antennas they been around for years. ozaukeeradioclub. Quickly switch bands and eliminate a tuner as one more thing to adjust. Dipole resonance is lower in frequency (dipole too long). Even with the insulated wire! I then added 25' that I considered to be an excessive additional amount to the long end, only to find that it only dropped it to about 1. This end cannot be raised. These Are A Very Efficient Multi Band Antenna. Some as low as 20 ohms. 004 WB2ULV Chuck 130 K1PAI Roger 160 N2SMB Mark Icom 7100 mobile and a hamstick 186 W1LTX Bob 187 K1WTX Jerry Kenwood TS-590sg Kenwood TS-140 SGC 2020 qrp rig 75m homebrew dipole at 25' high. The 160 meter dipole is fed with 450 Ohm "window line", a close-spaced variant of. Only the OCF series antennas come through with baluns installed. Answers like "I can work everything I hear", or "I have worked "X" amount of DX-stations in the first hour on the air" are nearly useless. The distance. Record peaks for both 10 MHz Receiver Calibration before and after each Frequency Measurement, and for each Frequency of interest. For example, a 160m dipole at 70 feet is about 1/8-wavelength above the ground. I used this to build mine but you can plug in ant freq. It is complete, cut, tuned, and ready to hang. With a 1064m2 (1/4 acre) town block with a depth of 60mtr (200') I intended to improve on my previous All Band HF Doublet with an antenna that would be suitable for all the HF amateur bands, including the so called WARC bands and including the 160 metre band. This is the smallest 160m antenna to date. 20M VERTICAL ANTENNA, 40M VERTICAL ANTENNA, Antenna, Cushcraft R9, DIPOLE ANTENNA, EZNEC, Flagpole Antenna, HF Antenna Flagpoles, HF DIPOLE ANTENNA, HF VERTICAL ANTENNA, Hy-Gain AV-680, MULTIBAND ANTENNA VERTICAL, OCF Antenna, Off-Center Fed Vertical Dipole, Portable HF ANTENNA, SOTA ANTENNA, Stealth ANTENNA, Vertical Dipole Antenna, vertical. Background. It will be difficult to get to resonance, will not have good band width, and you can make a much more efficient 6 meter dipole as a stand alone. The Best Dipole Setup Note that, somewhere between 20% and 15% wavelength height, in the chart above, the dipole's impedance crosses 50 Ohms. The larger the wire, the wider the bandwidth. The so-called "OCF windom" is also a misnomer, for the same reasons. The CAROLINA WINDOM is the antenna that has helped put many 160 and 80 meter stations on the map. The Wire Size can range from 16 AWG to 12 AWG. Being that I was building a 10 thru 80 antenna ( if you remember it was a 40) I had to change the length of wire also. 5 / 10 = 14. The RadioWavz DX (OCF) Windom is a off center fed (OCF) dipole antenna that exhibits outstanding performance on all bands. Results of photoluminescence (PL) measurements show the existence of two distinct regions: one that is related to the blue emission originating from oxygen vacancy defects in HfO2 and the other one characterized with a series of sharp orange-red emission peaks related to f–f transitions of Eu3+ from excited level 5D0 to lower levels 7FJ (J. " This is essentially a dipole cut for the lowest frequency of interest and fed with 450 ohm ladder line. Study of the Off Centre Fed Dipole Antenna - G8ODE Short Long Feed point The Off Centre Fed Half-wave Dipole The Off-Centre Fed Half-Wave Dipole, more commonly referred to as the OCFD, is very popular because it offers good performance as a multi-band antenna using an antenna matching unit in conjunction with a 4:1 or 6:1 current balun. ozaukeeradioclub. On the other hand, an OCF dipole is an ungrounded dipole antenna fed with twin-conductor line, either coaxial or open wire parallel conductors. OCFD UltraLite Dipole. The height above ground will affect the feed point impedance and the transformation ratio of the balun. 10m —Dipole at only 20 feet but I have worked the whole world with it on 100w. Each antenna is a full electrical half wave one each band. Of course you can get lucky and make as high as 75% efficiency with a sweet length of feed line. A second 1/2 wave dipole was built and mounted at 8 feet off of the ground. Add to cart OCF Antenna 10-160m 500W 256ft. Vertical 1/4 monopoles can be unwieldy unless you have some tall trees in your yard. That was suitable for the transmitters of the time where the wire could be tapped onto the output coil. I will make up the 80m traps from that plan, add it to my 80m dipole and see how I go. Some tweaking may be needed, but mine was built within an inch or two of those measurements. BUCKMASTER DX-OCF-160 160 80/75 40 20 17 12 10 6 Meters Off Center Fed Dipole Low SWR 300 Watts Max. WINDOM OCF DIPOLE 80- 6 meters 7 Band HF. stacked folded dipole, homebrew dipole wifi antenna grid, half wave fm dipole, multiband loaded dipole calculator, vertical dipole 160m, home made 800 mhz dipole antenna, quarter wave dipole twenty meter antenna. Our antennas are a great simple way to get on the air and work multiple. 2dB/100ft at 30 MHz. As the name suggests, the length of the antenna is about half of the wavelength of the frequency the antenna is cut for. Cheers Max. ) 160m full wave loop, at heights ranging from 15 to 80 feet in a rectangle shape, with the broad sides facing east and west, fed with 300 ohm ladder line, feed point at about a 20 to 30 foot height. 15 decibels per 100 feet at 10 MHz. The OCF Dipole or the Off Center Fed Dipole has been around for ages. The Evolution of a 160m Inverted-L with FCP (long version) The result was an inv-L with the vertical section that goes up 70′, then across 40′, and across again in a different direction for another 50′. The OCF dipole is a compromise design HF antenna which allows operation on several bands without using an antenna matching unit (ATU). (External tuners work also. for the 160 Meter Band. How well and antenna works is a difficult question to answer. The one great drawback for 160 meters is the size of the antenna, where a full-size horizontal dipole can reach more than 260 feet/79. The RadioWavz DX (OCF) Windom is ideal for those of you who do not use a tower and beam. Thanks for your response to my e-mails, I really appreciate it. 20M VERTICAL ANTENNA, 40M VERTICAL ANTENNA, Antenna, Cushcraft R9, DIPOLE ANTENNA, EZNEC, Flagpole Antenna, HF Antenna Flagpoles, HF DIPOLE ANTENNA, HF VERTICAL ANTENNA, Hy-Gain AV-680, MULTIBAND ANTENNA VERTICAL, OCF Antenna, Off-Center Fed Vertical Dipole, Portable HF ANTENNA, SOTA ANTENNA, Stealth ANTENNA, Vertical Dipole Antenna, vertical. 8 MHz) is exceptionally broad. The DX-OCF worked as good as a 6m dipole and I worked 8-10 grids in many January SS with a 20W transverter. 22 Different Wire Antennas. OCF-8010E-3K OCF antenna (Windom) This is OCF Dipole antenna also known as Windom antenna fed at 19% of one end(19/81% ratio). Located in Connecticut, this QRN quiet station with barefoot power and a high OCF wire antenna. The impedance of this antenna is around 300 Ω, so you may want to use a transformer or a λ/4 long piece of 120 Ω coaxial cable to match this impedance to 50 Ω. It works fair and would like to improve it. 0 Description and Theory 5 1. This simple figure also tells us that if we have to place our low-band antennas at a considerably low height, the suggested absolutely minimum height in terms of gain would be in the range of 0. What effect does the height of connection to the tower have on the tuning, and efficiency? What difference would placement of the loading coil make? I started with my OCF Dipole model, and removed the source generator from the feed point, so it becomes a passive element, like the others that I included in the model (tower, satellite antennas. 6 or less on 160 and 80. I want to use 50 ohm coax for feed or since I have a lot of it, maybe 75 ohm coax. OCF Dipole antenna BALUN 4:1 BL-41W-2K for OCF / Windom antenna with insulators. I have in place an OCF dipole for 160 meters. The size of the antenna makes a Half wave length on 80 meters, and with the traps a half wave on 40m with a SWR (standing wave ratio) of 1:1-1. One wavelength at 600 MHz is = c / f = 0. We have used an antenna electrically equivalent to this for over 7 years with outstanding results. The Windom (or OCF Dipole if you prefer), offers a true multi-band, experience without much use of a tuner. Haven't really updated the site in a while, been busy and have not had much of a chance to do anything more than some 2M/70cm FM while driving to work. A second 1/2 wave dipole was built and mounted at 8 feet off of the ground. A properly tuned OCF also does not require the use of a tuner. 26 feet from one end. The gain difference between the spiderbeam and a dipole is at least one S-unit, most of the times 2 S-units. One may argue that 560 feet is ridiculous for a 40 meter dipole, but keep in mind that the data can be scaled down to a 10 meter dipole with similar results. Vertical 1/4 monopoles can be unwieldy unless you have some tall trees in your yard. 05 Is trying to build a trapped dipole for 160/80/40 meter bands. It is a simple spiral loaded vertical dipole, 17 meters high and with the spiral arms extending to almost 4 meters out, for a total space of just under 6x6x17 meters. To find the half wave, dividing 123. Hopefully we can improve on the antenna situation before too long!. The OCF Spiral Dipole can be matched with a small tuner. A dipole that is ½ λ high has a characteristic feed impedance of 75 ohms. NR5NN - NR5NN/6: WOW! It's a vast and sparsely populated 160m landscape here in the west, especially on 160m. Of course you can get lucky and make as high as 75% efficiency with a sweet length of feed line. This is what it was designed for. 60 meter antenna. Each model resonates at the low end of the respective 160, 80 or 40m band: Part Number Length in Feet Band Coverage DXE-WA-260 260 160m to 10m DXE-WA-135 135 80m to 10m DXE-WA-70 70 40m to 10m Specifications All DX Engineering Multi-Band Dipole Antennas are usable from their lowest resonant frequency. A conventional center fed dipole has the lowest feed point impedance at the center, 50-75 ohms depending on height above ground. 5MHz and you get 130'. nearly every HF rig these days covers all bands from 160m to 10m. 80 and 160m. Because the dipole – and therefore the vertical - would be limited to 25’ height (a small fraction of a 160 meter wavelength,) we knew getting it to tune up on frequencies as low as 2. 16 feet by 2 gives 61. height of the feed point is critical but the ends may droop or be bent with little effect. 5-1dB less than copper depending on steel composition. Sandpiper antennas sold here,we update our stocks to keep in touch with modern improvements in antenna design. Example — 80 meters: If you are operating on 3. Like many people, I'd like to have one simple cheap antenna that handles 1500 watts, has a low SWR, and radiates efficiently on all primary HF bands. I acknowledge that it isnt very efficient, but it is better than no 160m antenna at all (and hopefully will be a little more effective than the dipole I took to Niue last year). This is the length of a standard dipole but instead of dividing the result in half, use a 36/64% offset to determine the feedpoint. The RadioWavz DX (OCF) Windom is ideal for those of you who do not use a tower and beam. (Metric measurements are 14 meters and 28. It was the first antenna support put up at the new QTH. FT-891 Bundle Accy Yaesu DX-80 OCF w Mic PSU Dipole Auto-Tuner FC-50 Desk Desk Dipole FC-50 Auto-Tuner FT-891 w Mic OCF Bundle PSU Yaesu Accy DX-80 $789. On the other hand, an OCF dipole is an ungrounded dipole antenna fed with twin-conductor line, either coaxial or open wire parallel conductors. The 220 ft W8JI multi-band dipole is based on the design guidelines presented in this reference on page 7. I have an OCF dipole that works very well on 6,10,20, and 40. For example, a 160m dipole at 70 feet is about 1/8-wavelength above the ground. Of course you can get lucky and make as high as 75% efficiency with a sweet length of feed line. The first is an 80m dipole kit with instructions to build a very rugged legal limit half wave dipole. - 160/80/40 meter band - trapped dipole - 2007. The Half-Wave Dipole Antenna. C $163 2KW Stainless Steel OCF. 75 wavelength height over ground is the best of all possible setups, providing both DX communications and NVIS communications at the same time. Aug 24, 2018- Explore kevinpinscoe's board "Dipole and Wire Antennas", followed by 295 people on Pinterest. The dipole is a very simple antenna to construct and understand and will give you the highest value in cost effectiveness. Another antenna added from the antenna plan is a 160 meter ¼ wavelength inverted L. 7 % wavelength, with a length of 47. horizontal dipole, however, is most effective when its height above ground is at least 3/8 of a wavelength. 5MHz and you get 130'. We're pleased to offer two "starter" 80 meter antennas. ) by offsetting the feed of the folded dipole (closer to the top or bottom edge of the folded dipole in the picture). COM is a new antenna concept for combining extremely lightweight wire antennas with lightweight telescoping fiberglass poles, enabling rapid deployment of efficient antennas (within minutes) at heights previously unobtainable with a portable product. Steve Yates - AA5TB. Holding true to the original Windom formulas, I used a ratio of 37. Compared to a dipole a Bazooka provides a gain up to 3,6dB. Figure 1 - Dipole Voltage and Current Distribution The most common method of feeding energy to this type of antenna is at the center where the current is maximum and the voltage is minimum. The dipole will have more ground loss than the loop. The half-wave dipole is very simple to construct. I have 1 coax into my station RAT-PAK antenna selector, from an outside relay box for my 6 antennas (actually 7, since one is a fan dipole for 160/75). Dipole Antenna Radiation Patterns Article used with permission and courtesy of John, WB4YJT - Ventenna. I have in place an OCF dipole for 160 meters. So here I am, out of my element with the most basic thing. A good general height guideline is half a wavelength or more, but that's impractical for many of us, especially on 40, 80 and 160 meters. OFF Center Fed/Loaded HF Antennas VE3KL •Searching for the elusive 40,30,20 m Short Antenna •Small, no bulky traps, minimum of components •Leads to a general design approach for a broad class. Antenna Pictures: Image #2 - This is the right-of-center point antenna installation overview shot. 800 MHz Web SDR on 160m, 80m & dipole at a height of 8. On 15 through 20 meters, the higher angles of radiation will often limit communications to domestic contacts within the first-skip region. Go with a winner and break away from the pack. So the measurements are based on a 40 meter 1/2 wave dipole. The feed point is at 9 feet, then the wire is run for 150 feet to an insulator on a tree at a height of 20 feet. 160m dipole 160m dipole pattern The structure of the 160m dipole is very simple, 75 meters of wire with a feed point in the middle, 15 meters over ground. 95 from Ham Radio. I used these measurements from Radioworks, who sell pre-assembled Windoms, but other sites also show measurements and formulas for cutting a Windom for any band. Get homework help fast! Search through millions of guided step-by-step solutions or ask for help from our community of subject experts 24/7. 5:1 on 6, 10, 20, 40 & 80m bands and can be operated without an antenna tuner. Ham radio 40-meter dipole: your first antenna. If I may put in my two-cents worth, a dipole is a dipole. Connect the Coax to the SO —239 run the to a le. Nashua Area Radio Society › Topics In All Forums › Elmering Forum › OCF Dipole Help This topic contains 12 replies, has 3 voices, and was last updated by Fred Kemmerer 1 year, 11 months ago. 9 foot each upper and lower part of the dipoles due to the height of my tower too low ( tnx the my neighbour who let me anchor the North West dipoles in to his property ). Most are 1/2 wave dipoles, but also an OCF (75-10) and a MOXON beam for 6M. The Wire Size can range from 16 AWG to 12 AWG. It was the first antenna support put up at the new QTH. These are basically similar but vary in small details. 6 MHz and you arrive at an overall length of 130'. Other names include the "tuned doublet" and "dipole with tuned feeders. text 66pacific. I read a nice article by A. A commercial antenna system, the Buckmaster 7-band OCF Dipole, exploits this property. Hanging at correct height, the Double Bazooka is the ideal DX antenna supporting capacity up to 4kW. Answers like "I can work everything I hear", or "I have worked "X" amount of DX-stations in the first hour on the air" are nearly useless. 5dB less gain than the vertical H antenna over the very poor ground in New Hampshire. It's a dipole, fed 14% off center with a 4:1 voltage balun. 160m/80m Broadband Antenna by K5GP A presentation to CTDXCC September 22, 2008 The 160m/80m broadband antenna design objectives were to have: 160 and 80 m antennas since I had no antennas for these bands, the antennas had to be hidden because of covenant restrictions, open wire feeders would be too visible to be allowed,. This is the length of a standard dipole but instead of dividing the result in half, use a 36/64% offset to determine the feedpoint. I just wanted to see how many of the problems I have been Off Center Fed Dipole: the "Windom" experience. The OCF dipole is a compromise design HF antenna which allows operation on several bands without using an antenna matching unit (ATU). With a 1064m2 (1/4 acre) town block with a depth of 60mtr (200') I intended to improve on my previous All Band HF Doublet with an antenna that would be suitable for all the HF amateur bands, including the so called WARC bands and including the 160 metre band. How to Construct a Dipole. I tuned the traps for the middle of the phone portion of the bands. Each model resonates at the low end of the respective 160, 80 or 40m band: Part Number Length in Feet Band Coverage DXE-WA-260 260 160m to 10m DXE-WA-135 135 80m to 10m DXE-WA-70 70 40m to 10m Specifications All DX Engineering Multi-Band Dipole Antennas are usable from their lowest resonant frequency. Quickly switch bands and eliminate a tuner as one more thing to adjust. •Answers the (BIG) question of, “Now that I’ve. 80M-Dipole @110ft. Yes, most 160-meter antennas are big. Tuning the antenna is simple. All information, images, and documents on this website are the sole property of MFJ Enterprises, Inc. 2EØZEH has built a 40-m OCF dipole and would like to add an extension for 80-m. That’s a luxury that the majority of us ham’s can only dream of enjoying. 160m dipole 160m dipole pattern The structure of the 160m dipole is very simple, 75 meters of wire with a feed point in the middle, 15 meters over ground. Thanks for your response to my e-mails, I really appreciate it. Otherwise all your radiation will be at high angles. Buy EAntenna 160OCF3 OCF WINDOM 160m 3kW - R2010025 EAntenna online at £137. If I may put in my two-cents worth, a dipole is a dipole. Loop Skywire (average height of about 35 feet) 80/40 Loaded Dipole (inverted V, center at 21 feet, ends at 5 feet) 80/40 Resonant End Fed (sloper, loaded end at 25 feet, feedpoint at 3 feet) Test Procedure. you need and it works the same. 2dB/100ft at 30 MHz. K1POO 4 Band Off Centre Fed Dipole (40-20-15-10m ) MMANA-GAL K1POO Antenna model's 3D far field results The antenna at 8m height above real ground 5mS/m and dielectric 13, SWR ref 200Ω. Current type 4:1 (200:50 Ohms) BALUN is another product designed for OCF antennas (Off Center Fed) also known as Windom antenna. Although the traditional OCF dipole had very broad band-segments, the VSWR-minima of either the 80 m or the 40 m-band could not be perfectly aligned to the respective band-centers. 8 MHz, dividing 3. The optimum height for 160m antennas for any purpose is almost always a lot higher than anyone can actually install them. 2:1 or better and once I had the OCF up, adding the fan with such short lengths was not much trouble. At first, most hams will ask, "Will it perform as well as a full 160m half wave dipole?" of course it will not, a full size 160m dipole requires a minimum of 260 feet. The depth estimated for the generator site of the 100m component shows a logarithmic dependence on test frequency whereas no similar behaviour could be observed for the 160m component. To optimize the antenna for a frequency RANGE, do the calculations twice, once for the low end of the range and once for the high end; then average the two and plan to adjust the VSWR on both ends of the range as needed. An antenna tuner with a built in balun matches the feed-line impedance to the 50-Ω coax to your radio. Buy OCF 8 Bands 160-6 HF Windom Antenna Flex-Weave: Electronics - Amazon. 160M Band Pass Filter. 6 MHz and you arrive at an overall length of 130'. I worked my lower back while winding but I'm confident the helical wind itself met my exacting standards. Understanding And Building The OCF Dipole by Ron Bertrand. With a 1064m2 (1/4 acre) town block with a depth of 60mtr (200') I intended to improve on my previous All Band HF Doublet with an antenna that would be suitable for all the HF amateur bands, including the so called WARC bands and including the 160 metre band. About a year ago I moved to a larger city and now have a back yard space restriction and I'm struggling with antenna height due to the limited number of trees I have in the back yard. Greater height means a trend to lower frequency and longer length. For an 80-10 meter OCF dipole antenna, start with a total length of 135. Think of the "Carolina" windom antenna (the modern version of the windom) as an "upside down vertical antenna", hanging down from its counterpoise strung (more or less horizontally) some 10 meters (or more) above ground. The impedance of this antenna is around 300 Ω, so you may want to use a transformer or a λ/4 long piece of 120 Ω coaxial cable to match this impedance to 50 Ω. Even zip cord such as what is used for lamp cords will perform quite well. You must get it up in the air to get it to emit low angles of radiation needed for distance work. I have been doing a study for a couple of years now on the off center fed dipole.