Hf Mobile Antenna Loading Coil

Coils are used in a variety of different methods to match, tune, and resonate circuits. What a bad mistake that was! The butternut antenna I once own was a 5 band vertical and work really good considering I did not have any radials down, and did not have the space to put any down. One way to roughly determine the quality of an inductor without fancy test equipment is to compare out-of-circuit self-resonant frequency (SRF) of an open inductor (do not short the ends together) to the expected operating frequency. Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Old Air Band Antenna for Mobile ( Sold ) Larsen NLA-150 Mobile Antenna For 2 m Special old Transceiver HF General coverage RF power 150 Watt Q mac HF-90 Portable Base Station Package ( Sold ) Motorola GP 308 VHF and UHF (SOLD) Sagant MTX-240X HF All Band Antenna ( SOLD ) Create CL 15 Antenna 15m band 5 element Japan ( SO. The more I read into all the options the more I think I'll need to gear up on SWR meter, tuner and various other test gears. I didn’t do much, but I did characterize where things were not the same as what was written in the manual. Coil "Q" = 620 - Measured on the HP 4342A "Q" meter. This basic tutorial is hands- on, simple, and to-the-point. Greetings gang! Welcome back, TowerTalk! A big thank you to George, K0FF, for the tip to use nylon grommet strips for winding inductor coils. Some manufacturers have chosen to provide very lossy loading coils. Find many great new & used options and get the best deals for 392 M HF Mobile Antenna Coil All Band Ham Marine Mars Cap Military 80 10 Meters at the best online prices at eBay!. MFJ MFJ1664, MFJ-1664, HF PORTABLE MANUAL SCREWDRIVER 80-6m 24. EZNECmobileAnt EZNEC Modeling of a Mobile Antenna Jim Andrews, KH6HTV My primary ham station here in Hawaii now consists of mobile operation from my 1996 Audi convertible. HF Mobile Antennas AK4XO Screwdriver •These antennas are shortened versions of vertical antennas •Use loading coils and capacity hats to match and increase efficiency •Screwdriver antennas use a motor to adjust the tap on the coil •Hamsticks are helically wound, single-band antennas. This antenna was designed for amateurs with limited space who also wanted to operate the low bands. My rig is the 100 watt, 160m-70cm, all-mode, Yaesu FT-857. Steppir 4-Element 20m - 6m HF Yagi Up for sale is my 4-element Steppir 4-element yagi antenna with SDA-100 controller. We sell MFJ-67 40 METER HI-Q, MOBILE LOADING COIL at Radioworld UK for all your MFJ accessory and MFJ Loading coil needs call 01922 414796. Typically, radiation resistance is in the 1-4 ohm range, and coil losses are in the 3-5 ohm range for short (8-foot) antennas operating on 80-20 meters. The 12' mobile whip will be fine for my use because I will be tying it over my car in an NVIS configuration mostly. MDC40HX(7MHz/40m): Replacemant coil for MD200. Provides low SWR on ALL the HF ham bands, good RF efficiency, durable construction, light weight, with convenient installation. When using the MFJ 901B tuner, the "6 Band" CB to 10 meters Multiband Vertical Ground Plane tunes up nicely on ALL ham bands from 40 thru 10 meters giving a great match near or at 1:1 swr on all the hf bands from 40 thru 10 meters. It was my hope to be able to install a series of different loading coils to be able to operate on the other HF bands. It is the only frequency group in the MF band of 300 KHz to 3 MHz that is assigned to region 2 for Amateur Radio usage. net Article: Make Your Own Loading Coils - If they look like DUX and walk like DUX and quack like DUX, maybe they ARE DUX! - eHam. EXECUTIVE SUMMARY. All information, images, and documents on this website are the sole property of MFJ Enterprises, Inc. This article is the introductory article of a series I plan to post as I document the construction of an HF mobile loop antenna for my Jeep. In fact for many stations you'll be their first pedestrian mobile contact. EZNECmobileAnt EZNEC Modeling of a Mobile Antenna Jim Andrews, KH6HTV My primary ham station here in Hawaii now consists of mobile operation from my 1996 Audi convertible. 46 Uk bidders only any bidders from overseas will be cancelled and payment is required within three days of the end of the auction Happy bidding. Higher Efficiency—Better Mobile Signal! DX Engineering Mobile Antennas and accessories provide the highest efficiency under the less-than-optimum environment presented by a mobile antenna installation. End fed HF wire antenna Published on April 9, 2016 April 29, 2016 by pa1ejo For a HF antenna you can make a half wavelength dipole, but the problem is that it is only resonant at the wavelength you design it for unless you insert some loading coils. I attempt to improve the feedpoint impedance of my HVU 100 HF Mobile Antenna configured for 40. Yes, this IS the complete antenna with the two section whip! You will need the desired mount and coax. It is NOT an automatic fold-over, you must manually lift the element up out of the socket and lay the antenna whip down in order to enter garages, parking structures etc…. It has a highly efficient loading inductor. If you read carefully you will see why a long helice behaves more like a radiating transmission line and less like a conventional inductor. The Toyota HF mobile vehicle with antenna fully deployed and ready for moving operation on 80m. The main category is Antenna design calculators that is about Antenna design calculators. This article describes a specific procedure to adjust a shunt matching coil to assure that the input SWR will remain relatively low (≤ 1. I remember making one coil that was 16" long, and consisted of 1/2" soft copper water line wound around a 20" form. I can even change the tap on the 40/30 to any of the other bands. HF Antenna [BNC] Order #5302 List Price: $99. (Four different rigs). The reason for selecting the 5λ/8 wave ground plane is that for a simple single element antenna it appeared to have increased capture aperture when compared to the standard λ/4 wave length ground plane antenna and has a relatively low angles of radiation in comparison with other similar antennas. Here's a "sketch" of a Base-Loaded mobile antenna: The base loading coil has to be mounted on a strong enough mount to take the normal flexing seen during mobile operation. I'm very new to HAMs and buying a Yaesu ft 857d. Key Features/Specifications:. Key Features/Specifications: Frequency coverage 2 - 30MHz ; Power rating 250W (PEP). (4) Continuous loading: At electrical lengths of 1/8 wave or greater, this is may be the most efficient way to shorten an antenna. Your HAM deserves the best type of dual/quad band base capabilities around. Going back to that reference we can see on page 109 Fig. Homemade HF loading coil for short antennas. About Mobile Dual-Band 2m/440 -- Roger K6XQ advises-Can I build a 2m/440mhz 5/8 mobile antenna? A 1/4 wave on 144 MHz is 3/4 wave on 440. As with all trap dipoles, this one has less-than-ideal bandwidth due to the load- ing effect of the traps. Mobile antennas are usually large, expensive, poor per- formers and a general nuisance with five or six separate coils to keep. Part # Diamond Antenna HVC Loading Coils provide your Diamond Antenna HV7A multi-band HF/VHF/UHF mobile antenna with resonance on a specific. Once assembled it works on all bands. About Mobile Dual-Band 2m/440 -- Roger K6XQ advises-Can I build a 2m/440mhz 5/8 mobile antenna? A 1/4 wave on 144 MHz is 3/4 wave on 440. And ground losses typically are in the 7-15 ohm range. Each is ruggedly constructed. Secondly, the 2:1 SWR bandwidth tends to be. HF Antenna: Initially I considered a big-coil, adjustable load (or “screwdriver”) HF antenna that would use some fancy circuitry and mechanisms to. Adjustable taps on the matching and loading coils are made with small alligator clips. We decide to load this antenna by introducing a loading coil in series with the antenna, and would like to know where this coil should be placed for maximum radiation efficiency. Current category hierarchy. Hi-Q On the Move HF Tactical Antenna : Hi-Q On the Move antenna that mates with the Shakespeare Mil. Get the best deals on HF Mobile/In-Vehicle Ham & Amateur Radio Antennas when you shop the largest online selection at eBay. " The antenna support is a fiberglass whip carried on a backpack. Details about 392M HF mobile antenna coil all band ham marine mars cap military 80 - 10 meters. Browse your favorite brands affordable prices free shipping on many items. Carl Oliver has done an excellent job of explaining what a coil is and how it's used to reduce the physical length of a resonant antenna. Base loading is mechanically better as the antenna's centre of gravity is low. Google some articles on grounding/bonding for mobile HF. Hi-Q antenna components under COLD test. The larger that loading coil (to some extent) the shorter the thing can be, but there are limits to that "shorter" thingy. They were then connected to each end of the short dipole. Since I wrote that blog post, I put up a homebrew version of the Cobra Antenna. The average radius of the radiator is 0. King, KM4IE A $20 HF Mobile Antenna A few hours of fun with PVC and wire and you’ve got yourself a respectable road radiator! hile returning home from a W brief business trip one evening, I was listening to the chatter on a 2-meter repeater. Its BTV (vertical) antennas continue to set the standard for trapped vertical antennas, delivering the best reliability of any multi-band vertical on the market. Click the button below to add the MFJ-1640T 40 Meter Mobile HF HamStick Antenna. HF Mobile Antennas AK4XO Screwdriver •These antennas are shortened versions of vertical antennas •Use loading coils and capacity hats to match and increase efficiency •Screwdriver antennas use a motor to adjust the tap on the coil •Hamsticks are helically wound, single-band antennas. The best information on loading short verticals in contained in the chapter on mobile antennas. 56 MHz ISO-compliant RFID technology is a proven, globally accepted solution for a vast array of markets. Greetings gang! Welcome back, TowerTalk! A big thank you to George, K0FF, for the tip to use nylon grommet strips for winding inductor coils. A loading coil may be used, on its own or in conjunction with a capacity hat, to tune the antenna to resonance at a lower frequency. If you read carefully you will see why a long helice behaves more like a radiating transmission line and less like a conventional inductor. Hi-Q TriPod for quick antenna set field set up. Last edited by ke0ipr. Full view of roof mounted HF monopole antenna showing top hat with swept wires. ) Good success was seen with a MFJ 1988T. The loading coil is often placed at the base of the antenna, between it and the transmission line (base loading), but for more efficient radiation, it is sometimes inserted in the center of the antenna element itself (center loading). A T-antenna, T-aerial, flat-top antenna, or top-hat antenna is a capacitively loaded monopole wire radio antenna used in the VLF, LF, MF and shortwave bands. Radiowavz Patriot P80 Coil adjustable HF Mobile Antenna Adjustable loading coil system. This link is listed in our web site directory since Tuesday Dec 8 2009, and till today "Antenna Loading Coil Calculation" has been followed for a total of 14292 times. HF/VHF Antennas (SSB) HF/VHF Antennas (SSB) To ensure durability, you can opt for MF/HF antennas with an extra wide diameter to 52 millimeters. Be very suspicious of any mobile antenna that has broad bandwidth and low SWR with out a base loading coil. The more expensive one had a motor that could be controlled from inside the vehicle. By using a mobile antenna loading coil you will minimize ground related losses. This is post #1012 in a continuing series of "Simple Ham Radio Antennas. My reasoning was that since that portion of the antenna carries the highest RF current, then adding more length there would increase the radiation efficiency of the antenna more than would adding the same length to the antenna above the coil. As with all trap dipoles, this one has less-than-ideal bandwidth due to the load- ing effect of the traps. As of June 2013 W6HIQ is an official HFN Pilot Station! Under W6HIQ call letters. Get the best deals on HF Mobile/In-Vehicle Ham & Amateur Radio Antennas when you shop the largest online selection at eBay. The smaller model Outback 1899 supports only the 5 clasic bands 80/40/20/15/10m, but can additionally be used on 2m and 70cm and on the airband 118 to 136MHz. I would still appreciate some. Easily pack it away when parked to prevent theft or vandalism. The HV7A is supplied with HVC28 (10m) loadi ng coil. Given the title of this article - "Choosing the Best CB Antenna" perhaps we should have put this one at the top. A loading coil may be used, on its own or in conjunction with a capacity hat, to tune the antenna to resonance at a lower frequency. A typical application for an RF coil would be in a tuner at the output of a transmission line at an antenna. IMPORTANT READ ALL INSTRUCTIONS carefully and completely. Amateur radio, ham radio, cb, GMRS, FRS,marine band and electoinc components. Find many options of HF, mobile, and base antennas at Walcott Radio. It is commonly known as: "The Screwdriver Antenna" The antenna uses a wide-band unbalanced to unbalanced matching transformer to match the low impedance of the antenna to the 50 ohm output of your transceiver. Handles 1 kW PEP SSB. MV3A Mobile Antenna System General Information MV3A has 4 band capability—2m/6m, plus 2 HF bands though use of loading coils. See the Materials List before you go shopping. Learn vocabulary, terms, and more with flashcards, games, and other study tools. In these circumstances a vertical might be a better antenna option. Microearphones. radio coil rf coil antenna coil 3/8 antenna loading HF mobile antenna. Figure 1—Schematic (A) and pictorial diagram (B) of the $20 homebrewed mobile antenna. I found that 6 meters may be useable also. This antenna is 54 inches high and does not include mount or coax. With my Dentron Super Tuner, I can tune the antenna on any HF band 80m and above, and it seems to work just as well or better on 40m and 30m as did the fan dipole. 63 wavelengths. It is a non adjustable antenna and may require an ATU to get the SWR to less than 1. Buxton, W8NX, and features innovative coaxial-cable traps. E9D09 : Why should an HF mobile antenna loading coil have a high ratio of reactance to resistance?. Let's assume we have a transmitter in our shack, and were feeding a vertical out in the backyard. See the Materials List before you go shopping. The other thing is climates: One common 'downside' to using a giant coil antenna for those that mobile in cold climates, the giant coil antennas will ice up when below freezing, and in snow will fill up. Mobile Antenna System. I have all the plans how to make it. 150 Watt power load. I found another whip that will work and its longer than the original can be cut to desired length. •Use a circle (or square) of burred ground rods and bare ground wire. Lots of radio amateurs build their own verticals. Amateur radio, ham radio, cb, GMRS, FRS,marine band and electoinc components. At Walcott, all Diamond Antenna orders ship same day!. HV7A is a mobile antenna system with 5 band capability: 70cm, 2m, 6m, and 2 HF bands. Easily pack it away when parked to prevent theft or vandalism. Most of the tomes used by the last generation of AM consulting engineers date back to the 1940s and are no longer in print. Lowell, N1LO Moxon Antenna Projects-- 17M and 20M Via KD6WD. This calculator is designed to give the vertical length (height) of a particular antenna, for the frequency and wavelength chosen. PCB and LTspice simulation provided. This is why very large mobile antenna loading coils generally offer marginal improvement over smaller inductors. Get in touch with our technician during Central Time business hours for questions, installation help, and repairs. This video belongs in your amateur radio reference library. This online calculator tells you how the amout of inductance your loading coil will need to have. An HF mobile antenna loading coil should have a high ratio of reactance to resistance to minimize losses. Going back to that reference we can see on page 109 Fig. It intended for use with lightweight transceivers such as the Elecraft KX2 an KX3 that are equipped with aninternal antenna […]. Are you looking to shop for the best mobile antenna coils for sale? Antennas. RWB – Suppliers of World Class Two-Way Land Mobile, Marine, Aviation and Amateur Radio Communications RWB Communications is the exclusive importer and distributor of top quality, Japanese-manufactured two-way business and personal radio communications products in New Zealand. This shortened easy-to-build vertical, with no-radials, is made from surplus military camouflage poles. We'll assume that the frequency is 1,850 KHz, and have 1,000 watts of power. It's widely used for FM radio broadcasting, two-way land mobile communications, long range data communications, radio modems, amateur radio and marine communications. I found another whip that will work and its longer than the original can be cut to desired length. A loading coil adds inductance to an antenna and can be adjusted to allow an antenna to cover several frequencies.  HF wide-band antenna ideal for limited space gardens similar to the BB6W except that it has a vertical section after the loading coil/balun instead of a horizontal wire. The coil wire itself was some 18 gauge hook up wire that turned out to be too large for my protoboard, so I am glad it found a good home in the matching coil. Why HF Mobile? With today’s modern compact transceivers it is possible to have portable HF communication in our vehicles. Why should an HF mobile antenna loading coil have a. I need a solution for a center loading coil. This is my strategy using a monoband 20 meter coil loaded antenna and another dual band coil for 40 and 30 meters which I can change quickly. So, final word, this is a great choice for portable and mobile HF operation. Ham Radio and Amateur Radio online equipment sales. 63 wavelengths. 10 metres (28 MHz) is the easiest band to get a mobile antenna for. Scegli la consegna gratis per riparmiare di più. If you read carefully you will see why a long helice behaves more like a radiating transmission line and less like a conventional inductor. Remove the antenna from the packaging. hf antenna new without tags but never been used having a major clear out hence cheap price of 18. Includes company and product information, product specifications and dealer locations. It consist of 2 parts whip, one fixed and one. (2) The "bandwidth" of the antenna will be reduced. r&l electronics mobile hf/50/144/440 mobile hf/vhf mobile hf mobile 144/220 dual band ht 144/440 dual band ht style antenna. The HF mobile antenna is a Hi-Q 3/80 screwdriver antenna with a 1 foot mast extension, a 4 lobe capacity hat, and a 4 foot whip from a 75 meter HamStick. 150 Watt power load. Home of the. It's widely used for FM radio broadcasting, two-way land mobile communications, long range data communications, radio modems, amateur radio and marine communications. Portable use is where these coils really shine, they set up fast and with an adjustable whip antenna, you can tune just about anywhere on the bands. Instead of typical lossy can traps, the AV-640 resonators are placed in parallel not in series. This shaft had slid down the antenna such that the coil stuck out at a strange angle. A black anti-static jackets protects the loading coil and blends with any. 4ghz quarter wave? Lastly could one build a collinear antenna style antenna with a coil at every point instead of a loop?. The SA-680 covers all HAM bands from 80m - 10m (160m operation will also be added to this antenna - more on this in a later post). • Use NEC to model antenna and predict inductance required to resonate the the antenna – or: Use Vector Analyzer to measure feedpoint Z of an existing antenna that’s too short, export data to SimSmith and predict inductance • Coil winding formulas in ARRL Handbook are very accurate. An HF Mobile Antenna This antenna is what I call a "Variation on a Theme" because it has been built and written about many times in many different configurations. HF Antenna: Initially I considered a big-coil, adjustable load (or "screwdriver") HF antenna that would use some fancy circuitry and mechanisms to. Get an instant quote for top performing parts such as TDRFT14035, TR57C000, TR57838, TR57839, 659596 following under NSN number 5985000011870, 5985000011875, 5985000011876, 5985000011877, 5985000012334. Buxton, W8NX, and features innovative coaxial-cable traps. Folds at roof line 15" above the base. It clears about everything. High performance and high quality transmitting antennas for the mobile marine coastal in fishing boat with passenger plane and coast defense ship services, and duplex for simplex SSB. The loading coil does replace some, but not all, of the degrees missing from the shortened antenna. E9D09 : Why should an HF mobile antenna loading coil have a high ratio of reactance to resistance?. I changed that last night, the coil is now 1. The impedance of such whips is always quite low so there are serious impedance matching issues to overcome as well as the tuning of the loaded antenna to resonance. Contact me; VK1AD Antenna Projects. Resources listed under Mobile antenna category belongs to Antennas main collection, and get reviewed and rated by amateur radio operators. This shortened easy-to-build vertical, with no-radials, is made from surplus military camouflage poles. I would still appreciate some. By using a mobile antenna loading coil you will minimize ground related losses. Receiving antennas for MF/HF bands and SSB. The larger that loading coil (to some extent) the shorter the thing can be, but there are limits to that "shorter" thingy. In no way would i run a Wilson 5000 with a tuner for all band HF operation. But few of us have the space or the money to have individual antennas for each band! Ham Radio Antennas on HF A Setup To Avoid!. The Hustler MO-1 is a 54" fold-over mast. Place a 3/8“ lock washer onto the 3/8 X 24 thread of the desired whip. I didn’t do much, but I did characterize where things were not the same as what was written in the manual. Coil-Shortened Vertical Antenna Calculator. The following receiving amplifier can be used for any kind of signal in the HF and VHF bands from about 1 MHz to 400 MHz. A high-Q loading coil should be placed near the center of the vertical radiator to minimize losses in a shortened vertical antenna. Mobile and Maritime Antennas 16-3 Coil losses in the higher-power loading coils are usually less (percentage-wise), with subsequent im-provement in radiation efficiency, regardless of the power level used. Attention Hi-Q HF Mobile antenna owners! We are receiving inputs from customers, mostly from 18 wheelers that they have surpassed the Million miles on the Hi-Q antenna installed on their rigs. This loading coil is a good example of why high-reactance loading inductors should be longer and narrower than inductors used in low-impedance systems. EXECUTIVE SUMMARY. Try Prime All. Use the Coil Inductance Calculator to design your loading coil. While mobile installation is the dominate application for our coils, they can be used for apartment dwellers, amateurs dealing with confined space or stealth antenna installation, portable applications, camping or anytime you need to load an antenna without the need of a tuner. The advantage of a high Q antenna is its shortened length, so you’ll often see these mounted on vehicles for mobile HF operations. 1 a current distribution on 1/4 wave radiator. Last edited by blaap. Since I wrote that blog post, I put up a homebrew version of the Cobra Antenna. HV7A Mobile Antenna System General Information HV7A has 5 band capability—6m/2m/70cm, plus 2 HF bands though use of loading coils. I took a small piece of dowel and pushed it into the coil to straighten it and set the coil back to a more even spacing. " In fact, the elongated coil is the antenna. HF Antenna: Initially I considered a big-coil, adjustable load (or "screwdriver") HF antenna that would use some fancy circuitry and mechanisms to. A lumped loading coil may be a short, fat, single-layer solenoid. Whenever anv sertical antenna is shortened from its full physical 1/4 wave length it is compromised in certain ways. Tube rigs are/were very forgiving for loads. This shaft had slid down the antenna such that the coil stuck out at a strange angle. Antenna is Hi-Q 80/4 with their quick release base, see hiqantennas. NEW from Hi-Q-Antennas: HOW GOOD IS a Hi-Q Antenna? Follow one 24/7/365. Since the bandwidth of the antenna is wide the adjustment parameters are relatively broad and fine adjustment is not usually necessary. This calculator is designed to give the vertical length (height) of a particular antenna, for the frequency and wavelength chosen. Mobile antennas, particularly those for the lower HF bands, are always something of a compromise. HF Antennas; VHF/UHF Mobile Antennas; VHF/UHF Base Station Antennas; VHF/UHF Portable Antennas; Antenna Accessories; Power Supplies; Audio Accessories; Other Accessories; CB-Radios and 11-Meter Transceivers. Are you looking to shop for the best mobile antenna coils for sale? Antennas. But it's less electrically efficient than top loading with the coil at the top. tubing for adjustment). net Article: Make Your Own Loading Coils - If they look like DUX and walk like DUX and quack like DUX, maybe they ARE DUX! - eHam. Diamond Antenna's HVC loading coils feature a brilliant-chrome finish. The center loading coil is adjusted with a sliding tap, just move the outer part of the coil up and down. Learn vocabulary, terms, and more with flashcards, games, and other study tools. 6:1) over the operating range of an 80 through 10 meter, remotely-controlled, HF mobile antenna. Last weekend I did some mobile antennas experiments on the field. com and go to Accessories and see GCD (giant quick disconnect). This should improve the performance on 20 and 40m. Unfortunately, since the antenna is mounted on top of a van which is a rather high vehicle, that would. All other giant coil antennas get weird looks from her or negative comments. when i built up a wifi antenna with a quarter wave GP and 7mm coil per youtube video that works great, why is the straight length past the coil much longer than 2. Home of the. How come? Well, the loading coil must always "trail" the antenna mast; that is, the coil must be directly behind the antenna mast when the vehicle is moving. net Article: Make Your Own Loading Coils - If they look like DUX and walk like DUX and quack like DUX, maybe they ARE DUX! - eHam. Z is now 50+j0. High Performance 40 Meters Vertical. The MV3A is supplied with HVC28 (10m) loading coil. Universal mobile- and portable antennas for HF and VHF/UHF. I was wondering what the best option for a mobile antenna would be? I'd like an antenna that handles HF/VHF/UHF if that's possible. Whip Antenna Design Calculator. W2KI HF Mobile Antenna Installation The mobile setup here in my 2000 GMC Yukon consists of a Yaesu FT-100D HF-UHF transciever with a Diamond SG-7500 on the roof for VHF and UHF, and the excellent Model 200 Screwdriver antenna from Tarheel Antennas in North Carolina for HF and 6 meters. The same is not true of HF antennas on the radioamateur bands or mobile antennas for 27MHz (11-metre) CB operation. Hi-Q TriPod for quick antenna set field set up. The Toyota HF mobile vehicle with antenna fully deployed and ready for moving operation on 80m. the coil for each band. hf antenna new without tags but never been used having a major clear out hence cheap price of 18. Use the Coil Inductance Calculator to design your loading coil. Background. The AV-640 uses quarter wave stubs on 6, 10, 12, and 17 meters and efficient end loading coil and capacity hats on 15, 20, 30, 40 meters. The loading coil was only a few inches above the cab, and wrapped somewhat inconsistently around PVC. Gordon West talks about HF mobile antennas, and getting the feed-point impedance at 50 Ohms. The screwdriver antenna is based on the use of a loading coil with a whip antenna (typically 102"-120", like those used for 11-metre CB radio installations). Download Presentation HF Mobile Installation and Operation An Image/Link below is provided (as is) to download presentation. ( Brand: Diamond ), ( model : HV-7A ), ( Frequency Band(s): HF ) Review (mpn: hv-7a for sale) HV-7A Diamond Multi Band Mobile Antenna Loading Coils. Does it have to be the color white?? The reason I ask is that my local supplier have the plumbing black sked. With coaxial mounted loading coils, this is not a problem, but this antenna has the loading coil mounted off-center from the mast. The telescopic antenna and the MFJ-67 loading coils are ⅜ " - 24 threaded and can be easily combined. Diy multiband mobile hf antenna keyword after analyzing the system lists the list of keywords related and the list of websites with related content, in addition you can see which keywords most interested customers on the this website. I took a small piece of dowel and pushed it into the coil to straighten it and set the coil back to a more even spacing. MFJ-1668 Instruction Manual Screwdriver Antenna Mobile Setup 1. antenna! – Proximity to earth changes the impedance – High dipoles are closer to 75 ohms – Low dipoles are closer to 50 ohms • Feedline SWR (and loss) depends on the match between feedline and antenna – Use feedline that matches the antenna • XMTR will reduce power if mismatched – Use an antenna tuner to make the rig happy. Texas BugCatcher. It was first described in July 1992 QST by A. I would still appreciate some. The least problematic method would be to add a loading coil towards the top of the radiating element and / or capacitive loading. The base loading coil will overheat due to very high RF current on the lower bands and may even arc between turns on some bands if the RF voltage gets too high. 79 meter antenna wire is supported by a 18. The actual coil length is 7 ½ inches long and wound with number 18 enamel wire. Find many great new & used options and get the best deals for 392 M HF Mobile Antenna Coil All Band Ham Marine Mars Cap Military 80 10 Meters at the best online prices at eBay!. The loading coil was only a few inches above the cab, and wrapped somewhat inconsistently around PVC. Traditional HF mobile vertical antennas commonly use a whip and loading coil configuration. Anyways, the question I have is the loading coil form is made of 1 1/2" skep 40 PVC pipe white. Carl Oliver has done an excellent job of explaining what a coil is and how it's used to reduce the physical length of a resonant antenna. By moving the adjustable coil on the antenna you should be able to work the entire 160 meter band. the HF bands and 2 meters. The MP-1 is a universal antenna with 180cm length and max. While mobile installation is the dominate application for our coils, they can be used for apartment dwellers, amateurs dealing with confined space or stealth antenna installation, portable applications, camping or anytime you need to load an antenna without the need of a tuner. The actual coil length is 7 ½ inches long and wound with number 18 enamel wire. This shortened easy-to-build vertical, with no-radials, is made from surplus military camouflage poles. Continuously adjustable loading coil is 15 inches long by 2 inches in diameter and weighs 1. The most common form of loading is with a base coil (inductor). We try to build antennas to meet the needs of most Hams. 5 TPI to make tapping easier and to keep the losses down, 11 turns were sufficient. Jorgenson KE7HR NSS 39382FE The need arose for a compact, cheap, antenna for the 75 meter HF amateur band to be used for cave radio communications. The larger that loading coil (to some extent) the shorter the thing can be, but there are limits to that "shorter" thingy. This is called a "grounding clamp" in the electrical trade, but is actually being used here to make the RF connection to the copper antenna pipe. when i built up a wifi antenna with a quarter wave GP and 7mm coil per youtube video that works great, why is the straight length past the coil much longer than 2. This antenna covers 65 kHz of 160 meters, 75 kHz of 80 meters and the entire 40-meter band with SWRs under 2:1. The Primary Mission of LocustLABS(sm) is to hopefully develop what might be best termed as "The Mother of All (Small Yet Efficient) Portable Expedition Antennas" for those situations when an extremely small footprint is needed for both travel packing and ultimate "unique" installation(s).  HF wide-band antenna ideal for limited space gardens similar to the BB6W except that it has a vertical section after the loading coil/balun instead of a horizontal wire. The Hamwaves Inductance Calculator. (And all my responsibility is hereby disclaimed!) I haven't personally tested these designs, but others have and found them to be satisfactory. com FREE DELIVERY possible on eligible purchases. I have in my shack two of them, one “don’t remember brand” dual band VHF/UHF and one HF antenna, Proxel PRO-X1, which I never use them before. 3- Screw the fiberglass loading coil and stainless steel whip assembly into one of the 3/8 X 24 connections on the MFJ-347. While transmitting with power, I was getting about 1. This is the price paid for multiband coverage and physical short- ening. There are four optional HF coils available: HVC7 (40m), HVC14 (20m), HVC18 (17m), and HVC21 (15m). I have all the plans how to make it. Modeling this 160 meter inverted-L in EZNEC shows surprisingly useful patterns and gain on most HF bands above 160. Quality Built by GLA Systems "The SERIOUS HF Mobile Antenna" 4" and 6" Diameter High "Q" Coils for 3 to 30 Mhz Operation Stainless Steel Mast and Hardware - Aircraft Aluminum Capacity Hats All Parts Have Standard 3/8-24 Threads - Tunes All HF Bands. The first photo shows the Hi-Q antenna, center loaded, with the top whip antenna topping out at 11 feet 4 inches from ground. Hi-Q HF Antenna Accessories. Mobile HF is a tricky thing, NVIS or no NVIS. If you have a screw driver type antenna, this coil can be placed between the top whip and the top of the screw driver's coil. Add series inductance (base loading coil).