Anyone i hear on 804020171512and 10 meters ssb so far, i can qso with, and also compliments me on my signal and audio. The cobweb is a 5band antenna that is really suited for space retricted qths. The antenna is resonant on the bands it has been designed for, and to my delight i also find that it is resonant on 6m. Oct 22, 2012 last summer i built myself a cobwebb antenna and was fairly pleased with the results. If you have no particular preference within a given ham radio band, then simply enter its center frequency i. Spacing is the distance from the boom to the gammamatch. Cobwebb discussion, 4band cola antenna 20171510m, cobweb. What i realised quite quickly was that the cobwebb was much quieter than the wire and exhibited much better signal reception. This link is listed in our web site directory since thursday apr 12 2007, and till today cobwebb multiband folded dipole has been followed for a total of 7942 times. G3tpw cobwebb antenna for the 14, 18, 21, 24 and 28 mhz bands the main advantages of the cobwebb over other 5 band 14 to 28 mhz antennas are that it is small, lightweight, strong made from fibre glass, only requires a single support, needs no rotator, gives full size dipole performance on all 5 hf bands. All antenna lengths in the information below are in feet and are the results based on the standard formula of 468 fmhz total length in feet. Sep 07, 2016 i built a cobwebb 5band antenna for hf. Here is a handy chart for determing 14 wave verticals, 12 wave dipoles, and full wave loop lengths.
G3tpw cobwebb antenna for the 14, 18, 21, 24 and 28 mhz bands all the other small multiband commercial antennas that are available are less than. This clip illustrates my progress from start to finish building a homebrew single wire cobweb antenna for the five amateur bands. G3tpw cobwebb antenna for the 14, 18, 21, 24 and 28 mhz bands the main advantages of the cobwebb over other 5 band 14 to 28 mhz antennas are that it is small, lightweight, strong made from fibre glass, only requires a single support, needs no rotator. G3txq hexbeam, gm3vlb delta, g3tpw cobwebb, moxon, vk2abq etc. About cobwebb multiband folded dipole the resource is currently listed in in 2 categories. We compare it to a 806 meter ocf, to a 20 meter delta loop, and to a. The table below shows the swr bandwidth with the antenna about 15ft high. This link is listed in our web site directory since thursday feb 28 2008, and till today cobwebb revealed has been followed for a total of 12765 times. Their length is 7ft which provides the correct length for arranging the twin speaker. Another good choice might be the cobweb antenna, which is small, horizontal, omnidirectional, without nulls. Other useful information would include your experience with similar products, infomation on a product that you would purchase instead of this one, and so on.
So i had an email from jake asking why hes not getting out too well on 20m. Our software, consultancy and ongoing support make business processes easier and more enjoyable. Dec 29, 2012 regular contacts are made using this antenna with places like japan, australia, alaska, hawaii,south america, russia, italy and many, many more places using this particular design. As such, the source of the name of the antenna has been found. Mfj hf cobweb wire dipole antennas mfj1835 free shipping. This video i will be assembling both the mfj1836 6 band cobweb antenna with the additional 3040m addon kit. The cobwebb is an omnidirectional antenna and therefore it doesnt have any nulls in the pattern. After a few more weeks of not getting on the air i managed to man handle the portable hexbeam up to about 4 above ground level note. Where i was getting up to s6 of noise from the wire antenna, the cobweb was showing me a paltry s23. Cobweb antena is the best omnidirectional antenna for 6m, 10m, 12m, 15m, 17m, and 20m hf bands. The dipole was 1db better broadside on but the cobwebb, being omni directional was 4db better than the dipole when the dipole was endon to the direction of the signal. The antenna complimented my lowband horizontal dipole nicely and gave me the most useful hf bands 2010m without needing an atu. Jan 26, 2014 a checkup on my homebrew cobweb after the terrible storms recently, all seems well and still going strong after 3 years. Its a great dx antenna in a very small footprint package which covers 5 bands from 1020m without any need to use an antenna tuner.
It is made by srw commuications ltd steve webb, astrid house, swinton, malton, n. As this is the g3txq variant, i refer to mine from now on as a cobweb. Slim jim j pole antenna calculator radios, hf radio, ham radio antenna. Describe your experience with the mcr666 7 band cobweb antenna from 4 to 20 meters and tell us why you give it the rating you did required. This is a nosolder product and ready for mounting onto your cobweb metalwork and spreaders. So nine useful amateur bands on one antenna is not too bad note the cobwebb is omnidirectional, so no rotator required, and no tuner required on all bands. Note the spelling of cobwebb vs cobweb the original g3tpw was designed by steve webb, hence the spelling. My version is made up of a homebrew center hub and 5 fishing poles.
Cobwebb discussion, 4band cola antenna 20171510m, cobweb antenna construction details. Apr 24, 2015 the 5 bander cobweb antenna is a high quality designed antenna with products from europe. This link is listed in our web site directory since thursday feb 28 2008, and till today the cobwebb antenna has been followed for a total of 4589 times. If your main interest is dx, the 80 meter doublet is not a good dx antenna. Dx engineering 80 meter self supporting heavy duty vertical antennas, model dxe7580fsva2, are high performance vertical antennas specifically designed for the 7580 meter band. Hf dipole antenna this antenna software will help you design a simple wire dipole. The fibreglass poles have arrived for the cobweb antenna, these i suspect are fibreglass fishing poles but ideal for what i want and more to the point once i had removed the plastic ends with copious amounts of boiling water fit the metal sleeves perfectly. The list will grow with your help so lets start and share the knowledge. This was our first contact on 20 meter ssb using the homebrew cobweb antenna. You should consider a multiband vertical on that 7th floor roof, if roof is large enough to lay out several quarterwave radials. By using relays, a single feed line could be switched to 1 of 3 elements or to all for an omni position. Baofeng uv5r programming with chirp software or keypad.
Marcus jenkins is a freelance software engineer specialising in lbs, navigation, mapping and mobile. It looked like just the ticket so i copied the design and low and behold after a few evening work i finished it off. The design is the same as the low power cobweb antenna only using other materials to handle the load. Winter is rolling in here to western nebraska now, and to my surprise, i was finally able to hear north and south dakota qsoing during the a. Stations received at s34 were up to s9 on the cobwebb. The cobwebb is a five band 14 to 28mhz compact array of dipoles, bent into a square, almost omnidirectional and with unity gain. The cobwebb is a full size half wave dipole on each of the 5 amateur bands, 14, 18, 21, 24 and 28 mhz. The cobwebb is 5 separate full size dipole antennas, each bent into a square. The original frame made out of breadboards and aluminium plating. As the whole idea is to reduce weight on this new antenna i have to come up with better solutions than home brew breadboards etc. The cobwebb ticked the most boxes for me due to its 5band capabilities, reasonable size and not too tricky to build as its an omnidirectional antenna, i wouldnt have to faff about with a rotator.
The antenna was the brainchild of the articles author, c. My cobweb singlewire antenna build by tony breathnach ei5em. Over the past 15 or 20 years i have heard many good reports from users of the g3tpw cobwebb antenna. Antenna calculator for hf antennas ham radio secrets. Here is a simple antenna calculator for two popular forms of ham radio hf wire antennas. G3tpw cobwebb antenna for the 14, 18, 21, 24 and 28 mhz bands. Unfollow cobweb antenna to stop getting updates on your ebay feed. Computer modelling of this arrangement shows that one result of bending the dipoles is that the antenna is close to being. The weather here is still miserable, there is snow on the ground and it is very cold, so getting outside to play antennas is a bit of a no no at the. The antenna shown in the photo at the beginning of this thread is installed on a simple pole at 32 but if you look at the photo shown below, i have also used it a heights as low as 15. As an added bonus, the antenna is also resonant on 6m each dipole leg is made from twin cable and fed with 50ohm coax.
Cobweb ham radio antenna 6 feet off the ground youtube. Housed it in a grey pvc junction box and mounted a silverplated so239 on one end for the lmr400 feedline. About 5 band cobwebb antenna the resource is currently listed in in a single category. The other antenna was made by antenna specialist who are still in business and may still produce the super scanner. The design is the same as the low power cobweb antenna only. Cobwebb antenna projects category is a curation of web resources on, towertalk. I built a portable version of a cobweb antenna, it is based on a design by stephen webb g3tpw and my adaptation of the idea is to make it so that it can be collapsed easily and when required reassembled and mounted hopefully on a telescopic pole. Its multiband, omnidirectional and doesnt need to be located on a mahoosivetall mast to get decent performance. Way more information than you ever wanted on how to fell a tree.
Note peters plot of the dipole takes account of the effect of ground reflections which which fill in the theoretical nulls off the end of a dipole. The coax jumpers made the other 2 unactive elements. Design and adjustement is easy, as with the capacitor you can tune the resonance by some mhz with no effort. Reading a lot of enthusiastic stories on the cobwebb antenna originally by stephen webb, hence the webb and considering its dimensions i thought it would make a good compromise for my situation. Introduction the cobwebb is a five band 14 to 28mhz compact array of dipoles, bent into a square, almost omnidirectional and with unity gain. This antenna has superstrong large diameter fibergalss and heavyduty 14 gauge stranded hard copper wire. You can buy a complete cobwebb antenna, which can be purchased online from the web pages of steve webb g3tpw, the designer. Aug 10, 2016 cobwebb plan click for a larger image. After the success of my first cobweb antenna i decided to build a rigid version for my home qth, the design this time is based on one by g3txq. Here are my notes which should hopefully help anybody else heading down the same path. Click the view tab and ensure that the source is at the bottom of the antenna. Transmitter power gets converted to rf, not to heating the ground, coax, or matching network components.
I cant think of an instance where cobwebb barcode has failed. This antenna is built with pvc pipe as the spreaders, simple lampcord wire. The main category is cobwebb antenna projects that is about cobwebb antenna projects. Cobweb antenna and balun construction by amateur radio g3txq. This design permits the cobweb to be mounted at any height up a typical. Software modelling your vertical antenna ground radials with. About cobwebb revealed the resource is currently listed in in a single category. A cobwebb homebrew build by dave 2e0ddhm0mbd loughton. The cobwebb is a popular antenna due to its small size its a 5band hf aerial, under 8ft square, and is ideal for the small qth. Well, here it is, a few months after throwing the antenna up on a 25 foot pushup mast and i am still happy with it. Experiments with a homemade cobwebb type antenna posted on monday, july 8th, 20 by g4ddp over the years i have experimented with quite a few wire antennas at home increasingly to minimise the effect of the increasing noise level from the likes of plasma tvs, switch mode power supplies, plt and adsl routers but fighting a losing battle on hf. Experiments with a homemade cobwebb type antenna loughton.
Blue cobwebb red dipole so as you can see above, the cobwebb has more signal strength over a large majority of the antenna pattern when compared to a dipole. The cobwebb or cobweb aerial is an hf aerial for 20m10m and only 7ft square. Here is my setup for connecting to the mfj 259b analyzer that i have. Antenna calculator and design software electroschematics. The result is a much neater looking antenna on top of my push up mast. Cobwebb multiband folded dipole resource detail the. The actual field test, cobwebb antenna with the ft450 hf radio work well in blindspot, in addition to cobwebb antenna does not require the land to build a complex network system, set up. It has had 100% accuracy in the past 6 years since implementation. His cobweb is about door height and hes a lowpowered station. A noticeable improvement over the 4020 meter trap dipole. Yet even though the antenna takes up little physical space, the actual antenna elements on this design, are still actually full sized antenna elements anyways. Mfj1838, 1500w, 406m, super heavy duty cobweb antenna. Checking with antenna analyzer reveals resonance on 1020m bands, as well as 6m, 4m, 2m and 70 cms bands, as well as other nonamateur bands. The cobweb is a multiband hf aerial 20 through 10m of compact size and is almost omnidirectional.
Now head over to calculate and type in the freq box 7. Ultra light cobweb antenna is a very low cost multiband antena system. Mfj hf cobweb wire dipole antennas cover multiple bands and are suitable for many restricted space applications. The 5 bander cobweb antenna is a high quality designed antenna with products from europe. I built it from g3txqs tutorial posted on his website and used a pair of ft24061 toroids wound with rg316 teflon coax.
This hardware kit comprises a mast to boom clamp, a spreader clamp plate, central 1 inch diameter tubes, insulating fittings for the spreader arms and the necessary nuts and bolts pictured. G3tpw cobwebb antenna for 14, 18, 21, 24 and 28 mhz bands. This antenna beams into three quadrants without the use of a rotator. The most important design point about the cobwebb is that it is a completely horizontally. I was astonished that a cobweb isnt as bad as i thought it was, certainly in software modelling. However, the name cobweb came from his wife who said that the antenna looked like a cobweb. This link is listed in our web site directory since wednesday dec 26 2012, and till today 5 band cobwebb antenna has been followed for a total of 2712 times. About the cobwebb antenna the resource is currently listed in in 2 categories. I did think it was a bit heavy and was looking to repeat the build with some lighter weight wire until i came across this article from a wellknown antenna buff, g3txq. Antenna, ve3sqb ham radio antenna design software programs. The basic design is the similar to my portable version but this one uses a 1. The addon kit is intended for the current users of the original 5 band mfj1835 as well as the current mfj1836 6 band cobweb. See more ideas about ham radio antenna, ham radio and ham radio operator.
It is strongly made using fibre glass rods and comes pretuned, but is easily adjusted to ones own frequency ofread more. My design is based on the wellknown cobwebb antenna using standard speaker cable, however only one gamma matched dipole will be constructed for 11 m band use. Heres the antenna pattern when compared to a dipole. Feeding the antenna can be done at the director or at the reflector. The cobweb antenna meets the requirement nicely it comprises 5 parallel dipoles bent into a square shape and mounted on a support structure made of fibreglass poles. Last summer i built myself a cobwebb antenna and was fairly pleased with the results. Aug 08, 2016 dx engineering 80 meter self supporting heavy duty vertical antennas, model dxe7580fsva2, are high performance vertical antennas specifically designed for the 7580 meter band. I have a 200 ohm carbon resistor across the leads where you connect the antenna wires, then connect the core and shield of the 50 ohm coax to their respective wires. Com 0200 utc wed our program is also simulcast on famous.