I have a very small back garden and am limited with what type of antenna I can use. I built my first antenna in July 2004. If you are looking at this after speaking to me, you know it works. It is basically a 5 band antenna comprising of 5 full half wave dipoles for each band – between 10M & 20M. As an added bonus, the antenna is also resonant on 6M!! Each dipole leg is made from twin cable and fed with 50ohm coax. It is Omni directional and cost about £40.00 to build. I don’t know how much power it will take except to say it comfortably handles 400 watts, although I usually only use 50 watts. I used an MFJ-259B to help tune the antenna – this proved invaluable Below are some pictures that may help anyone considering building an antenna of this type. You are more than welcome to email me if you want more info.
Antenna Construction tips
| Band | Overall Loop (suggest you cut 15-20cm longer to allow for band adjustment.) | Each leg | Short point |
| 10M | 508cm | 254cm | 156cm |
| 12M | 586cm | 293cm | 179cm |
| 15M | 690cm | 345cm | 208cm |
| 17M | 812cm | 406cm | 222cm |
| 20M | 1030cm | 515cm | 272cm |
*(suggest you cut 15-20cm longer to allow for band adjustment.) Each loop is made from figure 8 speaker cable. The ends of each loop are folded back on themselves to adjust resonant frequency as well as providing an anchor point for the loop. The ends have been left approx. 3″ apart from each other, but are joined together using cable ties. Click here for a handdrawn diagram with additional fine tuning info (approx 254kb). Here are some of the countries I have reached using this antenna mounted approx. 15ft high over a 6 week period (between July and mid September 2004) using about 50 watts power. When next I get the time I will update this image to 2005 stats.
**Update July 2005**
I rebuilt the antenna using white fiberglass poles, white twin speaker wire and a white junction box. A good friend of mine, Pete – 2E0PRP, welded up the quad bracket.
The result is a much neater looking antenna on top of my push up mast. 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. The table below shows the SWR / bandwidth with the antenna about 15ft high. As you will see its’ turned out quite well – but you have to decide what mode you want as the antenna has not got a wide bandwidth. The pictures below show the revised antenna.
| Band | Low Point SWR | Mid Point SWR | High Point SWR | Bandwidth | |||
| 20m | 14.024 | 1:1.6 | 14.090 | 1:1.0 | 14.151 | 1:1.6 | 125Khz |
| 17m | 18.081 | 1:1.6 | 18.115 | 1:1.3 | 18.190 | 1:1.6 | 110Khz |
| 15m | 21.000 | 1:1.6 | 21.044 | 1:1.0 | 21.099 | 1:1.6 | 99Khz |
| 12m | 24.872 | 1:1.6 | 24.931 | 1:1.1 | 25.000 | 1:1.6 | 125Khz |
| 10m | 28.484 | 1:1.6 | 28.406 | 1:1.0 | 28.325 | 1:1.6 | 160Khz |
| 6m | 50.110 | 1:1.5 | approx 100Khz |
Copyright MOMRR
Hello Simone,
nice writings about this odd antenna! I wonder if you have some formulae about the T-matches positionning (spacing) to understand all dimensions provided?
The goal for me is to add two or three more bands : 40m, 30m and 6m, what do you think about? May I find mean to correctly place the shorts on the legs of these added wires?
Thank you for any advice and hope to see on air!
73 QRO DE DIDIER – F4ISC
Thank you for the great information on the Cobweb antenna. I now live in a strict HOA community and am wondering if this would work if polarized vertical. I have room to install this in my garage attic but it will only fit standing up. The other way I could get it to fit is if I mount it as a sloper. Have you had any experience with either? I am retired and finally have time to play radio only to have the HOA police on my tail. Any thoughts on this would be greatly appreciated. Thank you,