AWK Cobweb antenna parts
Recently I decided to take down my Western HF-10 multi band dipole, actually scrap that, a fox did the work for me and chewed through the kevlar guy ropes supporting it. They saved me a job really – just in a slightly less elegant way!
I’d contemplated a Cobweb antenna for some time, they have near the efficiency of a multi-band fan dipole, but seem to have some magic quality, which means you can get a good low angle takeoff, without having the antenna far off the ground. How this works, I don’t know – maybe something to do with the arrangement of the elements?
The finished Cobweb in the air
It’s essentially a multi-band fan dipole, but wrapped around fiberglass spreaders in a square arrangement, this means I can have access to 7 bands (20m, 17m, 15m, 12m, 10m, 6m and even 4m), with only a width of 2.7m on each side. It’s also omni-directional, which saves the hassle of a rotator.
I investigated building a Cobweb antenna, but eventually decided on buying one for £200 from AWK Antennas, a Polish amateur on eBay. The metal wrangling was the bit I have neither the tools or the skills for!
Here’s the video of putting it together and testing it with the NanoVNA:
So far I’ve had it for one week and I’ve worked Alaska, West Coast U.S, Mauritania, Lebanon and Saudi Arabia for all time new ones. It definitely works better for long distance DX than the Western HF-10 it replaced! The build quality seems really good and it’s really performing just 5m above ground.
NanoVNA sweeping the 17m band
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Hello…been watching the cobweb video, and looks very small and nice for a small garden, my question is, will it load up on 40 m…7.030 with a ATU. if so how does it perform if you have tried it….Martin.G0MVP
mjisted@btinternet.com
Hi Martin,
I have not tried this yet, but as I don’t have anything up for 40m I may well give it a go!
73 James M0JCQ
did it come with the mast?
great video by the way
mark M7RKN
Thanks Mark, no the mast was an existing one I had already.
73 James M0JCQ
Hi mark again mine came today . and only 12 and 15 will tune on my 7300 .the rest are well over 3:1 .i got a nano 2 just waiting for some 239 to sma’s . im brand new to all this. Any tips . although im sure its all in your great video . regards mark M7RKN
Hi Mark,
That’s strange, all the specified bands should be within 3:1. How high up do you have Cobweb? Is there anything else nearby which might be interacting with it?
Once you get the Nano VNA on it you’ll be able to see the real resonant points for the lower bands. I’d expect it to be narrow on some bands, so you might want to tune that element according to your preference (CW/SSB/Data).
73 James M0JCQ
James, that cobweb antenna looks very suitable for my small garden. Does it need an earth below the mast or does the coax come straight back to the radio which is the only bit earthed? The reason for asking is most of my garden is rocky and creating an earth is difficult.
Hi John,
It doesn’t need an earth, the coax comes straight back to the radio.
73 James M0JCQ
Hi yeah i have it in the loft . and the measurements provided (only for 20m) would mean i’ll have to cut some off the ends if i want it to appear like it says . im reluctant to do that . still waiting for bloody plugs ! Arrghh
It’s possible there could be something near in the loft which is detuning it.
You can try bringing in the resonance by simply folding back the ends (instead of cutting them), this is a good and less permanent way of tuning. It’s easy to trim, but hard to reattach 😉
73 James M0JCQ
Hi Martin
Do you know what the gain is?
May have to put one up to be compliant for emf
73 Mike G3ZCC