Building a Cobwebb

[David]

I finally started "doing" amateur radio. I'm building a Cobwebb. I thought I'd share the Cobwebb resources I've found with you.

Here's the designer's site: http://www.g3tpw.co.uk/

He sells them commercially and I reckon they're worth the asking price from a materials and labour point of view. I'll let you know if I think it's worth it from a performance point of view once I've finished and got it up.

Here's a pdf that someone put together when they reverse engineered (copied) it: http://test.g0mtd.co.uk/CB1.pdf

I think there's a mistake in it. The wires for 17m are listed as 4400mm long. I think that's supposed to be 4040mm but I've cut to the long length and will cut back just in case.

The cheapest place I've found for the speaker cable is Screwfix: http://www.screwfix.com/prods/24221/...ker-Cable-100m

I'm using the hub and poles from Amtools UK: http://www.amtoolsuk.com/antennapoles.html

You get a discount if you order the poles and hub together. They're not as strong as the ones used on the commercial version but if you're on a budget then you get what you pay for. You can source glass fibre rods and tubes to the same spec as the commercial version. The specs are all in the pdf.

A suitable enclosure for the feedpoint is available from Maplins: http://www.maplin.co.uk/Module.aspx?ModuleNo=43708

As are the chocolate blocks: http://www.maplin.co.uk/module.aspx?moduleno=42654

Although they'd certainly be cheaper elsewhere.

The only other bits and pieces you'll need are screws and cable ties (get some reusable ones for the tuning phase) which you can pick up from Screwfix and some coax for the air cored balun. The Amtools hub mounts on the end of a 1" TV aerial mast which you can also get from Screwfix while you're there.

I made a start last night cutting all the wires. I've made a start on triming them and cutting the gamma match points but it's quite slow going. I appreciate where the money goes on the commercial version now

Sorry all the supplier links are UK-centric and yes, I have rather fallen in love with Screwfix

[graysclassics]

David, Sounds very interesting - thanks for the info. I was going to build a full wave 80m loop, now I'm not so sure! Let us know how well it performs when you finally get it installed. Gordon G1NOR