CobWebb Balun Box

The CobWebb is a popular antenna due to its small size - it's a 5-band HF aerial, under 8ft square, and is ideal for the small QTH.  One of the issues for home-constructors has been how to cut+tune the folded-dipole elements.  Fortunately, G3TXQ came up with the idea of using single dipole wires and feeding the aerial via a 1:4 balun which transforms the 12.5-ohm aerial back to 50-ohms to match your transceiver.

Choose from our standard Balun or opt for the QRO version with increased power-handling.  Larger ferrites allow for higher power and/or continuous-duty modes like PSK/RTTY.

There are plenty of articles online about this balun and how it's built - but construction is not for everyone and it's certainly not a beginner's project so we've done the hard work for you.  This is a no-solder product and ready for mounting onto your CobWeb metalwork and spreaders.  The rugged box houses a 1:4 balun for use with the G3TXQ CobWeb design (the original, by G3TPW is known as the CobWebb) and is available in 2 version depending upon your power requirements.

• Standard: 2x FT140-61 and RG-316, approx 250-watt
• QRO: 2x FT240 and RG-316, approx 800-watt
• 2x 1" Stauff clamps for boom mounting
• 2x M4 screw-terminals (plus 2 sets of washers and lock-nuts) for wires
• Overall dimensions: 130(d)x90(w)x120(h)mm
• Overall weight: 660g (standard), 775g (QRO) - box is filled with potting compound for weather-proofing
• Fitting and tuning instructions supplied (once purchased, you can also access a PDF version from your Orders page)

This is not a complete aerial - You will need to add a mounting arrangement, fibreglass spreaders and 5 sets of dipole wires (we use CPC CB19907 on ours).  For the centre-fixing kit G4ZTR Aerial-Parts metalwork which includes a 1" boom that our balun slides onto, 22mm fibreglass spreaders from All Propped Up or Engineered Composites forms a complete 20m-10m HF aerial solution that can be assembled with a just a spanner, a pair of wire-cutters and an SWR meter or antenna analyzer.  You can read details of G4ZTR's own CobWebb build here.