Saturday, October 23, 2010

Visit boat supplier for wire dipole supplies

A new wire dipole for 40m has gone up at chez marxy.


As it's suspended by the wire itself I decided not to use a balun in order to avoid the weight. The coax to wire joins are attached to a perspex sample square the local perspex supplier appears to happily give away. It's soldered and the whole lot is smeared with silicone bathroom sealant.


The wire is held at the ends with 3mm braided cord from the boating supply shop. They sell 100m for $30 and I find cord made for yachts survives the weather better than venetian blind cord.

At each end I have a pulley mounted on the house and tree.


Finally, for ease of fix and release, I've mounted cleats suitable for 3mm cord.


All this makes it very quick and easy to raise and lower the dipole.

This (no balun) wire dipole seems to be working extremely well, at least according to my wspr spots. I called back on 40m after the VK2WI broadcast  this morning and they clearly heard me better than I could hear them. Despite the lack of balun I'm not getting RF in the shack.

I notice that the resonant dip is very sharp but I got it resonant at 7.1Mhz without too much trouble.

All the bits and pieces from a boat supply shop are tested on ships at sea and seem far superior to the stuff I get at the local hardware store. The tension on an antenna is much less than what a sail causes and the ability to survive salt air means that it will last in my yard.

3 comments:

Alan Yates said...

Very nice, I like the quick-release cleat!

long island used boats said...

Well done Peter. The knot installation was good excellent. Your boat will be safe now.

Peter B Marks said...

Clearly spam but it made me chuckle.