Hello.
I just joined the forum today so please excuse me if this subject has already been covered.

What I have is a quick method of building a very precise slotted waveguide antenna out of easily obtainable cheap materials and a free design program hlssa61e from Australia http://apache.airnet.com.au/~fastinfo/wire...ss/slotted.html

The basic materials are Styrofoam (the high density exterior house insulation type - typically blue) and heavy duty aluminum foil (the kind you wrap turkey's in for baking/BBQ).

With a veneer blade fitted to my circular saw, I cut the Styrofoam into precise 30mm by 90 mm strips and cut to length for the number of slots you want.

The aluminum foil is attached to the Styrofoam with spray-on contact cement (choose a kind that does not dissolve Styrofoam ) This gluing step takes practice and patience to get a smooth durable bonding. Make sure that the ends also have a smooth bonding.

Now mark the aluminum with a thin marker pen and cut the slots with an Exacto-knife.

For the signal receiver I use 1/4 inch copper tubing soldered to LMR-400 cable center wire. The length of the copper tubing is about 26-27 mm (just less than the 30 mm guide thickness). A clean hole for the tubing is cut into the waveguide with a flush ended drill bit (you don't want to puncture the aluminum foil on the back side). The tubing is inserted into the drilled hole and the LMR-400 braided shielding is flattened out into a disk; soldered to give it rigidity; and attached to the aluminum foil around the drilled hole. The best method of attaching that I have found is Crazy-Glue.

The antenna is ready for testing but is too fragile for normal use. To protect the antenna from abuse and weather, I use a 4 inch plastic drain pipe (the 30 mm by 90 mm cross section fits nicely); a plastic electrical box connector to fasten the cable; and end caps for the plastic pipe.

I have made and sold uni- and omni-directional slotted waveguide antennae from 4 and 4+4 slot to 20 and 20+20 slot using this construction method ( at the moment, I have a 4+4 omni listed on eBay http://cgi.ebay.ca/ws/eBayISAPI.dll?ViewIt...gory=45003&rd=1)

Larry