I have yearned for a WT-4a for years, but could not bring myself to "fork over" the $700-800. Recently, I came up with an approach that seems to work (for me anyway). It's a bit more than the $50 DIY that I have seen on the net, but it has a lot more range and easily covers a space equal to the typical football/soccer field (and then some). It is all done with "off the shelf" parts, and does not even "require" any soldering/repackaging (although there might be some advantages in doing that in the long term). Take a look at my posting a Flickr (http://www.flickr.com/groups/diyphotographynet/discuss/72157625174713209/) and let me know what you think.