I've constructed a new antenna for milair listening - its wideband and covers 230-400MHz ish. It beats hands down a discone and was a lot cheaper than anything I could have bought. It's enclosed in some 50mm PVC pipe for neatness, and is complete with a professional 'N' socket for feeding with low-loss coax.
I'm now in the process of manufacturing these for sale, so if you're interested, drop me a line!
I also make and sell simple 300MHz (or cut to your frequency) end fed antennas... not quite as wideband as the milair one, but cheaper and will work nicely over most of milair, with slightly degraded performance elsewhere.
£30 with an option for a feeder (extra) and your choice of plugs