I recently bought the new ADS-B antenna from DPD Productions and have it mounted on my roof, about ten feet above the rooftop. Absolutely outstanding antenna for Radar Box, it gets way better coverage just running into my 45 feet of LMR-400 than the three other antennas I have tried using with the mast-mounted Elad Pre Amp. I have now just taken the pre-amp down completely as this antenna works better without it.
Link:
http://www.dpdproductions.com/page_vhf_air.htmlScroll down to very bottom of page for pictures and complete info on the antenna.
I do not know if he ships out of the U.S.
Cost is about $86.95 and I have had numerous email exchanges with Dave, the owner of DPD and he is very responsive and really knows antennas. I also have his LP Miltenna for UHF and it too provides amazing performance.
For ADS-B before I never could "see" below 6500 feet before and am now seeing down to the runway at close airports and as low as 500 feet at KLAX, despite the mountains all around me. Traffic increase is big and range is much improved.
I'm not affiliated with DPD in any way just passing on a great product finally here in the U.S. that doesn't cost a fortune or need amps, etc.
Previously I have used the RadarRama, the 1050 antenna and the very expensive MyDEL BS1100 all mounted at the same height, all ran through pre-amp. Results varied from ok to poor. (I still cannot get any support for the Elad pre-amp or diplexer, short of sending them to the U.K. despite the $365 price.) Wish I had found this antenna before shelling out a fortune on seriously over-priced, underwhelming antenna systems and pre-amps that somehow start rusting inside after a week in Southern California with no rain! Sorry - end of rant. :-)
Just passing this along - hope it's helpful for anyone having trouble finding antennas in U.S.