Dual Band antenna for 900 mhz

[N4KVE]

Merry Xmas to all. I'm trying to have as few antennas on the car as possible, so I'm wondering if a VHF/UHF dual band antenna would work well on 900 MHZ since 900 is double 450. The antenna I'm using is a Diamond NR-770HBNMO, & 5.5 DB gain at UHF freq's. Would it work as well as a 3db 900 antenna & have decent swr or not? Thanks. GARY N4KVE

[Tom in D.C.]

Gary,

It's been years since I've had to recall this theory, but if I remember correctly it works so that the antenna cut for 450 will
not work well on 900 but will work okay and be resonant on 1350, which is three times the frequency of the basic antenna.
Thinking back to HF work, we always knew that a 40 meter antenna would work fine on 15 meters but not on 20 meters.
It looks as you'd need an antenna cut for 300.6667 mHz to get it to also resonate at 902 mHz and of course the 300 mHz
antenna probably would be of no practical use to you. Have you checked any of the catalogs for a dualbander that does
902 and some other band?

Regards,

[N4KVE]

Thanks Tom. None of the normal dual band antennas show to work on 900 except the Diamond D220 which is a mobile discone antenna. 2.15 gain on 144, 902, & 1200. 5.5 db on 440, but the antenna looks like it has 10 radials, so I think I'll just stick with my Dualband antenna, & 5 db 900 antenna. Besides, the discone can only take 50 watts, but I keep a TPL 100 watt UHF amp in the trunk when I need to talk to Miami from West Palm Beach. Thanks for the help. GARY N4KVE

[Pj]

I've tried that antenna (pretty sure) and other diamonds in outside of their rated bands, and I find that they do not play nicely (though you would think it would).

I have found that the Comtelco VHF 1/4 waves work very well as dual or triband antenna's. Currently I am using them with a diamond MX3000 on VHF/UHF/800 without any problems - cut for VHF in the 150 range for one, and 144.x with the other.