GRA-D220R 144/440/900/1200MHz 2M/70cm/33cm/25cm Mini Discone Multiband Wideband Mobile Scanner Antenna, 29.53 inch

Q: Is there a fixed/base mount available?

I bought this antenna and used it for base station for my scanner. I bought a TV antenna mask for approximately $18 that mounts to the side of my house. I then purchased a SO-239 3/8 mount attach that to the TV mast and mount the antenna on the SO/239. If you're looking for a better quality antenna that's all stainless steel comes with a mast and 32 ft of coax cable has a wider transmit receive range with center loads built in as I have recently purchased and it is a much better performing antenna check this one out much easier to mount as well. GRA-D3000 75MHz-3GHz Super Broadband Discone Scanner Base Antenna with 32.8ft RG-58A/U Cable

Q: What frequency range would be effected if the vertical whip is left off?

Without the vertical whip, it probably won't do as well below 200 MHz.

Q: Do you need to ground this antenna for outdoor use.

You would want to ground the mast the antenna's mounted on, which will in turn ground the antenna. However, this antenna isn't designed for mast mounting. It's primarily a mobile antenna designed to go on a UHF type mount.