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Well after doing some digging around i found a site AWH: See How Different Scanner Antennas/TV Antennas Rate!

They said quote "# Radio Shack: All-Band Magnet-Mount Mobile Scanner Antenna (cat.# 20-032)
25-1300 MHz receive coverage - 34" high - BNC connector.
Also for transmitting (up tp 25 watts) on 50, 144, 220, 440, amateur bands. RG-58 cable can be easily replaced with RG-6 or RG-8 for improved performance. Antenna elements can be cut to better tune the antenna for the scanner bands, instead of the ham bands. See this site for more information: Bear Wires Electronics (even though it lists the model number as Radio Shack #20-012 it is the same antenna)."

Well, that is the famous "discone" biconical antenna that was developed, I think, in the 1940's or thereabouts, for wide-band reception. I recall that it was intended for use in aviation. I put one about 40 feet off the gound
on the roof of my QTH about 20 years ago as an alternative "listening" antenna, and I've tried using it to Xmit on HF, VHF, and UHF. In no cases did it perform as well as my "regular" antennas for these bands. It's basically a compromise antenna. I mean, did you really think you could get a small antenna to cover 25MHz to 1.2GHx?

Here are some of the problems: The discone may be "omnidirectional" but has zero gain. It may bave an SWR of <2.5:1 over a wide frequency range, but do does a 50 ohm resistor...SWR is important in keeping your rig's finals happy, but it says nothing about how your signal gets out. Even on VHF and UHF, where this antenna is supposed to perform best, you will get out better with a properly tuned J-pole or mag-mounted ground plane vertical.

IMHO, the discone is acceptable as a broad-band scanning antenna if it is mounted high enough and in the clear, and if you just can't set up anything else...

Been there, used that on 2 and .7. Not the best but works ok.
Rich

I have used discones in one configuration or another for about 20 years.Some problems seen with discones may be due to the fact that the angle of radiation is near zero.The main lobe is aimed pretty much straight out. This makes it bad for working mountaintop repeaters from a low area or working the valleys from a high area. Tall buildings tend to get in the way also. When mounted in a decent location and working or listening to a distant station that happens to be in the main lobe of the antenna the discone does in fact perform quite well. The problem is of course,that only a small percentage of stations are in the antenna's sweet spot.

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Front/back ratio comes from the antenna. Forward gain comes from the wall socket.

the antenna in the first post is fine as a ham antenna. if you look on the specks page is states scanner/ham antenna as well as on the package. if you actually go to the store and look it has the freq's it works on listed on the package.

If any of these antennas are primarily for use with a scanner, then they will probably work just fine. If they are going to be used for transmitting, then they may or may not be better than nothing, you just have to judge that for your self (use it, or get/make an antenna for that transmitting). I can say that I have used one of the mentioned antennas on 2 meters with no problems. Wasn't the best, but it was certainly better than the alternative I had at the time. ('Rubber Ducks' are fowl antennas! , I like that one!)
Considering the cost of the things you'd need to make the equivalent of these antennas, I think I'd invest in a soldering gun. It ain't easy being this cheap! Keep that in mind.
- 'Doc