hello i have a uniden SC150B police scanner with a standard rubber ducky antenna and i want to buy a better anteena first off what kind of conector does my antenna have and second are there any reputable sites on the net where i can buy an antenna for my scanner
One key piece of information you failed to supply is what frequency/frequencies or band/bands to you monitor (note I'm not asking what your radio covers, that's not important unless you actually listen to the full range, most folks don't). This is important since an antenna is frequency dependent. A great antenna for the 800 MHz band (think 850 - 900 MHz here) will work quite poorly on the VHF-Low band (think 30 - 60 MHz here) and vice-versa.
Be aware that most of the antenna specs you see are written by two totally different types of folks, the engineers (where does the antenna actually work well) and the marketing folks (just how many bands can we say it works on without outright lying, misleading is just fine). The engineer may design an antenna to work on the VHF-Hi (think 140 - 160 MHz here) and UHF (think 430 - 500 MHz here). This is where the antenna will actually work well. They pass it on to the marketing folks that say it will work from 50 - 950 MHz so it will look like it matches pretty well with the range most scanners, their target audience, work. That antenna will work well on the VHF-Hi and UHF bands as designed and yes, it will work on the other frequencies as advertised. You may need to be standing right under the station's tower to hear it, but it will work there. The key may be where the antenna will transmit on (not that you plan to transmit, but that's where the antenna is designed to work well) since those numbers are much harder to fudge.
Don't get confused by someone saying that their antenna is designed to work with the "new digital systems". OK, while that may be true, the antenna doesn't actually know if the signal is analog, digital, TV, morse code, or a signal used to trigger an automatic door opener at a grocery store. If the signal is on 156.7890 MHz and the antenna is designed to work on 156.7890 MHz it's a good match! If that same signal is on 156.7890 MHz and the antenna is designed to work only on 789.1234 MHz it's not a good match.