I noticed when I'm scanning Wilshire Simplex (506.9625) on my Uniden 396T, I'm getting crosstalk with another frequency and it's very annoying. How can I eliminate it? Does it have anything to do with my Diamond 130J Discone antenna on my roof?
506.9625 is Wilshire "base" (dispatch), and Wilshire "simplex" is 484.55. But either way, there are some ways of reducing interference, but they all more or less depend of the cause. Depending on the model of scaner you have, if it's not an LAPD frequency and you can use the NAC setting, that may help block other users. I don't now the 396T's features, but if it has an attenuator, turn it on for that frequency, but that will probably block weaker Wilshire units that you DO want to hear. Or try adjusting the squelch knob tighter, which will have a similar effect, but it's global for all frequencies whereas most scanners' attenuators are selectable on a per-channel basis.
Since most scanners have less robust selectivity than commercial grade radios, your discone up on the roof may be a sort of double-edged sword. It brings in weaker and more distant frequencies that you do want to hear, but by the same token it's also prone to bringing in more "junk" that you don't want. The quick way to replicate that most dramatically is to unplug the roof antenna and use a rubber-ducky or other inside antenna.
I know I'm forgetting other possible solutions, but those may be of some help. If the source of the "crosstalk" is close to you and strong enough, you may just have to put up with it.
