just a word of advice-i went and purchased a mag mount antenna-turns out that the "rubber duck" furnished by uniden- is far better-at least where i live.so,my advice is- stick with what they give you. works for me,anyhow
I am sorry that your new antenna hasn't improved things for you. The HP-1's stock antenna works pretty well for me. It's just a little finicky at times. I guess we have to put up with it. Really, I can't complain. It does a good job.
I once posted a question here about a replacement antenna and received a lengthy dissertation questioning my question, if that makes sense. I resolved to never ask a question on here again. I'll research my own questions and find out for myself without posting something here. I prefer to offer assistance, if I can, rather than ask any questions. Sure, asking others can be helpful, but when those you ask reply in a manner that makes you feel stupid for having asked, that's not good.
Have you tried placing the mag-mount antenna on a large pizza pan or other large metal item.
Top of the fridge or a file cabinet would be good also.
I heard that it may improve reception by acting as a ground plane for the antenna.