I'm not sure about noise. Running power to the battery was a good idea to stop engine noise. If you have an ANL (Automatic Noise Limiter) on your CB i would try turning that on. My super basic Uniden 520XL has one so you probably have one too.
To get better reception your best bet is a longer antenna. That's a huge factor. I think the firestick FIREFLY (not other stiff models by them) are the best. You can get one 4' long and they bend like 90 degrees. You don't really need a spring with them.
For best performance you want:
-It as high as possible
-As long as possible
-And at least 1/3 of the length over the roof line.
From FAQ: CB Radios and Antennas | Right Channel Radios
Which CB radio will give me the best range?
All stock CB radios are limited by FCC regulations to 4 watts of transmission power. Accordingly, all radios will have the same output power regardless of their price. As all radios are limited by this bottleneck, the largest determinant of performance is antenna quality and installation. We’ve written an entire article that discusses antenna and mounting location selection which addresses important factors for getting the best performance possible from your CB system. This article is titled Choosing a CB Antenna.
Here they give you some numbers CB Radio Range Approximations | Right Channel Radios
Of course in hills and trees it's going to be a good amount less.
Single Fiberglass Antennas
- 2' Length: 2 to 3 miles
- 3' Length: 3 to 4 miles
- 4' Length: 4 to 6 miles
- 5' Length: 5 to 7 miles
There are places that can "Tune" your CB. Usually truck-stops from what I have heard. Basally they can make your CB transmit higher than the legal FCC range. I personally don't think that it would be necessary, and is more a trucker thing to do. Also it can annoy others by having too strong/loud of a signal. It seems like the Galaxy are one of the more "tune"-able cbs from the threads I have read though.
You need to tune your antenna's SWR if you haven't already.It can destroy your radio if you broadcast skipping that step, and you'll get bad reception.