Whistling receive

Hey cb guys,

I like to think that I'm not ignorant of many things, but when I am, I ask.

So here's the equipment:
Cobra 29 (stock, no tune)
Firestik 2 4' (because I can't find a 5')
K40 mount
Wilson spring
Wilson mirror mount perch
18' K40 coax
External visor clip speaker
Mounted on company cascadia passenger side through the door
Swrs 1.5 across the bands (external meter)
Range at least 2-3 miles, clear transmit.

Issue:
With rf gain all the way up sometimes i get a persistent high pitched whistle that isn't very loud but is annoying. I was wondering if this is a symptom of a problem or if it is normal to accompany the regular static.

Also wanted to know if there is a way to tune the radio to reduce the static and pick up the faint voices better.

Thanks in advance.

 

I'll try to remember next time it does it while not driving.

Any theories or potential reasons why it would do that until then?

 

So likely something electronic in my truck interfering with my signal. I was hoping it wasn't an issue with the radio itself.

What about tuning it to reduce the static noise but also gaining clarity on actual transmissions on the band, is that possible?

 

Hearing the whistle seems unrelated to whether or not others are transmitting. The sig meter wouldn't move, and it does it either way.

 

No one has ever complain about my noise in my transmission. I don't know for sure if it has happened with the engine off yet. It seems to be intermittent and temporary only.