Is RF return a form of noise I am hearing or is it something else?

[KF7NUA]

Curious about something, I have bonded bonded and mix 31 everyhing I can think of and I still have some noise, it is not engine, ignition, fuel related or whining or even pulseating, just a noise hash......
Sometimes during the day it is louder than other times.
If I disconnect the antenna it is quiet.
If the motor is off it is still there, it never goes away completely.
I just bought another 10 pcs of braided copper tinned straps and I will see what else I can bond togeter.
Being a 1 year old ham operator I am not sure if what I am hearing is atmosphere noise or just band noise but there is something I just thought of.

Can a coax that is attatched to another radio VHF\UHF cause RF or RF return on a HF radio if the coax to both radios are near each other inside the truck, this coax has NO mix31 splits on it anywhere?

Can a coax that is attatched to a spare antenna mount with NO antenna mounted on it cause RF or RF return on a HF radio, this coax has NO mix31 splits on it anywhere?
What about if the coax to both radios and the 3rd empty coax are near each other inside the truck?


I have Mix31 splits on the HF coax but not the other 2 coaxs coming from other locations to the inside of the truck?

[M6GOM]

You are hearing normal atmospheric band noise.

[G8YMW]

The Sun has been pretty active this last week (Quietening down now) with a few "M" class flares one of which (at least) produced a burst of noise caught by an amateur astronomer on 21 and 28 MHz.

http://spaceweather.com/

[NO2A]

Hash could also be your truck`s onboard computer.

[K1CJS]

If your rigs are isolated from the truck ground, you may have ground loops through them.  There is an easy check--just disconnect the antenna and the power harness from the second rig.  If the noise lessens or disappears, then you've found your answer.

Another thing that you can check is the vehicle exhaust system.  Is that bonded to the vehicle frame?  If not, do so.  That may lessen the noise too.

[KF7NUA]

Thank you all that have replied.....

You are hearing normal atmospheric band noise.

I would hope this was it but still not sure, I guess time will tell.

The Sun has been pretty active this last week (Quietening down now) with a few "M" class flares one of which (at least) produced a burst of noise caught by an amateur astronomer on 21 and 28 MHz.

http://spaceweather.com/

A friend said the same to me but today it seemed worse for noise.

Hash could also be your truck`s onboard computer.

That would be one of the only things/wires that does not have any split beads mix31 on it. I will check it with a am\fm\sw sniffer and see if it is the problem, thanks....

If your rigs are isolated from the truck ground, you may have ground loops through them.  There is an easy check--just disconnect the antenna and the power harness from the second rig.  If the noise lessens or disappears, then you've found your answer.

Another thing that you can check is the vehicle exhaust system.  Is that bonded to the vehicle frame?  If not, do so.  That may lessen the noise too.

My HF radio is grounded but now that you mention it I am not sure about the 2m/440m, I will try your suggestion and see what happends.