I will share my experience since it may help but also because I am open to advice.
I have an 802 with a whip antenna
. I hear what I think is excessive noise
. I have been told that if the background noise is a constant 3 bars, as it is, at just over 10 Mhz, I have excessive noise. I am not sure that is true?
I have turned off everything, except the circuit driving the radio
, and still have the same 3 bars. Even when I am away from shore, I pretty consistently have 3 bars.
I happen to own a second 802 (both were brand new, factory sealed when I purchased). I hooked it up temporarily, using a dedicated power supply (120v - 13.8v converter), but I still used the installed system's ground, AT140 and antenna
. Perhaps it is relevant to note that I put the replacement 802 on the flybridge, about 4 feet from the AT140, while the original 802 is in my pilot house helm
. The coax from the original 802 to the AT140 runs through a 3" diameter conduit that is stuffed with wires -- it is easy for me to imagine that my original 802 is picking up RFI interference there. It is also easy for me to imagine that the original 802 is picking up interference from all the wires that are connected to / run parallel to / the 12v supply. In any event, I get 1 or zero bars with my new temporary installation
At this point, I need to decide whether to go with the new unit on the flybridge, or to continue to swap parts
and locations in and out until I locate the problem. It could be that I have a bad 802 in the original location (right)? The biggest problem of moving everything upstairs is that although I can run my pactor modem
(7800) from the pilot house with a blue tooth connection, I will not be able to look at its screen
(which presumably is providing useful information).
BTW, unlike OP, I am able to make airmail / winlink connections at stations from 100 to 600 miles away (but not consistently).