I recently was given a new ICOM IC-A24, and I wanted to upgrade from my JHP-520 since I was having some trouble with the tower responding to my transmissions. The A24 is also bit easier to read with the larger display and buttons, and it has a 12v battery option to connect to a SLA battery that I use to power my GPS.
I tried the IC-A24 today, and it works great with the engine off. However, once I get the C-85 running the radio picks up noise that interferes with the reception. I put the JHP-520 back in and its fine. I do not have shielded spark plugs in the C-85. The IC-A24 cuts out every 10 seconds too so maybe its a bad unit? Ah - I just pressed Function WX-Alert, and it stopped cutting out every 10 seconds.
The antenna is just a 50ohm coax cable routed under the back seat, and an BNC adapter M/M adapter sticks out through the fabric under the belly. The antenna from the radio is then connected outside to the adapter.
Any ideas why the ICOM IC-A24 picks up so much noise and the JHP-520 doesn't? Maybe the ICOM is a bad unit?