Can sonar interfere with VHF signal
I bought a new RIB last year. I had a Icom marine VHF and a Garmin 550S installed as part of the package. Ever since I took delivery of the boat I have had problems both receiving and transmitting. Sometimes I can not transmitt at all, other times the coastguard can receive my signal, but with difficulty.
I bought a hand held back-up to test the installation. With my boat sitting on my driveway I can transmit to and receive from the boat from several hundred metres away, even loosing line of sight to the boat. However, when I get out to sea, I find that I can't contact the coast guard with the ficed VHF (Icom IC-M411). I've tried both high and low power, but to no avail.
I can't understand why it works fine while siting on my driveway, but then won't work at sea. Then it dawned on me that when I've tested on my driveway, the sonar/ GPS is not switched on. The sonar transducer cable runs alongside the VHF coaxial cable and as the cables are routed over the transom, they are actualy lying right next to each other for a ~600 mm route length.
Is it at all feasible that the sonar signal is the culprit and that rerouting the sonar cable will fix it? I plan to test this tomorrow evening on my driveway. Use the handheld to contact the boat radio, then switch on the sonar and see if I loose signal.
Thanks, Brian D.