Can sonar interfere with VHF signal

[Brian Dinsley]

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.

Thoughts???

Thanks, Brian D.

[chewy]

In an ideal world you wouldn't run power and signal cables next to each other.
In industry you actually use seperate cable tray to seperate them.

Let us know how you get on.

[Brian Dinsley]

Well I tested the unit on my driveway using the handheld VHF and with the sonar switched on. The sonar obviously isn't the problem since I got perfect reception and transmission. So, I pulled on the antena to make it waggle from side-to-side and then tried to transmitt. Sure enough, the transmission didn't work until the antenna stopped waggling. So, it looks like I've either got an antenna problem, or a bad connection to the antenna.

The antenna is a VTronix Rib Raider and I've seen poor reports for this product on this web-site. This is the second Rib Raider I've tried. I'll check the bullet connection and if I still have problems, I'll get a new antenna.

Any suggestions for a good quality brand and model?

Thanks,

Brian D.

[willk]

Originally Posted by Brian Dinsley

The antenna is a VTronix Rib Raider and I've seen poor reports for this product on this web-site. This is the second Rib Raider I've tried. I'll check the bullet connection and if I still have problems, I'll get a new antenna.

Any suggestions for a good quality brand and model?

Thanks,

Brian D.

By all accounts they're pants. I've seen them just snap off too. Most of the ribs in these parts are using Glomex Powerboat 1.1m antennas, probably for max range as opposed to looks. I like mine - clear comms from Islay to Malin Coastguard.

[DJL]

I've just, after many years of putting up with V-Tronix aerials, replaced my RIB Raider with a Pacific SeaMaster Pro. So far I'm very impressed with the Pacific kit.

http://www.pacificaerials.co.nz/Mari...ProSeries.aspx

I'm using the through-deck mount with 0.45M Heliflex due to height limits on the drystack where I keep the boat, but I also have the 1m UltraGlass to fit when on longer cruises. The heliflex wobbles around a lot less than the rib raider so I suspect it will last. Even if it doesn't its only £16 for a replacement.

I bought mine from Mike (MikeCC) at allgadgets.co.uk - great service and he had all the parts I needed in stock.

[mark-f]

Originally Posted by willk

By all accounts they're pants. I've seen them just snap off too. Most of the ribs in these parts are using Glomex Powerboat 1.1m antennas, probably for max range as opposed to looks. I like mine - clear comms from Islay to Malin Coastguard.

Yep I'm with Willk on this one, I have had a Glomax on my last two boats and never had a failure once prior to that I had three rib raiders in 4 years just make sure you get one with a mount that allows you to fold it down when towing and you will be well sorted.

Mark

[Brian Dinsley]

Thanks for the input guys..

Cheers,,, Brian D.