How hot does a fixed VHF get?

jgrace · 19 March 2006, 10:17

My current dinosaur of a VHF is in a box attached to the back of my rib's double jockey console, which is pretty useless for anything except emergencies. I want to have the new unit within convenient reach as I drive but the console is too small to fit any more kit onto it.

The only possible way I can see to install a new radio is to remove the first 4 inches of the jockey cushion (which is never sat on anyway), replace it with a horizontal console panel and drop the unit in vertically so that it's facing upwards.

However, that means the back of the radio is quite close to the fuel tank. And as all fixed VHF sets seem to have heat dissipating fins at the back, perhaps this isn't a very good idea. Does anyone know how hot a fixed VHF can get? I'm guessing the worst scenario is heavy use at 25 watts in a mayday situation. If I was already in trouble I wouldn't want to be worrying about blowing up the petrol tank as well!

archie720 · 30 March 2006, 14:22

If I were you I would save myself a lot of trouble and just get a hand held vhf!

roycruse · 30 March 2006, 14:39

Or do this - although I wouldn't recommend doing it with a Silva S10 like I did (they are not very waterproof) should be fine with a icom though.

jgrace · 30 March 2006, 16:20

Quote:

Originally Posted by archie720

If I were you I would save myself a lot of trouble and just get a hand held vhf!

That would certainly make life easier, but I'm still kinda set on getting a fixed set. There's already a whip aerial on the boat, plus in the wide open spaces of the West coast 25 watts is somehow comforting.

Quote:

Originally Posted by roycruse

Or do this - although I wouldn't recommend doing it with a Silva S10 like I did (they are not very waterproof) should be fine with a icom though.

Very simple solution! Does it not get knocked, though?

DJL · 30 March 2006, 17:00

Handheld is ok, but reception isn't anywhere near as good as fixed.

You shouldn't have any problems with the radio that close to the fuel tank. The heat sink shouldn't get that hot, not any where hot enough to ignite petrol anyway (200 ish degrees).

Although if you blow yourself up don't blame me..

jyasaki · 30 March 2006, 17:48

Standard Horizon (if they're available over there) makes a "Black Box" VHF; you mount the black box inside somewhere, and the only thing exposed is the mike and cable (and antenna, of course.)

PS1000 and PS2000.

Probably other manufacturers have the same thing.

jky

jgrace · 30 March 2006, 18:17

Quote:

Originally Posted by DJL

You shouldn't have any problems with the radio that close to the fuel tank. The heat sink shouldn't get that hot, not any where hot enough to ignite petrol anyway (200 ish degrees).

Although if you blow yourself up don't blame me..

I won't. I'll just haunt you

Actually, I met an old salt a couple of days ago who also told me that a bit of heat near the fuel tank is OK. He was more concerned about static discharge, saying I should make sure that petrol fumes can't get to the radio or the line to the aerial.

Cookee · 31 March 2006, 08:44

Simrad do a black box radio for the UK market - a little expensive though! Icom are just about to bring out a unit that is fully controllable from the handset which would be a cheaper option.

jgrace · 31 March 2006, 09:19

The Standard Horizon and Simrad black boxes look very interesting - I didn't know that format existed - but for better or worse I've already ordered an Icom M-421.

Roycruse's external mounting is the simplest option for my situation, but I'm considering a slightly raised console panel to give me a couple of inches clearance between the back of the vhf and the fuel tank. I need a new panel anyway coz I've got to cut into the old one to get the new bigger fuel tank in.

jwalker · 31 March 2006, 10:03

Quote:

Originally Posted by jgrace

.. ..Does anyone know how hot a fixed VHF can get?

From memory, the typical maximum junction temperature of a transistor is about 120°c and it is good practice to design to limit the temp to about half of that. I would reckon on it getting warm only after prolonged Tx.

jgrace · 31 March 2006, 12:37

Quote:

Originally Posted by jwalker

From memory, the typical maximum junction temperature of a transistor is about 120°c and it is good practice to design to limit the temp to about half of that. I would reckon on it getting warm only after prolonged Tx.

Sounds like I should stop worrying!

Thanks

benc · 31 March 2006, 14:41

Quote:

Originally Posted by roycruse

... should be fine with a icom though....

Are you suggesting an ICOM is properly waterproof

Rouge Wave what do you reckon ?

Cookee · 01 April 2006, 08:01

Quote:

Originally Posted by benc

Are you suggesting an ICOM is properly waterproof

Rouge Wave what do you reckon ?

By the way the new Icom is the M505

- I think it's out in April?