Mast Wiring Plans (PAFog Horn)

[Hull152_Patrick]

It is HailerFog Horn I will to hook to my ICOM m504 VHF. I plan to use it for the alarm clock. 😉

According to the ICOM manual the output to the horn is 25 W nominal at 13.8 V/4ohm

I=P/E
25w/13.8v = 1.8A

Shouldn’t I use 12v though?
25w/12v = 2A

Still that’s odd, I had previously calculated the Amps of the PA at 3.33. Hmmm…

So using 2A I can use 10Awg wire instead of the 8Awg.
NOTE: At 2A the 12Awg wire has a voltage drop of jsut over 3% which is not acceptable, but at 1.8A 12Awg would be just under 3% (2.9).

I’m getting a nice cluster of 10Awg wire needs appearing in my list so I think going with the slightly heavier wire and getting a reel or two might be cheaper as well.

-p

—-
s/v Deep Playa | Pearson 424 Hull #152 | http://www.DeepPlaya.com

From: “Robert Fine” <>
Sent: Wednesday, December 30, 2009 8:10 AM
To: “Pearson 424 owners listserve” <>
Subject: Re: Mast Wiring Plans

Patrick,

I don’t know what kind of horn you have – but if it’s a pa/fog horn connected to your VHF then 12 gauge is more than enough – I doubt there are 3.3 amps going to it. The little speaker coil would turn into a heater core before you could put that power in it. I have the Standard Horizon speaker mounted below the radar antenna and used simple speaker wire to attach it – it works like a champ. In fog horn mode, I really can’t stand being in the cockpit!

Bob

—
Bob Fine
s/v Pelican
Pearson 424 Hull #8
http://thesailinglife.blogspot.com
Follow me at: http://www.tinyurl.com/WhereIsBobFine

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Owners no more...
Thanks Dawn and Patrick!

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