Fog/Hailer horn mounting proximity to radar dome

H

hardee

New member
If this is posted any where I could not find it. I have looked through the album pages and used the search function. Does not appear to be many C-Dory's with fog/hailer horns on board.

I want to mount a fog/hailer horn, and not having a radar arch, but rather a 6" mounting post for the dome. The horn is a 6x11" trumpet, and because I use a storage cover, I want to mount the horn with the opening in the horizontal orientation, and below the Radar dome, so that the storage cover will not be adversely affected, (still fit without extra wear). The Speaker horn is ABS, and it would be mounted low, next to the roof line, forward of the radar mount, but aft of the running light plug/post.

My concern is that there my be some adverse interaction between the horn, speaker device and the radar. Either affecting the radar or the horn, (as in the magnetic output from the horn [30watt] skewing the radar returns. Anyone with any knowledge of these relationships, or experience in rigging have any input on whether this will work or not?

Am I being over cautious here, is this something I need to rethink?

Thank in advance for any/all opinions.

Harvey
SleepyC :moon
 
I just mounted my 4X11 horn last Thursday on the arch next to the radar dome. The magnet on the speaker is about 12" from the dome at about 4 oclock. I may remount it under the arch if there is any notable interference. It sounds like the same speaker horn you have. I will let you know.
 
The reason to keep the horn oriented in the vertical direction, is that the sound is spread wider to the sides with this orientation--sort of the opposite of what you might imagine.
No problem with mounting just below the radar--have been doing this for about 30 years.
Page 1 of "Thatway" album.
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Shouldn't pose any problem. I don't recall reading anything in radar installation instructions about hailer horns- GPS antennas, VHF antennas and the like, but no hailer horn.
 
Dave, Bob, and Matt. Thanks for your response. Bob, you are right, that orientation is counter intuitive. I was planning on a horizontal orientation with a slight downward tilt, ( maybe 15 degrees) to facilitate having the inside base of the horn somewhat more protected from driving rain or spray. Maybe that is an unneccessary worry even here in the PNW.

Harvey
SleepyC :moon
 
Your sound radiation pattern will be more oriented up and down, than laterally. For example my horn would have 150 degree degree beam width in the horizontal plane, if it were mounted as you propose, it would only have a 110 beam width (of course this is not just one focal point, and there are amounts of dB fall off as you deviate from the foreward axis. I prefer to send as much sound to each side as possible, vs in the up and down direction.

We have not had a problem with water in the horn--but it would not hurt to have it oriented down a couple of degrees. We get about 65 inches of rain here in Pensacola vs about 15 in Sequim, and over 140 in Seattle--so you takes your choice.

On the other hand--a good air horn is a better fog horn, but does not have the PA convenience (rarely used) or the auto fog / anchor signals (more frequently used). The Fog Mate will make any fog horn automatic.
 
Dr Bob,

Thanks for the additional clarification on the horn orientation. In our case the size of the vessel dictates multi-purpose devices get priority if they are reasonably as effective as 2 single purposed units.

Harvey
SleepyC :moon
 
My original horn mount got broken. When I re-mounted it, I used U-bolts to secure it to the radar arch tubes since I cut off the tab from the arch where the horn had previously been mounted (to give me a little more room for the dink.) Now the horn is gone, having broken off somewhere between FL and WA.

So -- two questions:

1. Any recommendations as to brand, model, etc. of new horn?

2. Any suggestions (links to photos in albums, maybe) of successful mounts to radar arch tubes or to cabin top (I was wondering about under the eyebrow shade?)

TIA for any help.
Warren
 
Warren,

I am just now replacing a failed hailer horn.

The important thing is that the max power rating and the ohm rating match the amplifier.

The older Lowrance hailers, like mine, use an 8 ohm horn, while the newer hailers that are combined with a VHF use a 4 ohm horn of lower power rating.

I found the needed information in my hailers manual.
 
Warren,

I found Defenders Marine supply to be very helpful, and had what I needed. My first purchase was from WM, A "Speco 6.5' X 11" 40watt, 4 ohm, mod # SPC-40RP/4. Turned out it was too large for where I needed to mount it, so I went looking and found the Standard Horizon, 240SW7.25" X 4.75", 40 watt, 4 ohm which will fit where I need it.

Speco has a stainless mounting bracket, but is bigger and heavier, and the SH is smaller, lighter but with a plastic mounting bracket. Speco also has a second wire set for use with an alarm system if desired.

Important that the ohm rating matches the ohm rating output of your VHF, and that the max Wattage is equal to or greater than your VHF output. (See Larry H post, above)

Once I get one of these mounted I may have an extra PA/Hailer horn available. Sure wish I was headed up to Anacortes to see you all this weekend.

Harvey
SleepyC
 
I just mounted a Speco 40 8 ohm vertically at the centerline on the eyebrow (slight tilt down). I used the 2 holes in the speaker lip through the lip on the roofs eyebrow and one on the mount. Mounted there it is below the radar line and at least 18"away (There is a pretty big magnet in the speaker). All the holes for the screws and wires are in the eyebrow with just a small upward sloping hole under the brow to route the wires. Not much chance of leaking. Is fairly ugly though and if I had it to do over I would consider smaller.

Chris

Will add a couple pics at end of album
 
Anybody looking into adding a speaker/hailer horn might want to keep in mind that they come in multiple sizes, as well as the electronic variations, (4 or 8 ohm and various wattages,) which all need to be considered. My mistake was to purchase what WM had on the shelf without doing more research into it first. The first one would have worked fine on a larger boat, or on a radar rack, high or low, but not having those options, I got to do a redo :wink Many different options for many different situations, and to each his own. Obviously YMMV.

Harvey
SleepyC :moon
 
Chris,
Good ide to tie down the forward lip of the speaker horn. Mine bounces, even with the mount tight. I suspect that some sealant will do the same thing for me--since my horn is set back further (does not seem to be a problem with the radar when closer, but below the dome level).
 
Since the new horn is White ABS plastic, :evil: I'm thinking that a good UV protectant might be a good idea. Is the 303 good for the ABS? Tried to come up with something in metal but everything in this shape and size seemed to be plastink.

Harvey
SleepyC
 
OK, so after using the Fog/Hailer for part of last season I am very impressed with the Ray218 hailer and fog function. The Defenders Standard Horizon, 240SW7.25" X 4.75", 40 watt, 4 ohm seems to be a nice match. Good volume capability, clarity (make it understandable up to about 100 to 200 feet, and the auto fog function seems reliable. The listen back feature is marginal, (seems to have a background hum even in a quiet setting.) I did mount it in the horizontal orientation due to the need to "hide" it under the radar somewhat for storage cover purposes. It is forward of the radar post, slightly starboard, and tilted down about 15 degrees. (I will try and get some photos in to my album soon.)

Thanks all for the discussion here. Good help as always.

Harvey
SleepyC :moon
 
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