Marine Electronics Forum - VHF Antenna Mount

The location I want to attach the VHF Antenna mount is inaccessible from underneath to use bolts and nuts. Can I use large self-tapping screws to attach the mount to the rear deck? I have an 8' Shakespeare Galaxy 5225XP antenna and rachet mount.

I would like to mount the antenna so that it lays down across the tansom from port to starboard rather than forward towards the bow when not in use. Antenna would only overhang about 4 inches.

Any ideas or suggestions?

I would find a spot where I could use bolts and nuts with washers. Self tapping screws or sheet metal/wood screws ill never hold with an 8' antenna whipping back & forth.

That is what I thought. Figured it would be a long shot to be able to use the self-tapping screws.

Depending on location, you may also be able to 'make' some access by installing a small access cover.

Ken

Depends what you're screwing into...
If it's the thin fiberglass of a hardtop, no.
If you're screwing into the side of a cabin, console or gunnel with thick plywood, s.t. screws are fine for holding an antenna, just be sure to pre-drill your holes to the appropriate size. Use proper sealant around the holes whether you screw or thru-bolt.

If you use 5200 under the antenna mount when you install it - it will probably stay there forever.

If screwed on a thick support, you might look first at drilling a larger and deepr hole where the screws are supposed to bed, fill these holes with epoxy and filler/thickener and let cure. After you would follow the normal screwing procedure (drill, screw) and possibly add some "glue" for the base. That would be strong and prevent water infiltrations. When drilling the first holes, you may play and expand them at the bottom, making them even stronger.

Just my opinion.

Or you could use wellnuts

http://i102.photobucket.com/albums/m91/ollifl/WellNut.jpg

I would like to mount the antenna so that it lays down across the transom from port to starboard rather than forward towards the bow when not in use. Antenna would only overhang about 4 inches.

That's a accident waiting to happen when the antenna is down and the dock tears it off or catches on the guid on at launch time.

Never mind not thru bolting it. Lot's of stress on the mounting points of the mount.

Bad ideas all the way around. http://bestsmileys.com/thumbs/6.gif

warthog5 - 5/17/2007 10:35 PM

I would like to mount the antenna so that it lays down across the transom from port to starboard rather than forward towards the bow when not in use. Antenna would only overhang about 4 inches.

That's a accident waiting to happen when the antenna is down and the dock tears it off or catches on the guid on at launch time.

Never mind not thru bolting it. Lot's of stress on the mounting points of the mount.

Bad ideas all the way around. http://bestsmileys.com/thumbs/6.gif

How would laying the antenna down from transom towards the bow be less likely to be torn off or snagged by the dock? Laying the antenna that way would also block a couple rod holders. But I am a novice, so any suggestions or opinions are greatly appreciated. My boat is a Sailfish 1900 Bay Boat. What other options do I have?

If you have a poling platform like I do, you could always install it on the side of that and pull the cable inside the frame down to your bilge then snake it inside your console.

I'm using a Digital 4" antenna on the side of the console, gives me plenty of reception, it also fits under the bimini top my wife made me put on.

IMO 8' antenna on that boat is an overkill.

I would use one of these to mount the 3-ft. stainless whip or 4-ft. fiberglass antenna of your choice to the console grabrail:

http://www.thegpsstore.com/Shakespeare-4188S-SS-Rail-Mount-fits-78-to-1-inch-P985C0.aspx

That will be plenty for a 19-ft. bay boat.

Is there a reason you don't want to mount it to the railing on the console with a ratcheting mount? I did this on my 19 footer and it worked great.

saltyric - 5/18/2007 6:45 AM

Is there a reason you don't want to mount it to the railing on the console with a ratcheting mount? I did this on my 19 footer and it worked great.

It is an 8' foot antenna. It would have no place to lay down when not in use.

My dentist told me I only had to brush those teeth I really wanted to keep. So, with a four foot VHF antenna, just stay within sight of anyone you really want to talk to!

( VHF is line of sight: height means miles. )

Where will he be in a little 19-ft. bay boat that he won't be within easy range of other boats with a four foot antenna mounted on the console grabrail (probably 8-1/2 feet above the waterline)? If he mounts the 8-footer on the aft deck (about 12 inches out of the water), his "line of sight" will only be about six inches more.

sandyda - 5/19/2007 4:46 PM

My dentist told me I only had to brush those teeth I really wanted to keep. So, with a four foot VHF antenna, just stay within sight of anyone you really want to talk to!

( VHF is line of sight: height means miles. )

Are you telling me that my 4 foot antenna can only transmit 4 miles? :rofl: :rofl:
I quess you have a pretty good "sight" if you can see as far as my four foot antenna can transmit :thumbsup: , good for you.

jmbfin - 5/18/2007 12:28 AM

warthog5 - 5/17/2007 10:35 PM

I would like to mount the antenna so that it lays down across the transom from port to starboard rather than forward towards the bow when not in use. Antenna would only overhang about 4 inches.

That's a accident waiting to happen when the antenna is down and the dock tears it off or catches on the guid on at launch time.

Never mind not thru bolting it. Lot's of stress on the mounting points of the mount.

Bad ideas all the way around. http://bestsmileys.com/thumbs/6.gif

How would laying the antenna down from transom towards the bow be less likely to be torn off or snagged by the dock? Laying the antenna that way would also block a couple rod holders. But I am a novice, so any suggestions or opinions are greatly appreciated. My boat is a Sailfish 1900 Bay Boat. What other options do I have?

Sorry I misread. I thought you were laying it Stb to port side. Stlll, anything hanging over will get snagged and not thru bolting a antenna mount will get ripped out as the antenna snatches on the mount while it whips around.

Just mount it with a ratchet mount on the windshield grab bar. They make them with a band to go around the grab rail.

That is how I have it on my 162 Scout. For towing the antenna lays forward. If it's in your way casting lay it back a little. I never had that problem.

Grumpy Finn - 5/19/2007 6:43 PM

sandyda - 5/19/2007 4:46 PM

My dentist told me I only had to brush those teeth I really wanted to keep. So, with a four foot VHF antenna, just stay within sight of anyone you really want to talk to!

( VHF is line of sight: height means miles. )

Are you telling me that my 4 foot antenna can only transmit 4 miles? :rofl: :rofl:
I quess you have a pretty good "sight" if you can see as far as my four foot antenna can transmit :thumbsup: , good for you.


Line of sight is a term used to describe a type of transmission. VHF transmits on "line of sight" which is a straight line to the horizon and does not mean that it can transmit as far as you can see. VHF signals do not bounce like other frequency transmissions. The formula for line of sight transmission distance is:

D = 1.33(SQRT(2Hr) + SQRT(2Ht))

Where D = distance to radio horizon (miles)
********** Hr = height of RX antenna (feet)
********** Ht = height of TX antenna (feet)

So if you have 2 boats with the tip of their antennas 10' off of the water then they can theoretically communicate up to almost 12 miles.* The transmission/reception distance is also affected by transmission power, receiver sensitivity, and VSWR.* The maximum effective range for VHF communications is 20-25 miles regardless of antenna height, power, or sensitivity.

We should add that the Coast Guard transmits from very tall towers at much higher power and sensitivity, so you can talk to them much further away. But its still line of sight; reception range corresponds with antenna height.

Would it be possible to mount the antenna on the center console either between two of the rodholders or along the side of the console? Any advantages or disadvantages?

That's exactly where I have my antenna, upper part of the center console so that it does not interfere with the rods at all, it kind of goes inside between the grab rail and the console. You also get the greatest height for you antenna.