I have bought a new VHF radio and antenna. I have downstepped my mast. Is it necessary to place the antenna on the mast head. My cable is located there however I want to use that spot for a wind/speed instrument instead. Since I plan on only sailing the coast line and no blue water passage, can the antenna be placed on the stern rail and be as effective?
Placement of VHF Antenna
- Thread starter jsgonz
- Start date
- Status
Not sure why there is a problem. My mast is only sllightly larger than yours but I have both up there. The can bracket for the antenna is on the side of the mast so there is plenty of room on the flat top for the anemometer bracket.
line of sight for an antenna at 6 ft above water is 3 miles; at 50 ft, it would be 10 miles.
That excludes consideration of the antenna of the station to whom you are talking.
That excludes consideration of the antenna of the station to whom you are talking.
I will examine the mast head closer as the coverage of broadcast is significant with height. I guess I will replace the antenna on the bracket designed for it. There is a fitting just off the mast head that is broken off and that I believe that was for the wind direction arrow device so I think that is where I should try to fit the anenometer. Thank for the good advice.
JS...
Assuming that the anemometer you mentioned is electronic, they usually come with a mounting arm and bracket. Place it at the front of the mast head casting to get the best wind angle and speed info.
VHF sailboat antennas such as the 5215 come with a bracket that the loading coil bolts up to. Mount that to one side of the mast at the hightest point possible and be sure it clears the wind vane's swing on the apparent wind electronics.
Lastly, mount a Windex-15 on its available extension bracket off the back of the mast head so you can see it from the cockpit and shine a flashlight on it at night and see the reflective panels. (Why, I have electronics!--birds, spiders, gremlins, glitches, dead batteries, bad connections, severed wire, etc.). Make sure it clears the antenna in full swing!
Assuming that the anemometer you mentioned is electronic, they usually come with a mounting arm and bracket. Place it at the front of the mast head casting to get the best wind angle and speed info.
VHF sailboat antennas such as the 5215 come with a bracket that the loading coil bolts up to. Mount that to one side of the mast at the hightest point possible and be sure it clears the wind vane's swing on the apparent wind electronics.
Lastly, mount a Windex-15 on its available extension bracket off the back of the mast head so you can see it from the cockpit and shine a flashlight on it at night and see the reflective panels. (Why, I have electronics!--birds, spiders, gremlins, glitches, dead batteries, bad connections, severed wire, etc.). Make sure it clears the antenna in full swing!
Replacement of VHF Antenna
JS, here is a shot of the stuff on top of mine.. You can enlarge it quite a bit to better see the layout. Ken, the problem with the higher gain is that the narrow radiation zone from the arial is in the horizontal plane. When the boat heels over, the sides of the arial are seeing the water or the sky and the fore and aft quadrants are the the only directions from which you can send and recieve..
JS, here is a shot of the stuff on top of mine.. You can enlarge it quite a bit to better see the layout. Ken, the problem with the higher gain is that the narrow radiation zone from the arial is in the horizontal plane. When the boat heels over, the sides of the arial are seeing the water or the sky and the fore and aft quadrants are the the only directions from which you can send and recieve..
Attachments
While I think there is adequate room atop the mast of an H28.5 for both wind/speed instruments and a VHF antenna using offset brackets, I think that mounting your antenna on the stern pulpit or similar location would be adequate for most coastal cruising uses. Since you would hardly ever be broadcasting to, or receiving from, a water level target, I think your range would be ok. I also think most emergency/rescue/USCG towers are hundreds of feet tall, giving you decent line-of-sight to/from them. Talking to shore-based locations/marinas could be an issue, but you may be better off calling them on a cell phone anyway.
Thanks Warren and others for your responses. I do plan on going to the barrier islands which are a good 12 miles from the gulfcoast. However the marina has Coast Guard station which based on the responses, plays a factor in the range of transmission due to their tower. Never noticed the tower but I am sure there is one. I will ck next time I am there. So I think I have an option to either mount on the masthead or the stern rail for sufficient range judging from the responses. Thanks for the help.
- Status