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Antenna Etiquette

  • Thread starter Thread starter Pete
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Pete

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  1. OWNER - I own a Hatteras Yacht
Hatteras Model
48' LRC (1976 - 1981)
I am now to the stage of remounting antennas on our LRC. When repainted I had most all the holes on the exterior of the flybridge filled and faired, unless I was certain I would reuse them.

So, today I started with the SSB antenna. Remounted the base in the existing holes and then set the antenna support such that the antenna would be perpendicular to the flotation water with the boat trimmed in its "normal" cruise trim. No doubt in my mind, antennas are suppose to be mounted straight up from the water surface. Then I noticed from the inside of the flybridge that the previous position had a slight angle to the aft of the boat. Certainly not the best for range, but ? ?

Anyone know of any tradition for mounting antennas other than straight up? Sounds like a dumb question, but I also noticed that the boat deck mast has a significant angle to the stern.

Pete
 
Straight up is the only answer. Chance's are the time that you need it the most the boat will be level or going slow.

BILL
 
Anything other than straight up - they might mistake your boat for a Sea Ray.
 
It makes virtually zero difference on performance, especially SSB (note the type of SSB antenna system cruising sailboats use). So, it is really a matter of aesthetics.

As a side bar, on VHFs, I have my big ones folded down a lot of the time for bridge clearances and there is no noticeable effect while coastal cruising. Here is a handy calculator for VHF:

http://www.qsl.net/kd4sai/distance.html
 
2 or 3 years back while headed north on the lower Chesapeake, I decided to do a VHF reception experiment, just for something to do. I used the WX weather stations as my signals and tried them with the antenna up and laying down, at about a 45 degree angle. Nothing scientific, but there was a significant difference in the number of stations received and clarity of the voice. This was with a Galaxy 23', 9db antenna with the base at about 12' off the water. So, on that day, in that spot, with that equipment, different results. Anyone else notice a lack of difference or difference with their VHF antenna up versus down?

Pete
 
I did the same type of test a couple of times, once at the dock in Hollywood, Fl and once while underway up near Ponce Inlet (New Smyrna Beach). Got all the same WX's and reached the same # of bridges on 09. I would in no way characterize either test as scientific.

Now of course, the extra 16 feet ( about 8 really, but that's another issue so we'll just think in terms of the tip), does make an absolute difference at some point and as quantified in the link I provided: two miles going from 17 feet to 33 feet. Listening to a WX transmitting from a 150 foot antenna, that's 25 miles vs. 23. I make sure the antennas are up when in the boondocks or off shore. I may try again here in New Bern, which is semi-boondocky as the CG stations are somewhat distant in Hobucken and Ft. Macon.

I believe the radios to be one of the (if not the) most critical systems on board. Although I likely won't perceive a performance enhancement in the coastal cruising we do, I plan on someday switching out the newish Shakespeares that came with the boat for Digitals or Morads.
 
All marine and all mobile stations use vertical polarized antennas. You may not see a tremendous difference in your reception at close quarters. But where any distance is involved you will see a major loss in signal. You need to take into consideration that the vhf signal is not influenced by the FM mode of transmission as much as it is on SSB or AM. The transmitter does not very in its signal strength in the FM mode as much as SSB or AM. For example it does not matter how loud or how soft you talk into a FM mike. The signal strength will not change. The same with your cell phone. The only thing that will happen if you holler in the mike, is you will drive the audio into over modulation an will garble the audio. So in turn until the signal drops below the set threshold of the receiver. There will be no change in the quality of the audio. Breaking up is the first indication that the signal strength is down. Without a signal strength meter you will never see the antenna signal strength fluctuate. I use both vertical and horizontal polarized antennas at the house for 10 meters through UHF. From my 65ft. tower a station 80 miles away will be unreadable if the antennas are switched. It doesn't matter if I'm vert or horz the signal will be lost if the polarization is reversed. I use one vertical antenna and one horzantal antenna phased together to access the satellites which are circular polarized. I also reverse the phase in order to change the rotation from right to left. It depends how they spin in orbit. Polarization is the cause for the sail boats to loose contact when there boat heals over. The antennas on our boats belong straight up and down. So don't go out and try to see the difference. You will only see the extremes. Weather stations and the Coasties have antennas hundreds of feet in the air. Which will screw your test up.If there is enough power from the signal source you will not see a signal loss from any angle. You can place your antenna upside down and there would be no loss but change the phase and your screwed.
BILL
 
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