VHF ANTENNA CONNECTION

[Russ]

Antenna beam pattern is very important on a healing sailboat or bouncing in waves as it is like a flashlight beam that is focused on a spot or wide. Spot is brighter if you hit the spot, but the rest is left dark. Wide flood isn't as bright, but accuracy isn't important as you flood a wider area.

An antenna’s dB rating (or antenna gain) indicates the apparent increase in transmitting power due to its ability to focus energy. Antennas with a high dB rating concentrate energy perpendicular to the antenna shaft in a field that is shaped like a disk. This makes your radio signal appear stronger to receiving stations around you.

It also reduces the amount of energy transmitted above or below the antenna, which can be a problem if your boat is pitching or rolling in seas. A concentrated signal can actually fade in and fade out as the boat rolls and pitches. As the dB rating of the antenna increases, so does the height of the antenna, but the horizontal angle diminishes. The broad radiation pattern from a low dB antenna allows a sailboat to heel over and still send signals toward the horizon. Sailboats should use a 3dB antenna mounted at the top of the mast whenever possible.


http://www.westmarine.com/WestAdvisor/S ... HF-Antenna

One important aspect of VHF is that it is line of sight. For most of us, this is not an issue. However consider if you are in deep ocean swells. You can see boats literally disappear in the bottom of a trough. The makes your VHF signal also invisible. Walk down a marina dock and look up. There is a reason most sailboats have mast mounted antennas.


Macgregor installed foam at the top of the M mast. This creates a obstacle for running cable. There are several methods to get past this. While at it, pull a pull string to run other wires such as anchor light.

--Russ

[budgates]

Thanks for the info Tom and Russ. I never understood the difference between the fiberglass and the whip antenna before. It makes a lot of sense the way you explained it. I guess I'll stick with my whip antenna.

As for mounting location. A lot depends on where you plan to sail. Mast top antennas do give more range but add two more elements to set-up and take-down in that I have to unscrew the connector and remove the antenna when I pack the boat up and visa-versa. A simple rail mounted antenna is perfectly adequate for a typical lake where you can see from one end to the other. For those of us who sail on the ocean the extended range is worth the small amount of time invested.

[BOAT]

I'm no expert at all on this stuff, but I will tell you that my setup from the factory seems to work very well. I hear things all the way up in Los Angeles all the time. I have a really long white Shakespeare fiberglass whip mounted thru the side of the cabin way back at the rear on the port side. It came that way from the factory. It's the kind that you turn the handle and swing it up and then turn the handle back again to hold it with those little "teeth" inside that round clampy thing. I think it's for power boats.

[Tomfoolery]

I'm not surprised, BOAT, as the higher gain (though closer to the water) helps. But if the boat is heeled, the signals will be weaker off the sides (both sides), but unchanged fore and aft. Though getting into big rollers will block the signals when in a trough, as VHF is line-of-sight, as Russ said. If I was sailing out to Catalina (~25 miles off shore?), I think I'd want the antenna at the top of the mast. For virtually all the sailing I do in this boat on Lake Ontario and elsewhere, my hand-held is perfectly adequate, and the fixed VHF is the backup.

But I don't cross the Lake, either. When I had a bigger boat, the handheld would lose the signals not far from shore. It's 45-55 miles across from Rochester to Canada, depending on the landing spot in Canada, and in the middle of the Lake, the waves can get rather nasty. Short interval, rather than big rollers, so lots of rockin' and rollin'. My 6W (on max power setting) hand held, just a few feet above the water, stands no chance, and even getting out to someone with a full-power 25W with mast antenna might be a crap shoot.

But I stick to shore these days, once in a while out to 10 miles or so, so I like to think I'm covered as far as radio range goes. But mounting a whip or fiberglass to the hull or arch would be fine for me, as long as I'm not getting beaten up far from shore or other boats.

[BOAT]

I'm not surprised, BOAT, as the higher gain (though closer to the water) helps. But if the boat is heeled, the signals will be weaker off the sides (both sides), but unchanged fore and aft. Though getting into big rollers will block the signals when in a trough, as VHF is line-of-sight, as Russ said. If I was sailing out to Catalina (~25 miles off shore?), I think I'd want the antenna at the top of the mast. For virtually all the sailing I do in this boat on Lake Ontario and elsewhere, my hand-held is perfectly adequate, and the fixed VHF is the backup.

But I don't cross the Lake, either. When I had a bigger boat, the handheld would lose the signals not far from shore. It's 45-55 miles across from Rochester to Canada, depending on the landing spot in Canada, and in the middle of the Lake, the waves can get rather nasty. Short interval, rather than big rollers, so lots of rockin' and rollin'. My 6W (on max power setting) hand held, just a few feet above the water, stands no chance, and even getting out to someone with a full-power 25W with mast antenna might be a crap shoot.

But I stick to shore these days, once in a while out to 10 miles or so, so I like to think I'm covered as far as radio range goes. But mounting a whip or fiberglass to the hull or arch would be fine for me, as long as I'm not getting beaten up far from shore or other boats.

I am not a real good example because I only use my radio to listen to channel 16. In over 40 years of sailing I think I can count the total numbers of words I have broadcasted on a VHF radio on two hands. The only words I can ever remember using on a radio are "Okay" and "Roger" and "Thank You". That's pretty much my radio experience. I only listen and never talk unless someone it telling me to do something. A normal day here is going out over 12 miles and the trip to Catalina is one I have done so many times over my lifetime I never think much about it. I guess I don't really know what I'm NOT hearing out there, right? But sailing out here all my life has me conditioned to not pay much attention to the radio anyways because most times we never had anyone to listen to anyways. Even today I run the squelch up pretty high so I only hear folks that are very clear signals. Sometimes a whale will get stuck in a net or get a rope around his tail and a bunch of big fisherman boats will circle round the animals trying to get the coast guard to help the whale and my wife likes to listen to the fishermen talking about the creatures when we are on the boat if they encounter one in trouble. She will yell "Whale Rescue! Turn it up!" Usually the creature is way down in San Diego 30 miles from us - that's why I think the radio on 'boat' works pretty good because I hear them way down there - but - as you pointed out - those big fishermen boats have anntennas way up high in the air so that might explain why I hear them, not because my installation is so great.

I'm no expert radio man.

[LoHo]

Hey Boat, do you sail from Monterey to Catalina on a regular basis?

[BOAT]

No, we always sail the coastline until we get into the lee of the island and then head west. That's the best way to do it even if your coming from the north like you guys up there in the Bay Area go. The seas are really rough 20 miles out - the swells double in size as soon as you get past that point so 4 footers become 8 footers and 6 footers become 12 footers. It's better to sail along the coast and then tack west for sure if you are coming from the north because there are no swells between Catalina and the coast. You just need to make your turn early or you will not have a good tack (you will be beating).

From where I am at I have taken it straight on a few times but it's not 26 miles doing it that way - it's 45 miles. When I am retired I may do that more often, (takes more time).

That's why I prefer to sail up to Dana Point or even better - put in at Alamitos Bay or Long Beach and then it's only 25 miles across the channel. Now, this is all talking as a SAILBOAT.

One thing I still am getting accustomed to is the idea of being a POWER BOAT which really makes a HUGE difference when doing the Islands in the San Pedro Channel. I can actually MOTOR to Dana Point in a little over an hour - That's not a lot longer than it takes to TRAILER to Dana Point with the boat on the freeway! Still, I usually trailer to Dana Point because I can't leave my car parked overnight in Oceanside.

The only places with overnight parking for my car and boat trailer are Dana Point, Long Beach, and Alamitos Bay, so motoring to Dana point is no good for Catalina because I like to spend the night in Avalon. Can't do that with the car parked in Oceanside. There is no ramp in Newport (for us sailboats) so even to get into Newport I need to put in at Dana Point. It's all about parking the car when your sailing a trailer boat!

For you it might be nice to trailer to Ventura and do the Channel Islands but be warned - the ocean is big there (you probably already know that if you have ventured much outside San Francisco Bay) - Much bigger stuff there than we get down here. It's been many years since I put in at Oxnard or Ventura so my memory is a bit dim.

[Russ]

Much depends on where and how you sail your boat.

When I lived in the East, ch 16 radio traffic was annoying. Weekends were full of traffic.

Out here, we leave the thing on ch 16 and get shocked when it springs to life occasionally.

--Russ

[BOAT]

It's really very calm and quiet over here too Russ. You would think it would be busy but it is not. Go to SHIPFINDER.CO and you will see the actual traffic along the California coast. You will see that there is a huge swarm of activity up near Long Beach and San Diego will have a similar swarm with nothing in between.

We were out just 2 weeks ago testing the remote control for the AP steering and the radio did not pick up ANYONE for a whole 4 hours.

It might be because of the "radio Nazi" out here - if you try to do a radio check or talk a lot there is this 'radio Nazi' that will come on and tell you that Channel 16 is not for radio checks and remind people about the rules. I think it's the Coast Guard guy in the San Diego office that is the 'radio Nazi' but I can't remember who it is - there is very little chatter in this area.

[Russ]

The word needs to get out how to do a radio check.

https://www.seatow.com/service-locator/arc

--Russ

[Seapup]

It looks like people are split 50/50 on mast vs rail mound on macs.

Spending too much time winter reading I was paranoid about range & signal loss when I spent hard earned money on a AIS VHF last year.

My takeaway was splices if I did them myself would lose a couple db and standard cable up the mast would lose a couple more db. So don't splice myself or skimp on cable.

So I paid to get custom lengths of LMR 400 with professional pl259 fittings so there was no excess cable loss or slop loss on my part. While testing the AIS and 3db whip on the rail I found I was able to pick up cargo ships AIS signal at 20 miles and recreational boats at 10-15 miles over water. The bay is only 20 miles wide so I just left it on the rail and never mounted it at the masthead So I still have a brand new custom made LMR400 patch cable and double female pl259 for the mac mast if someone is in the market...

I found cable comparisons shocking since a lot of antennas come with rg58 (6db loss for 100') or the slightly better rg8x, and that's basically what you see in the store.

Usual good read on vhf connections http://www.pbase.com/mainecruising/vhf_cable

[LoHo]

Sorry, Boat, I was thinking Seaside, near Monterey, which is more of a trip than from Oceanside.

[BOAT]

No biggie Loho - I just figured you were probably putting in near Monterey but wondered if you were doing the Bay Area because you were so close to both areas. Do they have a ramp at Moss landing?

I have only done Santa Cruz and the Bay Area and it's been MANY years since.

Seapup brings up the thing that keeps me up at night - AIS.

Most of my days out in the open ocean we never used the radio for night time safety because it was useless - the best safety was either a 'watch' (loosing a lot of sleep), or in my case we would just haul a bunch of galley junk up the mast (pie tins or old pots and skillets) to reflect radar signals for large ships. Later they had these nice round aluminum radar reflectors you could buy at the store that were much lighter than kitchen junk. (Big improvement).

But, AIS changed all that. You never knew how many 'close calls' you had while asleep but with the AIS now you will know so now they wake you up. Is it better to get sleep and have a close call or get woke up every time someone gets close to you? I dunno - I don't have AIS yet so I have not tested that. Still, I'm going to worry about it until I get AIS on board.

That to me is more important than the communication part of Radio - the AIS during the night watch would be a really big deal to me. Thus, I would then care about my antenna.

[LoHo]

Russ, that SeaTow page come up No Results Found...am I missing something?

[budgates]

Russ, that SeaTow page come up No Results Found...am I missing something?

I would guess that that means there is no automated radio check system in your area.