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Discussion Starter · #1 ·
Hello everyone, I'm new to the SailNet community, but have spent a lot of time reading the forums here. I am about to close on a boat later this week and have a question regarding a vhf antenna.

The vessel is a 1975 Irwin 30 and although I see it has a fixed mount vhf, I did not notice any vhf antenna. From what I have read, most suggest mounting the vhf antenna on the masthead. My questions are:

1) Which is cheaper...bringing down the mast and doing the installation myself or having someone install it on a bosun chair? Any other installation options?

2) What would be the cost for installation?

3) Is this something that the marina mechanic or personnel can perform? The vessel is at a wet slip at McCotters Marina in Washington, NC.
 

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congrats on the new to you boat. you may be jumping the gun a bit. there is most likely an antenna somewhere on the boat. does the radio work? does it have a backstay antenna. my previous boat had a coiled antenna on the mast head that was about 10" long and very hard to see from the deck. i now have the antenna on the stern pulpit and it works just fine for coastal cruising
 

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Overbored is doubly correct. Congrats, and, why not test the radio? Listen to 16 for a half hour, and you'll get a sense of how far away you can receive. Then go to a working channel and ask for a radio check with location feedback from responders. You should get something like 7 miles-ish from a good setup.

If that doesn't work and you do in fact need an antenna, pull the mast. You can then do a nice job by yourself. It's not hard.
 

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Seatow has an automated radio check on channel 27 in Washington. Just call in and it repeats what you said back to you.
 

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If you have any doubt as to whether there's an antenna, DO NOT TURN ON THE RADIO. Deltaten was right, it could damage your radio's finals. Unplug the antenna lead from the back and test the center wire and threaded outer contact of the co-ax cable. If you have somewhere around 50 ohms of resistance, there is likely an antenna somewhere. If you want to get fancy you could use a thing called a standing wave ratio meter, or SWR. That will tell you neat stuff like whether the antenna is 'trimmed' correctly to optimize power transmission or in your case, whether there's any antenna at all! Good luck! ~LL
 

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So there is no reason to turn on a radio when there is no antenna. But it's not likely to blow a modern unit. I turned on my west marine radio into a busted antenna lots of times before I finally realized the coax was blown at the deck connector.

I was also going to add that a handheld isn't a bad option for a season if you're not heading too far offshore and/or to unpopulated areas. Take the mast down at the end of the season and get the antenna fixed up then.
 

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Although this suggestion presents some theoretical problems, mounting an antenna on the push pit has many practical advantages over a masthead mount -- much shorter run, less signal loss, no connectors, no cable in the bilge, no weight aloft, cheaper, easier to service. Many years ago I yanked my masthead VHF antenna and masthead anchor light; never regretted the choice.
 

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Discussion Starter · #9 ·
Everyone, thank you for your responses. I'll be headed over to the marina this weekend and I'll be sure to do a better job of inspecting the vhf setup this time. I have a handheld as a backup, so at least I'll have some peace of mind while on the water. I'm weary about stepping the mast down because I have no experience doing that. I'm hoping I'll find some kind of workable setup.
 

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Although this suggestion presents some theoretical problems, mounting an antenna on the push pit has many practical advantages over a masthead mount .
I agree.

When I got AIS I wanted it on its own antenna so I added one to the pushpit. The VHF is now on the rail and the AIS is on the mast head.
The range I get from the pushpit is fine. I have not noticed anyone having any difficulty with receiving me... And I use the damn thing every day.

So if its a matter or doing things economically then go the aft rail.
 

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If you have any doubt as to whether there's an antenna, DO NOT TURN ON THE RADIO. Deltaten was right, it could damage your radio's finals. Unplug the antenna lead from the back and test the center wire and threaded outer contact of the co-ax cable. If you have somewhere around 50 ohms of resistance, there is likely an antenna somewhere. If you want to get fancy you could use a thing called a standing wave ratio meter, or SWR. That will tell you neat stuff like whether the antenna is 'trimmed' correctly to optimize power transmission or in your case, whether there's any antenna at all! Good luck! ~LL
This is not all together true! Many VHF antennas will look like either an open circuit (Ohm meter reads infinity to several hundred K ohms) or a dead short (near zero ohms). If your volt-ohm meter reads anywhere near 50 ohms, the feed line, antenna or both are likely bad. Either that or a dummy load is connected.

Most modern radios will not be harmed by transmitting into an open or shorted antenna for a few seconds.

Now if you know someone with an antenna analyzer, a SWR bridge or a forward / reflected power meter, you may be able to find out whether the antenna and feed line are good.

If the feed line is old or water contaminated, the SWR and reflected power may look great. The problem with water damaged coax/feed line is almost all of the power gets turned into heat before it gets to the antenna.
 

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Jxvega,

Welcome to the Irwin community, be sure to check out the owner group on Yahoo.

Going up the mast in a bosun's chair is not that hard if you can handle heights and have someone to do the cranking. If you are indeed missing the antenna but have a masthead connection with good cabling it's a simple "screw in the antenna" job that will take less time to do that it takes cranking you up.
Borrow a chair and a cranker, follow the advice of someone at the marina who knows what going aloft is about, check it out and don't forget to take pictures while you are up there.
--- Irwin 38 CC MkII by the way :)
 

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You will most probably will not read 50 ohms for the antenna. If there is any type of resistance (not open circuit) that means you have an antenna. A bosuns chair is the simplest method if you do not have the antenna.

A wireless will send messages with any antennena, but for a good receipt is possible if you mount it the highest possible.
 

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Discussion Starter · #14 ·
I was able to check out the vhf radio and there is a cable connected to the unit. I keyed the mic and was able to communicate with my handheld vhf. I tried to see if I can make out the antenna and it seems there is one that is part of the wind vane, but I'm not entirely sure.
 

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Maybe you're ok. But on the other hand I can say from experience that you can talk to a handheld with a broken antenna. My cabling was busted at the deck fitting and I could talk to people nearby no problem. I then set off on a cruise and soon saw all the harbor activity fade away.
 
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