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Old 07-12-2018, 10:01 PM
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Default Indoor VHF Options

Hi everyone,

I'm a new user here, though I've been reading posts on the forum for years. I've got a situation that I can't seem to find a solution for.
Our local Sea Tow office (for which my bother works) needs to set up a radio for their very small office that they can talk to the greater marine world. Because they are in a historic building, they are unable to put any kind of exterior antenna up.

What I need is an indoor option that will give them the best possible range so they can keep in touch with the CG and the area traffic.

Thanks for your help on this.
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Old 07-12-2018, 10:56 PM
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I moved your post here for better visibility.
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Old 07-12-2018, 11:37 PM
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Quote:
Originally Posted by Ahroun View Post
Hi everyone,

I'm a new user here, though I've been reading posts on the forum for years. I've got a situation that I can't seem to find a solution for.
Our local Sea Tow office (for which my bother works) needs to set up a radio for their very small office that they can talk to the greater marine world. Because they are in a historic building, they are unable to put any kind of exterior antenna up.

What I need is an indoor option that will give them the best possible range so they can keep in touch with the CG and the area traffic.

Thanks for your help on this.
A couple of things to considerů
Marine VHF radios transmit with 25 watts. That's kind of high to use in close proximity to humans. You can often turn the radios down to 1 watt, which would be safer.

Or, you move the antenna to a location that is several feet away from the occupants.

However, it's really going to depend on a number of variables.
Depending on the building construction, having an indoor antenna may not work. Metal roof, siding, reinforced concrete, masonry, conduit, plumbing, drop ceiling frame work, metal studs, HVAC ducting and other materials all run the risk of blocking the signals.
Only way to know if it's going to work is to give it a try.

You don't need a big marine VHF antenna, you can try something smaller and less expensive. A simple mount with a 1/4 wave antenna would be an easy approach:
This antenna: https://www.theantennafarm.com/catal...gies-qw152-720
This magnetic mount: https://www.theantennafarm.com/catal...es-gmb8pi-7517
The magnetic mount antenna will have the correct connector already installed to match the antenna connector on the back of the VHF radio. Screw the antenna onto the mount, hook the cable up to the radio, and try putting it on top of a file cabinet, on the drop ceiling frame, or other metal base (doesn't need to be steel, other than to hold the magnet.) The metal under the antenna base is necessary to act as the ground plane and help the antenna to work properly.

Try the antenna and see if it works. You can try moving it around to different locations to find one that works.

Inside a building, it might have issues, and getting it outside might be your only option. Since this antenna is pretty small, you might find a place you can put it where it will blend in.

If that doesn't work, there are ways to remotely control a radio, where you could install the radio and antenna at another location and connect to it remotely. That gets more expensive and complicated, so try the magnet mount antenna first.
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Old 07-13-2018, 12:46 AM
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For the local office of a similar customer here near Tampa, we setup a 25w vhf motorola lmr radio with a tone remote adapter to a 4 wire circuit. Then had the local telco provide the dry 4 wire back to their office where a tone remote sat on a desk. After a few years, the local telco could not keep the 4 wire up, so we went to a Telex IP223 on either end of a DSL connection to provide our own 4 wire transport. Oh, and the radio, tone remote adapter, ip223, and dsl modem is on top of one of the largest bridges in the area. Huge foot print. TT
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Old 07-13-2018, 1:58 AM
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Like TT suggested, a remote would be a good way. The potential problem is finding the location to place the equipment. Something taller is better, typically, but might not be necessary, depending on the coverage area desired.

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Old 07-13-2018, 12:17 PM
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Due to the nature of VHF marine communications (mostly simplex), I doubt that any kind of an indoor antenna will provide the coverage that a commercial business would consider adequate... Unless, of course, your facility is located on a high bluff overlooking the water.

With VHF radio coverage, antenna height is about 90% of the battle and more is almost always better. I happen to live on the coastline (in winter) and our local Sea Tow seems to have pretty good coverage throughout the area. Given the nature of the business, I would expect wide radio coverage to be a minimum requirement!

From your description, it sounds to me that the remote arrangement (perhaps on a tall building) would probably work best for you. Also, I believe that a special FCC license might be necessary for a shore station operating on marine channels, so you might wish to check into that as well. Sea Tow should be able to help in that regard.
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Old 07-13-2018, 2:23 PM
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This is what we did for either Sew Tow or its competition many years ago in So Cal, put a remote Motorola Radius on Palos Verdes hill at about 1,000ft elevation and ran tone remote back to their office in Huntington Beach, CA.


Quote:
Originally Posted by TampaTyron View Post
For the local office of a similar customer here near Tampa, we setup a 25w vhf motorola lmr radio with a tone remote adapter to a 4 wire circuit. Then had the local telco provide the dry 4 wire back to their office where a tone remote sat on a desk. After a few years, the local telco could not keep the 4 wire up, so we went to a Telex IP223 on either end of a DSL connection to provide our own 4 wire transport. Oh, and the radio, tone remote adapter, ip223, and dsl modem is on top of one of the largest bridges in the area. Huge foot print. TT
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Old 07-14-2018, 9:08 AM
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I moved your post here for better visibility.
Thanks Kevin!
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Old 07-14-2018, 9:20 AM
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Thanks for the advice. I agree that the indoor option probably wont work very well, but it's what they were asking for . They are in a historic brick building at the head of the pier. While they are on the third floor, the walls are thick brick.
I will have to do some research on the remote operation. I don't have any experience in setting those up.
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Old 07-14-2018, 11:13 AM
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Quote:
Originally Posted by Ahroun View Post
I will have to do some research on the remote operation. I don't have any experience in setting those up.
A commercial off the shelf "marine VHF radio" won't do what you need. They don't have the necessary interfaces to be remote controlled.
You'd need to purchase a VHF mobile or base station with FCC Part 80 certification that had the interface (most of them do). Setting it up in a better location with a good antenna, as well as reliable internet connection back to your office would be necessary.

Won't be cheap, and you'd want an experienced tech to set it up for you.

Give the 1/4 wave antenna I mentioned above a try first. While it won't have great coverage, it may be sufficient to hear and talk to the USCG. USCG usually has their remote radios in ideal locations. Most of their systems are designed to hear a 1 watt VHF portable at water level over the intended coverage area.
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Old 07-14-2018, 12:09 PM
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Ahroun -

Found a very comprehensive description of Tone Remote Control here (at least, the quick glance I gave it):

https://cwh050.blogspot.com/2018/04/...e-control.html

And there's a wikipedia article on Tone Remote Control:

https://en.wikipedia.org/wiki/Tone_remote

As the 2nd article mentions, there are many different functions that can be performed using the other tones (1850Hz, 1750Hz, etc). so you can change channels or other things.

As so many projects, a lot depends on what the user wants, how that can be translated to real-world hardware, and how much it ultimately costs.
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Old 07-14-2018, 12:42 PM
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A tone remote would certainly work, but that would require a dry pair phone circuit from the office to the radio location.
Most phone companies are already planning forced retirement of dry circuits in the near future. We've already been told by AT&T that ours will be going away in a few years.

It can still be a good solution if the company has their own copper cable plant from the office to the radio location.

Modern technology has surpassed tone remotes. IP enabled remotes allow for more features to be controlled remotely. Using existing internet connections can also be a cost savings in the longer term.
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Old 07-14-2018, 2:26 PM
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Is the office on the upper floor? Does it have a window facing the area of coverage? There may be a solution like a yagi that might work, but proximity of a 25 watt transmitter to humans and office equipment is not good. The computers will jam the receiver anyway and you will hear noise all day.

As others have mentioned, remote control might be your only option. If I understand the application correctly, you will probably need to monitor the hailing channel and then change to a correspondence channel to conduct business. You will need a remote control setup that gives you 2 to 4 channels. Radio Over IP is the best way and there are commercial products that do this well. Stay away from Chinese RoIP solutions as they don't work and have no channel switching. Expect to spend money.

Back to your building. You could consider getting permission for a roof mounted fiberglass marine antenna and set it up as a flag pole with some decorative flag that suits the history and purpose of the building. Be creative in your design and do some research, was it a coast guard station or customs house? What flag of authority might have been used back then? Maybe you can adapt a historic crest or logo to the flag. Failing that even a small 1/4 wave antenna on the roof will work well if it can see the horizon.

You will then need some 1/2 inch diameter coax like 9913F to connect your radio. Don't forget about lightning protection. This will be your cheapest solution as you will need an antenna and radio where ever you install it.
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Last edited by RFI-EMI-GUY; 07-14-2018 at 2:32 PM..
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Old 07-14-2018, 3:45 PM
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Companies like Sea Tow must be able to communicate with customers in order to make money and although many boaters have cell phones its desirable for them to talk a good distance over VHF marine channels to both customers and their vessels on the water. An indoor antenna on low building is just bad for business. They need to spend a little money and get a remote radio at a high location for hopefully 50 to 100mi up and down the coast and 75mi offshore. Otherwise they are not serving their paid customers very well.

If they don't already have one they will need a specific FCC shore station license for any VHF marine radio on shore.
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Old 07-14-2018, 3:52 PM
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Quote:
Originally Posted by prcguy View Post
Companies like Sea Tow must be able to communicate with customers in order to make money and although many boaters have cell phones its desirable for them to talk a good distance over VHF marine channels to both customers and their vessels on the water. An indoor antenna on low building is just bad for business. They need to spend a little money and get a remote radio at a high location for hopefully 50 to 100mi up and down the coast and 75mi offshore. Otherwise they are not serving their paid customers very well.

If they don't already have one they will need a specific FCC shore station license for any VHF marine radio on shore.
I know here in Florida they can charge a fortune for pulling boats from sand bars. We have an abundance of dumb people here in FloriDuh and many of them operate boats! Like shooting fish in a barrel!
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Last edited by RFI-EMI-GUY; 07-14-2018 at 5:29 PM..
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Old 07-14-2018, 8:03 PM
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The US Coast Guard Auxiliary used to used to respond to vessels in distress and would tow a vessel back to port and there was no cost for that service. At some point they stopped doing that, which opened the door for commercial tow trucks at sea and hefty towing bills.


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I know here in Florida they can charge a fortune for pulling boats from sand bars. We have an abundance of dumb people here in FloriDuh and many of them operate boats! Like shooting fish in a barrel!
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Old 07-14-2018, 8:07 PM
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I believe it was the towing companies lobbied to take over towing. Claims that the USCG, a government agency, was taking business from the industry.

However, when a towing company is unavailable, USCG will still tow vessels in. Often they'll even tow them closer to land and the towing company will take over.
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