VHF Antenna Installation

[unbusted67]

I am kind of wondering if this is where I should stop and just hire a professional to do the job. We have a trailer sailor and will be taking it through the Erie canal etc. With that said we will have the mast down a lot. Right now the boat has no antennae, I have a Standard Horizon hand held HX850 that I would like to eventually uprgade to a permanently installed unit. Until then I would like the option of plugging a masthead or whip antenna into this unit. How hard is it and how exacting do I need to be in order to install a masthead antenna? Should I just hire out a professional? Should I install a tall whip antenna for use when the mast is down?

[Hydra]

Unbusted,
IMO, a tall (expensive) whip antenna isn't necessary when your mast is down, because range is greatly reduced anyway. For this situation, a cheaper solution could be to improve the range of your hand-held radio by replacing the original antenna with a quarter-wave one, that gives some more gain.

Regarding masthead VHF antennas, I installed mine without hiring a professional and without unstepping the mast. I bought a good quality (stiff fiberglass) antenna with a length of cable attached. The antenna base is riveted on the side of the mast.

The most difficult step was to pass the antenna cable in the conduit inside the mast. I succeeded by using the anchor light cable for pulling a messenger line, that I used to pull both cables together.

In the boat, the antenna cable goes through a flexible conduit between the ceiling and the deck, for protection against chafe and for maintaining large radii of curvature (better for reducing loss of signal). This was easy, as well as soldering the cable to the PL259 connector (just had to be careful).

I'm sure that the final result is good because I get long-range reception (often more than 50 NM) with a low-end radio. I think that the budget was 150€ for the radio and 120€ for the antenna (in 2005).

Alain

[Pblais]

You could just make up a cable and just run it direct from the radio for the duration of the canal. To be honest you don't need very much range in the canal. Transmitting across land is pretty limited in any case. In open water 40 ft will double the distance and that is worth having on the open water. You can get a shorter antenna that you eventually can rivet to the side of the masthead for now.

For running the cable you really don't want a cable just running top to bottom unsecured. It flogs around inside the mast unless you have a conduit designed for that purpose. Eventually you'll trash the wires and same goes for a wind instrument cable and masthead light. Making a single bundle of wires and securing it is just going to prolong the wires in the mast. Many masts have a conduit for this purpose. If you have the mast down that is just a whole lot easier to do. Plan the job so you have enough cable to unstep the mast when you need to. You can get a decent 3 db gain metal antenna about 36 inches on an L bracket you pop rivet in place for about $70. Exit the mast just before the top and use a grommet with sealant to connect it up. If you need more details just post back we have a lot of good radio members to help with the details. Getting the details right gives you crystal clear VHF with great range.


Just redid mine after a brush in with a tree in the Dismal Swamp last fall. You need to watch out for tree branches in narrow canals. I did pretty good until I back away from a dock. Snapped the antenna off clean but saved the light and wind instrument. Broke the basic rule of boating: Don't hit anything! Very embarrassed.

[unbusted67]

The other issue with this project is that we have no ceiling liner in our boat, the deck is the roof, so there is no where to hide the wire once it is inside the boat. The masthead light wires disappear into a compression post that I don't want to tangle with. Does everyone have a deck junction where you disconnect your antenna when you un-step the mast? Does anyone know of a web site where someone has taken step by step pictures of this project? I understand the words but would feel a bit better if I saw someone else actually doing it.

[unbusted67]

http://www.saltyjohn.co.uk/resources...stallation.pdf

Like for example, this link? Is there anything anyone would like to add to what Salty John is saying here before I take what he says as gospel?

[fairbank56]

I started to respond about the article but my post was getting too long and technical. I'm a professional marine electronics service technician with 34 years of experience. The article is so full of errors it's ridiculous.

Eric

[Boracay]

To my untrained eye the use of a split rubber sealing ring to allow the use of an unbroken coaxial from the radio to the aerial looks sound.

I would be very interested to hear an explanation (no matter how technical) as to why this should not be done.

I recently installed a VHF radio in Boracay and, despite numerous joins and old, too small coaxial the not so local Marine Rescue station assures my my transmissions are loud and clear. I have also been able to receive from stations some distance up and down the coast.

[unbusted67]

Originally Posted by fairbank56

I started to respond about the article but my post was getting too long and technical. I'm a professional marine electronics service technician with 34 years of experience. The article is so full of errors it's ridiculous.

Eric

Please by all means. If you don't want to correct the whole article then maybe you could give us a distilled version of a solid step by step install. Or at least you could point us in the right direction to an article.

Originally Posted by Boracay

To my untrained eye the use of a split rubber sealing ring to allow the use of an unbroken coaxial from the radio to the aerial looks sound.

I don't actually think that is what Mr Dog intended. I think he was just using the "deck gland", as he calls it, to assure that the junction between connectors occurs inside instead of outdoors.

[GordMay]

A cable gland is a generic term for, what, Blues Sea Systems calls a Cable Clam.
➥ CableClams - Blue Sea Systems

I saw nothing glaringly wrong in “Salty” John Schofield’s practical installation instructions.

[fairbank56]

Sorry, it's just that a few things in that article that perpetuate common myths just make me shake my head. You have already received excellent advice from Hydra and Pblais. The deck fitting is fine, I use them frequently although they are expensive but hey, it's marine so it's 3 times more than it should be. The photo looks like a Newmar CCX-T which runs around $35. The Metz Manta 6 is a popular and good choice for a masthead antenna but if you go with that model, be very careful when tightening the compression nut that secures the antenna rod. Iv'e seen too many of these antenn'a ruined by that. These antenna's are not all stainless steel. The part that sticks up from the base where the compression fitting is, is just chrome plated brass and the internal screw that attaches the coil to that fitting is brass. It's fairly easy to apply too much force on the clamp nut which will rotate the whole fitting within the epoxied base unit which then shears off the internal screw. The antenna is then nothing but about 4 turns of the internal coil! Another area of concern is the installation of the PL-259 connectors. 95% of DIY's and many Pro's do not know how to properly install these.

Eric

[GordMay]

Originally Posted by fairbank56

... Another area of concern is the installation of the PL-259 connectors. 95% of DIY's and many Pro's do not know how to properly install these.
Eric

That sounds like another subject for a good tutorial.

An interesting example:
➥ The PL259, a Tale of Woe

[dixonwj]

Never been on the Erie Canal, but we did the Illinois, Missippi, Ohio and Tenessee from Chicago to Mobile with a hand held with stock rubber duckie antenna. Tow boat operators and locks don't want to hear from you unless you are close. I guess they have been lied to about when to expect recreational boaters once too often.

Marinas all list their phone numbers in the cruising guides. Even in the dark ages of the mid 90's we had a cell phone aboard to inquire about vacancies far down the river.

[unbusted67]

Originally Posted by fairbank56

The Metz Manta 6 is a popular and good choice for a masthead antenna but if you go with that model, be very careful when tightening the compression nut that secures the antenna rod

Yeah about that, What is a good alternative to that antenna? I will be doing my shopping at West Marine and notice they don't carry any Metz stuff. It looks like most of the Vhf antennas they carry are made by Shakespeare.

Originally Posted by fairbank56

Another area of concern is the installation of the PL-259 connectors. 95% of DIY's and many Pro's do not know how to properly install these.

Eric

You are truly a man of mystery Eric. What is the proper way to install one of these connectors? All of the Comcast guys have Coax cable crimpers. Do we need what the pros have?

[fairbank56]

Originally Posted by GordMay

I saw nothing glaringly wrong in “Salty” John Schofield’s practical installation instructions.

While looking like an ad for the Metz Manta 6, the article is decent but has technical error's and while 3db antenna's are commonly used for masthead use, they are not the universally accepted choice for boating applications in general.

Antenna gain does not increase signal power.

SWR is not a measure of transmission power that is lost. (even in very simple terms)

An SWR of 2.0:1 is not a 1/2db loss nor is a 1/2db loss barely acceptable.

The implication that RG-8U is not waterproof or uv resistant is mis-leading since the term "RG-8U" is a generic one that is applied to cables of quite varying specifications.

Foam core dielectrics are closed-cell in construction and do not suck moisture into the cable.

Regardless of the quality, PL-259 connectors are not waterproof. It is faulty weatherproofing technique that allows water into the cable.

Crimped connections are fine if properly installed. Proper weatherproofing will keep moisture out, regardless if it's a soldered or crimped connector.

That is not an SO-239 at the base of the Metz antenna, it is a PL-258 barrel connector.

Eric

[SoonerSailor]

You can find step by step tutorials on soldering PL-259 connectors on the internet. One key to successfully soldering the connection is to heat the connector rapidly. That means that you need an 80 to 120 watt soldering iron with a heavy tip that holds a lot of heat. A soldering gun, even if 120 or 240 watts, does not work as well since the tip is low mass and does not transfer heat as quickly. Some use a butane torch, but I've seen arguments against this, though I can't remember the rationale. When done, you need to use an ohmmeter to be sure you don't have a dead short between conductors, or an open outer or inner conductor connection. Even the most experienced installers occasionally make a bad connection.

Its not hard to do, and may look complicated, but mostly just a matter of careful preparation and attention to detail. Careful attention to weather sealing the connector, using something like "Coax-Seal" and quality electrical tape is also very important in the marine environment if you want a long-lasting connection.

Crimping will require a special tool for that. I have one but prefer to solder.