Mast is down for refit,,,Antenna ???

[alexanick]

To tkeithlu,

Why do you recommend the upgrade to R8 or R213?

[alctel]

What I did was

- installed condiut
- changed out all the nav lights for purpose built LED versions
- added a red over green mount at masthead (lets me run that + deck lights unlike a tricolour)
- added a radar
- added fog horn/hailer under radar
- added LED spreader lights (these things are GREAT)
- reran all cabling including coax
- added AIS antenna on spreader

A lot of good advice in this thread

[Jammer]

Originally Posted by alexanick

To tkeithlu,

Why do you recommend the upgrade to R8 or R213?

I'm not tkeithlu but I can tell you that the main reason is lower loss. Due to the length of the cable run up the mast it can make a difference of several dB.

Coax Attenuation Chart

You give up some flex with RG-8 or RG-213, though, and it's heavier and uses up more space in the conduit. There is some variation from one manufacturer to another, particularly in durability, so choose a reputable source.

Originally Posted by Pete7

Worth having a read of this thread:

http://www.cruisersforum.com/forums/...nna-99651.html

The VHF antenna and coax is just one of those thing worth doing the research and buying quality items, not the cheap and chearful stuff in the chandlers. Its not so much about range but about achieving clear comms at distance.

I don't know much about boats but I have spent some years working with amateur and commercial radio systems.

Usually any cheap antenna will work OK for a while. The difference is that good antennas will withstand wind and rain and ice and sunlight over a period of years and still perform properly. That is what you are paying the $$$ for. For a masthead mount you want a center-fed dipole as it will not require a ground plane and will be relatively unaffected by heel. The Shakespeare antenna mentioned in the linked thread would be a good choice. There are other good choices.

The only problem with center-fed dipoles, and it affects them all regardless of manufacturer, is that they're around 4' long, and so if bridge clearance is a critical thing for you they are not ideal. There are some base-loaded antennas that are shorter but they are not as weather resistant.

[tkeithlu]

You can certainly stick in an LED that is not as visible as the former incandescent. You can do that by using a lower wattage incandescent bulb, too. That's what I would consider "dumbest thing you can do," not replacing incandescents with LEDs per se. It is important to know the output of the substitute. In fresnel lens situations (large nav lights) it is also important that the light come from the right place, but that's not difficult.
As for color filtering, incandescent bulbs are so red that 70% of their energy is inflared - heat. Getting green out of that is a job. I've had no problems with brightness or radio interference using LEDs in former incandescent sockets.

We had a thread awhile back on masthead anchor lights. The conclusion was largely that anchor lights, no matter how bright, are easily lost among other lights and supply no information regarding distance, given they are point sources. We use multiple lights (yes, LEDs) to outline our boat at anchor.

[tkeithlu]

I am tkeithlu, and I think Jammer answered the question on upgrading antenna cable. It's unlikely the manufacturer used "the good stuff." RG58 is cheap, but entails a big loss up a tall mast. R8 and R213 are more expensive, but less loss. In addition, antenna wire and antenna wire fittings are prone to corrosion loss, and yours have been around a long time.

[Bor the Wolf]

Originally Posted by tkeithlu

RG58 is cheap, but entails a big loss up a tall mast.

Nah. A big loss? it has an attenuation of only 5 dB per 100 feet. In a mast of 30 feet you loose only like 1.5 dB.

But a thicker cable does help a little of course. The trouble with a thicker cable is that it often does not fit through existing holes and ducts. Maybe you should consider a modern cable instead. Those modern coaxial cables used in satellite receivers or in cable television networks have much less attenuation at the same diameter. I have used Belden H-155 in my mast. It has a similar attenuation as RG-213 but it only has the diameter of an RG-58 and it fits neatly in the existing ducts and holes.

To name just a few modern types for your consideration (but there are many more):
Belden H-155
Tremoflex-10 (Professional stuff, used on large vessels and rigs)
Cellflex LCF12-50
Aircom-7 (Great characteristics but kinks easy)

[Dallasron]

I want to thank everybody for the great info !! Just a few cents on the LED replacement bulbs.

* 12vdc rating is not going to work long term. Ideally you need something that will work from 9 to 16vdc. Without the range your charging cycles will burn them.

* Do not use the watts rating to determine brightness and don't believe it when they say a 4 watt led is equivalent to a 50w bulb. You have to have the lumens figure to make that call. Good rule of thumb is that 60 watts is about 800 lumens.

* Check the color of the LED. While I want the 6000k for my anchor light (very bright fluorescent color) I only want around 2700 for deck lights. (incandescent)

* Depending on location make sure they are dimmable. I have 2 red led replacements in the cockpit arch on a dimmer and they are perfect for those midnight sails with friends. I can dim them to just a faint glow.

I will

[continuouswave]

Originally Posted by Dallasron

...I want to get a new VHF/UHF antenna...

Please elaborate on the frequencies and services to be received or transmitted at UHF bands from your boat. Is the UHF antenna to be provided as a combination with a VHF Marine Band antenna, that is, a dual-band antenna?

[Rick]

The R8 has a much larger current-carrying capability on the shield in case you get hit by lightning I was hit by lightning in Panama and the larger shield on the R8 save my butt carrying the discharge to the bonding system

[Dallasron]

Continuous Wave

Based on my needs today and those I may need when we take it to the coast.

Just deliverd: Shakespeare 3004 SeaWatch Marine TV Antenna, 4" with a splitter for AM/FM and will be mounted on the masthead in place of the old analog antennae. Replace old coax with RG213.

Replacing the old Masthead VHF antennae and cable with a Vesper VA159 and RG213 coax. We dont need the AIS at the moment but will be able to add the splitter when we do.

Still looking for the latest greatest waterproof marine wireless repeater (6db) to put on the spreader. When connected this would also serve as a wireless router to other devices. Cat6 wiring with power.

Whoever wired the masthead previously did a prettty job but technically s--t. Wire is all pulled down tight with sharp 90's. I will be using radius loops along with heatshrink, covers, and liquid electricians tape.

lots of other stuff but that is the signals

[continuouswave]

In reply to my request for elaboration on the UHF bands necessary for his antenna refit:

Originally Posted by Dallasron

...Based on my needs today and those I may need when we take it to the coast....

I am afraid I did not understand any of your remarks. I still have no idea what sort of UHF frequencies you want to employ on your boat.

For any sort of UHF antenna that will be connected to a transmitter via a long run of transmission line, the transmission line loss must be held to a minimum. If you are serious about UHF (that is, frequencies above 300-MHz) then the transmission line should be selected to limit loss at those frequencies to under 1.5-dB. This generally means some seriously large, good, and expensive transmission line.

[Dockhead]

Originally Posted by Bor the Wolf

Nah. A big loss? it has an attenuation of only 5 dB per 100 feet. In a mast of 30 feet you loose only like 1.5 dB.

But a thicker cable does help a little of course. The trouble with a thicker cable is that it often does not fit through existing holes and ducts. Maybe you should consider a modern cable instead. Those modern coaxial cables used in satellite receivers or in cable television networks have much less attenuation at the same diameter. I have used Belden H-155 in my mast. It has a similar attenuation as RG-213 but it only has the diameter of an RG-58 and it fits neatly in the existing ducts and holes.

To name just a few modern types for your consideration (but there are many more):
Belden H-155
Tremoflex-10 (Professional stuff, used on large vessels and rigs)
Cellflex LCF12-50
Aircom-7 (Great characteristics but kinks easy)

Sure, but who has a 30 foot mast? Maybe a 19' Flicka? My mast is 75', plus another 10 meters to the nav table, for over 100' altogether. At 157mhz (ch 16), RG58 would be producing well over 6dB of attenuation; compared to only 2.8dB or so with RG213. That's a big difference on a logarithmic scale -- your 25 watts output power is attenuated down to 6 watts (!), compared to 13.5 watts with the RG213.

Of course power is not the most important or even second most important thing in how well your signal gets out, but 6 watts delivered to the antenna is just a little too little, in my opinion.

I chose RG214-U for my installation. Yes, it was much harder to pull, but I eventually got it, using a lot of baby powder and persistence.

As to the Belden H-155 -- like the LMR-400 (which I use on my boat for some other applications, like sat phone external antenna and UHF ham radio), this is foam/gas filled. I would be skeptical about using it up the mast considering the risk of crushing, water penetration, etc. RG213/214 has solid insulation.

[Dallasron]

Continuous Wave,,After reading all the words I see what you are asking . I am not going to address the UHF at this time since we are currently on a lake. What I am doing is leaving a block with a messenger tied off at the top of the mast for the sole purpose of running an antennae from the deck up for the SSB. Havent thought it through since this is something that could change quickly. The boat is for sale as we are refitting. That said, I am refitting as if we will take the boat to the coast and take off with it. If the stars line up to where we can get 18months free, I plan to have a fire sale and buy another boat in the med and we will move onboard.

It sounds like you could tell me what would be the best and I would welcome any input.

thanks

ron

[continuouswave]

About the only useful UHF radio service I can see for a small boat on a lake is the GMRS or FRS radio service. To learn about them see

https://en.wikipedia.org/wiki/Genera..._Radio_Service

A good radio for use in those services on a boat might be the Midland MXT 100 transceiver. See

https://midlandusa.com/new-extended-...d-to-everyone/

These radios will be useful in the USA (and Canada) to make legal transmissions and communications between a boat and a personal shore station or a person on shore with a handheld radio. The Marine Radio Service does not permit use of marine radios to communicate with personal shore stations, and it is unlikely you could get a license for a shore station. Of course, most people on lakes have cellular service so the just phone home.

[Bor the Wolf]

Originally Posted by Dockhead

As to the Belden H-155 -- like the LMR-400 (which I use on my boat for some other applications, like sat phone external antenna and UHF ham radio), this is foam/gas filled. I would be skeptical about using it up the mast considering the risk of crushing, water penetration, etc. RG213/214 has solid insulation.

H-155 is not foam filled. Tremoflex is what is on the RNLI and KNRM lifeboats and on Royal Navy vessels. A 30 foot mast is the maximum in my neck of the woods due to a couple of low bridges. Obviously we can have two instead of one. And no, it is not a 19' dinghy.

The point is that today we have much better coaxial cables available than good-ol' RG58 / RG213. etc. Talk to Belden or a professional marine VHF rigger!