VHF antenna splitter

Previous topic - Next topic

0 Members and 2 Guests are viewing this topic.

scotty

I want to put a VHF radio at the helm of my boat.  In a post by Ron, on a thread about RAMs, he mentioned a slider switch to go back and forth between radios.  My questions are:  Can I use a splitter to connect both radios to the same antenna?  Does there have to be a slider switch?  Perhaps I would be better off putting a separate antenna on the radar pole at the stern (which is my preference).  Can I just tap into the 12 supply to the instruments, or should I run a dedicated line to it?
Scotty

chuck53

I suggest a radio with a RAM.

waterdog

#2
A splitter will reduce antenna gain / output power by at least 3 dB.   That is half the power.   A switch  is an improvement, but will also add insertion loss.  Your best choice performance wise is two antennas.  I even go so far as to not have a connector at the base of my mast.  

Tapping into the power is a separate issue and not as big of a concern.  
Steve Dolling
Former 1988 #804, BlackDragon - Vancouver BC
Now 1999 Manta 40 cat

stevewitt1

Steve
Upgrading my coax and antenna are planned for this spring.  I'm planning on a Celwave antenna (I've had great luck with them) and like a RG-8u coax.  You mention no connection at the base of your mast; how do you connect?  I step my mast every year.

Steve

Jim Hardesty

Scotty,
Your plan to add a second radio at the helm has it's advantages, it's a total back-up.  The only draw backs, the clutter at the helm, and due to the antena being lower somewhat shorter range.  A RAM would reduce clutter but is no back-up if the main radio or mast head antena breaks.  If your MKll is like mine, there is 12v power to the engine panel wired to a lighter plug.
I would not use a splitter or selector switch.  I'm the guy at the club with a SW antena tester and have seen a lot of problems with them.
Me, I have a RAM (realy a wireless RAM that I wouldn't recomend) and a hand held for back-up.
Jim
Jim Hardesty
2001 MKII hull #1570 M35BC  "Shamrock"
sailing Lake Erie
from Commodore Perry Yacht Club
Erie, PA

waterdog

Quote from: stevewitt1 on December 22, 2012, 03:50:24 PM
Steve
Upgrading my coax and antenna are planned for this spring.  I'm planning on a Celwave antenna (I've had great luck with them) and like a RG-8u coax.  You mention no connection at the base of your mast; how do you connect?  I step my mast every year.

Steve

I have a single uninterrupted cable from the masthead antenna to the radio.   I have pulled the mast only once since installing it pulled it back through to the bilge when I did.   If you pull the mast every year you might appreciate the convenience of a connector.   The downside of a connector is that they have a some loss and are subject to corrosion and increased signal loss over time.   
Steve Dolling
Former 1988 #804, BlackDragon - Vancouver BC
Now 1999 Manta 40 cat

Ron Hill

Scotty : I've used a manual Shakespeare switch for a cockpit VHF and a cabin VHF for about 25 years.  The down below cabin VHF has a 2nd speaker in the cockpit.  Everything has operated flawlessly for all that time.

I like the redundantcy of the second VHF.  One below was the old cockpit radio when I decided to go to DSC.
When we are at anchor and down below, it's nice to monitor the radio and not have to go into the cockpit.

A few thoughts
Ron, Apache #788

pablosgirl

Hi Scotty,

I have a friend that uses the Shakespeare switch for his cockpit VHF and it has worked flawlessly for the last 12 years.

Have you considered using a hand held VHF for the cockpit?  That is what I do.  It is very convienent to not be tied to the NAV station or the wheel pedistal.  I cary  a spare for the dingy

Paul
Paul & Cyndi Shields
1988 hull# 551 Tall Rig/Fin Keel
M25XP

Ron Hill

Paul : I have 2 hand helds on board and found it much more efficient to use a regular VHF in the cockpit.

The battery status of a hand held is always questionable and for me it's easier to steer / talk / listen above engine and surrounding noises / change frequencies with cockpit mounted VHF.  My thoughts  :santa
Ron, Apache #788

scotty

I've heard various reports on how well RAMs work.  Mostly about speaker volume and clarity.  Any comments on that?
Scotty

Dave Spencer

Scotty,
I have an ICOM RAM (ICOM RAMs are called Commandmic I think) and I am very disappointed in it for exactly the reasons you outlined.  The speaker volume is not even close to loud enough and transmissions are weak and muffled.  Thinking the issue might be poor cable routing, I bought a new cable and tried it by simply connecting to the appropriate connector in my ICOM 502 radio and snaking it through the companionway.  No notable improvement.  Even connecting the Commandmic directly to the "RAM" connector on the main radio provides unsatisfactory results.  To compensate, I have fitted a remote speaker in the cockpit so I can hear properly.  I rely on my handheld for routine communication and head below to the main radio if I am range limited by the handheld.  I like Ron's idea to have a second VHF mounted in the cockpit and use a switch for the mast top antenna.  A project for this year or next.
Dave Spencer
C34 #1279  "Good Idea"
Mk 1.5, Std Rig, Wing Keel, M35A Engine
Boat - Midland, Ontario (formerly Lion's Head)
People - London, Ontario

mtullier

I mounted a 2nd VHF under the knot meter with a dedicated antenna mounted on the stern railing.  Works very well and is out of the way.  I also mounted a GPS under the depth meter.  I will post a few pics if it will help you with ideas.
Mike

Dave Spencer

Mike,
Thanks for the offer of pictures.  I'd appreciate seeing them and would welcome all ideas on how and where to mount a cockpit radio.

Dave Spencer
C34 #1279  "Good Idea"
Mk 1.5, Std Rig, Wing Keel, M35A Engine
Boat - Midland, Ontario (formerly Lion's Head)
People - London, Ontario

Ron Hill

Dave : There is a Mainsheet article written with a picture to answer your very question!

I mounted mine just below the engine instrument panel on the port side of the cockpit.  A thought
Ron, Apache #788

mtullier

VHF under pedestal.  Out of the way, but close enough if needed. No additional holes in the boat made up my mind
Mike