VHF Radio and Antenna Install

[cwoav8r]

Just FYI, here are the details of my VHF radio and antenna installation as posted on YJB years ago:

Finished the VHF installation on my AR-230. Happy with the way it came out with one exception... after I got the power connected and turned the radio on I realized that I did not take one thing into consideration. The radio display is not very visible when viewed from the seat. The reflection in the gel coat is great so you can get a really clear view upside down and backwards. It is more visible in daylight than at night for some reason and a little better if you view from the sides. For what it's worth I do not think it would have changed my mind, I would have still mounted it here.






Folded...

With the correct size aluminum pipe (and a wrap or two of duct tape) inserted in the top of the mount it will double as a flag holder. I'll post some pics of this as soon as I can get back on the boat. I can't remember where I got the folding antenna mount... but I found these links (hope the links don't die)

The mount:

http://shakespeare-marine.com/style-4188-s
http://www.walmart.com/ip/Shakespeare-4188S-Stainless-Steel-Rail-Mount/25991378
http://www.amazon.com/Shakespeare-4188-S-Stainless-Steel-Mount/dp/B000SMTTSY

The antenna:

http://www.westmarine.com/buy/shakespeare--mariner-4400-3-vhf-stainless-center-console-antenna--6966097

1 7/8" to 1" universal rail mount adapter here:

http://www.fishmaster.com/products/Universal Rail Mount.htm

More info available on request...

Noteworthy... Fishmaster is owned and operated by the inventor of the Monster Tower, they made the towers for the '07 to '09 Yamaha's. Not sure about other years...

 

[Geoff Cooper]

Lovely installation very neat and tidy, Nice to see an antenna mounted correctly, Shakespeare are a very good company i used there equipment 30 years ago, I bet your SWR is around 1.1 on that antenna with that wake tower for a ground plane, I wouldn't worry about the LED readout it's not as if your going to use it all the time anyway, I'm an old English Radio Ham so my ears pricked up when i read your article, Well done to you Sir you deserve congratulating.

 

[sysinu]

Do you happen to know if they make the same universal mount for a 2 3/8" tower tubing?

 

[Geoff Cooper]

Hi James I'm sorry i cant answer that but my suggestion would be to go to any Amateur Radio outlet ie Radio Shack in the States if they are still going and ask them, There are many different universal Antenna mounts and they should have a selection there, Ebay is also a good place to locate radio gear, Punch in Amateur Radio Equipment or Ship to Shore Radio and that will put you on the right track, When you do get to the stage of mounting an Antenna make sure the radiating element is clear of any metal or this will affect your standing wave ratio and reduce your performance greatly, Good luck with the search let me know how you get on and give me a shout if i can be of anymore help,

 

[cwoav8r]

Do you happen to know if they make the same universal mount for a 2 3/8" tower tubing?

Last time I checked with them, all their mounts were 1 7/8... I'll look around and see what I can find.

Thank you @Geoff Cooper and by the way, I am KE4MGM...

 

[Geoff Cooper]

Nice to meet you KE4 MGM from G4 VQO

Just a thought and please don't take this the wrong way it's not a criticism but I'm of the opinion that if you mounted that 5/8 whip Antenna in the middle of the top of the wake tower you would certainly increase your Tx and Rx performance, I have been looking at this and that whip is close to the wake tower and also has metal above it, Your radiation pattern would be elliptical and forward facing for receive and Transmit, On the top of the wake tower it would be perfectly omnidirectional also if possible i would take the coax if there is enough left over and loose it behind the helm and around the front seating compartments and take it that way to the Transceiver, If you roll it up it will add capacitance and the standing wave ratio will increase and output power and RX signal will be reduced, That Wake tower is the perfect ground plane and maximum performance would be achieved, A quick tip when your moored wrap a piece of cable around your Wake tower and drop it into the water then watch your receive signal increase, Let me know what you think,

From G4 VQO

 

[MEShep]

That's a very nice set up. One question about the ground plane effect. I see that with a nice uncoated tower you have a solid electrical connection between the ground wire on antenna mount and the tower (ground plane). Would the tower still act as a ground plane if it was powder coated and there was no direct electrical connection to the antenna ground wire? And if a electrical connection is needed, would grounding the tower at the bottom be suitable or does it need to be grounded at the antenna?

 

[Geoff Cooper]

That's a very nice set up. One question about the ground plane effect. I see that with a nice uncoated tower you have a solid electrical connection between the ground wire on antenna mount and the tower (ground plane). Would the tower still act as a ground plane if it was powder coated and there was no direct electrical connection to the antenna ground wire? And if a electrical connection is needed, would grounding the tower at the bottom be suitable or does it need to be grounded at the antenna?

If you have a powder coated wake tower you would need to clean the paint from where the ground side of the Antenna makes contact with the wake tower, Some antennas are made not to use a ground plane as inside they will have a small wound coil actually built into the circuit board which acts as the ground plane, Antennas work on reflection ie if you are using a 5/8 wave and when you connect it to a ground plane the Antenna thinks it has another 5/8 wave underneath it facing downhill so it works well, The bigger the ground plane the better and a wake tower is perfect, If the Antenna is mounted in the middle at the top with no obstruction to it's radiating element you will get 100% performance as it is an Omni directional Antenna it radiates in a complete circular pattern as opposed to a directional Antenna which will only receive and transmit where the elements are pointed ie a TV Antenna, If you move a TV Antenna away from the direction of the Transmitter you loose signal same applies to a satellite dish it's directional any Antenna has 2 parts the radiating element and the ground plane side and neither will work without the other as it makes a complete tuned circuit. If the ground plane is not of a sufficient size then it will send the Standing Wave ratio high and it will not perform correctly also it puts unnecessary stress on the output transistors of the Radio and after a while will damage them if for example the radio produces 25 watts then that calculation is based on it transmitting into a balanced load ie an Antenna set properly at that frequency, If the Antenna is not set well then it will be unbalanced and power will return to the output transistors and they will get very hot and reduce there performance, The excess power has to go somewhere that's why you use an SWR meter to check that your Antenna is correctly set, Another problem that can occur is if someone had rolled up the excess cable as that produces capacitance and again will affect performance better to loose the cable by spreading it out and not coil it up, Don't cut the cable as it is a measured length to balance with the Antenna as it forms part of the circuit.

 

[ToddW850]

Nice! Looks good. I currently have a handheld VHF and it definitely gets the job done. But been thinking about getting a mounted one. Maybe a winter project.

 

[cwoav8r]

Let me know what you think,

Sorry so long to reply... I completely agree. It was more about aesthetics at the time and less about range. If I get the chance I might move it to the next rail up, but I don't want it on the top of the tower because in rough water, I have bent the crap out of the whip with it extended. Because of that, I decided it better to have a point to secure the end of it when stowed. I did not coil any of the cable... it is stretched from bow to stern as far as it would go.

I know I can receive at 20 miles (a trip to the Marquesas when I was in Key West) and would expect better than that, but I did not try to transmit at that range. I have transmitted 10 miles with no problem, and will rarely be further out than that. For an extended trip I rely on an EPIRB.

And, after reading your post you have reminded me... I will now have a six foot piece of cable that I keep on the boat... just in case.