Antennas...

Bygracealone · #1 08-20-2009, 10:39 AM

Hi guys,

I need to buy antennas for my VHF and my stereo. I can't find any previous holes on the gunwales, but there are some holes on the console that may have been where the previous owner had antennas at one time. Because I have a bimini top, I can't buy the 8 footer antennas unless I want to mount on the gunwale. I'd rather not, if I don't have to (I don't want to make any unnecessary holes on her, plus I'd rather not have to try and route the cable).

For those reasons, I'm thinking that I may go digital with some 4 footers mounted directly on the console. I'm looking at these two:

http://www.bestboatingdeals.com/prod...8vw-white-45db

http://www.bestboatingdeals.com/prod...ft-531aw-white

Do you guys know anything good or bad about going this route? Am I overlooking anything?

bcmarinamanager · #2 08-20-2009, 10:50 AM

Either is nice, but I'd look at a VHF spliter, which allows you plug your fm radio antenna into the line for the vhf as well without interfering with either. I think you can find them at West Marine, and any boat store.

Bygracealone · #3 08-20-2009, 11:10 AM

Quote:

Originally Posted by bcmarinamanager

Either is nice, but I'd look at a VHF spliter, which allows you plug your fm radio antenna into the line for the vhf as well without interfering with either. I think you can find them at West Marine, and any boat store.

I was reading about those and I noticed some comments about the splitter causing a weaker signal. Have you heard anything like that?

Thanks for the help!

Here's the comment I'm referring to:

Question: Does Digital Antenna offer an AM/FM and VHF splitter or band separator for use with a VHF antenna?

Solution: A VHF/AMFM splitter drastically degrades the VHF performance. Digital Antenna does not promote such a function. VHF antennas are your lifeline and it is never wise to degrade the performance. A splitter to combine frequencies should never be used especially when the systems are not even the same impedance. VHF is 50 ohms and AM/FM is 75 ohm. Combining two different impedances creates an instant mismatch which detunes the antenna performance. As with any 2-way splitter, a minimum 3dB loss (50% power loss) is present. This loss drastically cuts the performance of a VHF antenna. These laws of physics can not be avoided. Digital Antenna does not recommend using a VHF/AMFM antenna splitter.

Blu_Lunch · #4 08-20-2009, 11:22 AM

I read the ad for the antenna, they state there "hand tuned" I've been a ham for over 20 years and you need to check your SWR with a VHF 144MHZ meter it's really important you want a 1:1 to 1:3 reading, the higher it gets more RF is reflected back in to the radio and will burn your TX finals out. I would be careful of the placement antenna close to electronics, it will play hell when you TX. Don't use a splitter they do cause losses and with a 4db gain you could save money and use a coathanger instead.

Bygracealone · #5 08-20-2009, 11:36 AM

Blu, given your comment about the gain, I take it your saying I should stick with an 8 foot antenna? Whether digital or not, I believe I can't do better than 4db with a 4 foot antenna...

Thanks for the feedback, much appreciated. I'm clueless when it comes to this stuff.

jjjtronics · #6 08-20-2009, 11:49 AM

BGAlone,
Your VHF radio and its antenna, are the most important gadget in any boat.
In case of an emergency, your Marine VHF is the best chance of getting help from boaters in the area, and those boaters are the only ones who can reach your boat quickly. A cell phone is great, but our friends on land can not do much without a boat.
As already said, ANYTHING you install between the radio and the antenna, ( besides the needed coax cable of course ), induces losses in signal strenght and, adds chances for connection problems, etc.
The best and most expensive radio unit, is worthless without a good and properly installed and tuned antenna system. An improperly installed antenna, specially a shorted connector/cable install, renders the antenna useless and will damage the radio.
I recommend getting an 8 foot, 6db gain Shakespeare unit. They are long lasting and VERY reliable. Then have a local Ham radio guy or radio tech do an SWR check after the install.
I think antennas make a boat look good if installed with style and properly.
Your music radio antenna can even be hidden inside the hull and still work because of the high power from local radio stations.
Also, I never leave the Marina until I do a radio check ( on low RF power ) and verify my VHF radio. If my boat ever starts sinking, I will reach someone to haul my Family and me out of the "Blue Pool" with sharks and else...

Blu_Lunch · #7 08-20-2009, 11:56 AM

Ham operator can help you out. Try this link for QRZ database type you town and state hit search and all the hams in your town will be displayed, click there names and addresses will be displayed.. Buy the best attenna with the highest gain possible
Ted KE1DK look me up in the database

http://www.qrz.com/db/?cmd=1

Blu_Lunch · #8 08-20-2009, 12:03 PM

Here is a excellent really informative marine antenna page; anybody needs a clarification on something I could try to help make sense of it............

http://members.toast.net/boatguy/vhfant.htm

Bygracealone · #9 08-20-2009, 12:04 PM

Gracias hermano (JJ)...

Okay, I'll go with the 8 foot Shakespeare. Is there really that much difference between the models? I understand the 5225 XP is the top of the line, but would a 5101 or a 5202 get the job done well?

Also, do AM/FM antennas interfere with electronics too? Would it be okay to put a short AM/FM antenna on the console or should that also be an 8 footer installed on the opposite side of the boat?