VHF Range

Converse48

Converse48

Well-Known Member
Nov 20, 2006
2,161
Chesapeake Bay
Boat Info
2010 McKinna 57 Pilothouse
Engines
QSM-11
What's a reasonable range for a VHF radio? I have an 8' antenna mounted pretty high... yet I can't seem to get beyond a few miles.

Yes, I have checked to make sure the radio is not on low power!
 
With your boat and antenna, in the open Chesapeake, I would expect a good 10-20 miles, even with all the variables involved with VHF transmissions (height, obstructions, etc.)

Is your trouble sending, receiving or both?

Esteban
 
I've found that more important than a top quality radio, a top quality antenna is most important.

When I outfited my last boat, I bought a very good antenna, ($200 or so, ten years ago) and many people asked about the fact that I could transmit and receive much farther than them.
 
Prodigalson-

The likely culprit on your boat was the delivery. When they deliver the sedan bridges, they often just cut through the whole bundle of wires in the starboard arch. Most times the splices, if any, leave a lot to be desired. Removing your seat back to gain access to those wires isn't too bad, but I'll bet that's the source.

I recently found a 2005 420DB where even the bonding wire had been cut and not put back.
 
What range can I expect from the antenna?
Here is the formula to determine range:
Calculation for Range of an Antenna:
6db Antennas: Square Root of Height (in feet) above water x 1.15= Range in miles
9db Antennas: Square Root of Height (in feet) above water x 1.52= Range in miles
Remember to perform the calculation for BOTH vessels, then add the results for the range between two vessels

If Pirate is correct that the cables have been cut that is your problem. I would not splice but would pull a new coax after I calmed down. If your coax is not cut the most likely problem is the PL 259 connector.

By the way can you recieve OK?
 
Solid antenna connections.

Anytime I have VHF range issues I go right for the antenna connection and any splices. Clean the cable ontacts, retighten securely and make water tight.

My semi lame Ray 220 still gets about 12 miles on open water and I've got that cheapo Shakespear antenna from the factory. I'm considering upgrading this whip to the top end 8' footer ... it sin the 170 buck range ..

Sorry for the HiJack, but any one got better suggestions?
 
estebanj said:
Is your trouble sending, receiving or both?
Click to expand...
It appears to be both. Does that point me in a certain direction?

pirate said:
The likely culprit on your boat was the delivery. When they deliver the sedan bridges, they often just cut through the whole bundle of wires in the starboard arch. Most times the splices, if any, leave a lot to be desired. Removing your seat back to gain access to those wires isn't too bad, but I'll bet that's the source.
Click to expand...
I think you may be right! Although the dealer will take another run at this (they've already replaced the handset), I will check that. Access is pretty good via inspection panels.

Thanks!
 
you can buy a swr meter from west marine for about 70 bucks and hook it up yourself. (if you can get to the back of the radio) youll also need another short piece of coax (radio to coax to meter to coax to antenna)

This will give you a ver good idea of the effeciency of the entire system.

THe swr (standing wave ratio) of your system should be in the 1.5:1 ratio area.

Heres a pretty good article that might shed some thight on things for ya!
http://www.saltyjohn.co.uk/resources/Marine%20VHF%20Antennas%20(aerials)%20and%20their%20installation.pdf


Hope this helps

Wade
 
Just remember that 1.5:1 is only probably likely at the center of the VHF band.

If you look at Shakespeare VHF Marine antennas, they can achieve close to 1.5:1 at the band center, but across the VHF band, the specification is 2:0.

So when you are measuring the VSWR, it depends on what channel the VHF is tuned to. I always felt that it be best to try it at the lowest frequency, mid-band, then highest frequency.

Remember that the antenna will only be cut for a single frequency - usually at the center of the band. And without an antenna tuner, as you go to each end of the band, there will be a slight mis-match of antenna to frequency.

If you get 1.5:1 at the center, that is great, but its better if you can get 2:0 at each band end.
 
Tim,

Remember that VHF is line of sight and so land obstructions are going to impact you some up there on the Chesapeake River. My Ramarine crap radio gets about 15-20 miles boat to boat on open water but much better with the Coast Guard towers. I have a 16 foot VHF antenna I am going to mount this winter that will add about 4 feet to the current height of my VHF (the way the bracing works and all) but it's a Digital Antenna and better than the thing on the boat now. I'll probably replace that crappy radio also... it's the Raymarine thing you hold like a phone and I have always hated it. The main reason for me going to 16 feet on the VHF is that I have to match the SSB 16 footer on the otherside so it matches.

Why don't you get an SSB and then you'll be able to talk to me down here during the day?! Ha ha ha ha.
 
I forgot about that! Tim? You one of these north-bay antenna fashion experts that tilt the 'tenna back to look fast?

pic1-17.jpg
 
Gary- Why does the boat in the picture feature a hailer aimed at the captain? Is that some strange form of entertainment for those long trips at displacement speeds?
 
You guys kill me... and yes, the antenna is vertical.

Maybe the six foot wind sock attached at the top has something to do with it?
 
I should have noticed that wind sock before. It really is pulling over your antenna... that could be it.

timsock.jpg
 
and the winner is......



Pirate!

The antenna wire was cut and poorly spliced. A new antenna is on its way.

Thanks!
 
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