I've done a lot of work with radio communications. From my days as a teenage ham, through broadcast engineering, to installation and use of VHF radios on several boats, and completing the circle of life, back to ham radio.
Seriously, if you have a boat, and a VHF radio, there are some non-geekish things you need to know. First is that the finest VHF radio you can buy isn't worth more than about a nickel unless your antenna system is up to speed. I'm amazed at the number of boaters who buy and install a new radio with not one bit of what I consider common sense analysis.
Unless your radio is older than the hills, and unless there have been some outside influences that could cause a premature death, you may want to have an analysis done before shelling out big bucks for a new piece of electronic marvel that may not perform any better'n your existing radio.
Radios do two basic things. They transmit and they receive. With the number of NOAA weather radio stations, operating 24 hours a day, you can usually check out the receiver with some ease. A fellow boater can tell you how many of the weather stations you should be able to pick up, and how strong they should be, given your boat's location. If the guy in the slip next to you can hear three channels, and one is strong, you should be doing the same thing. If not, you could have either an antenna problem, or a malfunctioning radio.
I'm not going to analyze your radio issues, step by step. At least, not here. I do want to share a couple points about antennas. Here are some pictures of a couple antennas I took out of service. One looks awful. It's seen a lot of use...about 15 years worth. To have survived harsh marine elements, that's pretty darn good. When removed from service, it was actually still performing well. But, you'll note the coax cable...the wire that connects the antenna to your radio...is a little frayed. You'll also note the condition of the fiberglass shell. It's coming apart.
Notice the frayed coax. Not good.
The internal element had separated. Not only did it affect the transmitting signal, a trained, experienced ear could tell that the regularly-received weatber stations weren't being heard so well.
If you're having what you think are radio problems, you might want to have a technician check out your entire system. He/she can tell you, with a couple simple measurements, whether you have a radio problem, or an antanna system issue (system includes the antenna, coax cable AND the antenna connector... the thingie that hooks up your radio to the antenna).
A radio that is transmitting at one watt, going into a good antenna system, will outperform a 25 watt radio connected to a defective antenna like the one described here.
While I'm discussing antennas, don't go the cheap route if you're buyig a new one or replacing one that's terminal. In the beginning, a 6 db gain cheap antenna will generally perform as well as a 6 db gain expensive antenna. The better made, i.e. heavier-duty, antennas will continue to give good service after years of whipping back and forth when you're on the high seas. And, depending on your requirements, you might want to consider the longer antennas. Those marine VHF channels depend on antenna height as much as they do antenna gain and transmitter output power.
Were you able to follow that? If you did, you might be a bigger geek than I am.
Seriously, if you have a boat, and a VHF radio, there are some non-geekish things you need to know. First is that the finest VHF radio you can buy isn't worth more than about a nickel unless your antenna system is up to speed. I'm amazed at the number of boaters who buy and install a new radio with not one bit of what I consider common sense analysis.
Unless your radio is older than the hills, and unless there have been some outside influences that could cause a premature death, you may want to have an analysis done before shelling out big bucks for a new piece of electronic marvel that may not perform any better'n your existing radio.
Radios do two basic things. They transmit and they receive. With the number of NOAA weather radio stations, operating 24 hours a day, you can usually check out the receiver with some ease. A fellow boater can tell you how many of the weather stations you should be able to pick up, and how strong they should be, given your boat's location. If the guy in the slip next to you can hear three channels, and one is strong, you should be doing the same thing. If not, you could have either an antenna problem, or a malfunctioning radio.
I'm not going to analyze your radio issues, step by step. At least, not here. I do want to share a couple points about antennas. Here are some pictures of a couple antennas I took out of service. One looks awful. It's seen a lot of use...about 15 years worth. To have survived harsh marine elements, that's pretty darn good. When removed from service, it was actually still performing well. But, you'll note the coax cable...the wire that connects the antenna to your radio...is a little frayed. You'll also note the condition of the fiberglass shell. It's coming apart.
Notice the frayed coax. Not good.
The other antenna, the top one in this shot, looks pretty good. Only a couple years old, it should have been working just fine. Well, it wasn't. In fact, a simple test with what radio tech types call an SWR/power meter showed it, in layman's term, was deader'n a doornail. For you techie types, the SWR was slightly less worse than 10-to-1. A total mismatch.
Time for the autopsy. With a hacksaw, I started removing the outer shell. These fiberglass shells house and protect the actual antenna element. The guts of the system. Should be intanct, from the bottom to the top. The sections are constructed to work, electrically, in the marine VHF band, and to deliver as close as possible a perfect match. Meaning that most of your rado's transmitting power actually gets out of the antenna.
Not the case, even though it looked pretty good. Looks, as we all know, can be deceiving.
If you're having what you think are radio problems, you might want to have a technician check out your entire system. He/she can tell you, with a couple simple measurements, whether you have a radio problem, or an antanna system issue (system includes the antenna, coax cable AND the antenna connector... the thingie that hooks up your radio to the antenna).
A radio that is transmitting at one watt, going into a good antenna system, will outperform a 25 watt radio connected to a defective antenna like the one described here.
While I'm discussing antennas, don't go the cheap route if you're buyig a new one or replacing one that's terminal. In the beginning, a 6 db gain cheap antenna will generally perform as well as a 6 db gain expensive antenna. The better made, i.e. heavier-duty, antennas will continue to give good service after years of whipping back and forth when you're on the high seas. And, depending on your requirements, you might want to consider the longer antennas. Those marine VHF channels depend on antenna height as much as they do antenna gain and transmitter output power.
Hello can anybody help, I have a marine vhf radio, Which I get incoming calls but cannot put out calls The radio is 1 year old as the antenna is new Cheers,
ReplyDeleteIf your radio is a year old, you should be able to get it repaired under warranty. If, indeed, there is a problem. You write that it's transmitting, but you can't receive. If you'll drop me an e-mail at raefordbrown@gmail.com, and include your phone number, I might be able to help you narrow down the problem. Could be something simple. Raeford
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