Will a hand held radio perform better with a 8 foot antenna?

Mark42

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Oct 8, 2003
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I have a Cobra hand held marine radio (model HH300). Was wondering if it is worth the expense to install a traditional 8' antenna and connect it to the hand held to get better coverage?

The cobra has the common 1 and 5 watt transmit spec.

Thanks!
 

milmat1

Petty Officer 2nd Class
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Apr 29, 2010
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Re: Will a hand held radio perform better with a 8 foot antenna?

Yes, All the Difference !!
 

NYBo

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Re: Will a hand held radio perform better with a 8 foot antenna?

Absolutely. The length and particularly the height of the antenna makes much more difference than the output power difference between 5 and 25 watts.
 

Mark42

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Re: Will a hand held radio perform better with a 8 foot antenna?

Thanks! Something I've been meaning to look into. Just need to find a screw on RF cable connector to connect the antenna cable to where the short antenna screws into the radio.
 

milmat1

Petty Officer 2nd Class
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Re: Will a hand held radio perform better with a 8 foot antenna?

Thanks! Something I've been meaning to look into. Just need to find a screw on RF cable connector to connect the antenna cable to where the short antenna screws into the radio.

Yep! You need a UHF to BNC Adapter!
 

jhebert

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Re: Will a hand held radio perform better with a 8 foot antenna?

The length and particularly the height of the antenna makes much more difference than the output power difference between 5 and 25 watts.

I completely disagree. An increase in power to 25-watts from 5-watts represents a fivefold increase, which in decibel measurement is +7-dB. There are few--if any--VHF Marine band antennas which are usable from a small boat which can provide 7-dB of actual gain, and, if the do, it is only in a narrow lobe of their main beam. On the other hand an increase in power to 25-watts from 5-watts provides an actual 7-dB increase in power all the time and in every direction. This is much more important than the often much over-stated gain of any antenna.

In the case of a hand held device, the antenna probably has less than isotropic antenna performance, so it could be considered to have a gain of -3-dB, that is about half the power of an isotropic. Connecting a real antenna, even one with only unity gain, would be an improvement.

We used to have a saying about antenna gain and transmitter power: with antenna gain you are just hoping you get some actual gain, but with transmitter power increase you know you are getting real gain.

On the other hand, antenna gain is reciprocal and will improve reception, too.

I would dispense with the notion of trying to use a hand held transmitter and wire it into a fixed antenna. The cost of a fixed Marine Band VHF radio is very low, only about $100 for an excellent radio, and it would make more sense to get one, rather than fiddle around with a hand held. When you really need the hand held radio, its battery will be dead.
 

Bifflefan

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Re: Will a hand held radio perform better with a 8 foot antenna?

After many years of CB use (i dont know if its the same) you do need a good antenna first, then go for the power.
Power without a good antenna is useless.
 

Barnacle_Bill

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6,469
Re: Will a hand held radio perform better with a 8 foot antenna?

After many years of CB use (i dont know if its the same) you do need a good antenna first, then go for the power.
Power without a good antenna is useless.

I use to be into CB radio big time too and it always amazed me that people would buy a 500 dollar radio, put a $1.98 antenna on it, then wonder why it didn't work very well. Play it safe and go with a bigger radio and keep the handheld for a backup.
 

NYBo

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Re: Will a hand held radio perform better with a 8 foot antenna?

I completely disagree. An increase in power to 25-watts from 5-watts represents a fivefold increase, which in decibel measurement is +7-dB. There are few--if any--VHF Marine band antennas which are usable from a small boat which can provide 7-dB of actual gain, and, if the do, it is only in a narrow lobe of their main beam. On the other hand an increase in power to 25-watts from 5-watts provides an actual 7-dB increase in power all the time and in every direction. This is much more important than the often much over-stated gain of any antenna.

In the case of a hand held device, the antenna probably has less than isotropic antenna performance, so it could be considered to have a gain of -3-dB, that is about half the power of an isotropic. Connecting a real antenna, even one with only unity gain, would be an improvement.

We used to have a saying about antenna gain and transmitter power: with antenna gain you are just hoping you get some actual gain, but with transmitter power increase you know you are getting real gain.

On the other hand, antenna gain is reciprocal and will improve reception, too.
I think a 5 watt transmitter with an 8' antenna will have better range than a 25 watt transmitter with a hand-held "rubber duckie" antenna. Line-of-sight and all that. Granted, a 25-watter will punch through a lot better. Reception would unquestionably be better.

I would dispense with the notion of trying to use a hand held transmitter and wire it into a fixed antenna. The cost of a fixed Marine Band VHF radio is very low, only about $100 for an excellent radio, and it would make more sense to get one, rather than fiddle around with a hand held. When you really need the hand held radio, its battery will be dead.
On this, we agree! Once he goes through the trouble of buying an mounting a full sized antenna, might as well do it right. Wouldn't hurt to keep a BNC adapter to use the handheld, though.
 

Mark42

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Re: Will a hand held radio perform better with a 8 foot antenna?

.....
I would dispense with the notion of trying to use a hand held transmitter and wire it into a fixed antenna. The cost of a fixed Marine Band VHF radio is very low, only about $100 for an excellent radio, and it would make more sense to get one, rather than fiddle around with a hand held. When you really need the hand held radio, its battery will be dead.

Don't go making assumptions. That closing remark totally derailed any credibility you were building with your post.

FYI.... The hand held is on a charger the entire time its in the boat. So, no, it will not be dead when its needed, plus I can take it to shore on an isolated beach or island and have it for emergency or just to listen to the boat chatter. That is the whole point of a hand held. It goes where I go.
 

jhebert

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Re: Will a hand held radio perform better with a 8 foot antenna?

I think a 5 watt transmitter with an 8' antenna will have better range than a 25 watt transmitter with a hand-held "rubber duckie" antenna.

I agree. You have set up a straw man argument. As I already mentioned, the antenna on a hand-held radio has negative gain, or loss, compared to even an isotropic antenna.

My comments were in support of my position that is contrary to the statement that antenna gain is more important than transmitter power level. Again, this is not true. Antenna gain is often nothing more than a number assigned by the sales department to a product, and particularly in the case of VHF Marine Band antennas, the gain is generally overstated. An increase in power to 25-watts from 5-watts is a substantial increase in signal strength, 7-dB more. There are really no antennas that can be practically installed on a small boat which will produce anywhere near 7-dB of gain. And, even if they did, the gain would be concentrated into a very narrow lobe. Whenever the boat rocks, that narrow lobe may move away from the horizon and in its place a deep null will replace it.

By increasing the transmitter power to 25-watts from 5-watts, the range of a VHF Marine Band radio will be substantially increased, more than could be produced by installation of an antenna with higher gain.

Antenna height is probably the most important influence on radio range, and my opinion is that antenna height should be increased in preference to antenna gain. I would rather have an antenna with half the gain but mounted twice as high.
 

Mark42

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Re: Will a hand held radio perform better with a 8 foot antenna?

BTW, I would like to get the stainless steel rail mount, but budget constraints says go with the nylon. Looking at the nylon rail mounts, I am afraid they will break over time from the stress of an antenna flopping back and forth.

Are the nylon mounts OK? Do they have a reasonable life time (ie 5-7 years?)??? Assume the boat gets about 40 hours of engine run time a year, and about 120 hours anchored at a beach bouncing in the waves.

And long term plan is to put in a fixed mount marine radio. Anything with good ratings is around $150 or more. So for now I have the hand held, and that is what will be supported.
 

NYBo

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Re: Will a hand held radio perform better with a 8 foot antenna?

Antenna height is probably the most important influence on radio range, and my opinion is that antenna height should be increased in preference to antenna gain. I would rather have an antenna with half the gain but mounted twice as high.
It was antenna height I was thinking of all along (but failed to explain:redface:). Sorry about that! Hard to hold a handheld so its antenna is as high up as an 8-footer!:D
 

dewey0726

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Jul 11, 2006
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Re: Will a hand held radio perform better with a 8 foot antenna?

I agree with most of what is said here. But to be realistic, VHF radios are only good for line of sight. That's not very far from most boats, especially the ones that mostof us have. The higher you get the antenna the better is definitely true. The more efficient the antenna is, the better. The larger antenna is probably better quality than the one that comes on the radio. You can check this with a directional RF power meter. See how much power is reflected back into your radio, the less reflected power the better. The power that is not reflected back is radiated through your antenna. Not just for transmission but for receiving too. I agree that a 25 watt radio is probably the way to go, especially off shore, but also realize that most aircraft only use a 10 watt VHF radio. It's a lot more about the line of sight than anything else if you have an efficient antenna and reasonably good power. There are a lot of variables to consider. If you want to upgrade, get a quality antenna and see if it performs like you want with your handheld. If it doesn't you'd have to get an antenna with a bigger radio anyway. Who knows you may be completely satisfied with the handheld and the improved transmission and receiving from a better and higher mounted antenna. Good luck.
 
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