Do VHF antenna's break down?

Thepipdoc

Thepipdoc

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I've just had new Raymarine 240 dual station DSC VHF radio fitted and very nice it is too!
However, I'm not overly impressed with the reception. It's not that the sound quality is inaudible or so bad that it cant be understood but I would have expected better.
Is it possible that the VHF antenna is breaking down?
 
Other possibility to consider is interference from other electronics - especially if cables run alongside other signal/power cables. Easy to test by switching everything else off. Not forgetting less obvious things like air-con, fridge etc...

P.S. if using existing antenna, check all connections for corrosion too...
 
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antannae antanae test

Simple test to see if the antannae is bucked. Try to transmit to a known station miles away ie Coastguard or a marina that you have just left. Generally a tired out antannae will not transmitt but will receive. This is a simple acid test remember even an old wire coat hanger will receive signal but you need a good antanae to transmit.
 
Just for reference ...there is no point in using a multimeter to check if the plug has continuity across inner pin and outer case of plug as 99% of marine aerials are constructed in such a way as to show a short if you try to test this way.
Unless the aerial is very old or maybe has had a bash at some point or the plug cable joint has failed,it is very possible that your new radio has no better audio than your old one.
There is a tendency to put a weedy tinny sounding speakers in some makes of new radio whereas in older stuff a large speaker and hence clearer audio with nicer tone.
IMHO much new stuff has no obvious improvement detectable by any boater with a set of standard ears.
An extension speaker may be the way to go,unless external,would buy cheaper CB type thing as opposed to mega marine priced "objet d'art".
 
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Thepipdoc said:
I've just had new Raymarine 240 dual station DSC VHF radio fitted and very nice it is too!
However, I'm not overly impressed with the reception. It's not that the sound quality is inaudible or so bad that it cant be understood but I would have expected better.
Is it possible that the VHF antenna is breaking down?
Click to expand...

Worth troubleshooting the antenna system:
http://www.saltyjohn.co.uk/resources/Troubleshooting your VHF antenna system.pdf

But it may just be that you have higher expectations from your new radio than it can deliver.
 
VHF antenna's do tend to deteriorate with age as does the coax cable where it is exposed to sunlight.

Visually inspect the antenna, if there are any signs of the plastic or fibreglass crazing or going powdery, or cracking, it's probably had it.

Feel the coax, if it's lost its flexibility, UV has affected the outer jacket. skip it.

How old is it? over 10 years? good chance it's getting near end of life.

a SWR meter is the best way of checking the state of the antenna and cable.

You can invest in a SWR meter, but check it has sufficient frequency range for VHF, the cheap "CB" ones won't do the job. Also getting one with Power measurement will confirm what your transmission power is.

Doing nothing is not good, not only is the performance of the VHF affected, it has the potential to damage some VHF's output circuit.

Kevin
 
Thepipdoc said:
I've just had new Raymarine 240 dual station DSC VHF radio fitted and very nice it is too!
However, I'm not overly impressed with the reception. It's not that the sound quality is inaudible or so bad that it cant be understood but I would have expected better.
Is it possible that the VHF antenna is breaking down?
Click to expand...

hi check the ariel plug at back if its not the soldered type cable can come loose when tightening plug to radio happened to us new radio poor sound quality sound tightend up plug perfect sound:):):)
 
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