VHF antennas, health risk

[truebrit]

Reading the manual on my new DSC radio, (early Xmas pressie from Swmbo, persuaded her that it would be best to fit now rather than lose months of guarantee,lucky b arent I) and it says that the height of base of antenna should be 5mtrs above deck on vessels with suitable structure, or failing that at least one metre above head height on other vessels. This seems to be American reccomendations for safe distance from radiation when transmitting on high power, which I wont be doing much of unless in an emergency, and then antenna radiation would be the last thing on my mind! I realise that the higher the twig the greater the range, but I have a Bayliner cuddy with no radar arch, and without serious modification, ie a mast of some sort , wont be able to get the base of the antenna much higher than my shoulders. I have been using handheld for some years, is my brain pickled? or what are you good folks views on antenna mounting on little boats.

<hr width=100% size=1>Mike....... V8s are sweet music

 

[derekh]

at 25 watts at low frequency I cannot see how there could be much of a health risk.Probably some who knows facts will differ. I have an aerial about 1 meter from the helm and I have never suffered any obvious noticable memory loss.I have never suffered any obvious noticable memory loss. I have never suffered any obvious noticable memory loss. I have never suffered any obvious noticable memory loss. I have never suffered any obvious , sorry what was the question ?

<hr width=100% size=1>Work ? don't be daft , the suns out.

 

[PhilF]

only danger would be if you poked it in your eye

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[TrueBlue]

Agree, It's only up at microwave frequencies (eg. mobiles, Radar etc) that one runs any risk of cooking your brain or goolies (which ever is more important to you).

The higher frequencies boil your waters. Who's ever heard of a VHF cooker??

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Stop what you're doing and wait my signal

 

[MapisM]

The trick with swmbo is a great idea, thanks for that!
Re. your question, you could consider an antenna extension.
There are many lengths available, from 2' up to 8' or so, but probably 4' is good enough for your type of boat.
Dont' know about the difference for your brain...
...but it doesn't hurt for sure.
And in any case, for VHF, the higher the antenna, the greater the range.

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[[2068]]

>
> Who's ever heard of a VHF cooker??
>

Made by English Electric, about the size of a small terraced house, consumes 7.3Gigawatts, and takes 7 hours to boil an egg. Absorbed £385M in government grants before being cancelled.

dv.

 

[steverow]

All electromagnetic radiation poses some sort of risk, even very low frequencies...note the clusters of unexplained cancers and other medical problems around power grid distribution cables/pylons, much in the news a few years back.
However, before I alarm you unduly, most known problems occur when constantly exposed day in day out for years. Given that you are transmitting in only short bursts fairly infrequently, any risk is so low as to be incalculable.
Problems could occur if your radio is very badly tuned and giving off loads of harmonic radiation much higher in frequency than 156Mhz. But even this is going to be far less invasive than your average mobile phone.
If you are at all worried then use low power setting, which is usually sufficient, and always good radio practice anyway.
Get the antenna as high as possible, make sure you have a good RF ground
and stop worrying about it.

As a footnote, it is known that engineers working constantly with very high power transmitters, 50kW or so and above, can be subject to depression and personality changes, usually temporary, most research on this having been done in the US.
Slightly more worrying is the seemingly high incidence of medical problems
and mental illness amongst those that worked on offshore radio during the 60's and 70's, although these guys are probably getting to the age where these problems are going to hit anyway, and may be due to other "lifestyle" factors.
The study of the effects of EM radiation is very much in it's infancy not a lot is known, mainly being driven by mobile phone worries.
Whats the betting, however, that the mobile manufacturers know more than they are letting on??



Steve.




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