question about aerial (technical)

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craigsa

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Hey guys can i ask you techies a question?

The aerial comes with a cable that plugs into the back of the UTD and in turn connects to the actual cable of the aerial unit.
What i have noticed is that if the first cable is plugged into the UTD without the external aerial connected to this cable, the UTD's standard aerial does not work. (please comment).

The other question is: Is it dangerous to have the external aerial near to a me? How much wattage is comming out of the aerial ? is it dangerous in terms of high frequencies comming out of the unit ? i know it should be in the roof but i just left it on the table and worry about the impact on the body.

Thanks guys
Craig
 
What i have noticed is that if the first cable is plugged into the UTD without the external aerial connected to this cable, the UTD's standard aerial does not work.
Click to expand...

The UTD has an RF switch. When you plug the pigtail in i.e. the bit that connects your patch antenna cable end to the socket on the UTD, the UTD's integral antenna is switched out.

The other question is: Is it dangerous to have the external aerial near to a me? How much wattage is comming out of the aerial ? is it dangerous in terms of high frequencies comming out of the unit ? i know it should be in the roof but i just left it on the table and worry about the impact on the body.
Click to expand...

I don't think it's harmful. The UTD transmits at approx +22dBm which is less powerful than a cellphone. Cellphones are set to transmit at +32.5dBm max power. Remember the UTD also adjusts it's output power dynamically
 
Thanks Kei. I will be back monday then i can come past and we can do the tests mate.
 
if this were slashdot I'd reccomend a tinfoil hat for the radiation :p
 
craigsa, look up radio waves and brain cancer. you will be surprised out hoe harmful radio eaves are, especially cellular. I think one only has to worry about it being on 24/7 and near you like lets say an iburst modem...
 
Any directional antenna can be harmful, It is like micro wave links, the signal is concentrated to cover greater distances and not have a wide spread, like an omni directional ant. Slim's tin foil hat pun is not far off .
 
2 GuRu:
Please don't tell nonsence!
You can sleep on the top of iBurst antena . . .
 
GRES said:
2 GuRu:
Please don't tell nonsence!
You can sleep on the top of iBurst antena . . .
Click to expand...
And if I want to nuke some potatoes using the patch antenna, do I make sure the shiny side of the tinfoil is on the inside, or should I use without the tinfoil...:confused:
 
GRES said:
Doesn't matter which side, but u have to use 500 - 800 modems :-)))
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I don't think any of the resellers have that many in stock, will have to twist someones arm @ HiFi Corp...ic with his sack 'o tatoes @ HiFi Corp...Hillbilly clothes...:D
 
RF levels above 10 watts are considered dangerous.. Shows you how many people on this forum think they know electronics but in fact don't
 
Hi kei so its safe? just worried dont need another device thats gonna kill me - ha ha thanks buddy
 
With the double sided tape and metal piece provided you can disconnect the attachment without actually removing the above by pulling it out slightly, and reconnect by pushing it back in. This would be a much less dangerous option than removing the entire attachment tape and bracket each time... the attachment is fragile... be carefull
 
Using or attaching tinfoil to the patch antenna, depending on where, might actually cause it to change it's impedance, thereby causing even worse connectivity.

As for levels of RF in the GHz range, many communications systems use power output levels of 10 watts into a dish. Those levels are considered harmful to health and therefore a warning sign can be seen in such an installation. At those levels, the signal is usually sent through plumbing to the waveguide in the dish (yes, through a rectangular metal pipe, rather than a cable)

RF has the effect of heating tissues and is used for therapeutic purposes in medicine too. Bear in mind it takes hundreds of watts of RF energy to heat water. To nuke a potato, i.e. burn it over short time I estimate you would need approximately 4500 watts at 2.4GHz. Lower frequencies are less efficient. To generate that amount of energy you would need a large magnetron tube and a massive power supply and a lot of money to pay for the electricity to be consumed in the process.

RF levels in common use, +32,5dBm (approx. 2 watts) have not harmed me nor have I heard of any reports of health problems. Research in this regard has been inconclusive.
 
Kei said:
RF levels above 10 watts are considered dangerous.. Shows you how many people on this forum think they know electronics but in fact don't
Click to expand...

Agreed . Actually a good laugh to read this thread
 
a few examples below about cellular radio frequencies:

Research by other scientists indicates that prolonged use of cellular phones may cause hot-spots to develop inside the brain, causing damage which could lead to Alzheimer’s disease or cancer.

Recent research has shown that GSM pulse-modulated radiation can cause various physiological effects, such as alteration of the calcium balance in the nerve tissue of rats and also inhibition of cell growth in the human amniotic epithelium. Changes in the EEG pattern have also been observed.These subclinical effects do not always have to lead to disease but do call for alertness. It is assumed that GSM has no mutagenic characteristics (investigated in yeast cells) but can further the development of tumors (in rats).

Researchers at the Royal Adelaide Hospital in Australia discovered earlier this year that the electromagnetic field that surrounds electrical appliances can be positively linked to development of cancer in mice (or negatively linked, if you look at it the mouse’s point of view).

http://www.cancer-health.org/Brain_cancer.html
 
My (computer) mouse is also in front of the monitor, thus receiving even more radiation...
 
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