Directional antennaes

Do directional antennaes on radios interfere with a pacemaker? I was told they do.

Rodney S

2 Comments

Depends - not underwear

by donr - 2012-05-24 01:05:15

It really depends on the strength of the field & the frequencies involved. take a regular dipole antenna w/a omnidirectional pattern & it would be a lot less likely to affect your PM than a directional array. The field strengths would be much less for the dipole.

Electric Frank has some real experience w/ this, look for him to be by tonight sometime after midnight - he lives in CA. He can give you some specifics. All I can give you are arm waving generalities.

Don

Directional Antenna's

by ElectricFrank - 2012-05-27 10:05:31

It a bit of a complicated issue. The simple answer is that any potential interference is related to the signal strength arriving at you body. all a directional antenna does is to concentrate the signal in a particular path. So if you are inline with it's direction the signal can be increased by several times. However, in any other direction the signal is greatly reduced. There's also the vertical pattern affect where the antenna is designed to reduce transmissions into the ground. So a cell phone towers are design to keep the signals above ground level for a mile or so (my guess).

To complicate matters though is a thing called the "near field". This is an area very close to the antenna where the directional effect is distorted and reduced. The near field distance depends on the wavelength of the transmitted signal so it is very close for cell phones, wifi, etc., and far for AM broadcast antennas.

Modern pacers are designed with RFI interference in mind and aren't very susceptible to it. I've stood a few feet from my CB antenna on the Jeep and transmitted with no problem. I've also been around ham radio rigs running several hundred watts and no problem either.

We are saturated with radio signals in todays environment so they have to deal with these issues. Most problems reported around antennas are simply due to anxiety. Many are reported when the transmitter is not radiating or very low power.

Hope this helps. If you have any specific situations let me know and I'll try to give an opinion.

frank

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