Tuesday, January 29, 2019

5G Doesn't Mean Microwaves

One of our most popular posts, The Enemy Fighting 5G, received a few comments about the health aspects of 5G Wireless.  The same fears were expressed years ago about cell phones and how most humans will fall to cancer from all that RF exposure.  Now, with billions of wireless users, it just hasn't happened.  With the proposed use of new frequencies to accommodate the new 5G bandwidth, new fears have surfaced: 5G must be harmful to our health.

Let's look at what 5G means:  new methods of delivering greater amounts of data in the wireless environment.  It does not mean new radiation exposure in unsafe spectrum.  It may mean new radiation on channels already being used.  If indeed more sites are built at higher frequencies, the exposure to signals on these channels is limited by the physics of RF: the higher the frequency, the more the exposure is lessened based on distance, as well as the limitations of transmitter power.  The power used on a typical UHF TV transmitter is 1,000,000 watts.  The power from a cell site above 1.9 GHz is less than 16 watts, and the transmitted power from your handset is normally less than .2 watts.


Keep in mind, the source of 5G coverage will be on channels as low as 600 MHz.  Carriers are also building systems that use multiple channels from existing cell sites.  It's the same fear that you'll be hurt more by a wireless phone painted red vs. one painted green.  Yes, lab rats have contracted cancer when exposed to radiation at cellular frequencies, but they also suffered from exposure from other channels.

While an incandescent light bulb will severely burn your finger if you hold it too closely, it is perfectly acceptable at a normal distance.  Microwave ovens operate at 2.45 GHz.  Why don't they use higher frequencies?  It becomes too expensive to create enough power to cook food.  With wireless, you can use lower power...and they do.

Friday, January 11, 2019

5G Coverage Meets the Laws of Physics

5G Wireless has been identified as the catalyst for everything from driverless cars to finding life on Mars.  What 5G needs to accomplish these miracles is lots of bandwidth.  The easiest way to get more bandwidth is to move up in frequency.  Unfortunately, the higher the frequency, the shorter the range, and the less the coverage. It's the law of physics, a law we can't break.  Coverage for the "low" cellular frequencies (600MHz, 700MHz, 800MHz) is measured in miles.  Coverage for the "high" cellular frequencies (24GHz, 28GHz, 32GHz) is measured in feet.

A well-located cell site could cover a radius of 5 to 30 miles with the lower and maybe mid-band (1 to 5GHz) frequencies.  But a site at, say, 28 GHz (2,800 MHz), would not cover even one mile from the cell site.  The tradeoff is that more bandwidth is available on the higher channels.


How do we overcome this frequency disadvantage?  The answer is getting more signal at the user's location, and that is most easily provided by an outdoor antenna, which limits us to getting the most from 5G at a fixed location.  There's nothing wrong with getting faster Internet access wirelessly at home, but of course, most of us would rather have it in our pocket wherever we travel.

T-Mobile plans to provide 5G Wireless on their new, low-band assignments at 600 Mhz.  Yes, there are bandwidth limitations there, so T-Mobile plans to let your wireless device access other, higher wireless channels where there is more bandwidth, if you're within the more restricted coverage area of those channels.  You see, you can't break the "law".

The other method of getting more 5G signal to more users is more cell sites...spaced about a mile or two apart.  Just look at all the fun in that!