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1) Metals and water can act as medium to conduct a signal so it should come as no surprise that the airwaves can also be used conduct a signal. However, the airwaves are not as good as a conductor as copper. Radio Frequency (RF) signals are essentially any signal oscillating above 3 KHz. Unique to an oscillating signal is that it generates electromagnetic power waves over the air and these waveforms can be transmitted and detected without using a physical conductor (i.e. the atmosphere is the conductor).

Wireless communications depend on transmitting an RF signal and detecting the same RF signal. The property of the oscillating waveform allows us to select particular RF frequency ranges for the particular application. For example, the 2.4 GHz and 5 GHz RF frequency ranges are ideal for transmitting over relatively short distances and require a small antenna. AM radio uses the frequency range of between 300 and 3000 KHz and has pretty good range (especially in the evening). FM radio and analog television use the frequency range of between 30 and 300 MHz, but the range is not a great as AM radio. The medium to receive and transmit communication signals 3 KHz and above can also be, and often is, a physical conductor. For example, a cable provider delivering High-Def television, Telephone services, and Internet all on the same wire transmits those signals at RF frequencies

Why do think some RF signals, such as those delivered by a cable ISP (Internet Service Provider), are transmitted and received using a physical conductor?


2) Coleman (2014) observes many different types of standards and standards organization Chapter 1, but when it comes to products or even new wireless standards we (as technology users or developers) must discriminate between marketing hype and meeting as need. For example, these days — a successful standard is more than likely proposed by a consortium of companies possible working with (or for) government and educational institutions, e.g. WiFi Alliance. The final standard is usually a result of much input, hard work, and debate. It is quite likely that many compromises were made along the way to satisfy all those with political or financial interests. Hard to say if the final outcome is the best or not. Great technology often fails because it may be too expensive to implement. Lesser technology may be extremely successful , because it met the demands of a wider audience.

The claims made by standard promoters often confuse veterans and novices who are looking to select an appropriate standard to build to. Promoters of standards usually have a vested interest in seeing their particular standard saturate the marketplace. For example: the use of non-objective terms (“powerful”, “limitless” “adaptable”, “seamlessly integrates”, multi-purpose”, “universally accepted”) to describe a particular wireless standard is common place. Each consortium claim’s their standard is the utopian solution! You should note these consortium’s web sites tend not to say anything negative about their technology.

Although standard sponsors advertising material and web pages contain excellent sources of information – a researcher should always remain objective (i.e. don’t believe all the hype). As the course progress I hope the class can see that for every new (and old) technology there are upsides AND downsides.

What is a de facto networking standard? Can you provide an example ?

3) ne of the requirements of devices having Wi-Fi capabilities is to have robust security network (RSN) built into them. Devices must support Wi-Fi Protected Access (WPA) and Wi-Fi Protected Access 2 (WPA2) security mechanisms for personal (WPA2-Personal) or enterprise (WPA2-Enterprise) environments (Coleman & Westcott). I had not thought about these not having the capabilities to have them but does make sense that a company could try to get away with selling access to Wi-Fi but not giving you the security options to use leaves you open to attacks. Even though we have these options some still refuse to use them or do not understand how to set them up to work properly. I have always like how recently when the cable companies come out and set these up they try to help you and already come with a preset password on them that is attached to the device so you don’t have to remember it. These are better than them leaving it open and telling you its installed but not setting up the Wi-Fi Security for you. We here in this class should all know how to set this up ourselves but for individuals that are not so computer savvy can find this difficult.

WPA uses a 256 bit key and is entered as a string of 64 hexadecimal digits or a passphrase of 8-63 characters. I thought we were still on 25 characters did not know we had gone all the way up to 63 characters.

4) In Chapter 3 of Coleman (2014) the concept of signal power is discussed at length. If we desire to increase the range of a signal can we simply increase signal power? The answer is not really … for several reasons. One reason is that the spectrum is already heavily occupied/reserved. Increasing the power of our signal may interfere with another signal using the same part of the frequency spectrum.

Another reason is the US Federal Communication Commission (FCC) may legally prevent us from doing so. The FCC both licenses and regulates the airwaves (such as AM and FM broadcasts), but the FCC also regulates unlicensed transmissions, such as home Wi-Fi. The FCC regulations regarding low-power transmission essentially limit both the Wi- Fi transmitter and the antenna to 4 watts.

How could a wireless signal’s range be extended if increasing signal power off the table?

5) The amount of RF energy that can be captured by the aperture of an antenna is smaller with higher frequency antennas (Coleman & Westcott). By this statement it is import not only for our transmitter to be able send the signal out freely without things getting in the way but to have a proper antenna to be able to receive the frequency. For some reason at our job we were losing connection with our RF Unit or hand held devices that we use throughout the warehouse. I had not thought about them having an antenna on them. Since Wi-Fi is inter graded into the motherboard (of a NIC card correct?) how does this effect the way our signal performs?

Higher frequency signals will generally attenuate faster than lower frequency signals as they pass through various physical mediums such as brick walls (Coleman & Westcott). Through our research at work we came to realize that when our building was set up it was only set up with a few access points and the building was empty so signal had no problem being connected throughout the warehouse. They did not put into the aspect of the racking and or the freight being put in and we had to have a few more installed in order to correct our hand held from losing connection. We have one building that seems to struggle with connectivity even with being in the same aisle as the transmitter? Anyone have ideas on why this happens? The area is surrounded by metal storage and sprinkler systems.

6) Minimizing interference is one very good reason why you would use a cable to conduct to transmit a signal. In my line of work we sometimes test over-the-air RF signal quality using antennas between the receiver and transmitter. To do this requires an FCC clearance (often referred to as a Frequency Clearance). Not only does a Frequency Clearance take a lot of time to submit paper-work ~ approval ultimately be denied because the FCC has determined that there is a chance (sometimes very small) that we would interfere with another signals sharing the same frequency.

To avoid the need for a Frequency Clearance altogether we simply connect the receiver and transmitter using an RF cable and then attenuate the signal as if it were being sent over the air (OTA) via antennas.

Another think about is that, relative to free space, there’s not much power loss when transmitting a signal using a copper cable. However there is quite a bit of power loss when transmitting over-the-air ~ particularly as range between the transmitter and receiver increases. A powerful FM radio station can use up to 50,000 Watts to get their signal out over the air. I can now listen to almost any AM radio station using the Internet, but much-much-much less power is necessary for me to receive the FM signal over the wired Internet.

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