Thread: Getting Started
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Old 7-Dec-2009, 4:32 AM  
Join Date: Dec 2009
Posts: 54
Signal Analysis Tool

Quick links: Try it here (TV Fool), or here (FM Fool).

There is a version of this tool for TV analysis (TV Fool), and one for FM analysis (FM Fool), with some minor differences between the two. This guide is based on TV Fool, but for the most part, both of these tools function the same way. The tools start with a few paragraphs like the following:

"Have you ever wondered what television signals are being broadcast in your area? Perhaps you've recently purchased a new HDTV and you're looking for some High Definition content. Or maybe you're just looking for some additional sources to compliment your existing cable and/or satellite services. Well, here's a tool that can analyze your location to help determine what FREE broadcasts might be available in your neighborhood.

This tool can help answer questions like

* Which broadcasters are transmitting locally?
* How far are the transmitters from me?
* Which direction should I point my antenna?
* How strong are the signals in my area?
* What analog and digital channels are available?"

STEP 1: Click on the words [>> Click HERE <<] to begin using the tool.

STEP 2: Fill in the form for the location you would like analyzed. You can enter your location as a street address or as a coordinate. To use coordinates instead of an address, select the appropriate radio button where it says "Select input method".

You can enter a location at any level of accuracy you wish (e.g., zip code only, cross streets, exact address, etc.). It is recommended that you enter your full address or exact coordinates, if possible, because this affects the accuracy of the report. If there are any terrain obstructions in your vicinity, a rough analysis might not be accurate enough to give you a realistic view of what you can get.

If you know how high your antenna will be mounted, you can enter that information too (in feet above ground level). You may want to re-run this tool multiple times using different heights to see how much of a difference it makes. BTW, there's an even easier way to play "what-if" scenarios if you use the Online Interactive Maps tool (see next post).

You can optionally enter a title for the report. This text will be included at the top of the report so that you can reference it later and remember what it was for.

STEP 3: Click the button marked [Find Local Channels]. This will run the analysis and take you to the results.

At the top, you have some options (radio buttons) to view different subsets of the data. You can view all channels, digital only, or analog only. Now that the analog transition is over, there are mostly just digital transmitters on the air, however, there are still some "low power" analog transmitters that are still operating (they were not subject to the same shut-off deadline as the "major" broadcasters). If you are an area that depends on some of these "low power" transmitters for service, you may still want to pay attention to the analog stations in the reports.

The reports themselves have been put into image files. If you click on any of the "save image" links, you can download a copy of the reports and save them on your computer for later reference.

The "radar plot" in the report shows the strength and direction of your local stations. Longer bars represent stronger signals. The top of the circle represents true north (like on a map). There is also a red "N" in the outer ring of the circle representing magnetic north. This can help you aim your antenna if you using a compass to orient yourself.

The numbers next to some of the bars represent the real channels that those stations are brodacasting on. If you see any bars that are a little thicker and have a yellow outline, it means they are on VHF channels (2 thru 13). It is important to know if any of your desired channels are VHF because some antennas are not designed to work at those frequencies. You must make sure that your antenna type matches the types of signals you want to receive.

The table in the report lists individual stations, ranked from strongest to weakest, along with more detailed stats about each entry. For each station that interests you, be sure to pay attention to the real broadcast channel (this will tell you if you need a VHF-capable antenna), the background color (green, yellow, red, or gray), the Noise Margin (NM), path type, and azimuth.

A graph along the bottom of the report shows the stations plotted according to channel and signal strength. This provides additional visual cues regarding channels that require a VHF antenna (if any). This graph can also be useful in identifying any co-channel or adjacent-channel interference issues. For example, in some situations, it's possible to have a very strong signal right next to a weaker one (because one is very close and the other is far away), and this might impact your receiver's ability tune to the weaker station.

You can optionally click on any row in the table to see a "profile" view of the terrain between you and the selected transmitter. This cross-section plot is a way to visualize how the signal traverses the terrain on its way to your house. In the profile view, the transmitter is always shown on the left, and your house is always on the right.

STEP 4 (optional): If you are not sure about how to interpret this information, you can share the report with others to get advice. There is enough information contained in these reports (by design) to allow more experienced users to fully understand your situation and provide appropriate recommendations.

You'll note that your exact location is hidden in the reports, so you can share these openly without fear of giving away your mailing address to junk mailers or other unintended recipients.

These reports can be shared in many ways, and you can choose the method that works best for you, depeding on who and how you want to ask for help.

Option 1: Cut and paste the URL for your report. There should be a line in bold that looks like "" (the numbers at the end are a unique identifier for your report). You can give that URL to anyone, and they should be able to get to your report from any web browser. They will see a page that looks exactly like the one you are seeing.

Option 2: Use the "save image" links to save a copy of the report on your computer. The file you get (with a name like Radar-All.png) can be sent to anyone for review. The image contains all the relevant information that an experienced user would need to understand your situation.

Last edited by andy.s.lee; 7-Dec-2009 at 8:57 AM.
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