Thursday, December 13, 2012

The Long and Short of Cable Length

Determining how much cable you’ll need to install your new antenna, amplifier or repeater system can be tricky.  You want to use the shortest length necessary to minimize signal loss, but you also don’t want to run it so directly that it hangs like a clothesline across the room!  Dealing with a return for the incorrect length and a new order for the right one can be costly and delay your project.  You also don’t want to tack on an extra length of cable if you guessed short since each connection degrades the signal (“daisy chaining” cables together is not recommended; it’s much better to use one 50’ length of cable than to string together two or three shorter lengths, for example).  

Follow these steps before you order to get the correct length of cable the first time!

1.  Plan the location of each piece of your solution.  Will the outdoor antenna be mounted to the roof, a pole or a wall?  How much separation to you need between each antenna? Will you want (or need) to move any of the pieces later on (for instance, if you rearrange the office or move the unit to another room)?
2.  Consider where you want the cable to live.  Do you want to hide it behind walls and only have the terminal end available for connection?  Do you have access to run the cable where you want it (or permission, renters!)?  If you can’t get in the walls, do you want it running across the open space of ceilings or floors, or do you want to minimize the visual and run it along the joints?
3.  Use string or guide wire to lay out a test run.  Run the string/wire then measure how much you actually used.  This serves two purposes.  One, you’ll get an accurate measurement of how much cable you truly need.  Two, the dry run install may help polish your positioning as you run into obstacles or find shorter routes to run it.  A bonus effect may also be that you can then use the string or wire to pull the cable through the installation, making it that much easier!

Once you have your final plan, taking into account locations, shortest distance you can achieve with for your needs (or limitations), and required separation, you are ready to order!