Link Creation / Edit

Link Name

The name field is required and it is suggested that you use a naming method that identifies the Link.

Example: TwrA-TwrB 5ghz BH This Link is the Point to Point, 5 GHz Back haul Link between Tower A and Tower B

Site 1 / Site 2 Name

Select one of the Tower Sites you set up already from the drop down menu.

Site 1 / Site 2 Antenna Height

By default, when you select the site, TowerCoverage.com will automatically pull the height from that site’s properties. Once you have selected the proper tower site name, you can manually adjust the antenna height for this specific coverage map. If you enter the height in feet TowerCoverage.com will automatically convert it to meters for you.

Tx / Rx Antenna Gain

This value is the advertised gain of the antenna alone, without the radio power. This value along with the Power and Line Loss settings are used to calculate the EIRP.

Tx / Rx Power and Line Loss

TX Power is typically the max power that the transmitter will have. Most manufactures list the TX Power on the radio equipment datasheet documentation. You should refer to the manufacturer datasheet for the piece of equipment you are using. TowerCoverage.com stores this data in dBm, however some radios are listed in mw or watts. TowerCoverage.com also includes a mw to dBm converter in this field. There are a number of converters on-line that will help you with watts to mw conversion. For example: if you have a 600mw TX Power radio. If you enter 600 in the mw field, TowerCoverage.com will automatically convert the 600mw to dBm instantly on the site, giving you around a 27.78 dBm transmitter.

The Line Loss is the loss that you have between your transmitter and your antenna. Many WISPs will have integrated or nearly integrated systems, this means that there is VERY little transmission coax and connectors between the radio output and the antenna. For many of these systems the .5 default value is acceptable. However, if you have a long run of coax, for example a 6 ft. or longer run, you will need to calculate the loss. You will need to refer the manufacturer’s coax datasheet to get this (some manufacturers print this information on the cable as well). To get exact numbers, you would have to refer to the manufacture specs, but for short runs, or what we would call nearly integrated, the .5 dB loss default would be more than enough. For example: you have a 120 foot run of LMR-400 cable with no other connectors or converters. The manufacture datasheet states that at 5800 MHz, or 5.8 GHz, the attenuation is 20 dB over 1000 ft. In order to find the Line Loss for 120 ft:

Calculate the Line Loss per foot = (20 / 1000) = 0.02 dB loss per foot Calculate the Line Loss for the amount of cable you are using

Line Loss Per Foot * Feet of cable used 120 * 0.02 2.4 dB loss for 120 ft.

2.4 dB loss is the value you would put in for your TX Line Loss.

10.8 divided by 100 foot, then multiplied by 120 foot, would give you your line loss of 12.96 dB. 12.96 is the TX Line Loss.

Another example would be a radio mounted to the back of a sector with 1-2 foot of LMR.

Rx Threshold

The Rx Threshold is the setting that determines where the Coverage is shown during overlay creation. This value is suggested to be set to the minimum signal you require during an install. This value and the Strong signal margin will determine where the Strong and weak colors are displayed in your Coverages and Multi Maps.

Reliability %

This is an important variable in your coverage calculations. This percentage adds additional statistical loss based on distance and frequency to get to a more reliable link. For WISPs, the default value of 70% usually is a good number. The longer the link more statistical loss is added, giving your more padding on your link.

Use Land Cover

This tells the site whether or not to take you Land Cover settings into account in the calculations. See also Land Cover for more information.

Use Two Rays

Two rays are used for multi-path calculations. Most WISP use radios cannot do multi-path reflections so by default this option is turned off. If your radio system can use multi-path reflections then you may want to turn this value on.

Land Cover Type

In your Account Settings under LandCover, you can create multiple LandCover Types. This allow you to specify tree densities according to different regions of your network as well as specify different heights for each type of tree or clutter data. This also allows you to create a Type with lower density for frequencies such as 3.65 GHz and 900 MHz that can get through tree coverage and a type with higher densities for frequencies such as 5 GHZ that cannot penetrate tree covered areas.