The Antenna section of the web interface contains more advanced settings for specifying antenna radiation patterns.
- Template / Custom Option
- My Patterns (Template only)
- Radial Images
- Azimuth and Downtilt
- Horizontal and Vertical Beamwidth (Custom only)
- Antenna Gain
- Front to Back Ratio (Custom only)
- Feeder Line Loss
The Antenna panel can be expanded and collapsed by clicking on its title . It will automatically collapse if you open any of the other interface panels. We'll explain each part of the Antenna panel in this article, including the Template/Custom selector , My Patterns , Radial Images , Polarisation , Azimuth and Downtilt , Antenna Gain , and Feeder line loss :
There are also three additional fields that are only accessible when using the Custom option : Horizontal and Vertical Beam Width  and Front to back ratio :
Template / Custom Option
The Custom option allows users to create a pattern on the fly by defining key fields (Azimuth, down-tilt, horizontal beamwidth, vertical beamwidth, forward gain, and front-to-back ratio). As values are changed within these fields, the pattern will automatically update.
The Template option opens up the My Patterns button and a drop-down selector to choose which pattern to apply to the current calculation.
This button appears when you have the Template option selected. It opens up a new browser tab that lets you build a smaller list of patterns from the massive database of manufacturer patterns available. We have over 2700 patters from more than 20 OEMs.
In the new tab, you'll see your current pattern list in the top left corner . To add more patterns, click on the grey heart icons  under the Favorite column. Once you click on a heart you will see that pattern added to your list . The heart will turn red  and it may be moved to a new location in the master antenna pattern list.
You can select a particular manufacturer from this drop-down menu , and expand the number of entries shown on each page . Also, the search field  allows you to filter the entire list base on any text or numbers you enter:
There will always be two adjacent radial images showing the antenna pattern. The left image depicts the horizontal, bird’s eye view. The right image depicts the vertical side view:
Antenna polarisation (US: polarization) describes the physical orientation of the antenna relative to the ground. Most broadcast and handheld systems are vertical, while some data systems are horizontal to reduce (vertical) interference. The default is vertical. Changing this value won't affect the images.
Azimuth and Down-tilt
These fields are only applied when the Custom Antenna option is selected.
The azimuth is the horizontal angle that the antenna is pointing in reference to grid north. Values of 0-360 are allowed. Do not confuse azimuth with beamwidth.
If your horizontal antenna pattern is circularly asymmetrical, then you'll see the horizontal (left) radial image change as you update the Azimuth field. Please note, if you have selected the Template antenna mode, changing the AZimuth value will have no effect.
The down-tilt is the vertical angle that the antenna is pointing relative to the horizon. Acceptable values are -10 to (+)90 degrees where angles above the horizon (pointing up) are negative and angles toward the earth (pointing down) are positive. A directional antenna parallel to the ground would be 0 degrees. This value is used typically when a directional antenna on top of a hill is pointing down toward lower ground. It would have a positive down-tilt. A similar antenna down in a valley pointing up would have a negative down-tilt as it would be looking up the hill. The default value is zero (no tilt).
If your vertical antenna pattern is circularly asymmetrical, then you'll see the vertical (right) radial image change as you update the down-tilt field. Please note, if you have selected the Template antenna mode, changing the Down-tilt value will have no effect.
Horizontal and Vertical Beamwidth
The horizontal beamwidth describes the angle in degrees between the two half power (-3dB) points of a directional antenna in the horizontal plane. For example, a directional ‘one third’ panel on a GSM cell tower would have a beamwidth of 120 degrees. Note, this setting can only be applied in the Custom pattern Antenna mode.
The vertical beamwidth likewise describes the angle in degrees between the two half power (-3dB) points of a directional antenna in the vertical plane. For example, the previously mentioned 120-degree horizontal beamwidth GSM panel may have a smaller vertical beamwidth of only 30 or 45 degrees to avoid wasting energy radiating in a direction where there are no receivers. Note, this setting can only be applied in the Custom pattern Antenna mode.
The directional gain of an antenna is measured in dBi (or occasionally dBd). For CloudRF, This is a numerical value between 0 and 50. For a 1:1 gain (no additional power) then a default figure of 2.14dBi should be used. A high gain antenna would typically be greater than 3dBi. Adjusting this gain value will result in an automatic adjustment to the ERP value immediately to the right. You can manipulate the gain value to accommodate other gains and losses in your system. For example, a system with 9dB antenna gain and 3dB line loss could be said to have a positive gain of 6dB.
The Total Effective Radiated Power (ERP) is the total RF output of a system and is automatically calculated using the following formula:
ERP = Transmitter Power - Feedline Loss + Antenna Gain
Other losses can be factored into the link budget by removing them from the antenna gain values at either end.
Example: 25dBm ERP = 20dBm Tx RF - 3dB feedline loss + 8dBi antenna gain.
These values are for example purposes only. To change the ERP, edit either the RF Power under the Transmitter panel one or edit the antenna gain under the Antenna panel.
Front to back ratio
The front to back ratio (FBR) is measured in dB and relates to the difference in power between the front and the back of the antenna. A value of 3dB would mean the antenna is twice as powerful in the front as in the rear. This default value is twice the forward gain, so a 5dBi antenna would have a 10dB FBR. The maximum value is 70dB.
Feeder line loss
The loss caused by cabling and connectors can be represented here. For higher frequency systems such as UHF / SHF this can be substantial, especially when 75 ohm 'standard' cabling is used. For example, when dealing with a 2.4GHz signal each meter of cabling could lead to a 1 dB line loss. So, in that case, a 10m cable used to elevate an antenna may do more harm than good. Using at least 3dB is a good rough figure if any cabling or additional connectors are in use between the transmitter and the antenna.
And as always, if you have any comments or questions please reach out to us at firstname.lastname@example.org.