1) Site your antenna by panning and zooming the map so it is centered on it OR press menu > settings and enable GPS within settings to use your location.
2) Press either the Center key or tap the icon in the bottom right to open the calculate form. More settings are available with the MENU key in here.
3) Enter your Transmitter's key parameters: Frequency, Power and Height (above ground).
4) If you need to change any advanced parameters, press MENU then click settings.
5) Finally, click the Big button in the middle and wait for your overlay to appear.
Note: Your request will be passed to a server where calculation takes place. The result will then be downloaded by your phone. The time this takes depends on your calculation radius, internet connection speed and server usage / other users.
An average calculation should take no more than ~8 seconds.
Upon loading you will have a Google map with an antenna icon in the middle. The location of the antenna determines your Transmitter location and is visible at the bottom of the screen in decimal degrees.
At the top of the screen is a colour key which depicts signal strength colours using the currently selected units of measurement. Orange is strong and purple is weak. A calculate button is available in the bottom right to create a new calculation.
2.2 App Menu
The menu is accessed from the map view with the MENU button. There is a second menu within the calculate form which is accessed also with the MENU button. CALCULATE - To create a new coverage calculation. HELP - This page. SETTINGS - Access advanced settings and 'about' page ARCHIVE - Full version only. If SD card is enabled, created overlays are saved in /RF_SIGNAL on the SD card as KML files (along with local PNG images). Selecting this allows you to pick and load them Offline later on. MAP - The map can be switched from Map to Satellite. RESET - Clear the map and/or settings. ^Top
The tabbed settings menu contains a variety of options that govern the Apps functionality, extra information is available on each by pressing the 'i' next to it.
USE GPS - By selecting this, you can have the app center on your location which is handy for mobile radio users. You will be prompted to enable/disable GPS yourself as the app is not allowed to do this. MEASUREMENT UNITS - Antenna Heights and Radius can be either Metric (Metres / Kilometres) or Imperial (Feet / Miles). Changes take effect for the next calculation. ANTENNA POLARISATION - An Antenna is typically either vertical or horizontal. For Line of Sight (LOS) paths, the Transmitter (Tx) and Receiver (Rx) must be of the same polarisation otherwise Signal degradation will occur. A handheld VHF is vertical, US TV Broadcasts are Horizontal. RECEIVER (RX) HEIGHT - The Receiver height (above ground) will make a big difference. TERRAIN - The ground conductivity will make a big difference when you're using groundwave propagation. If you're using VHF/UHF and your antenna isn't above the MEH then this will affect you.
COVERAGE TYPE - There are three output types available in the full version. The colour key will automatically update when the type is changed. Path Loss is measured in decibels as a ratio (dB). This displays signal attenuation over the earth and varies with height and frequency but power is NOT a factor. This is useful for getting a feel for the conductivity of the surrounding terrain. Received Power is measured in decibel milliwatts (dBm) as a negative ratio. On a mobile Phone 1 bar would equate to about -100dBm and 5 bars would be greater than -60dBm. This is useful for finding out where you can get a good signal. Field Strength is measured in decibel Micro Volts per metre (dBuV/m). This is the actual electrical power present in the earth at a given point. RECEIVER SENSITIVITY For 'Received power', the sensitivity is measured in decibel milliwatts (dBm) as a negative ratio with -73 being strong and -100 being weak. Enter -75 for a cynical calculation and -110 for an optimistic one. -90 is workable. Anything beyond the limit you set will not be shown. Be careful with this as an incorrect value here could easily result in nothing been shown! RESOLUTION - The ouput resolution will greatly affect computation time. Choose a lower resolution to speed up calculations and reduce overlay size. Tile resolutions vary with latitude and values shown are based upon 40 degrees N/S where High=70m,Medium=140m and Low=280m.
TRANSPARENCY - Adjust the opacity of the next overlay only. RANDOM GROUND CLUTTER - Add a degree of realism by adding a generic layer of obstacles to represent trees and buildings. DATABASE CLUTTER - Add precision realism by using pre-defined buildings from the cloudrf.com database. As standard there is major clutter for New York and London and you can upload your own buildings as a KML overlay. Tutorial: http://www.youtube.com/watch?v=X6j_ph3SAL8 COLOURS - Reduce the filesize of your overlays by dropping the colours. Ideal for users on low bandwidth connections or with limited memory. MULTIPLE SITES - Full version only. By selecting 'Multiple' you can view more than one emitter. Use with care as multiple layers will affect performance. OVERLAY STORAGE - Full version only. By default, overlays are saved on the device's internal memory. By selecting the SD card, KML overlays will be generated which can be reloaded OFFLINE in the app or viewed with Google Earth on a desktop computer. Be aware that when your SD card becomes full, you won't be able to create any more overlays.
2.4 Calculate form
The calculate form allows you to enter your Transmitter's key parameters and action the request by sending it to a UK server for calculation. Tap in your parameters and click the big button in the middle. FREQUENCY - Measured in Megahertz (MHz). You may enter a value between 20 and 20,000 with decimal places. POWER - Measured in Watts (W). You may enter a value between 0.1 and 1,000,000 with decimal places. This value is the total effective radiated power of the Transmission system so if you have a +3dBi antenna, you will need to use an ERP calculator to computer the ERP in Watts. HEIGHT - Measured in Metres OR Feet. You may enter a value between 0 and 1,000 with decimal places. This is taken as Above Ground Level (AGL). The server knows how high the ground is at each location as it has lots of elevation data on it. RADIUS - Measured in Km or Miles. The larger the radius, the longer the calculation will take (unless it's low res in which case it's fast!). A graph of calc times is available at www.cloudrf.com
Underneath the 'calculate' button are the advanced settings taken from the settings menu. To change these, press either the settings icon in the bottom right or MENU > SETTINGS.
Within the calculate form, press MENU to see the load and save templates options.
Saving a template
Click save template to open a form. Within this form, your key technical parameters are already loaded and taken from your last calculation. Give your device a name eg. IC-M24 and then categorise it properly so VHF > Marine VHF.
Next, give it a useful description so others can find it: "ICOM IC-M24". Finally submit your template to the server. If you completed correctly you will be notified.
Loading a template
To open a template, click load template to open a search form. You can search by keyword and frequency. Enter some values and click the filter icon to the right.
To use a search result, click it from your results list to open a dialogue box. You then click 'use' to populate the settings in your phone, ready for your next calculation. Always pay attention to what settings your loading in, especially with things like sensitivity. What's good for someone else might not be good for you.
Reporting bad data
As the template system accepts anonymous submissions, a quality control system is in place to ensure any bad data is identified and removed. If you find a template with incorrect or unhelpful values, click 'report bad' to open a report form. State in here why the template is bad and click send. An administrator will investigate the template and either edit or remove it completely.
2.6 Receivers (Rx)
Once you have performed a calculation, you will see a button appear on the right of the screen half way up titled 'Rx'. This allows you to place a receiver on the ground and measure the distance and bearing to and from the transmitter. Just zoom in to your receiver site and hit 'Rx'.
TIP: To clear receivers whilst preserving the RF overlay, rotate your phone. To clear everything, use the RESET button on the menu.
The algorithm used on the server is the Irregular Terrain Model (ITM) commonly known as the 'Longley Rice' model. This planning model was developed in the US for TV Broadcasting and is optimised for 20-20,000MHz (VHF-UHF-SHF). It's incorporated into an open source program called Signal Server which is a server optimised version of SPLAT!. This program performs the calculations on a high performance server containing elevation data for the entire world.
The elevation data used is NASA SRTM2 which has a resolution of 90m and 99% global coverage between -/+60 degs latitude. Additional high latitude tiles have been added for Norway,Sweden, Finland and Northern Russia. Much more detail about this service is available through www.cloudrf.com.
Minimum Effective Height (MEH)
Spacewave / LOS propagation is much better suited than groundwave for VHF frequencies due to ground attenuation. To determine if your antenna is high enough for spacewave you need to work out the wavelength. So for 30MHz, divide 300 over 30 and get 10m. For 145MHz: 300/145 = 2m.
3.1. Offline Usage
Full version only. Once you have performed a calculation, you can disconnect from the internet and recover it later on with the archive feature. This is handy if you're going to be moving around an area served by a transmitter and want to see where the hot/not spots are.
You will be viewing the overlay in the app on Google Maps so clearly you need to think about your map cache. Fortunately, the map cache is pretty good and so long as you've looked at your target area recently at the right scale, you'll be able to revisit that place later offline.
The size of the archive is limited by your SD card. Filenaming conventions use the year/month/day/hour/minute/second_Frequency. These files are also available on the web server if you know your device's serial ID. They are stored at m.cloudrf.com/app/users/(devID)/.
3.2. Unique filenames
When you select your SD card for storage, you will be given the option prior to each calculation of saving it with a distinct nickname eg. 'repeater3'. This name will help you recover it later in your archive and also appears within the KML overlay so when viewed in Google earth, each icon is tagged with a nickname.
The nickname is appended to the time stamp already in the filename (year/month/day/hour/seconds) eg. 120113140033_repeater3.kml. Only alpha numeric characters are allowed.
4. Trouble Shooting
Map is slow
Using a ground overlay on a smartphone map is very resource intensive as the bitmap must be redrawn and layered every time the map moves slightly to keep it aligned with the earth. You may notice after a few calculations that navigating the map becomes slow, this is normal. Clearing the map with the RESET button from the menu or restarting the app will help this.
First check you have an internet connection and that you're supplying valid input so check your settings: If you've tried a dB 'Path loss' calc with a receiver sensitivity of 80 you won't see anything. Try 'Received Power' instead with a receiver sensitivity of -100dBm. If you've entered an incorrect value it will generate a brief alert prompt on your phone so check you're not getting these. If the input is ok, check for any errors after calculation. A tell tale sign of a calculation error is an alert prompt 'm.cloudrf.com'.
To test if the server is OK, open up the following service status URL in a web browser: http://m.cloudrf.com/app/status.php.
Alternatively it's possible your phone is being lazy when drawing the overlay, rotate the screen 90 degrees to initiate a redraw then back again to see if that helps.
If you still can't get it working, get in touch with your handset model at the link below.
Archive is empty (Full version only)
To use the archive feature you must have external storage with space on it, usually an SD card, present and to have selected 'EXTERNAL' from within your settings.
Crashed after completing a calculation
This app is by it's nature, resource intensive, especially when performing large calculations. If your device is low on memory you will run the risk of crashing the app when trying to overlay a large calculation.
Drop the resolution to low and try to free up memory where possible but if the problem persists, email the location, radius and handset model to dev at address below.
You can see the filesize in kilobytes for each overlay by tapping the antenna icon in the centre of the coverage.
dis game is not wurth da mony!!
RF planning is a complex engineering discipline which takes time and careful consideration of variables. Just pressing the big button and expecting a realistic prediction isn't how it works.
As a minimum, a literacy age of at least 16 and experience with radio systems is essential to get the most out of this application.
4.1. Update problems
Crashed after an update
If it crashed after an update or when you clicked settings do this:
Open your phone's settings, then Applications, find 'RF Signal' under installed apps and clear it's data, or if you've got the latest version, use the reset settings option from the menu. This will remove config files from the old version and wipe the slate clean.
No terrain data for my area?
The terrain data on the server covers 99% of the World's land mass but typically stops at 60 degrees north and south with exceptions for Scandanavia. Paid users can test coverage for free with the free app before purchasing. If you really want coverage in an area beyond 60N OR you've found a blackhole, these can be fixed: email requests to dev.
I don't like the new version. I want the old one back!
You won't find old versions in Market but the APK files can be emailed on request.
4.2. Do's and Don'ts
Take your time with your input and double check each value you pass to the server.
Try to do as many calculations as fast as you can. You will violate the Terms and Conditions of this service and your device will be blocked.
Learn all the advanced features. You will get a more accurate calculation.
Use this app with a non stock keyboard. You could enter an illegal character (not a number!) - which will crash it.
Turn on the GPS if you want it to use your location
Leave your GPS on after use. It will drain your battery
5.RFSignal full version
The full version gives users the ability to perform much larger calculations and significantly access them offline so you can perform calculations, disconnect from the internet and then go climb a mountain with the overlays in your pocket. Overlays are saved as KMLs on the SD card and can be loaded within the app or taken off the card and viewed in Google Earth or NASA WorldWind.