Rangecast FAQ
[FAQ-1227] Measuring quantity of radio traffic


Page Type: REFERENCE


OVERVIEW

It is sometimes useful to quantify the amount of radio traffic captured. This information is made available on the status page. Attention should be given to when a measurement period is started, and when data is read, to ensure that the reception conditions are representative during the sample period.


METHOD

To estimate the quantity of traffic received through an originating hub (a hub that operates and programs scanners), with optional filtering based on a minimum duration (transmissions only over a certain length), agency type (e.g. police or fire), or city/county of origin:

1) Access the Status Page (link on the hub administration screen)

2) If you want a count including content from all counties, select the CHANNELS link on the navigation bar.

Alternatively, if you want a count for content from a specific city or county, select the GEOCODE link on the navigation bar, find the row for the desired city or county, and click the CHAN link on the left side (chan = channel list)

3) You should now be on a page listing channels. Scroll to the bottom of the page, and you will see a table titled "Erlang tiers, by length of transmission and channel type"

You can read the result from this table, measured in Erlangs. One Erlang is a single continuous audio stream (e.g. an average of 60 minutes of audio recorded in one hour)

For all agency types, read the top row (channel type "---"). For a specific agency type , find corresponding row (the format is R followed by the code type used elsewhere in Rangecast, e.g. RF1 is fire dispatch.)

For all transmissions, read the left column ("ALL"). For restricting to transmissions over a certain duration (in seconds), read the corresponding row. For example, the column "3+" shows the quantity of traffic counting only transmissions of at least 3 seconds in duration.


EXPECTED PROBLEMS

The values reported are based on cumulative measurement of transmissions actually recorded since a data collection start time. The accuracy of the results is therefore limited by how well the measurement period reflects normal activity levels. Three specific factors that may lead to inaccurate results:

a) Any programming changes during the measurement period. If channels were added or removed, or some channels were reassigned to a different receive site with better or worse reception, then the measurement period will include a sample of conditions different from current and expected future reception. If programming is changed, it is recommended that prior data is cleared.

b) Any feed site being offline during part of the measurement period. If channels were not being recorded, the cumulative count of reception (and therefore the reported quantity of traffic) will be incorrectly low. If feed sites were offline, it is recommended that prior data is cleared.

c) Time of day, and day of week. If the measurement period is biased towards times of higher or lower levels of traffic, this bias will carry through to the reported numbers. It is recommended that a measurement period be started at a certain time of day, and the results read at the same time of day, to correctly sample daily variation.

To clear prior data, and start a new measurement period, on the status page click Advanced in the navigation bar, and then "Clear channel statistics (begin new measurements)"


Rangecast FAQ - ID 1227 - last updated 16 October 2018     Images shown - [block]