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Interference between channels

Inteference among channels:

Digi XStream and XCite FHSS radios hop among 25 different frequencies (50 frequencies for the XTend). Each channel (''''HP'''' parameter) actually uses the same frequencies in a different pseudo-random sequence. In other words; each Channel uses a different Hopping Pattern to navigate through the same frequencies.

Because the same frequencies are used for each channel there is some interference when 2 pairs of radios on different channels are operating in the same vicinity at the same time. Because Digi radios only transmit if their is payload to be transfered, a system with infrequent data transmissions will experience almost no interference between channels. If the channels are used at near full capacity we have found a decrease of 4% to 8% in the percent of data packets received per additional channel operating in the same vicinity.

If a base station broadcasts to two remote stations who then reply at the same time, then certainly there will be some interference. The more stations that transmit at the same time, the more interference there will be. Again, this interference can usually be overcome by enabling Reliable Delivery mode. 

Here is a formula for predicting the collision rate.

Last updated: Aug 23, 2018

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RF

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