Did you know that the PTP 820 has an RF Loopback?

Products PTP
1

RF Loopback is under Radio, Diagnostics, Loopback

RF Loopback is quite intrusive—expect the link to go down during this test!

RF Loopback allows you to test one radio at a time—mute all of the other radios that you’re not testing. (Be sure to mute the far end radio as well!)

RF Loopback provides 60-70 dB of attenuation, good MSE, and zero defective blocks.

Select a fixed modulation mode, disable Adaptive Tx power admin, and set the Tx power to maximum.

Under Radio, Diagnostics, Loopback, turn “On” RF Loopback, and observe the following:

  • Go to Radio, Radio Parameters
  • The RX Level should be 60-70 dB less than the Operational TX Level
    • For example, if the TX Level is 22 dBm, the RX Level should be -38 to -48 dBm
  • MSE at -40 dB or lower
  • Zero defective blocks

If the radio doesn’t pass this test, consider replacing the hardware! (You might have a bad transmitter or receiver.)

Note that you can also select IF loopback for PTP 820G to test the IF cable up the tower.

Use in good health!

Dave

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2

We are troubleshooting a PTP 820S link remotely.  I turned on the loopback to test.  Since starting the test I can no longer communicate with the radio.  We only have one cable connected to the radio using the POE/ETH port.  It appears the Ethernet port shut down?  Any ideas on how to stop the loopback test without physically going to the radio location?

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That is not normal behavior and may indicate a larger problem.  The RF loopback has a configurable timer operation and should resume normal operation after the configured loopback time expires (it also shouldn't lock you out of the radio).  Unless you have a way to remotely reboot the radio I think an onsite visit is needed, unfortunately.

A typical time limit of 3-5 min should be sufficient to enable the loopback, monitor the statistics and diagnose.  The radio will resume normal operation after the timer expires (except in this case, it appears).  I would contact our support group and open a ticket.

If it does come back, I would consider upgrading the firmware to 10.5 (latest at time of this post).  Read the release notes first to ensure single upgrade capability.