4 essential steps for successful microwave link deployment

102018 July

Successful deployment of a microwave network requires the proper link budget planning, bench testing, pre-configuration and staging of each microwave link. Failure to perform these steps may lead to unwanted and expensive delays in deployment. Have you ever been in a situation where your tower crew says: “These radios are bad, no matter what we do they won’t link up and they won’t pass the traffic!” And you have no arguments against that because the radios were not pre-configured and bench tested.

To avoid these headaches, and to ensure the most efficient installation for your tower crew, follow these steps:

  • Have every microwave path designed and optimized by a skilled RF professional
  • Get all microwave links preconfigured to your network requirements
  • Label properly each microwave radio and its accessories for ease of deployment
  • Have each microwave link thoroughly bench tested and make sure all RF and throughput tests are passed

There is always an option to go the DIY route if you have time, knowledge and resources. For a seamless deployment follow these guidelines:

  1. For microwave path design and link budget, it is suggested to use professional software such as Pathloss 5.0 to account for terrain, diffraction, reflections and multipath impact on the microwave path. Another option is to use simplified online path calculators that are typically provided by microwave radio vendors. These are good for basic estimations like Rx level, line-of-sight verification, and annual path availability. SAF offers an accurate and intuitive path calculator: https://www.saftehnika.com/PathCalc/calculator.php
  2. Pre-configuration can be performed in your office by connecting your laptop to the radio’s management port. You don’t want to leave this task up to the tower crew. You need to reference your FCC coordination sheets and know your configuration parameters for each radio unit, i.e. frequency pair, Tx power, channel width, IP address, gateway, VLANs configuration, time server settings, SNMP settings etc. Reference the user manual in order to be able to apply and understand your planned configuration. If you are setting up multiple radio units with similar parameters, save the configuration file and upload it to another unit to speed up your work. Keep your work organized and track the applied configurations in a separate spreadsheet. Save the configuration and diagnostic files on your laptop for reference.
  3. Proper labeling of your equipment is a key to successful equipment installation and future maintenance. Create labels with site ID and IP address for each unit. Also place a copy on each box, so that your tower crew recognizes the right equipment for each site. Tower crew will be able to access the radio unit management via a specified IP address on the label for alignment or troubleshooting purpose.
  4. Bench testing is necessary to make sure you have all the parts needed for installation and to document that the microwave link performs as per your expectations. A test-kit with attenuators is recommended for the bench test. However, with some inspiration you can build your own test-kit using either the reflected signal from the ceiling or by inserting two reams of copy paper as the attenuators substitute:

The purpose of bench testing is making sure the RF and Data Layer performance meet your expectations. Bench testing main tasks:

  • Simulate the approximate Rx level that you expect to achieve for deployed radios
  • Verify that the SNR (signal-to-noise ratio) is within acceptable levels
  • Confirm that the radios talk to each other (modem lock) at your expected modulation level – typically the highest modulation level
  • Make sure that your Data Layer is going through the link, i.e. when testing the Ethernet connection, a ping test from source to destination is sufficient, an ASI or E1/T1 data stream would require a special test device
  • Perform the throughput tests. For Ethernet throughput measurements a dedicated hardware L2 tester is recommended. As an alternative, some software-based test tools like Iperf could be used. If you are deploying a 1+1 or 2+0 setup make sure to test for link protection failover or confirm the aggregated throughput

An alternative and more efficient approach is to leave the link planning, configuration and staging in the hands of SAF trained RF engineers. SAF configuration and staging service includes:

  • Review and validation of customer-provided engineering configurations
  • Per customer labeling requirements: Site ID, radio settings, and any other information requested
  • Replication of the customer’s planned setup in a laboratory environment along with the associated connection diagrams
  • Individual RF links established through the use of attenuators to achieve Rx levels close to expected levels at the customer’s deployed links
  • Customer-defined radio configuration: frequency, bandwidth, modulation, Tx power, IP settings, login credentials, time zone etc.
  • Configuration and setup tests, i.e. 1+1 protection switching
  • Data throughput tests
  • Receiver sensitivity threshold control measurements
  • Modem SNR and modem error rate measurements
  • Test report generation
  • Division and packaging of equipment, shipment of each package directly on customer Site

A sample test report excerpt:

Inquire with a sales representative about SAF link planning, pre-configuration, and staging services. Contact us here.

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Tatjana Dunce

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