Andrew Tower-mounted BIAS-T "Warranty" Weatherproofing Revisits

Discussion in 'Tower, Rooftop and Antenna Installation' started by Steve Jones, Nov 19, 2012.

  1. Steve Jones

    Steve Jones Friend of the Community

    Over the past year, we've encountered an unusually-high number of warranty revisits to replace top jumpers on T-Mobile "RRU" sites (Tower-Mounted 3G FRIA radios, with one jumper from radio to antenna, another from radio to BIAS-T to antenna--3 jumpers total per sector).

    • Per customer spec, we have been using "fusion tape" to weatherproof 1/2" jumper connections on everything but the mainline connectors.
    • We're thinking it's a quality control issue on our part, but every revisit has involved water in the jumper connectors at the BIAS-T only, which raises some questions regarding the actual/possible cause.
    • BIAS-T is an Andrew model ATSBT-TOP-RF (FF?). This seems to be a physically well-designed component with long ports that are easily weatherproofed. It has an AISG/RET port for the cable between it and the antenna.
    Has anyone else had a problem with this type of weatherproofing failing at this model BIAS-T? We're traditionally very good on the quality side and are having trouble believing it's simply a quality-control issue from our personnel who have a good track record in this area. To prevent future revisits of this nature, we have begun replacing the jumpers and weatherproofing them with traditional tape/butyl. ***Perhaps this model BIAS-T is heating up the fusion tape and causing it to fail?
    My main concerns are 1. To notify the customer that they will need to change their specification to require tape/butyl weatherproofing on these BIAS-T connections, and 2. Avoid further warranty costs for an issue that, at this time, can only be traced back to faulty weatherproofing installation. *I am in no way trying to blame the manufacturer or the customer for this issue.
    I plan to follow up with Andrew to see if they have any operating temperature specs on this component.
  2. tracy wampler

    tracy wampler Friend of the Community

    well i have found that the 3m electrical splicing tape is about the only thing i trust.all the others dont seam to have the stick to keep creeping moisture out.

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