Close-out package for DAS: why do we 'really' need it?

Over last 8 years we have compiled hundreds of closeout package (a.k.a. COP) after completing DAS installations.  Although these packages can be quite extensive based on client’s requirements, there are only a few important items really needed ‘for the long run’. Why only a few - you may ask?

Well, why do we put together a COP anyway?  2 principal reasons:

1. Prove to the client that the installation has been properly completed.

2. Use COP as a reference for future maintenance or troubleshooting activities.

The first reason (i.e. proof of work) loses its value right after invoice is paid. The second reason is ‘for the long run’.

So imagine you get called in for troubleshooting a DAS that was built over 2 years ago. What would you ask for - i.e., what information would add most value in your troubleshooting effort? I am guessing the following:

1. Location, contact and access information: you want to know the address, who to talk to when you get to the building, and how to get to the equipment rooms, antennas, donor antennas etc.

2. System Overview: a short, quick overview of the system - coverage objective of the original system, type of DAS, number of antennas, remotes, hubs etc. Helps you prepare for the troubleshooting exercise.

3. Layout of the DAS: besides the antennas most of the elements of the DAS are hidden. Layouts - block diagrams, line drawings, or as-built with floor-plans - in my opinion, are the most important documents for close-out. Without layouts, hours will be wasted just to figure out heads and tails of the DAS.

With these 3 items you can have a fairly good start. Other value-added information:

4. Post-installation signals under the antennas: quick way to isolate the problem by comparing current RSSI under the antennas vs. when the system was turned up. If RSSI is down under all the antennas, this would be a system wide problem. You may now focus on head-end equipments. If it is under a few clustered antennas - it’s localized.

5. Power output of different devices: this can be helpful when the answer is not obvious and you have your power meter out. Original base-line ERPs help in these scenarios.

6. Donor signal: if the DAS is powered by a BDA, donor signal can become a important factor mainly to assess if the macro RF environment has drastically changed which may be causing this degraded performance of the DAS.

There are other minor information that might be needed based on the site and scenarios (e.g., materials list, people involved in the original project, etc.).  But from value-add perspective, above list is adequate.

Few more items on COP:

Over-hyped COP item: Sweep results. This just adds to the girth of the COP. The older a DAS gets, less value the sweep has; but for some reason sweep results are de facto requirement by a lot of clients. Fiber test results are another one.

Potential to add a lot of value if properly done: a photo or media album… I’ll keep that for another post.
(First posted on 12/30/10)