{"id":266,"date":"2012-07-30T07:45:58","date_gmt":"2012-07-30T14:45:58","guid":{"rendered":"https:\/\/bpapaloalto.org\/newbpa\/?p=266"},"modified":"2013-04-19T15:11:23","modified_gmt":"2013-04-19T22:11:23","slug":"das-cell-phone-antennas","status":"publish","type":"post","link":"https:\/\/bpapaloalto.org\/newbpa\/das-cell-phone-antennas\/","title":{"rendered":"AT&T’s proposed DAS cell phone antennas in Barron Park"},"content":{"rendered":"

A report by Doug Moran..with his u<\/span>pdated Map of Proposed Towers (July 2012)<\/span><\/p>\n

https:\/\/maps.google.com\/maps\/ms?msid=209482381320120716761.0004a3aa50f14ecb36fa0&msa=0<\/a><\/p>\n

Report from the AT&T Open House June 20 on proposed DAS cell phone antennas<\/span>\u00a0for Barron Park (and elsewhere).\u00a0<\/span>Barron Park attendees included me, Art Liberman and Bob Moss (and<\/span>\u00a0possibly others).<\/span><\/p>\n

AT&T had two engineers there who could answer the sorts of questions<\/span>\u00a0mentioned in the earlier messages (one that we had asked over a year<\/span>\u00a0ago). The engineer we were talking to said that this was the first<\/span>\u00a0time anyone had asked him about these sort of details, so apparently<\/span>\u00a0Barron Park _is_ different. Below is the info gathered.<\/span><\/p>\n

1. The City’s database of cell towers had multiple errors. The<\/span>\u00a0relevant one was that it didn’t show AT&T using the tower at the VA<\/span>\u00a0Hospital (I have updated my map to reflect this). \u00a0This tower provides<\/span>\u00a0coverage for much of western Barron Park. The proposed DAS antennas in<\/span>\u00a0BP follow the contour of the limits of the coverage of that antenna.<\/span>\u00a0EXCEPT, the antenna at the top of Matadero is intended to provide<\/span>\u00a0coverage for the nearby section of the Research Park. For the small<\/span>\u00a0coverage areas that DAS is intended for, AT&T prefers to put the<\/span>\u00a0antennas on telephone poles because those poles already have the high<\/span>\u00a0capacity link (optical fiber) to their network node, whereas adding an<\/span>\u00a0antenna to the roof of a commercial building involves significant<\/span>\u00a0costs for the additional cabling. I didn’t get an explanation for the<\/span>\u00a0Chimalus site (because we had already monopolized the engineer too<\/span>\u00a0much).<\/span><\/p>\n

<\/p>\n

2. Although the AT&T presentations characterize DAS as having an<\/span>\u00a0effective coverage radius of 2km, the existing installations in Palo<\/span>\u00a0Alto (in the north) typically are about 1500 feet (0.46 km). This is<\/span>\u00a0based both on obstructions — trees and buildings — and anticipated<\/span>\u00a0usage levels. Separation between antennas is less than this, partly<\/span>\u00a0because coverage is not a circle (obstructions) and because<\/span>\u00a0eliminating coverage gaps means that some areas will be covered by<\/span>\u00a0multiple antennas. The separation for the proposed sites in BP is<\/span>\u00a0about 1300-1500 feet.<\/span><\/p>\n

3. There is no dead zone (a “null”) underneath the antennas. This is a<\/span>\u00a0misunderstanding by the non-techies who give the presentations. The<\/span>\u00a0signal under the antennas is very weak _relative_ to the primary beam,<\/span>but because underneath is so much closer, a weak signal is more than<\/span>\u00a0enough to provide a solid connection.<\/span>
\nAside: most diagrams of the signal strength from an antenna are highly<\/span>\u00a0idealized — there are “hot” and “cold” spots resulting from the<\/span>\u00a0antenna not being the idealized “point source”. According to the<\/span>\u00a0engineer, the DAS antennas do have these effects, but not over the<\/span>\u00a0<\/em>thresholds that affect cell reception<\/em>.<\/span><\/p>\n

4. Summarizing from much earlier: DAS antennas have pros and cons.<\/span>\u00a0Because they are intended to provide coverage for only a small area,<\/span>\u00a0they operate at much lower power than conventional cell towers.<\/span>\u00a0Because the towers are closer, your cell phone does not have to use as<\/span>\u00a0much power to make and maintain a connection. It has been argued (by<\/span>\u00a0AT&T) that the benefits of having your cell phone radiating at a lower<\/span>\u00a0level during calls more than offset the effects of having the tower<\/span>\u00a0closer to you (which is always on). This is an argument I would tend<\/span>\u00a0to believe. Also, lower power usage during calls and data transfers<\/span>\u00a0translates into longer battery life for your phone\/device.<\/span>\u00a0Additionally, since the area to be covered is smaller, it is argued<\/span>\u00a0that service can be more reliable because it is easier to predict<\/span>\u00a0demand.<\/span><\/p>\n

— Doug Moran<\/span><\/p>\n","protected":false},"excerpt":{"rendered":"

A report by Doug Moran..with his updated Map of Proposed Towers (July 2012) https:\/\/maps.google.com\/maps\/ms?msid=209482381320120716761.0004a3aa50f14ecb36fa0&msa=0 Report from the AT&T Open House June 20 on proposed DAS cell phone antennas\u00a0for Barron Park […]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_et_pb_use_builder":"","_et_pb_old_content":"","_et_gb_content_width":"","ngg_post_thumbnail":0,"footnotes":""},"categories":[9,10],"tags":[],"class_list":["post-266","post","type-post","status-publish","format-standard","hentry","category-city-of-palo-alto","category-public-works-and-utilities"],"_links":{"self":[{"href":"https:\/\/bpapaloalto.org\/newbpa\/wp-json\/wp\/v2\/posts\/266","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/bpapaloalto.org\/newbpa\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/bpapaloalto.org\/newbpa\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/bpapaloalto.org\/newbpa\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/bpapaloalto.org\/newbpa\/wp-json\/wp\/v2\/comments?post=266"}],"version-history":[{"count":0,"href":"https:\/\/bpapaloalto.org\/newbpa\/wp-json\/wp\/v2\/posts\/266\/revisions"}],"wp:attachment":[{"href":"https:\/\/bpapaloalto.org\/newbpa\/wp-json\/wp\/v2\/media?parent=266"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/bpapaloalto.org\/newbpa\/wp-json\/wp\/v2\/categories?post=266"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/bpapaloalto.org\/newbpa\/wp-json\/wp\/v2\/tags?post=266"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}