Ive been following this thread for several days but have been on the road and havent had time until now to sit down and weigh inapologies.
Jack Unger obviously knows a good deal about this topic; his comments highlight several relevant issues: A) The factors which govern microwave path engineering are indeed cut and dried, well proven and well understood; B) Interference issues do go away during the licensing process itself, well prior to hardware deployment. Jack defined this side of the equation nicely, simultaneously illustrating why licensed spectrum is so valuable; C) Antenna and radio manufacturers offer models varying in gain and price, among other factors. (For example, weve successfully used 18 GHz, 400 MHz-wide paths to cross over a two hundred foot railroad ROW, and to go farther than 13 miles). AGC/ALC and/or variable attenuation circuits have been around for a LONG time and work very well. There is simply NO excuse for a properly designed and licensed path to not perform correctly. Any engineer who cannot design a link which fires up within 5 dB of a link budget (remember, 3 dB means either halving or doubling the power) either isnt particularly competent or was given bad data; and D) As someone pointed out previously, each and every microwave path embodies some unique circumstances, and a one-size-fits-all approach merely demonstrates naiveté. Lots of people seem able to hang and activate equipment, and make it work; smart operators who wish to build and retain a satisfied customer base in an increasingly competitive environment first take steps to ensure that the system will perform properly. It needs to be said again: Problems with real world versus theoretical performance are usually caused by bad field data or incompetenceat the engineering and/or installation sideor both. All of the above said, it makes little sense to me, in a forum such as this, to delve too deeply into the arcane minutia of antenna design engineering. Nonetheless, a few minutes of research in a good catalogue will demonstrate that, for any given frequency band and design configuration, the general rule is that the larger the antennas aperture, the more gain and the sharper beamwidth the antenna producesthis same rule of thumb applies to satellite antennas as well as to microwave dishes and grid packs. Thus, regulations which either limit or mandate antenna design and size will inevitably impose performance penalties upon system operators by eliminating design options. Folks, Ive been living in licensed space for many years, and have installed more microwave systems than I care to remember between the 2, 4, 13, 18, 28, and 38-42 GHz bands. One of the most important things Ive learned is that licensed spectrum is not a panacea, nor is it the monster-under-the-bed its sometimes made out to be. Another key point is that regulation is most definitely a two-edged sword, one that is ALWAYS wielded by someone my business cannot control. Therefore, it is important in my view that the limited resources of any trade association be applied to matters which most directly benefit its membersand comments from an association seem to carry more weight at the FCC than those from a couple of individuals. Speaking broadly and generally, almost ALL regulation of technology should be opposed or minimized to the fullest extent possible. I try never to forget that regulation which benefits my business today could easily lead to punitive mandates or restrictions tomorrow while benefiting someone else You all might also consider talking to my old friend Andrew Kreig of the WCAI about a joint responsesee http://www.wcai.com/. Just my 2¢ (and then some, as usual!) Ted {:-) Edward J. Hatfield III, President E.J. Hatfield & Company 5142 Edgemoor Drive Norcross, GA 30071-4342 USA 1-770-209-9236 - Office 1-770-209-9238 - Fax 1-770-560-0736 - Sprint 1-678-457-8411 - Cingular 154*273*18 - NexTel -- WISPA Wireless List: wireless@wispa.org Subscribe/Unsubscribe: http://lists.wispa.org/mailman/listinfo/wireless Archives: http://lists.wispa.org/pipermail/wireless/
