Very believable because it is so reflective of the everyday world we're all a part of anymore. Actually there are many communications technicians that don't have a full appreciation and understanding of antennas. Amateurs used to be the backbone of commercial radio because their motivation to learn went well beyond the limits of earning a living. Using "modern" testing methods, rote memorization can now earn an Extra class license, thus the loss of prestige that it once carried.
The proper antenna certainly would have been properly kitted at the time of sale. Point being, however, that if a service call was made (after point-of-sale) that other similar looking, compatible-fitting, but actually WRONG antennas might have been pulled from the truck’s inventory, and installed on site. It sounds like that was the situation.
As W.K. suggested, I believe the installers lacked the knowledge and/or equipment to properly test the antenna system (assuming they tested it at all).
On the story itself, you could have had an ideal feedline with a poorly matched antenna, and detected the Fwd/Rev power reported based only on where the wattmeter was inserted into the feedline.
A matched dummy load used during feedline testing would have been a more accurate test.
Unfortunately upgrading an amateur radio license to extra is not enough. I have met at least one individual who passedd the test simply by going through the sample examinations a couple hundred times and memorizing all of the correct answers.
But understanding about feed line losses and antenna matching is "a very big deal" in the area of making a radio communication system work correctly. My guess is that the installers of the poor performance systems did not have the correct instruments, or did not use them, or perhaps did not understand the results. That does happen. And there are even some extra-class amateurs who claim that reflected power does not matter. So even that level of license is not a guarrantree of excellence.
It's always a good idea, but it's essential when you have a niche area, such as 900MHz trunked radio, that you clearly specify your technical requirements to your vendors. Otherwise, you can be taken for a ride (by accident or not) by suppliers who don't understand what you need. At JEM Engineering, we test test every single serialized antenna that we produce. We have near-field and far-field chambers, plus several analyzer types, to cover testing antennas from 30 MHZ to over 40 GHz. We even offer testing services to our competitors.
From the information provided, the antenna wasn't part of the turn-key package. Was the antenna (and coax, for that matter) part numbers specified in the kit?
I’m laughing with a wry smile – I spent over 20 years of my career in Motorola product development and have seen your experience played out more than once. The caliber of the typical “third-party” installation guys was hard to guarantee, but as you experienced; occasionally at the level of fresh-hires direct from the Dominoes Pizza delivery routes. Lacking a thorough understanding of a radiating system, to say the least. In Engineering, product design and antenna design always went hand-in-hand, and the antenna performance was always engineered to the Nth degree in the anechoic chambers.But “fool-proofing” the antenna connection was not always done, and too often, the only guarantee that the proper antenna P/N was used would be the fine-print in the Field Service manual. So many looked alike, it could have been easily overlooked; either accidentally, or intentionally, as you suggested.But more likely, it was “accidentally” due to the limited technical skills of the installers.
As energy efficiency becomes more and more a concern for makers of electronics devices, researchers are coming up with new ways to harvest energy from sound vibration, footsteps, and even electromagnetic fields in the air.
The government wants to study your brain, and DARPA wants to use similar information to give robots true autonomy beyond any artificial intelligence developed to date. Sound like science fiction? It's not.
From Dell / Intel® New Paradigms in Design Work Scott Hamilton, vertical market strategist for Dell Precision workstations, 5/2/2013 3
Early in my career, I worked as a draftsman and remember the days of drawing on vellum with numbered pencils and Mylar with plastic lead. This was a fun experience in the sense that I ...
I've been using workstations for more than 10 years and love finding ways to get more performance from my system. With demanding professional applications that require more power each ...
A lasting memory from my first job as an engineer in an auto assembly plant is standing on hard concrete at six in the morning, vending-machine coffee clutched in hand, listening to ...
A quick look into the merger of two powerhouse 3D printing OEMs and the new leader in rapid prototyping solutions, Stratasys. The industrial revolution is now led by 3D printing and engineers are given the opportunity to fully maximize their design capabilities, reduce their time-to-market and functionally test prototypes cheaper, faster and easier. Bruce Bradshaw, Director of Marketing in North America, will explore the large product offering and variety of materials that will help CAD designers articulate their product design with actual, physical prototypes. This broadcast will dive deep into technical information including application specific stories from real world customers and their experiences with 3D printing. 3D Printing is
To save this item to your list of favorite Design News content so you can find it later in your Profile page, click the "Save It" button next to the item.
If you found this interesting or useful, please use the links to the services below to share it with other readers. You will need a free account with each service to share an item via that service.
Tweet This
1 
