HOME  |  NEWS  |  BLOGS  |  MESSAGES  |  FEATURES  |  VIDEOS  |  WEBINARS  |  INDUSTRIES  |  FOCUS ON FUNDAMENTALS
  |  REGISTER  |  LOGIN  |  HELP
Comments
View Comments: Newest First|Oldest First|Threaded View
WA4DOU
User Rank
Silver
Crazy Antenna
WA4DOU   1/11/2012 2:22:35 PM
NO RATINGS
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.

JimT@Future-Product-Innovations
User Rank
Blogger
Re: If only antenna couplings weren’t interchangeable
JimT@Future-Product-Innovations   10/12/2011 4:33:34 PM
NO RATINGS

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.

brett_cgb
User Rank
Iron
Re: The crazy antenna caper
brett_cgb   10/12/2011 12:26:21 PM
NO RATINGS
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.

 

William K.
User Rank
Platinum
The crazy antenna caper
William K.   10/12/2011 11:34:24 AM
NO RATINGS
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.

hweidig3
User Rank
Iron
There ARE good small antenna companies
hweidig3   10/12/2011 10:04:33 AM
NO RATINGS
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.

TJ McDermott
User Rank
Blogger
Re: If only antenna couplings weren’t interchangeable
TJ McDermott   10/12/2011 7:00:07 AM
NO RATINGS
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?

JimT@Future-Product-Innovations
User Rank
Blogger
If only antenna couplings weren’t interchangeable
JimT@Future-Product-Innovations   10/11/2011 5:38:56 PM
NO RATINGS

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.

vectorhappy
User Rank
Iron
CB shop work?
vectorhappy   10/11/2011 10:01:56 AM
NO RATINGS
tell Paul to get his amateur license renewed and get that upgrade to Extra - wouldn't want the CB'ers to get the wrong idea. 

 

mikey



Partner Zone
Latest Analysis
It's been two years since the Mac Mini's last appearance on iFixit's teardown table, but a newly revised version joins Apple's lineup this week.
More often than not, with the purchase of a sports car comes the sacrifice of any sort of utility. In other words, you can forget about a large trunk, extra seats for the kids, and more importantly driving in snowy (or inclement) weather. But what if there was a vehicle that offered the best of both worlds; great handling and practicality?
Kevin Gautier of Formlabs describes the making of a carbon fiber mold for an intake manifold, using a $3,300 3D printer, during Medical Design & Manufacturing Midwest.
Science fiction author Isaac Asimov may have the best rules for effective brainstorming and creativity. His never-before-published essay, "On Creativity," recently made it to the Web pages of MIT Technology Review.
Much has been made over the potentially dangerous flammability of lithium-ion batteries after major companies like Boeing, Sony, and Tesla have grappled with well-publicized battery fires. Researchers at Stanford University may have come up with a solution to this problem with a smart sensor for lithium-ion batteries that provides a warning if the battery is about to overheat or catch fire.
More:Blogs|News
Design News Webinar Series
10/7/2014 8:00 a.m. California / 11:00 a.m. New York
9/25/2014 11:00 a.m. California / 2:00 p.m. New York
9/10/2014 11:00 a.m. California / 2:00 p.m. New York
7/23/2014 11:00 a.m. California / 2:00 p.m. New York
Quick Poll
The Continuing Education Center offers engineers an entirely new way to get the education they need to formulate next-generation solutions.
Oct 20 - 24, How to Design & Build an Embedded Web Server: An Embedded TCP/IP Tutorial
SEMESTERS: 1  |  2  |  3  |  4  |  5  |  6


Focus on Fundamentals consists of 45-minute on-line classes that cover a host of technologies. You learn without leaving the comfort of your desk. All classes are taught by subject-matter experts and all are archived. So if you can't attend live, attend at your convenience.
Next Class: 10/28-10/30 11:00 AM
Sponsored by Stratasys
Next Class: 10/28-10/30 2:00 PM
Sponsored by Gates Corporation
Next Class: 11/11-11/13 2:00 PM
Sponsored by Littelfuse
Learn More   |   Login   |   Archived Classes
Twitter Feed
Design News Twitter Feed
Like Us on Facebook

Sponsored Content

Technology Marketplace

Copyright © 2014 UBM Canon, A UBM company, All rights reserved. Privacy Policy | Terms of Service