Well I finally got around to passing the code and am waiting for the good ol' FCC to send me the Novice license. I am definetly going to go for the Tech. class license ASAP. My question is what type of rig should I start my HAM life with. I have n
arowed my choices down to either a dual bander 2 meter/ 440MHz ora 220MHz handheld. Does anyone have any coments or suggestions on what band they like the best. I hear that 2 meter is very popular but is also very
crowded in the urban areas. (where I will be setting up shop) Any replys wouldbe greatly appreciated.
------------------------------
Date: Thu, 07 Dec 89 13:08:30 GMT
From: "Pete Lucas, NERC-TLC, Swindon U.K." <PJML@
Subject: EMC in fast-food environment (cross-posting)
Message-ID: <07 Dec 89 13:14:10 GMT #3415@UK.AC.NWL.IA>
The following is a cross-posting from RISKS list, which may amuse and entertain
you, bearing in mind some of the recent discussions.
Who needs to phone through the autopatch to order a pizza?
Just pull up outside the pizza parlor, switch on that 2Kw mobile linear,
and call 'CQ PIZZA' ??
>>>>>>>>>>>>>>>START OF FORWARDED MESSAGE>>>>>>>>>>>>>>>>>>>>>>>>>
>Date: Sat, 4 Nov 89 22:33:34 pst
>From: rh@well.UUCP (Robert Horvitz)
>Subject: McRisks - Electronic Interference in Fast Food Automation
>
>The Importance of EMC in the Preparation and Selling of Big Macs," by
>Fernando M. Esparza is a fascinating article in the September-
>October 1989 issue of "EMC Technology."
>
>
>
>Esparza, the author of McDonalds' "Electrical Disturbance Standards," has some
>great war-stories to tell about problems cropping up in these highly automated
>fast-food environments due to unforeseen interactions among appliances. One
>he described as "the most serious interference incident that McDonalds
>has ever experienced" involved toasters and timekeeping.
>
>It seems that when McDonalds decided to introduce McMuffin products, they had
>to install special toasters. Soon, many of their employee time-clocks
>inexplicably started to gain 2 to 4 hours each day, crediting workers with
>more hours than they had actually worked. After a lot of head-scratching (and
>testing), they discovered that the new toasters' voltage control circuits
>induced voltage spikes in the powerline during normal operation - sometimes as
>many as 120 per second. This disrupted the clocks on the same power circuit,
>since they monitored the alternating current's waveform for the purpose of
>time-keeping: the voltage spikes increased the number of "zero-crossings,"
>which were used as the metric.
>
>"By the time we were able to pin down the problem exactly, there were more
>than 5,000 toasters installed in the restaurants... Some restaurants reverted
>to manual procedures for payroll timekeeping, but there were a number
>of employees who were paid for extra time because of the clock errors.
>Although the managers were understandably upset, none of the crew complained."
>
>"Ghosts in the Drive-Thru" was another baffling problem, affecting the POS
>(point-of-sale) system of a McDonalds in suburban Los Angeles: "The POS system
>is a collection of computerized cash registers that are networked together
>in a somewhat sophisticated and proprietary network," Esparza explains.
>The problem was that bogus food orders showed up randomly in the system.
>"The restaurant could distinguish ghost orders from real orders because
>the quantity of the items displayed was the same - 11 cokes,
>11 fries, 11 hamburgers, etc.
>The items themselves were directly copied from the previous, actual order.
>These orders could not be cancelled but had to be cashiered out of the
>system, thereby rendering all product mix and sales information invalid
>and creating a potential security/theft problem, in addition to slowing
>customer service in the drive-thru."
>
>The restaurant's POS system and all of its software was replaced, but the
>problem continued. To make a long story short, this McDonalds happened to be
>near a cluster of radio and television transmission towers. The POS system's
>wiring acted as an antenna, capturing the signals, and corrupting some of the
>data that flowed thru the wires.
>
>One problem described in this article stands out as a potential threat to many
>more retailers than just McDonalds: "The Cash Drawers that Opened by
>Themselves." Again making a long story short, Esparza discovered that the
>problem began soon after the local police department upgraded their
>communications system with higher-power mobile radios. "Whenever they
>responded to a call while in the drive-thru, the cash drawers opened... An
>open cash drawer without a cashier to supervise it is...a large security
>liability."
>
>"EMC Technology" is a controlled circulation bimonthly.
>Subscriptions are free to those who qualify, $40/year for those who
>don't. For more information contact EMC Technology Circulation
>Dept., 5615 West Cermack Rd., Cicero, IL 60650-2290 USA.]
>>>>>>>>>>>End of forwarded message>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
++Pete G6WBJ
------------------------------
Date: Thu, 07 Dec 89 12:53:04 GMT
From: "Pete Lucas, NERC-TLC, Swindon U.K." <PJML@
Subject: Mobile overvoltage protection.
Message-ID: <07 Dec 89 12:54:34 GMT #3406@UK.AC.NWL.IA>
OK so i drew the SCR upside down! Thats because i used a triac in my
