My experiences < http://www.csm-gh.com/projects.htm > have been similar to the
fire station scenario Ken. We were expected to provide two way radio and paging
(two way paging like Blackberry) throughout the building campus including
basements, mechanical rooms, general office and executive spaces. However the
building was constructed as a complex of Faraday shielded boxes; metal floor
pans, foil backed ceiling tiles, foil backed wall coverings or sheet rock, and
metallic oxide glass. Signal ingress / egress was so difficult that one group
of buildings required 8,000 feet of Radiax® and sixteen bi-directional gain
block amplifiers feeding roof top antennas.
And while there was a requirement for the radio system (first Motorola Harmony)
for Security, Maintenance, Logistics to communicate, the Computing department's
security group wanted NO signal egress or electro-magnetic radiation. Just
because its called wireless, does NOT mean there's no wires or cables!
Best regards,
CSM(r) Gary Huber - AB9M
9679 Heron Bay Rd
Bloomington, IL 61705
(309-662-0604)
www.csm-gh.com
glhuber@msn.com
gary.huber@us.army.mil
--------------------------------------------------
From: "Ken Brown" <ken.d.brown@hawaiiantel.net>
Sent: Monday, December 08, 2008 10:44 PM
To: "Discussion of Ten-Tec Equipment" <tentec@contesting.com>
Subject: Re: [TenTec] OT Florescent Ballast's
> Hi all,
>
> This discussion brings up a couple of points, both fairly off the
> Ten-Tec topic, however they are certainly on the topic of two way radio
> and since the subject line has already been labeled "OT", it should be
> alright.
>
> First, retrofitting an older fluorescent fixture, which originally
> had a plain iron core transformer style ballast, with a new "electronic
> ballast" could possibly make more noise than the electronic ballast
> would have made in a fixture designed for a electronic ballast. This is
> because the fixture may have different shielding of all the wires, and
> different spacing between the metal frame and the fluorescent tubes, and
> therefore different capacitive loading of the switching devices in the
> ballast. I understand the motivation to change from T12 tubes to T8
> tubes and considering the cost of labor I wonder if it makes sense the
> change the ballasts in old fixtures to accomplish this, compared to
> changing the entire fixtures?
>
> Second, the story of the building design department and the
> wireless communications team not necessarily working together until
> after it is too late, reminds me of a snafu at a former place of employment.
> I worked for a county government two way radio shop. We contracted
> service to municipalities in our county, including the city fire
> department. We had been servicing the base station VHF FM radios in the
> city's fire station for years. The department outgrew their old station
> and got funding for a brand new state of the art fire station. They
> wanted new radio equipment (They were using some very old yet reliable
> equipment) and our shop advised them what radio gear they should budget
> for. We included transceivers, antennas and transmission lines. We
> calculated the length of transmission line needed, based on the location
> of the room they had specified as the radio equipment room and the
> location of rooftop antenna mounts they had specified. Based on the
> needed length, we specified the transmission line and connectors. They
> city fire department was looking forward to a top notch fire station and
> radio system, and they were sure they would get it because the
> architecture firm contracted to design the building was reputed to be
> experts at designing fire stations. We asked them for details along the
> way, and were always assured that everything would be just fine, because
> the designers of the building were fire station experts.
> The radio gear was all ordered and delivered waiting for the day we
> would install it. We expected a straight forward job, mounting a few
> antennas and running some heliax through conduits. We had already
> programmed the radios to their channel plan, and made up the cabling for
> power supplies and tone encoders and whatever else was required. Then
> came the day we were supposed to install the radio system. We brought
> all of the gear to the shiny new fire station. We were shown the
> designated radio equipment room and the designated location of the
> antenna mounts. We were surprised to find that the fire station design
> expert architects did not realize that fire stations used two way radio
> systems. There were no provisions for mounting the antennas where the
> fire department wanted them mounted or anywhere else on the building,
> and there were no conduits run from the radio equipment room to the
> roof. I guess they figured it is wireless, so who needs conduits?
>
> DE N6KB
>> Jim,
>>
>> I've been retired for six years and do not have the NEC and FCC manual sets
>> nor the ballast information available... It seems like this class of device
>> was industrial / commercial use only and was not considered part 15. As
>> previously stated the electronic ballasts were generating a lot of VHF -
>> UHF energy which was strong enough to QRM standard one way pagers that were
>> carried into the building. We ran a spectrum analyzer and the ballasts were
>> within manufacture's specifications and in compliance with FCC regs but we
>> could not use the slide projectors when the ballasts were energized. We got
>> what was specified by our building design department (no coordination with
>> my unit which was the company's "wireless communications team"
>> http://www.csm-gh.com/ECS-2000.htm ) and the manufacture was not liable but
>> replaced the A/V equipment anyway.
>>
>>
>>
>
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