[TenTec] OT Florescent Ballast's

[Ken Brown]

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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