Thursday, September 10, 2009

Tech Net Notes September 9, 2009


There was no topic for the Tech Net this time. Instead... we had rain. Lots of rain. Even though Tulsa proper did not get buckets full, Northeast Oklahoma received steady rain for the day and somewhat previous.

w9nbc, Steve, came on during the intro to report street flooding on Memorial from 101st to 111th. Though the rain was settling down a bit, the water, the rain, and the lightning was on our minds.

w2csl, Bob, was the first to check and posed two questions:

1. Why are we called "Hams"?
2. How many Hams checking in tonight have been commercial operators, licensed by the FCC?

kb5vdb, Ron, came on to take a stab at the first question. He mentioned that he had heard that it may have had to do with Hiram Percy Maxim, who is considered to be the "father of Ham radio". Ron said that his initials, HPM , may have been the source from which HAM was derived, although there is no known evidence to say that is definitely the case.

w9nbc, Steve, checked in and said that he had been FCC First Class licensed with radar.

ad5jl, Bob, said he remembered something in QST being written about the "ham" moniker, but doesn't recall exactly what was said. Bob was also licensed through the FCC as First Class. In addition he posed the question, "How do you check to insure that the safety ground lug in a receptacle in your house is wired correctly, going back to a ground rod?

wb5uuw, Earl, checked in and mentioned that he was FCC Licensed First Class. Regarding checking for a ground he said that first you verify that you have a physical ground (rod) tied to the breaker box. He mentioned that the ground should be connected to the ground bus in the breaker box. If that is the case, go to the receptacle and check the AC+ against the Safety ground socket for 110 (120) VAC. If it check's OK, check the return (wide part of the socket) against the Safety ground socket for 100 (120) VAC. If no voltage, that's good. You can then check for continuity between the return (wide part of the socket). There should be continuity.
It is important to mention here that you follow that sequence. Check for your voltages before you check for continuity...and...(of course) do not check for continuity between the AC+ (narrow part of the socket) and the Safety ground.

NOTE: Understand? If you've got voltage between two points and you try to check for continuity, it may melt your meter into your carpet...and it's so hard to get melted plastic out of your carpet. Plus it may blow up your meter and send the indicator needle through your forehead and into orbit. Those indicator needles are hard enough to replace as it is!

ke5lnn, Dave, said that he has one of the line testers (plugs into a receptacle and analyzes voltages and grounds) and that it's served him well. Dave also made the point that the the piece of equipment that your connecting to a ground needs to be opened up to make sure that the chassis is wired to the ground of the AC power cable into the unit.

ke5otq, Dennis, added that there are ground fault detectors that can be purchased which will do the trick. Regarding the origin of "Ham" he suggested that it may have related back to one of the first guys licensed.