Union City, Georgia

How To...
The 130 ft Rohn 25G tower takes on a different look around the holidays. This transformation takes place to the delight of the neighbors that stop and ask how it is done and wish us happy holidays. Cars drive by and stop to gawk once they see how tall it really is. In the picture below you can see the house in the dim light. The star is about 8 feet tall so you can get a feeling for the size of the whole thing.
Shot by Tony King, WA4UPE
with Olympus D-460z with no special effort.
Shot December 10, 2001 by Dale Heatherington, WA4DSY
Camera: Mamiya 7, Lens: 65mm @ f8, Time: 60 seconds, Film: Ilford Delta 100. (You should see this in 11x14!)
Start with 5 ten foot lengths of schedule 40 pvc pipe, some stainless screws and nuts, 19 strings of 25 colored lights, 3 strings of clear lights, black tape, tywraps, pieces of #14 and #12 wire to tie things off with and some excellent help.
Patty and Mike get the 8 ft. star ready while Tony is splicing the strings of lights together. Here we use about 53 lights (just over two strings) spliced together and taped to the PVC star to form the image. (2001)
Brandy is content to watch... good girl! (2001)
Tony helps Mike splice the strings of lights together for the star. (2001)
Patty works on making sure the bulbs are all tight in their sockets after Tony has spliced them together. Then they're tested. The strings of lights as they come from the factory usually have loose bulbs and sometimes missing or bad ones. (2001)
The star is on the way up. Tony feeds out just enough rope to keep the star away from the tower while Mike is up top pulling it up by hand. (2001)
The star is almost there. Does it seem like a long ways up there to you too? (2001)
Positioning the star and securing it is an awkward job but Mike makes short work of it and ties it off to the tower using lengths of #12 wire (about a foot long). (2001)
At this point Tony is just standing there watching and Patty takes the picture...
wouldn't ya know it? (2001)
The star is secure, the lights have been pulled up the guy wires and up the center. (2001)
Mike is on the way down tying the center string to the tower. (2001)

The lower portion of the outer strings is pulled over to the tower forming the bottom of the tree. The power for the bottom strings and the center string comes from a junction box right where the lower strings come to the tower. The power for the star and the outer strings is fed from a junction box at the top. Okay, figure it up... 25 lights per string... 21 strings... That's 525 lights... each light is 9 watts... that's 4,725 watts!

Now, for the rest of the story...
I don't feed the full 120 volts to the strings. The reason is that when you put the full line voltage on the strings of lights, they run extremely bright and the filament is very fragile. I half wave rectify the line voltage. That yields about 53 Volts DC (rms) to the strings of lights. The result is that the filaments run cooler with only a small reduction in brightness. They are no longer so fragile and bulb life goes up from a few failures a night to almost no failures in two months. Approximately half the lights are on one phase of the house supply and the other half on the second phase. That helps balance the load. Using a clamp on AC amp meter to measure the input AC, one leg measures about 9 amperes and the other measures about 8 amperes. That's about 1080 watts plus 960 watts for a total power of about 2040 watts. That's not quite as bad as 4,725 watts when it comes to spinning the meter.


Don't try this at home...

This is a simplified schematic diagram of how the lights are wired. The transformer represents the power transformer at the street. The fuses represent two 20 amp breakers in the breaker panel which feed two receptacles. The diodes and lights are controlled by a timer and relay and the whole thing is plugged into the receptacles.

The relay, diodes on a heatsink, a thermocouple type thermometer (to monitor the heatsink temperature) and receptacles to feed the DC out are all mounted on a board. A receptacle with all connections tied together and connected to a large ground wire tied back to the cold water pipe is also mounted on the board. The strings can be unplugged from the DC supply and plugged into this grounded receptacle to effectively ground all the light wiring.


Last update was on November 20, 2006 5:19