Jun 6 2012
A couple of months ago I posted an article about a “home made” antenna I made from plans on the internet. A couple of days ago I completed an antenna with a different design I also found on the internet. Last night I held a demo of it for some friends (including a couple of retired TV/RADAR/HAM professionals. They were fairly impressed with the results and sensitivity. Considering the darned thing was made of wood and mostly wire coat hangers it would be hard not to be impressed.
Here is some information on the design I was using… http://www.digitalhome.ca/ota/superantenna/ There have been some improvements since then… http://www.jedsoft.org/fun/antennas/dtv/gh.html However I chose to build the older version because there was less work involved.
The performance outdoors was fairly impressive. The design was for UHF only. While aiming it toward the center of town where most of the transmitters are located, it was able to pick up all four of the UHF stations in town. After a friend of mine suggested pointing it toward one of the VHF transmitters we all got the idea to see if we could get the two VHF stations as well. Sure enough with some careful aiming we were able to get both of the VHF stations. For one station we had to lift the antenna a couple of metres off the ground but that was to be expected when the transmitter is slightly farther away. Had I not left the remote for the TV at home we could have tried for a couple of North Dakota stations.
The demonstration took place on the other side of the city from where I live. This afternoon I tried it in the back yard. The UHF stations were clear but there was trouble with the VHF stations even when aiming at the transmitters. Even trying the American stations there was no signal. Given the back yard is surrounded on three sides by stucco buildings, and there are no transmitters on the fourth side, I suppose the difference in performance is reasonable. Indoor performance wasn’t anything to write home about. In the basement only three UHF stations were visible.
I have a picture of what it looks like. I chose the location because things are highly visible. Ignore the power cables coming out of the power bar.
Here is a short list of what people will need to get digital broadcast TV.
- A broadcast source (a TV station).
- An antenna (like the design I wrote about – rabbit ears don’t cut it any more).
- A TV
- A digital receiver (new generation TVs have this built in as do new TV tuner cards).
Here is some technical info for people to keep in mind.
- For the most part broadcast TV is line of sight.
- Buildings with a lot of metal (like a mesh for stucco) tend to decrease signal strength.
- Outdoor antennas are better than indoor.
- The higher up an antenna is located the more stations it can “see”.
- Directional antennas (like this one) should be pointed toward the broadcast tower for the best results.
- Digital TVs are fine with weak signals up to the point where not enough information makes its way to the TV.
- Night time reception is better than day time reception.
- TV stations over the horizon may occasionally be seen by the antenna but this phenomenon is not consistent.
- The further away the TV station is the weaker the signal.
- The quality of the antenna construction is very important.
My next antenna project will be to build one of the newer versions of the antenna. I’ll need some serious help to do a good job. Fortunately I know a few people.