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Every year we have an issue with ice dams on my metal roof. It really isn't much of a problem except for the dang...Falsejeff2011-01-27T23:50:40+00:00hot/groups/jeff/search/index.rss?sort=modifiedDate&kind=all&sortDirection=reverse&excludePages=wiki/welcomelist/groups/jeff/search/?sort=modifiedDate&kind=all&sortDirection=reverse&excludePages=wiki/welcomeRecent ChangesRecentChangesListUpdates?sort=modifiedDate&kind=all&sortDirection=reverse&excludePages=wiki/welcome0/groups/jeff/sidebar/RecentChangesListmodifiedDateallRecent ChangesRecentChangesListUpdateswiki/welcomeNo recent changes.reverse5search
Well with the advent of digital TV, I figured it was a good time to revisit over the air television reception. Unlike the spoiled crowd in Toronto, Kingston and Montreal, getting US television networks in Ottawa has been hit and miss.
Close up view of one end of the antenna
In my case I was aiming to received channel 7 from Watertown. If I can receive channel 7 (CBS & Fox) regularly, along with all the Ottawa Off the Air (OTA) stations, I would be able to finally get rid of Rogers cable. All the US stations are now digital, Canadian stations within the next 2 years.
The trouble with a channel 7 (VHF) single cut yagi antenna is the length. The design I required for a 14 dbi gain would be almost 15 ft long. Thus I decided to try a shorter antenna for my first try. I decided to try for the other Watertown station channel 21 (Real channel 21 - Virtual channel 50). Watertown 21 is ABC and CW. Digital stations such as Watertown 21 and 7 can carry sub channels such as Fox and CW. A channel 21 design for 14 dbi gain is only 8 ft. It would still be a long shot as channel 21 is a weaker signal in Ottawa than channel 7, but would, worst case, I would still be able to use it after to get channels 20, 22 & 23.
Best information to build an antenna is available on www.digitalhome.ca under the OTA forum. My actual design is shown here using www.k7mem.150m.com :
The Antenna was designed for 515 MHz or channel 21. I used a 1 inch square alum. boom and 1/4 " alum rods and 1/4 brass tubing for the DE. It was a 8ft, 13 director, 14dbd design. My elements were all isolated using the shrink-wrap method. I tried to radialize the DE but gave up as my brass bender did a pretty neat 90 degree bend on my brass tubing, so I went with it.
I figure the cost was $35 (metal supermarket plus hobby shop). I also had to buy a brass bending tool ($12) and radio shack project box ($6)
Results are interesting. I previously received channel 21 (WWTI) with my channel master 4242 once in a while. So far on many nights, my channel master 4242 does not register WWTI at all, but my new antenna is at 40+%, excellent but just short of locking in. It seems to lock it in a couple of nights a week. Maybe I'll need to buy a proper preamp for it. It seems to be much better than the CM around channel 21. It pulls in 20,22,23,25 & 27 extremely well. Higher than ch. 27 and for anything in the VHF range the CM is much better of course. As channel 7 is a much stronger signal, I have decided to go ahead with a 15ft channel 7 antenna. My only problem is that I”ll have to build it in my garage and my garage is just too cluttered at the moment. Probably won’t have it clean until late August.
Beyond all the standard analog stations , this is a list of current OTA digital stations I can receive.
7-1 is CBS, 7-2 is Fox, 20-2 is SUN TV, 50-1 is ABC and 50-2 is the CW network. The rest are all PBS variants or the two CBC.
Comments
jeff
Oct 14, 2011
Yes but only in the summer nights and mornings. I will upgrade the preamp and raise it before the winter. I am expecting better results after.
Peter (unauthenticated)
Oct 4, 2011
Did you make your 15ft long new antenna...did it work for WWTI ?