digital is transmitted over uhf; so yes it is.
On Thu, 23 Jul 2009, carl wrote: > is this antenna sutable for dijatle? > ----- Original Message ----- > From: Max Robinson > To: [email protected] > Sent: Thursday, July 23, 2009 1:00 AM > Subject: Re: [BlindHandyMan] Re: Build a T.V. antenna. > > > I think it's a variation on a UHF bowtie with reflector. Although the > crossed over feeders remind me of a log periodic. > > Regards. > > Max. K 4 O D S. > > Email: [email protected] > > Transistor site http://www.funwithtransistors.net > Vacuum tube site: http://www.funwithtubes.net > Music site: http://www.maxsmusicplace.com > > To subscribe to the fun with tubes group send an email to, > [email protected] > > ----- Original Message ----- > From: "Tom Fowle" <[email protected]> > To: "blindHandyMan" <[email protected]> > Cc: <[email protected]> > Sent: Wednesday, July 22, 2009 5:15 PM > Subject: [BlindHandyMan] Re: Build a T.V. antenna. > > > Here it is folks, hope it makes sense. > > BTW, the plans schematics and all are free under the good old "GPL" public > > license. > > > > Complaints about my discription welcomed, complaints about the resulting > > device > > are not my job! <GRIN> > > > > http://www.digitalhome.ca/ota/superantenna/ > > > > Text description how to build the Gray-Hubberman U.H.F. T.V. antenna > > > > Tom Fowle > > Smith-Kettlewell Rehab Engineering Center > > San Francisco > > > > This antenna will seem strange to anybody with experience in "normal" > > looking > > TV. antennas, it looks like it'd be seeing the sky but it seems to work. > > > > > > Materials: > > 1 piece of wood; 1 by 3 or 1 by 4, 22 inches long. > > about 25 feet of No. 14 bare copper wire. > > 8 No. 8 by 3/4 inch wood screws, round or pan head. > > 8 No. 4 by 1/2 inch wood screws round or pan head. > > 8 flat or fender washers for the No. 8 screws, mine are 3/4 inch diameter > > but that's maybe a bit large. > > 2 each metal screens 9 by 15 inches. I bought 4 vent screens measuring > > about 4 by 15 which had lighter frames and were cheaper than > > the 9 by 15 inch units. > > > > 1 each 75 or 300 ohm "Balun" or matching transformer, used to connect 300 > > ohm T.V. twin lead to 75 ohm cable. Available at Radio shlock > > or anywhere that sells T.V. accessories. > > > > Tools: > > ruler: > > drill with bits for pilot holes for the screws; > > wire cutters; > > screw drivers; > > "vise for holding the wood while measuring and drilling. > > > > > > The antenna consists of 4 pairs of V shaped elements whose points are > > mounted in pairs across from each other on one surface of the > > board. The V's have 7 inch legs and have 3 inch spread at the > > open ends. There points are mounted under screws and washers > > along the board in pairs with a separation of 1 inch across the > > board and 5-1/4 inches between pairs. These pairs of V's are > > connected together by "feeder" wires as detailed below. > > > > The two screens, called reflectors, are mounted on the opposite > > surface of the board centered between each pair of 2 V's. > > > > With the board long way pointing away from you, > > Starting from the close end of the board, measure up 2 inches for the > > first > > pair of screws for the V's. If you're using a 1 by 4, which is > > actually 3 and a half inches across, measure in from each edge > > of the board 1-1/4 inches. Thus your first holes are an inch > > apart and 2 inches up from the end of the board. > > > > Drill pilot holes for the No. 8 screws. Measure up from these holes > > 5-1/4 > > inches and locate the second pair of pilot holes also an inch apart > > centered > > on the middle of the board's crosswise dimension. > > > > Again go up from the second holes 5-1/4 inches for the third pair > > and similarly again up 5-1/4 inches for the 4Th pair. This > > should leave about an inch free at the "top" of the board. > > > > Now turn the board over. Starting from the bottom, measure up the center > > line of the board 4-1/2 inches. Mark this point. > > This mark is in the center of the long rectangle made by the > > lower 2 pairs of No. 8 screws but on the opposite surface of the board. > > > > find the center of the similar rectangle made by the upper 2 pairs of > > holes, > > not the middle of the entire antenna. Put another mark there. > > > > These marks are to be the centers of the two reflector screens. The 9 by > > 15 > > inch screens are mounted across the board centered below each 2 pairs of > > No. > > 8 screws. Since I have 2 scrreens each measuring 4-1/2 by 15,, I screwed > > the centers of each long edge of 2 screens to the marks I've mentioned. I > > then aligned the screens to be at 90 degrees from the long axis of the > > board > > and installed No. 4 screws in the remaining long edges of of each screen. > > > > Now turn the board back over with the No. 8 screws up and install > > No. 8 screws with flat washers in each hole. Do not tighten down > > all the way, leave room for wires under the washers. > > > > Cut 8 14 inch lengths of wire. Bend each into A "V" with 7 inch > > legs and 3 inches between the open ends of the V's > > > > Fasten each V under one of the No. 8 screws and washers with the open > > ends > > of the V's pointing out away from the center of the board. > > > > Now cut 2 lengths of wire about 22 inches long. These connect the pairs > > of > > V's as follows. > > > > With the antenna in front of you long wise pointing away from you, start > > the > > first feeder wire at the bottom left V's screw. It goes up and across to > > the V > > that's second up on the right. This first feeder wire then goes straight > > up > > to the third right hand V. Then it goes across to the top left V. > > > > The second feeder wire starts at bottom right, goes up and across to the > > second up left, then straight up to the third left and up and across to > > the > > top right V's screw. > > > > Make sure the feeder wire's don't touch where they cross, I had no trouble > > just bending them apart, but some tape between wires here wouldn't hurt. > > > > Now you can tighten down the No. 8 screws that hold the V's and feeders. > > Check that the V's still have 3 inch open ends and that they all > > point symmetrically outwards. > > > > Find the middle of each feeder wire.and install a No. 4 screw exactly > > adjacent to it. These screws also take the open "lugs" from your matching > > Balun or transformer. > > > > Connect your chunk of 75 ohm cable to the transformer and route it > > straight > > down the antenna's center and off the close end. > > > > If I were going to use this out doors, I'd give it a spray of > > paint the screws will probably rust pretty fast. > > > > Remember the antenna is to be mounted standing up on it's end. The most > > effective direction is from the reflectors towards the V's. > > > > Hook it to your.V. and move it about and turn it till you get best > > reception. > > > > Your sightlings will love you. > > > > Tom Fowle > > Embedded Systems Developer/ Rehab engineer > > Rehabilitation Engineering Research Center > > The Smith-Kettlewell Eye Research Institute > > 2318 Fillmore St. > > San Francisco, CA 94115 > > 415-345-2123 (Voice) > > [email protected] > > > > > > > > > > > > > > ------------------------------------ > > > > Send any questions regarding list management to: > > [email protected] > > To listen to the show archives go to link > > > http://www.acbradio.org/pweb/index.php?module=pagemaster&PAGE_user_op=view_page&PAGE_id=33&MMN_position=47:29 > > Or > > ftp://ftp.acbradio.org/acbradio-archives/handyman/ > > > > The Pod Cast address for the Blind Handy Man Show is. > > http://www.acbradio.org/news/xml/podcast.php?pgm=saturday > > > > Visit The Blind Handy Man Files Page To Review Contributions From Various > > List Members At The Following address: > > http://www.jaws-users.com/JAWS/handyman/ > > > > Visit the archives page at the following address > > http://www.mail-archive.com/[email protected]/ > > > > If you would like to join the JAWS Users List, then visit the following > > address for more information: > > http://www.jaws-users.com/ > > For a complete list of email commands pertaining to the Blind Handy Man > > list just send a blank message to: > > [email protected]! Groups Links > > > > > > > > > > > > > > [Non-text portions of this message have been removed] > >
