This is a skirt type antenna it's a fairly common "trick" used at some AM b'cast sites. This way the tower can be grounded rather than sitting on a base insulator.
Bill AD5OL ________________________________ From: "[email protected]" <[email protected]> To: [email protected]; Discussion of AM Radio in the Amateur Service <[email protected]> Sent: Monday, January 12, 2009 12:13:42 PM Subject: Re: [AMRadio] 160 meter antenna Hello Jack. I am familiar with the lynards that the climbers use as a safety line while climbing the tower. Their are however 3 vertical lines made out of what looks like guy wire with a circular ring near the base being fed by a box at the base. Just a FYI -------------- Original message from "JACK C. SHUTT" <[email protected]>: -------------- Hi Robert, We have several of those wireless towers and monopoles around here, as well Those side wires are safety cables that climbers can clip on to with fall-arresting lanyards and harnesses, they are not radiators. Anyway, the folded unipole is a worthwhile antenna to try. I have had excellent results with an inverted L running up the side of my 80' tower and the "horizontal" portion sloping out to a tree. The "L' perhaps looks more like a vee with one short leg. Total length is about 135 ft. I use a coil and capacitor parallel network at the base of the tower feeding the end of the antenna wire then coax back to the shack. As always, a good radial system really helps. 73, Jack, W9GT --- On Mon, 1/12/09, [email protected] <[email protected]> wrote: From: [email protected] <[email protected]> Subject: Re: [AMRadio] 160 meter antenna To: [email protected], "Discussion of AM Radio in the Amateur Service" <[email protected]> Date: Monday, January 12, 2009, 7:23 AM Neal. Thanks for the link on building the Unipole. I had worked for Sprint for some time and I noticed they were using that same concept on many of their towers. The link was exceptionally helpful -------------- Original message from neal Newman <[email protected]>: -------------- > Jim you only need 50 feet of verticle space. > why not just build yourself a Folded Unipole antenna if you Dont know how. > Ask. its really easy. Just Run 3 lengths of #12 wire or if you have it #6 > wire. short them up at around the 50 foot point and use 1" PVC > Tubing as Insulators with clamps Down the side of the Tower. > at the bottom Each wire is isolated with PVC from the Tower. > BTW Each wire should be about 12" or more off the tower. then Tie all 3 wires > together with a ring of #12 and take that as the Lead to the antenna tuner. > Run at Least 4 ground radials 50 feet long If you can get > the space make them 120 feet... > and you will have a Killer 160 antenna. if not make an inverted L Run a wire > thats 130 feet long. as far vertically as > you can then run the rest out horizontally... again you need at least 4 > ground radials.... the unipole is what we use for > Broadcast stations when we are tight for height or space on a grounded Tower. > > Neal-KA2CAF > CE- WTTM/WHWH/WJDM/WIBG/WFYL > > > --- On Sun, 1/11/09, Jim Miller WB5OXQ in Waco wrote: > > > From: Jim Miller WB5OXQ in Waco > > Subject: [AMRadio] 160 meter antenna > > To: "Discussion of AM Radio in the Amateur Service" > > Date: Sunday, January 11, 2009, 11:28 PM > > I always wanted to try am on 160 but like most do not have > > enough room for a full size antenna, so, > > I am considering building a 160 meter antenna at our > > clubhouse because there is a 80' tower there and over an > > acre of land to spread out a 1/2 wave dipole. Question is; > > 1 Is a 1/2 wave wire dipole the best antenna for the band > > considering there is room for it. > > 2 Is 80' high enough for the center of the inverted V? > > 3 How high do the ends need to be off of the ground? > > 4 Should I feed it with coax or ladder line to the 10' > > level (or other) then a balun to coax to the tuner (coax is > > the only acceptable line into the shack)? The shack is a > > metal building 30X60' and directly below the tower. > > There is no way to get ladder line to the operating position > > since all cables have to run through a 3" conduit for > > at least 30'. > > > > The tower is a free standing commercial tower made of 4 > > 20' sections bolted together with a 2 meter and a 440mhz > > antenna at the top, all ham antennas. > > > > Thanks for any advice. Jim > > wb5oxq______________________________________________________________ > > Our Main Website: http://www.amfone.net > > AMRadio mailing list > > Searchable Archives: > > http://www.mail-archive.com/[email protected]/ > > List Rules (must read!): http://w5ami.net/amradiofaq.html > > List Home: http://mailman.qth.net/mailman/listinfo/amradio > > Help: http://mailman.qth.net/mmfaq.html > > Post: mailto:[email protected] > > To unsubscribe, send an email to > > [email protected] with > > the word unsubscribe in the message body. > > > > ______________________________________________________________ > Our Main Website: http://www.amfone.net > AMRadio mailing list > Searchable Archives: http://www.mail-archive.com/[email protected]/ > List Rules (must read!): http://w5ami.net/amradiofaq.html > List Home: http://mailman.qth.net/mailman/listinfo/amradio > Help: http://mailman.qth.net/mmfaq.html > Post: mailto:[email protected] > To unsubscribe, send an email to [email protected] with > the word unsubscribe in the message body. ______________________________________________________________ Our Main Website: http://www.amfone.net AMRadio mailing list Searchable Archives: http://www.mail-archive.com/[email protected]/ List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:[email protected] To unsubscribe, send an email to [email protected] with the word unsubscribe in the message body. ______________________________________________________________ Our Main Website: http://www.amfone.net AMRadio mailing list Searchable Archives: http://www.mail-archive.com/[email protected]/ List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:[email protected] To unsubscribe, send an email to [email protected] with the word unsubscribe in the message body.
