X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml Date: Sat, 07 Oct 2006 22:05:50 -0400 Message-ID: X-Original-Return-Path: Received: from smtp101.sbc.mail.mud.yahoo.com ([68.142.198.200] verified) by logan.com (CommuniGate Pro SMTP 5.1c.5) with SMTP id 1448514 for lml@lancaironline.net; Sat, 07 Oct 2006 18:02:19 -0400 Received-SPF: none receiver=logan.com; client-ip=68.142.198.200; envelope-from=elippse@sbcglobal.net Received: (qmail 89890 invoked from network); 7 Oct 2006 22:01:59 -0000 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=sbcglobal.net; h=Received:Message-ID:From:To:Subject:Date:MIME-Version:Content-Type:X-Priority:X-MSMail-Priority:X-Mailer:X-MimeOLE; b=EHzlDRh6AWX98sEKeoolszH+VmwFkau8iIA5+ZCwrbaRLRDw2z/0Bqwquc45Ioj20xDQhu1ajTFevIzV18zsOozE/QugXE8Zx2sUZz826FOeRt5qd8ZUHJjryrHSj6LpO6TrHDSPkHpihGYqYnmhNd3YGOVjNjrmTfljJ7x5zfw= ; Received: from unknown (HELO Computerroom) (elippse@sbcglobal.net@75.6.2.251 with login) by smtp101.sbc.mail.mud.yahoo.com with SMTP; 7 Oct 2006 22:01:59 -0000 X-Original-Message-ID: <002701c6ea5c$3eca1640$fb02064b@Computerroom> From: "Paul Lipps" X-Original-To: "Marv Kaye" Subject: Good Com antenna X-Original-Date: Sat, 7 Oct 2006 15:02:12 -0700 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0022_01C6EA21.91D518C0" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.2869 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2962 This is a multi-part message in MIME format. ------=_NextPart_000_0022_01C6EA21.91D518C0 Content-Type: text/plain; charset="Windows-1252" Content-Transfer-Encoding: quoted-printable Here's a half-wave com antenna design that is easy to make and has a = very broad bandwidth and reasonably small size. It was tested to have a = VSWR of 1.3:1 or less from 110 MHz to 146 MHz, and 1.10:1 from 122MHz to = 130MHz. It was tested while fastened to a 1/4" fibreglass-coated foam = plate. It is made from two triangular arc pieces of thin aluminum and a = 24" long, 3'8" ID soft aluminum tube. The two triangles have a chord at = the outer ends of 13" with a 15 1/4" radius. Separate the inner points = by about 1/2". The antenna is fed through the tube which forms a bazooka = balun. The tube is attached but electrically isolated from one antenna = half with one end near the feed points. The coax shield is connected to = that antenna half feed point, and the center conductor to the other. The = coax shield is also connected to the other end of the tube. This is done = by stripping the outer dielectric from the coax and running a wire = around the bared shield and the end of the tube. It is also possible to = use one or two 1/4" ID X 1" long ferrites around the coax at the = feed-point to form a quasi-balun. This would allow the coax to leave the = array in the preferred perpendicular direction from the line of the = array. The The antenna can be mounted onto the curved fuselage in a = vertical orientation. Because it is a half-wave dipole, it has its best = radiation pattern normal to the array toward the horizon. As with all = antennas, it is best to keep it at least one wavelength, 8' or more, = from any metal that is in a parralel orientation to the antenna to = prevent deep pattern nulls. ------=_NextPart_000_0022_01C6EA21.91D518C0 Content-Type: text/html; charset="Windows-1252" Content-Transfer-Encoding: quoted-printable

Here's a half-wave com antenna design that = is easy to=20 make and has a very broad bandwidth and reasonably small size. It was = tested to=20 have a VSWR of 1.3:1 or less from 110 MHz to 146 MHz, and 1.10:1 = from=20 122MHz to 130MHz. It was tested while fastened to a 1/4" = fibreglass-coated=20 foam plate. It is made from two triangular arc pieces of = thin=20 aluminum and a 24" long, 3'8" ID soft aluminum tube. The two = triangles have=20 a chord at the outer ends of 13" with a 15 1/4" radius. Separate the = inner=20 points by about 1/2". The antenna is fed through the tube which forms a = bazooka=20 balun. The tube is attached but electrically isolated from one antenna = half with=20 one end near the feed points. The coax shield is connected to that = antenna=20 half feed point, and the center conductor to the other. The coax shield = is also=20 connected to the other end of the tube. This is done by stripping the = outer=20 dielectric from the coax and running a wire around the bared shield and = the end=20 of the tube. It is also possible to use one or two 1/4" ID X 1" long = ferrites=20 around the coax at the feed-point to form a quasi-balun. This would = allow the=20 coax to leave the array in the preferred perpendicular direction = from the=20 line of the array. The The antenna can be mounted onto the curved = fuselage=20 in a vertical orientation. Because it is a half-wave dipole, it has its = best=20 radiation pattern normal to the array toward the horizon. As with = all=20 antennas, it is best to keep it at least one wavelength, 8' or = more, from=20 any metal that is in a parralel orientation to the antenna to = prevent=20 deep pattern nulls.

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