And does not turn into toothpicks when struck by lightning! Paul
-----Original Message----- From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Laryn Lohman Sent: Friday, February 16, 2007 12:29 PM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Re: Antennas that work both in commercial and amateur > > I've been watching this topic and cannot recommend the half > wave dipole bay antennas as not really efficient gain wise for what > one gets for the effort.. > > The Station Master series has been mentioned, which has good > omnidirectional gain, in the order of some 10 db, and which is equal > to having a 10 element beam in all directions!! Far above a 4 section dipole arrangment! You are comparing totally different antennas. If you are going to talk about the Stationmaster with 10 dbd of omni gain, you are referring to a UHF antenna. The comparably-sized exposed-dipole antenna is a DB420 with 9.2 dbd gain. It has eight (basically), stacked dipoles, not four. Same basic length, same basic gain, and the 420 covers far more bandwidth. > > The Station Master series is made of stacked coaxial sections inside > the fiberglass. Unsolder the wire from the top metal cap and unscrew > the cap and look inside. First you will find that there is a quarter > wave element at the top, then phased half wave coax sections below > that. Research staked Coaxial vertal antennas on the Internet, > they're well covered. I favor them as out performing most anythinb > else. What are you basing your <out performing> claim on? > > Gonset discovered back in the 1960's era that the bandwidth aspect of > a halfwave antenna was the results of the ratio of the thickness of > the half wave antenna to the half wave length, and reinvented the "bow > tie" antenna, typically used for broadband TV!!! > Hahahahaha!!! > > It also depends on the radiation pattern, where it goes and how narrow > it is. I've had a single section coaxial vertical antenna, basically > a half wave vertical, mounted at ground level, out perform a mobile > 5/8th wave 3 db gain vertical, mounted on my vehicle out in the > driveway, with the same radio, but a few feet higher!! The mobile > 5/8th wave puts out a very narrow pattern at horizon level, and the > coaxial a wider donut shaped pattern also at the horizon.. It is very misleading to compare two antennas in a multipath-laden area such the typical driveway, especially if not mounted in the same EXACT place. Move an antenna to a new position a foot or two or ten away and you'll find completely new signal readings. You've experienced mobile flutter I'm sure. Same thing. > > While I think it said that the proposed antenna is to be on top of a > building, the same antenna on a mountain top repeater has to do the > same job in the weather, and over time, whether it's an Amateur Radio > or Commercial installation..!!! > > Best, > > Dick > Laryn K8TVZ Yahoo! Groups Links -- No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.5.441 / Virus Database: 268.18.0/689 - Release Date: 2/15/2007 5:40 PM -- No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.5.441 / Virus Database: 268.18.0/689 - Release Date: 2/15/2007 5:40 PM <p class="style1">Visit <a href="http://www.ourphonelist.com";>OurPhonelist.com<br>It's free and you'll never lose track of a phone number again! </a></p> Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ <*> Your email settings: Individual Email | Traditional <*> To change settings online go to: http://groups.yahoo.com/group/Repeater-Builder/join (Yahoo! ID required) <*> To change settings via email: mailto:[EMAIL PROTECTED] mailto:[EMAIL PROTECTED] <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
