> > 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
