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buckron
EVDO Fledgling
Joined: 10 Mar 2008
Posts: 17
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 Posted: Thu Mar 20, 2008 8:32 am Post subject: patch,panel, Grid antenna VS Yagi |
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| I have been reading..as far as i can tell the patch,grid and panel antennas are the same thing in fact one post said they are actually yagis but built different.They are directional ..true...but is the patch or panel a little more forgiving when it comes to catching the signal? I am thinking that without a clear line of sight to the tower the patch or panel maybe a better choice? Please help need to order sasp.[/b] |
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xrayman
EVDO Junkie
Joined: 23 Feb 2007
Posts: 251
Location: Kansas City
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| Posted: Thu Mar 20, 2008 9:06 am Post subject: |
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buckron,
Sounds like you have done you homework. Note that some on this forum have reported success with the 24 dBi grid antenna operating at PCS frequency even without a clear line of sight to the tower. |
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Alex
Site Admin
Joined: 19 Sep 2006
Posts: 1893
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| Posted: Thu Mar 20, 2008 9:21 am Post subject: |
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| yeah, but are we positive his canadian provide is single band? i'm not. |
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n6gn
EVDO Junkie
Joined: 22 Aug 2006
Posts: 337
Location: Northern California
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| Posted: Thu Mar 20, 2008 9:30 am Post subject: Re: patch,panel, Grid antenna VS Yagi |
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| buckron wrote: | | I have been reading..as far as i can tell the patch,grid and panel antennas are the same thing |
Well, no, they aren't the same thing but they are all antennas with directivity and therefore (hopefully) gain as well.
The short answer is that there are a lot of different ways of making directive antennas. For a moderately (or better) directive antenna, any of them done well, will result in a structure that works aproximately as well as something of it's *physical* size can. Very roughly this means that the cross sectional area is what really matters... it's how much signal an antenna "catches" which is another way of saying how tightly formed or focussed the transmitted beam is. Big antennas are therefore more directive and have to be pointed more carefully in order to achieve their potential, which is correspondingly higher than smaller antennas.
Generally speaking, at higher gains it is more difficult to make some types work as well as others. Above approximately 15 dBi gain, yagis tend to be quite long and difficult to both get as much gain as they should be able to produce and also tend to be narrower in bandwidth. That is, the range of frequency over which they work well is smaller. This can be an issue since transmit and receive frequencies are different for most mobile/cellular systems.
The same is generally true of patch antennas. They are convenient and relatively inexpensive to make but at higher gains, roughly the same limit as for Yagis, they are difficult or impossible to get full performance for their physical size from - as contrasted to parabolic reflectors, of which the 24 dBi grid antenna is an example. However, at low gains, below maybe 10 dBi, reflector antennas like parabolas tend not to be as effective for their area as Yagis or patches.
For very high gains, other than parabolics, pyramidal horns (the big cornucopia like things you may occasionally see at microwave sites) are about the only things that work well. That's what you see for very highly directive uses like some radars, deep space communications and similar.
So the question to ask yourself is how much size you can tolerate since that will first limit the possible gain and then look to see which type of antenna fits your needs in that range.
n6gn |
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Jim_in_VA
EVDO Junkie
Joined: 09 Apr 2007
Posts: 331
Location: Chesapeake Bay Area, Virginia
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| Posted: Thu Mar 20, 2008 10:54 am Post subject: |
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to illustrate n6gn's point:
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buckron
EVDO Fledgling
Joined: 10 Mar 2008
Posts: 17
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| Posted: Fri Mar 28, 2008 6:09 am Post subject: made my decision |
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| well i made a decision, i ordered a * 34" 19db gain yagi and a * rockies amp from maximum signal, Pretty excited about this stuff.I will have it tomorrow and post back when i get it setup.The fellow at maximum signal knows his stuff and there is nothing but good reviews on * equipment.[/b] |
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n6gn
EVDO Junkie
Joined: 22 Aug 2006
Posts: 337
Location: Northern California
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