cisco dish v grid antenna

why ? what will it be locally connected to, and how far is the cable run ? what will it be pointed at ?

It takes more than a dish to make a wireless network. What else you got?

Ouch. You must have money. About $700 plus shipping.

Yep. About $60 plus shipping.

Solid dishes are usually slightly heavier than grid dishes, making installation easier for the grid. In this case, it's not the weight of the dish, but the weight of the mounting. The Cisco dish is made from spun aluminum. The grid is made from either steel or cast aluminum.

The solid dish will have a higher wind load than the barbeque grill dish and therefore requires a more solid mount. However, if the grid ices up, the wind load is higher for the grid (due to ice surface roughness).

The solid dish has almost no pickup to the sides or rear, in the direction of the dish, and is therefore better for RF crowded roof top and mountain top installations. Solid dishes also block signals coming from the rear at all frequencies. Grid dishes pass higher frequency junk coming from the rear.

Solid dishes are usually made of aluminum, which will last for a long time on a mountain top. Grid dishes are made from coated steel, which doesn't do as well in a corrosive environment. One grid dish lasted three months after getting installed in the exhaust stream of a diesel generator.

Solid dishes can handle optional covers, which are useful for heating and prevent snow accumulation. You can probably craft some kind of cover and heater for a grid dish, but I've seen no commercial versions.

Some solid dishes are more difficult to align, as the grid dish can be bore sight aligned by removing the feed.

When dinged in shipping or during installation, solid dishes are a pain to repair (I use the local body shop). Grid dishes are much easier to pound back into some semblence of a parabola.

the dish will be connected to a PCI wireless card in a pc cable run will be about 10 meters or less it will be pointed at another location that has an access point - I want a direct connection to the other building, independent of the internet.

If your PCI card has a power output of approx 13 dBm. The Cisco Antenna is 21dBi. If you use 10 metres of LMR400 to connect them, say 2.5dB loss.

That would give you 13+21-2.5 = 31.5dBm which is 11.5 dBm more than you are allowed in the UK.

You will need to consider changing antennas on both ends of the link to stay within the limits, and for the link to be viable.

ps: I also have a fairly strong access point so I might at some point swap the ends around and connect the dish/grid to my access point. It's just a case of spending my money wisely that's all - I don't want to spend hundreds of pounds on a dish antenna if a grid antenna will do exactly the same thing.

lots of info here Jeff, thanks very much. On reflection I think a grid might be better for my needs as wind speeds do worry me. My proposed outside installation location isn't dish-in-a-hurricane proof so I may have to go for the grid simply out of safety and I'd much rather a storm wreck a £60 grid antenna than a $700 dish antenna. If I mount the antenna inside then I'm back to deciding if the expensive dish will be better than the grid antenna.

ends around

money wisely

grid antenna

Nobody's saying this outright, but no, you don't even need to spend $100 to get a decent antenna.

Our 12 dbi panel antenna cost $34 shipped, is tiny (4" cube) and unobtrusive. Our farthest client on the antenna is a laptop about 500 meters away.

Just out of curiosity, how did you to conclude how much gain you need for your system? Have you done any link calculations or tests? Do you know what cable you are going to use and what it's loss is?

I suspect that all too often people just decide to "get the best" which they imagine is the strongest or most powerful. But you really need to match the tool to the job. You don't buy a sledgehammer to drive a 16p nail, and you don't need 21 dbi dish/grill antenna to connect with the building across the street.

Another comment: Running a fat antenna (LMR400) cable into a PCI card could lead to damage. You may want to consider using a pigtail as a strain relief - if you go with LMR400. With LMR2xx not likely a problem, depends on length needed.

steve

You're paying for the name. Just because it says Cisco does not mean its better - case in point, someone took apart a $500 Cisco radome yagi and discovered it was identical to another one with a different branded label for only $45.

Cisco AIR-ANT3338 2.4 GHz 21 dBi dish - $700