Antennas for Airport Extreme base station

Discussion in 'Buying Tips, Advice and Discussion (archive)' started by Westside guy, Nov 24, 2004.

  1. Westside guy macrumors 601

    Westside guy

    Joined:
    Oct 15, 2003
    Location:
    The soggy side of the Pacific NW
    #1
    I've been thinking about adding an antenna to my Airport Extreme base station, mainly so I'll have a stronger signal outside the house (well, for summer anyway). We're in a semi-rural area so I'm not too concerned with freeloaders attempting to jack my signal.

    I've only found two omni-directional antennas - one sold by Dr. Bott, and another made by Hawking Technologies. The Dr. Bott antenna is basically $100 (US), while the Hawking Tech antenna is under $40. Obviously the price difference is rather substantial; so I'm wondering if there's a good reason why.

    Do any of you have experience with either antenna? I'm especially curious to know whether the Hawking Tech antenna is a piece of crap or not. :p

    Thanks!
     
  2. igucl macrumors 6502a

    igucl

    Joined:
    Oct 11, 2003
    #2
    I don't know anything about the Hawking antenna, but I'm now using the Dr. Bott. It fills my needs, but I have not tried to use it from outside, so I don't know how that would be.
     
  3. crazzyeddie macrumors 68030

    crazzyeddie

    Joined:
    Dec 7, 2002
    Location:
    Florida, USA
    #3
    It would be very helpful to link to the products, or at least list the given specs. I'm betting this has something to do with the gain on the antennae (dB rating).
     
  4. Viv macrumors regular

    Joined:
    Sep 11, 2003
    Location:
    Normandy, France
    #4
    Dlink provide a range of antennas from small indoor units to outdoor long distance beam and omni directional antennas.

    Basically what do you want to acheave? 5-km using two beam antennas is feasable or do you want to cover up to a half kilometer circle around your house?

    There range of antennas will do all of the above, I have used them for interbuilding connections and to provide a local games LAN for a small estate.

    The further you want to go the higher the DB gain of the antenna you need, think of DB or decibells as a performance figure, the best DB gain figures are for directional antennas as they focus all the signal in one direction, omni directionals have a circular radiation shape like a doughnut placed over the antenne, the higher the gain the thinner the doughnut.

    Remember the further you want to go the more important it is the have high gain antennas at each end! so one on the base station (access point) and one on the computer.

    High DB gain antennas are needed at both ends as they work not only for transmit power but also for received signal power.

    Hope that helps and I don't work for Dlink ether:) But I am a radio ham as well.

    Some acces points have two antenna sockets, watch out for this trap, this is called diversity, the signal is shared between the two antennas, if you use an external antenna then you have to go in to the setup and turn diversity off! and only put the signal out one socket, the DLink access points all have two antennas! the second one is in side! and a lot of others do too.

    Viv
     
  5. Westside guy thread starter macrumors 601

    Westside guy

    Joined:
    Oct 15, 2003
    Location:
    The soggy side of the Pacific NW
    #5
    Sorry if I wasn't clear enough. I very much appreciate the replies. As I said, I'm looking for an antenna that can be added to my Airport Extreme base station. My objective is simply to have a stronger signal available when I'm out in my yard. :D I don't expect to cover the full property, but adding 20-25 feet to the current functional radius of our wireless network would be great. I understand that ideally you'd have an additional antenna on the laptop too, but that won't be the case. Of course we don't really know that laptop signal broadcast strength is a (or the) limiting factor in this particular equation anyway - though I'll find that out once I've installed an antenna on the base station! :rolleyes:

    I'm really hoping that more people like igucl who have actually used either of these particular products (or similar alternatives) will also chime in. If every Dr. Bott owner says "yeah, it's great" while the Hawking Tech owners have a mixed or poor response, that says quite a bit.

    If you are curious about the product info:

    Dr. Bott's antenna note that it's listed as +3.5dB (so I'm guessing that's indicating a total of 5.5dB since the Airport Extreme has a 2dB antenna).

    Hawking Technologies antenna. You'll see that the gain on the HT antenna is quoted as 6dB.
     
  6. Viv macrumors regular

    Joined:
    Sep 11, 2003
    Location:
    Normandy, France
    #6
    Sorry I should have added that for each 3 db gain the signal doubles, so a 3db antenna is twice as good as a 0db antenna, an isotropic omni directional anttena is 3 db but its a mathamatical construct a real world one is "0"

    Marketing people list them this way to fool you:) dbi is decibells isotropic, db is real world.

    Sorry you cant add db from one antenna to another the way you did, its one or the other normally, so plugging another one in to the base station does not add to whats there all ready.

    2 db for the airport is probably being a bit creative with the numbers some were:) what you will find is that the airport antenna is a bit directional, if you look at it sat on a table the signal is around the airport and above it but is blocked from going under it, if the signal that would be under the table is added to whats above the table then it would give you the 2db gain quoted.

    This is important becouse if you have the airport mounted on a wall facing away from your garden then that garden area has a 2 db loss compared to whats in front of the airport in the house! I got called out to an installation were this happened, the car park had all the signal the building had none:)

    If the airport is sat on a table or surface upstairs in your house then the signal is shealded from your garden as well! so you want to mount it on an inside wall facing the dirction of the garden, also mount it in front of a window if yo can as walls cut the signal down depending on what they are made off, flint knapp walls cu the signal down terribly:)

    Imagine a soccer ball cut in half and placed over the airport, thats the shape of the signal coming off the base station, for an omni directional antenna imagine a doughnut placed over the antenna, for a directional antenna think of a cone, the higher the db the more pointy the cone is.

    The 6 db antenna is the better choise as you can turn down the transmit power of the base station to adjust the range but remember you want the 6 db gain for the reeived signal as well.

    Before you buy sit in the garden with the laptop and get some one to move the basestation around a bit and see if you cant find a way to get it to do what you want, some times moving it just a foot or changine its mounting direction will make it work!

    Viv
     
  7. Westside guy thread starter macrumors 601

    Westside guy

    Joined:
    Oct 15, 2003
    Location:
    The soggy side of the Pacific NW
    #7
    Viv, thanks for the extra info. My degree (from back in the dark ages) is in physics so I understand the principles of all this, but as the joke goes "physics has very little to do with the real world". :D This isn't the first time I've run into marketing claims that use technical terms misleadingly, so I appreciate the heads' up on that.

    I will try what you say regarding different orientations of the AE base station. We've got it sitting on a shelf right now. Unfortunately the way our cable internet comes into the house, we are stuck having it pretty much up against a wall - and the places we want the signal are mostly through that wall, of course. :p

    I found some mention of problems with the Hawking antenna - not functionally, but the way it (doesn't) play well with the Airport's antenna sensing circuit. So you may end up having to monkey with it every time you reset the base station...

    Some people in Seattle Wireless were recommending antennas from Hyperlink Tech. The 8.5dBi antenna I've linked to there looks interesting - it's main (non-technical) drawback is the 21-inch height! It comes with a 6 foot cable which would be a plus in terms of a more favorable placement. A longer cable would probably work against some of the antenna's gain, I imagine.

    It's hard to shop for antennas for the Airport Extreme, because nowhere does Apple actually mention the connector type! It took some digging to find out that it's an MCX connector.
     
  8. Viv macrumors regular

    Joined:
    Sep 11, 2003
    Location:
    Normandy, France
    #8
    Funny how the best place is all ways the worst place for a base station:)

    Nice looking antenna and the price is good too, I need one for our office and workshop so I may buy one of these now:)

    Look at the signal profile at the bottom of the page, that gives you a nice idea of what to expect.

    8.5 db gain is good for an omni like this, 21" well it takes a certain amount of length for a colinear design like this to resonate, but its shorter than a lot I have installed.

    Viv
     
  9. GrumpyJabber macrumors newbie

    GrumpyJabber

    Joined:
    May 11, 2005
    Location:
    Dallas, GA
    #9
    Lost signal strength

    The information on this thread has been great to seemingly fix my problem.

    I installed an Airport Extreme in my home. Have a couple of different computers connecting to it. One is a desktop that never moves. When I first installed the Airport, I always had "Very Good" signal strength to this machine.

    About 2 months later, I could not get more than a "Low" signal strenght to this machine. Nothing had changed or moved. I verified all settings on the Airport and tried every available channel to make sure that I had not started picking up interference. Nothing helped.

    Now, thanks to this thread, I have rotated my Airport 90 degrees in the closet and got back to a "Very Good" signal strength on the computer. This is very cool. :) However, it does not explain the original signal degradation.

    Any thoughts?
     

Share This Page