Antenna A/B Which antenna is which

Discussion in 'Tomato Firmware' started by zardiw, May 7, 2007.

  1. zardiw

    zardiw LI Guru Member

    Hey all....GREAT FORUM!!!

    Have a WRT54GL, and want to attach an external antenna.

    Which one is A, looking at the router from the front?

    Also, supposedly one antenna port has a shielded cable going to it from the circuit board. Is that the one I would hook an external directional antenna to?

    Found this ( ):

    Where to connect the external antenna

    WRT54g v1, v1.1, v2
    look at the backside and connect the external antenna to the right antenna connector

    WRT54g v2.2 v3 3.1 v4 and the WRT54GL v1.0
    look at the backside and connect the external antenna to the left antenna connector

    Also, do the settings really apply, i.e. if you pick A to transmit and B to receive, does that really work?

    What about just leaving it on auto?

    Thanks for any insight into this............ :confused: .....z
  2. GeeTek

    GeeTek Guest

    That is quite a website you found there. I cannot give a definitive answer on which antenna to use, or which is left or right. Trial and error will be your best guide unless somebody else is sure and can tell you, in which case you will try both ways anyhow. The RX/TX antenna selection should be supported. I was playing with a couple of radios last night, and found evidence in the commands for the RX/TX antenna control. Here is what I did, you may want to take a look also. Telnet into the router. At the prompt type Wl (dubya ell) and hit enter. Read down through all that good stuff. It's real intersting. Short slot is even in there. DD seems to use a newer version of whatever this is, and it has more options than Tomato.
  3. zardiw

    zardiw LI Guru Member

    Hey GeeTek! Well I've been doing some experimenting, but the results do not tell me which antenna is doing

    I'm using a directional pointed through brush and stuff to another directional 100 meters away.

    Best settings I've found is Rx - Auto, Tx - B. I've got the directional hooked to the right side looking at the front.

    These settings give almost identical results: Rx - B, Tx -

    All the other combinations where I use different antennas for Rx/Tx make it worse.

    Will test using the SAME antenna for both and see what that does.

    But it's interesting that nowhere does it say which is
  4. zardiw

    zardiw LI Guru Member

    Chat Session with LinkSys:

    James s. (29793): Hi, my name is James s. (29793). How may I help you?
    hans: Hi. WRT54GL. Which port to hook external antenna
    James s. (29793): Good day, how's your day?
    James s. (29793): I see.
    hans: Just peachy
    hans: Router inside, antenna outside
    James s. (29793): Can you take off the antenna at the back of the router?
    hans: YEs
    hans: It has TWO
    James s. (29793): If not, then it is not replaceable, Hans.
    James s. (29793): Okay, then you may attach the external antenna there, Hans.
    hans: WRT54GL.......BOTH unscrew
    hans: WHICH ONE
    James s. (29793): Please unscrew both.
    hans: And hook the external antenna to WHICH port
    James s. (29793): To those two ports from the original antennas.
    hans: Right, there is a cable going from inside to outside
    hans: ONE cable
    hans: To WHICH port do I attach it
    hans: There are TWO ports, because there are TWO antennas
    James s. (29793): Both of the 2 ports, Hans, or either of the one will do.
    hans: It doesn't matter?
    James s. (29793): Yes, that is correct.
    hans: I only have one antenna......a 24dbi directional
    hans: On the WRT54G'
    James s. (29793): Yes, you may use that if it is compatible with the router's port antenna.
    hans: there is a shielded cable inside the router that goes to the right port, looking at the router from the front, but no such cable on the left side
    James s. (29793): I see.
    hans: Are the WRT54GL's the same way? Should I take it apart?
    James s. (29793): Take it apart, Hans.
    hans: Ok, thank you...........I will
    James s. (29793): Thanks.
    hans: I'm assuming that is the official LinkSys response to my
    James s. (29793): ( Smiling Here).
    James s. (29793): If you need further assistance or run into any problems, feel free to log-in to this chat session again.

    hans: I'm taking a screenshot of your answer
    James s. (29793): Be sure to visit our Knowledge Base located at The site contains troubleshooting tips, how-to instructions, as well as solutions to common issues relating to all Linksys products.
    James s. (29793): Sure, no problem.
    hans: It's worthless
    James s. (29793): Actually, for your reference, a transcript of this session will be sent to your e-mail account, along with that is a case number that you can refer to if for some reasons you need to contact us again.

    hans: I can't believe you told me to take it apart
    James s. (29793): What happened, Hans?
    hans: Nothing yet.......I haven't taken it apart yet...where are all the screws?
    James s. (29793): I see.
    James s. (29793): Please disregard that.
    James s. (29793): Give me a minute or 2, I will try to check with my resources, Hans.
    hans: Are there 2 shielded cables coming from the circuit board?
    James s. (29793): No.
    hans: Which one has the shielded cable
  5. GeeTek

    GeeTek Guest

    For external antennas, setting RX and TX to the same port is the proper config.
  6. TexasFlood

    TexasFlood Network Guru Member

    I can never remember which is which. BUT, if you set both TX & RX to say, the left antenna... Then remove one at a time, the one you remove that makes your signal suck is what the firmware thinks is the left one. :)
  7. zardiw

    zardiw LI Guru Member

    Thanks...I have come to the same conclusion.......and also maybe answered my own question.

    Looking at the front of the router, A is Left, and B is right.

    I hooked the 2 12dbi's to B on each router, and set both Rx, and Tx to B.

    That get's me about -20db over almost 100 meters through brush and crap......At 42mw transmit power btw........I'll post my detailed results later...............z
  8. zardiw

    zardiw LI Guru Member

    I don't think it's a good idea to leave an antenna off while it's on......but what I did was move the directional way off the path, and my signal went down, so that's why I think that the RIGHT one (looking at it from the front) is B...........z
  9. TexasFlood

    TexasFlood Network Guru Member

    No, not a good idea to leave it off from what I've read, just long enough to check the signal. If you can't do it fast then it might be a bad idea. If you don't feel comfortable then don't do it at all. I've had mine off briefly while the unit was on and noticed no damage but maybe there was damage that I'm not aware of.
  10. digitalgeek

    digitalgeek Network Guru Member

    If you guys are interested in external antenna's you can google pringle antenna, and you can find some detailed info realting to home made antenna's
  11. rilles

    rilles LI Guru Member

    how do you get the antenna off the back?

    I tried twisting, but it just spins... i didn't want to spin it too much in fear of something going 'snap'.
  12. TexasFlood

    TexasFlood Network Guru Member

    If you have the right model, it unscrews easily, but not all models are removable. Don't twist them off if they aren't removable. I googled a picture to show what they look like on my WRT54G -
  13. GeeTek

    GeeTek Guest

    You must grip it and squeeze it as you spin it.

    Edit - I strongly recommend not turning the unit on with no antenna connected. If you must do so, set the power level to zero (which is not zero, but as low as it can go).
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