Better WR703N Antenna mod

EDIT: I recommend looking at this method: https://app.box.com/s/cispknq8b9zgog8k5vxn.

I blogged about a WR703N antenna mod earlier, I found some hints about a better way of doing it on the openwrt forum. There's a (0 ohm) shunt resistor in the antenna path - labeled J1. I undid the changes I did earlier, unsoldered the J1 resistor.

With the board oriented with the wired lan to the left, I then soldered the core of the antenna wire to the RIGHT pad of the now removed J1 resistor. There is a big empty pad "north" of J1, where the antenna shield can be soldered.

EDIT: See Diarmaid Ó Cualain comment below, he has been getting better luck leaving J1 bridged (and instead cutting the internal antenna) - while still soldering to the same location. There are two capacitor on the antenna track on the other side of J1, which could be the reason for this.

27 comments

  1. Cron.d

    Thanks for that. nice site you have here!

  2. Jefferson Nunes dos Santos

    Just what I was looking for! Thanks.

  3. Eric

    Hi, do I have to cut the pcb antenna as you did in the pervious post?
    Thanks.

    1. Stian Eikeland

      No, as far as I know, this disconnects the PCB antenna.

  4. DF

    Question: What wattage Solder iron are you using? I'm getting nowhere with a 15w and I don't want to over heat the board. Additionally do you know if this method will work on a TL-WR702N? If not I'll get back to you on it.

    1. Stian Eikeland

      Actually don't know, it's a cheap no-name iron without much information on it. I'm guessing it's a standard 35w.

      There is a trick you can try, add solder till you have a blob covering the entire resistor (as small as possible but still covering both pads).
      Give the iron enough time to preheat so that's it's really hot, then lay it flat on the top of the blob, hopefully 15W will be enough to heat it all (i think it will). Use a pincer or something to lift the resistor/blob.

      Be careful, the pads are apparently really easy to lift on this board.

      Have not looked at the WR702s.

  5. hracer

    I am having trouble soldering the copper wire to the j1. I will not stay. Is there a way to get this done better?

    1. Stian Eikeland

      Hmm, not sure what's causing the problems here.
      Try to make sure that the pad and wire is clean, pre-tin both pad and wire, use lots of flux and a warm iron.

  6. aslam

    hi, what type of antenna to use, thanks

    1. Stian Eikeland

      I use of a couple of different ones, a cheap directional one from ebay - and a the one that was bundled with my Alfa Network usb adapter ( http://www.alfa.com.tw/prod... ). I would recommend googling around a bit, as I haven't really done that much research on good and cheap antennas.

  7. Jefferson Nunes

    So, what you can tell me about this mod? It really improves the sinal strength?

    1. Stian Eikeland

      Hello,
      I haven't had much time for a comparative study, but what I use it for is a wireless bridge w/ a directional antenna.
      Before doing the mod and using the directional I experienced lots of disconnects and SSH sessions had high jitter.
      Now it's pretty stable for my purposes: Link Quality=70/70 Signal level=-39 dBm

      I do not know if the overall signal is better with a good omni compared to the on-board.

  8. Aerials Leeds

    Pretty sure that a directional aerial / antenna will make all the difference, I did a similar set-up and get a pretty high dBm and minimal jitter

  9. hich44

    mercie pour ce sujet interessant moi aussi jutilise cet appareil eller super mais je veut augmenter la porter de la reception wifi de mon appareil es que je peut ajouter ce tipe dantenne tp-link wifi externe grille parabolique Gain de 24dB et la souder sur mon appareil comme vous avez fait

  10. Diarmaid Ó Cualain (@DiarDan)

    I came across this antenna modification and a similar specified one on the OpenWRT forums. I performed the mod, but was disappointed with the antenna gain. By comparing the performance of my Buffalo router and the TP 703n using the same antenna, there was nearly a 50% improvement in signal quality from the Buffalo.

    However, I believe you were more on track with your first modification , a link to which you gave at the beginning of the blog post. If you cut the trace to the internal antenna, as specified in your first modification, leave C114 as it is, and then solder the coax of the external antenna to either end of the J1 0 ohm resistor, you should get better gain performance.

    By removing the j1 0 ohm resistor, you not only are removing the internal antenna from the circuit (which is a good thing, if you want to connect an external antenna), but you are also removing C29 C31 (beside the internal antenna). I believe this is the reason for the drop in signal quality.

    I have noticed now that my TP 703n router has comparable performance to my buffalo router using the same external antenna. I hope this helps!

    1. Stian Eikeland

      This is certainly interesting, I will try to bridge j1 again and see if I there is a difference in signal strength.
      Thank you :)

      1. darkside40

        Interesting mod. Did you already had the chance to check if bridging J1 and cutting the internal antenna gives you a better signal strenght?

        1. Stian Eikeland

          Sadly haven't had time yet :/
          Please let me know if you (or anyone else) try.

      2. hoschisubs

        Did you already had any time to try this?

  11. Valent Turkovic

    Hi, this is awesome mod.
    I have wrote about your antenna connector mod on openwrt forum and wiki:
    https://forum.openwrt.org/v...

  12. P Harrison

    Does this mod increase signal if you are using it as a 4G router? Is the antenna specific to the wifi only?

    1. Stian Eikeland

      Only helps with wifi

      1. P Harrison

        Thought that might be the case. Thanks.

        Guess I'll be cracking open the 4G USB modem I have on order. If I find the antenna location I'll post it here.

        ~P

  13. Bedlore

    Aghh, help. I must of overheated J1 and have burned it off completely and also lost the right-side pad. Can anyone advise what to do? Can I order a replaced shunt and where does the right pad go to, I can't tell anymore. Please help.

  14. Laguna Computer (@LagunaComput

    http://lagunabeachcomputer.... Here is how I did mine. thanks

  15. stefano

    thanks Stian for this post, can you help me with the D-Link 505, i need to know where i have to solder the external antenna, there are some photos of PCB on Openwrt http://galeria.tech-blog.pl...
    thank you.

  16. Ion Brezeanu