TX-only modification on commercial WiFi booster

  • EP-AB 003 features:

    • Operation Range: 2400-2500 MHz.
    • Operation Mode: Bi-directional, half-duplex, Auto-Switching via carrier sensing.
    • Frequency Response: ± 1dB over operation range.
    • Input Power: 3dBm (Min.)-20dBm (Max.).
    • Input Power 5 ~ 20 dBm.
    • Optimal Input Power 9 ~ 15 dBm.
    • Output Power: 8000mW/39dBm nominal for 802.11b/11Mbps.
    • Connector: SMA Receptacle, 50ohm.
    • Transmit Gain: 17dBm nominal.
    • Receiver Gain: 11dBm.
    • Receive Noise Figure: 3.0dBm nominal.
    • Operating Temperature: -40 to 70 degree.
    • Operating Humidity: Up to 95% relative humidity.
    • Material: Cast Aluminum
  • F1BPT

    Thank you for writing these well known technical paramteres from the box of this amplifier.

    But we all know about the big difference of these data and the reality we experienced ;-)

    Thus trust the real life reports/measurements not the chinese "dream-numbers"

    73 de Johannes

  • The Input is SMA. The Output is RP-SMA. But this is not really a problem.

    I just use an adapter RP-SMA to N. But there are also reports from OMs who changed the output connector to SMA.

    73 de Johannes

  • I measured mine as having 11dB gain - so if you keep the output power to 2w (33dBm) then the largest input is 22dBm. You can drive it to 4W but it splatters over the spectrum.

  • Hi,

    I will use the 8W pa with an Upconverter by DX-Patrol which made 100mw max output.

    Dio I have to make a modification ???



  • DJ9JY

    Hello Wolfgang,

    with 100mW a modification of the PA is not mandatory. It will work just out of the box.

    But if you want to tweak every mW you can think about the bridging of the Input RX-TX-switching diode (bringing a few more mW of drive to the transitors). And about bridging the Output switching diode (this improoved my signal via the transponder 1dB).

    73 de Johannes

  • @ HB9SKA, DL5RDI

    Thank you for your information. So I do not have to put my big fingers in the PA.

    SMD is not my thing. I will try it without any modification.

    Thanks for your help.


  • Hmmm... this is in contradiction to

    I can comfirm what DL5RDI said: the permanent TX-modification is neither necessary for SSB nor for CW. In my view the only valid reason to do this modification is when you want to reduce the power for whatever reason, for example to test low-power (below noise floor) data communication. As the HF-VOX switches only above a certain input power (in the range of 5 dBm), you can further reduce the input power only if you did this modification.

    Is full duplex operating in SSB really not possible without this modification ?

  • HB9SKA

    Hello Thomas.

    Wihout the modification the PA has a HF-Vox for switching between RX and TX. In this way you can use the PA for transmit or receive, like required for a normal simplex, terrestrial QSO in SSB, FM or CW.....

    With this modification the PA is in permanent TX mode. You can no longer receive a signal "through" the PA. Thus this configuration is only suitable for a TX only operation.

    Full duplex operation (on 2.4GHz two way) is not possible with this PA (neither with the unmodified PA nor with the PA modified in the mentioned way).

    73 de Johannes

    P.s. the "Power amplifier -PA" part of the QO-100 Wiki cited by DL4OCE is in my opinion of very "questionable" quality

  • Full duplex Operation is not possible with this PA (neither with the unmodified PA nor with the PA modified in the mentioned way).

    .. sure, but only for one band, 2,4 GHz.

    For QO-100 you need only the tx part of this pa. So, full duplex (tx on 2,4 and rx on 10GHz) is still possible.

    I think, what Thomas means, is the SSB problem with the vox in this pa type. During a ssb signal you have different output levels, so the vox will switch on and off during this tx period. (cause its still a carrier/no carrier vox)

    With modification, you have current the tx status, and are able to work in SSB via QO-100 in full duplex mode.

    73 de Robert

  • DD4YR

    ...but for full duplex operation in the way you mentioned the modifiaction of the "8W- PA" is not a "must have", but a "nice to have" (assuming >25mW drive level)

    You can take it just out of the box....and it will work in SSB ad CW

    73 de johannes