What TX amplifier do you plan to use?

  • Hi,

    Has someone tried this amp?

    It is advertised as a 2-W amp. If this is true, it would be quite convenient to mount the device right at the focus of the dish, because it looks much smaller thant the usual wi-fi booster, and maybe more weather-resistant with its shhrinked-plastic cover.

    They claim 11dB Tx gain (and 10dB Rx gain) and require a 3.7-5.5V supply. Input power is +4 to +20dBm.

    I suspect they'll run quite warm but it doesn't look too hard to strip off the heatshrink cover and attach a heatsink.


    https://fr.aliexpress.com/item…de-452d-b12a-b7bc705c07af



    73s

  • Hi

    What's the name of the push-on connectors on these Nokia PA boards?

    I've ordered 2 different models of these PAs from eBay (one with BLD6G22L-150BN and one BLF7G22L-130N), but I don't know which exact cable/adapter I will need. Based on pictures, it seems like MMBX, right?

  • DM5RM I have ordered MMBX and AFI adapters to test the amplifier. Is it safe to put it to use without any modifications?

    I don't want to get the maximum power. Even 20-25W is more than enough for me, but I don't know whether it would cause problems for the amp (because of high VSWR or bias issues or mismatch)

    I am not experienced with microwave modifications, so I would prefer not to modify and I read in this thread that you'd already managed to run it without mods. Any tips to share?


  • DF2HF,

    I did not modify mine yet.

    I started at 16v, moved to 24v, and did some more tests at 28v.

    Clear that performance/gain at 2250 MHz is 10dB better than 2400MHz.

    Input was an RS signal generator.

    So I will next snowflake the PA to get the higher gain also at 2400MHz.

    The tables give the initial results.

    My goal is DATV, intended use is to connect it to a Portsdown TX.

    What is your goal, WB or NB usage?


    Henk

  • Thank you very much for the detailed reply. That looks promising. The maximum output of my LimeSDR Mini is 8-10dBm and the output of my first stage amplifier (Analog Devices CN0417) is around 27dBm, so I can easily get the 25-30W based on your table by feeding it with 15-20dBm.

    Right now I am using a Chinese amplifier (EP-AB003 WiFi booster) which is rated for 8W but actually gives me 3W (35dBm) and I'm not happy with the result.

    For now I would like to operate in NB, but WB is my next step.

  • We need to be careful, for DATV we need to be within the -1dB compression point/range.

    Seems to be at 6dbm input, but of course, all this is my initial result.


    Also, check using an SDR, eg an Airspy, the spectrum of the portsdown output, the shape should not be distorded, the socalled shoulder for example.

  • Right now I am using a Chinese amplifier (EP-AB003 WiFi booster) which is rated for 8W but actually gives me 3W (35dBm) and I'm not happy with the result.

    This WiFi booster has an amplification of about 10dB. This is the reason why you are not happy with it. 35dBm are too much, about 100 mW are real.


    I'm happy with it to use it via NB transponder. 73

  • This WiFi booster has an amplification of about 10dB. This is the reason why you are not happy with it. 35dBm are too much, about 100 mW are real.


    I'm happy with it to use it via NB transponder. 73

    Hey Thomas.

    What do you mean by "100 mW are real" ?

    I have attached a picture of my setup and also a picture of my antenna's VSWR.

    I've measured the output of each step with an RF power meter.

    Output of LimeSDR Mini: 8-10dBm

    Output of CN0417 (which is connected to LimeSDR): 27dBm

    Output of the WiFi booster (which is connected to CN0417): 35dBm


    My cable has about 1dB loss and my antenna's VSWR is less than 2.



  • PA3GUO @OH3WE @G3XOU

    Hey. My connectors arrived today and I'm ready to test. Can you please give me some info about how to supply voltage to it? Based on the pictures, it seems I should just connect the two connectors across the board and then connect them to power supply, except the pin 1 which seems to have a different voltage (It's not connected to the other 4 pins in the line).

  • Thanks to everyone for your help and replies. I finally tested the amplifier and it works (without any mods)

    I used a SMA-to-AFI adapter for output, and made a SMA-to-MMBX cable for the input, so I don't have to desolder the existing connectors.

    I used a 24V Meanwell.

    The idle current is 1.8A

    With ~10dBm input, it produces 36dBm.

    With ~20dBm input, it produces 43dBm and draws 9.8A. This is enough for me for now. I may increase the input a little bit and get 1-2dBm more.

    I didn't feed it with more power, because I lacked the equipment (my power supply is 13A, my ammeter is 10A, and the power wires I used are not safe for more than 10A)

    Next step is to test it on the air!

    It gets a little bit hot but I guess it's Ok. I've attached a picture (the outside seems to be around 52C in less than a minute)