Posts by PA0P

    Dear Kornel,


    It seems that all the expert statements so far do not help you much in understanding.

    Focussing on the power amplifier as offered by BG0AUB I will try to clarify how to calculate.


    As you mention yourself about having a Adalm Pluto module, you must be aware that the TX output level can be programmed in dBm's (yes, we live in a dBm world, hi), so you only have to select the input drive level from the table for the PA output you aim for.


    With a PA input of -19 dBm you get 37.6 dBm which equals to 5.7 Watts; a drive of -18 dBm gives 38.6 dBm which equals to 7,25 Watts, etc. (40dBm = 10W, 43dBm = 20W, 46dBm = 40W but not linear anymore).


    By reducing the supply voltage to e.g. 24-28Volt you can lower the output level a bit.

    Also it may be wise for stability reasons to have a resistive attenuator placed between the Pluto and the PA.


    For further info you can contact BG0AUB direct via eBAY or on Twitter,

    Here is his latest offer on eBAY:


    https://www.ebay.com/itm/28440…ewItem=&item=284403687949


    The item description gives you additional information about the product:


    The package includes:

    1: Used S-Band power amplifier, which has 56dB high gain, and up to 20 Watts (43dBmW) output * 1 set

    2: Brand new multifunctional interface board * 1 set ( which is designed for working with Pluto SDR

    3: RF jumper (15cm SMA TO SMA) * 2 sets

    4: SMA to MMBX connector * 1 set

    5: One PCB for extending Pluto SDR PPT GPIO converter * 1 set

    6: PA power cable, USB OTG cable, 2x3 pins 2.0mm connector, retaining screws


    The multi-functional interface board provides the following functions:

    A: A USB network adapter, which is also working with Pluto SDR.

    B: 30V to 5V DC-DC converter, which could provide power source for PA pre-amp and Pluto SDR.

    C: 30V to 12V/18V DC-DC converter, which used for supply the LNB. Different voltage could be select via a jumper.

    D: Over-temperature protection and power supply reverse connection prevention function.


    Also here is something that should be noticed.

    A: Input voltage 24-30V, and should have at least 5A capacity.

    B: LNB power out is 12/18V, 250mA Max.

    C: USB OTG power out is 5V , 2A Max.

    D: 24V/30V power supply, Pluto SDR, LNB and network cable is not included in this item.


    OK, at last please be kindly advised again: Pluto SDR should be purchased separate, it is not included in this item.

    Thanks a lot !


    The amplifier has a good internal condition, PCB, but its housing case has some scratches which is not affecting the functionality.

    Each amplifier will be fully tested before shipping.

    The output connector of the amplifier is a SMA connector, and the input is a MMBX connector. A MMCX connector goes to an output direct coupler indicating the output power.

    A Pluto SDR can drive this amplifier working at the desired band with no modifications needed.

    Added Note: This PA comes with a baseplate with uniform heat at the bottom and an aluminum shielding cavity processed by CNC. The appearance has scratches and the bottom coating is partially peeled off. However, the PCB is guaranteed to be flawless, and 100% will be delivered after energized gain measurement and power test.The PA needs to be mounted on a heatsink !!



    Kornel, here is a typical duplex set-up from a French OM using the Pluto without the interface board:




    I do hope to have cleared the matter for you a bit with this.


    73 de Cor PA0P

    The product is definitely auto-switching via carrier sensing, which you have to disable for QO-100 operation.

    Look in the internet for the similar EP-AB003 booster with all the modifications done to it by many OM's.

    You therefore better can go for a real linear PA, preferably with a bit more power.

    As you mention the Pluto, the BG0AUB offering including his interface board is maybe the easiest and cheapest.


    Good luck!!

    Here is a very interesting addendum for your "big list".


    A very well specified PA with 56dB gain and 20 Watt RF.

    This is offered by BG0AUB who also has available an interface for

    a Pluto driver.

    Pricing is riduculous low. I ordered mine already 2 months ago.


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    73 de Cor

    It was a sole source product from NXP, which was discontinued end of 2014.

    As direct replacement was stated the BLF7G27LS-100,118, of which an Ampleon datasheet can be found on the Internet.

    Do assume the spec's will be useful.


    73 de Cor PA0P

    Hello Roberto,


    If the module is not oscillating, the decoupling will be OK..

    Do you have placed via's in the connection board to ensure the top copper is connected to the ground?

    I did solder copper tape around the edges and placed copper under both the connection board and module.

    Maybe you can add a copper strip between the module screw at the output side and the connection board.


    Succes!

    A pity to read your experience. Normally this module does not give any problems. Essential however is a good grounding,

    I used thin copper foil under module as well as the board. see my earlier photo.

    My module easily outputs 2.5 Watts without overdriving the input.

    I experimented with a trimmer at output, but that is really not necessary.


    73 de Cor

    I had to dig deep into my archives, but did find the modification I made long ago to my TS-811E for driving a 70cm linear.

    It was based on an article by DJ7ZZ, which cannot be found now anymore on the internet, so herewith a PDF copy.

    Also I did find 2 photographs of my actual modification, a small PCB just above a DIN connector.

    In contrary to the article I did put the PTT line on the new to mount ACC1 connector.

    So easy to do, good luck!!

    73 from Cor


    TS811-711 PTT Out DJ7ZZ.pdf

    Thinking out of the box you can do it also this way, see photo....

    Alternatively search for an old Stolle rotor in which the pipe can be put through.

    Of course it all is depending on the antenna system you will be using.


    73 de Cor


    In the attachment of this article you will find a detailed modification description of the xtal and input filters for 2300-2450 MHz.


    https://www.hamforum.nl/viewtopic.php?t=1943


    Success, Cor