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2x BLF578 >2KW amplifier

Discussion in 'Amateur Radio Amplifiers' started by SP5G, May 8, 2012.

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  1. SP5G

    SP5G Ham Member QRZ Page

    Hi,
    I ran the amplifier (1.8 to 50MHz), it has two LDMOS transistors BLF578, more info on www.sp5g.net
     
  2. KO6WB

    KO6WB Premium Subscriber QRZ Page

    That's an interesting article. The BLF578 still cost over $300.00 so two of them can be expensive. On the other hand tubes are not getting cheaper. It would be good to see the IMD performance as well as mismatched performance. The data sheet says the BLF578 is good to 13:1 SWR and not be damaged. This was in a pulsed condition. CW would be a totally different value. At the cost of them I would not want to be the one testing for that. The solid state devices are becoming more available and are attractive for linear amplifier service. It's just a matter of time and every amateur will think fondly of the days when you had to tune the amplifier and change bands with a switch. Sigh....
    Have fun
    73
    Gary
     
  3. 4Z4RB

    4Z4RB Ham Member QRZ Page

    I created that board for Robert SP5G
    it is a very powerfull board
    I have since then moded the amp and made many changes to it.
    Baruch 4z4rb
     
  4. SP5G

    SP5G Ham Member QRZ Page

    not really, because the amplifier is not prepared by a colleague working as it should, the one about which I write is a completely different design in terms of components and solutions.
     
  5. IZ2HFG

    IZ2HFG Ham Member QRZ Page

    Hello Guys!
    I hope that my friend Baruch will change the vendor of components also, because I have already said to him that I have a lot of doubts about the real functionality of the RF components used, in fact the "smoke" put out from the capacitors (with 1/10 of the power) is not the normality into the output circuit and I hope again that is not a symptom of the other big issue, because he said me that is the first one problem that occurs with these boards.
    Anyway I stop here my comment because I am waiting from Baruch of a new set of capacitors and after we will see.
    73 franco
     
  6. IZ2HFG

    IZ2HFG Ham Member QRZ Page

    Hi man, I'm waiting the your decision.

    - Resend me the two complete boards with mounted devices but absolutly and fully tested with the your report by
    frequency/power out/minutes or seconds of the test with max power out and so on.

    - Obtain the refund of the money that I have spent and I will send back your boards, the two copper bases and all destroyed devices.

    Sincerely and with all my good will I see no other possibility and there are not alternatives, to go out of this situation, honestly and with high head for you.

    As already wrote, let me know your final decision
     
    Last edited: Nov 1, 2012
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