Has an electrical engineer dev HF AMP with new mosfet MRFE6VP61K25h?

Discussion in 'Amateur Radio Amplifiers' started by W7EET, Oct 10, 2011.

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  1. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    Zowie.;)

    To make this long enough, Zowie again.
     
  2. W7EET

    W7EET Ham Member QRZ Page

    Thank you very much for the link for the 2 meter amplifier.
    I am still waiting for the other email from juma.
    Rich/W7EET
     
  3. W8JI

    W8JI Ham Member QRZ Page

    So they say 1 dB compression point is 950 watts, but no mention of IM3 or IM5 tests. Probably a 700-800 watt PEP amp at acceptable IM3.
     
  4. W7EET

    W7EET Ham Member QRZ Page

    I never heard from Juma. I do not know what is going on there at the company. Maybe they are having economics problems call money. I did contact beko on their 2 meter amp and they also have a 6 meter amp with that same mosfet transistor. The us dollars is 2900 bucks not 3300. There is a shipping cost of 200 bucks. That looks like a really nice amp for 2 meter SSB and CW. If I had one of those amps I would certainly want to not use it only on a occasion or not all the time due to the repeaters just above in the145 range. I am sure there will be some intermod.
    Rich/W7EET
     
  5. W7EET

    W7EET Ham Member QRZ Page

    Here is the up grade information about Juma as of today. They have replied to me by email. The reason why it took so long because they were swamped with email for information on the amplifier. Here is a copy of that email Thank you everyone for your support
    Rich/W7EET

    Hello all,



    Thank you for your interest in JUMA PA1000 linear amplifier. We have got lot of emails concerning the availability, price and other issues.



    We published the JUMA PA1000 preliminary information www.nikkemedia.fi/juma-pa1000 in a very early stage because there are very limited HF application information available for the new Freescale MOSFET.



    Currently we have two working prototypes. The MOSFET and main functions are performing very well and we will continue testing. We are not yet fully satisfied with some functions and we need to improve some circuits e.g to reach the targeted broad band performance. Additionally there are some concept issues, like more sophisticated user interface, auto band selection, lighter power supply etc.



    Unfortunately we are unable to give any price information or schedule yet. It will take some time to get ready with all the tasks.



    Please follow Juma Forum board.jumaradio.com We have opened a new topic there for JUMA PA1000 information and conversation.



    73 Juha OH2NLT and Matti OH7SV
     
  6. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    Sounds to me it's not ready for prime time. It will be interesting to discover what they find out as they continue testing.

    Thanks for the update.
     
  7. VK4KGW

    VK4KGW Ham Member QRZ Page

    Well after making enquireis a month ago this arrived via email today

    ""Hello all,



    Thank you for your interest in JUMA PA1000 linear amplifier. We have got lot of emails concerning the availability, price and other issues.



    We published the JUMA PA1000 preliminary information www.nikkemedia.fi/juma-pa1000 in a very early stage because there are very limited HF application information available for the new Freescale MOSFET.



    Currently we have two working prototypes. The MOSFET and main functions are performing very well and we will continue testing. We are not yet fully satisfied with some functions and we need to improve some circuits e.g to reach the targeted broad band performance. Additionally there are some concept issues, like more sophisticated user interface, auto band selection, lighter power supply etc.



    Unfortunately we are unable to give any price information or schedule yet. It will take some time to get ready with all the tasks.



    Please follow Juma Forum board.jumaradio.com We have opened a new topic there for JUMA PA1000 information and conversation.



    73 Juha OH2NLT and Matti OH7SV





    -- All the recipients are intentionally as "Bcc" in the mailing list --""
     
  8. W7EET

    W7EET Ham Member QRZ Page

    I was not impressed or over thrilled of the email response time either. It will be interesting to find out the kit price and shipping. I hope they get everything ironed out with the minor problems of their design.
    Rich/W7EET
     
  9. VK4KGW

    VK4KGW Ham Member QRZ Page

    here is a 4z4 using the chips I think and making some serious claims about ithem ( or might be similar not sure) , he is an engineer and I have used his designs with success but can't comment on his current developments , and yes ebay might bring a lead
     
  10. W4QBQ

    W4QBQ Ham Member QRZ Page

    Some few nights ago I was listening in on a QSO between a few Hams about Amps., there was one in particular that was holding my attention as he seemed very knowledgeable on the topic. This particular individual said he was a radio/tv broadcast engineer in the Maryland area. I thought I copied his call, but when looking it up the next day there was no such thing. He was extolling the virtues of Transistor over Tubes and how virtually all commercial stations now use Transistors or are changing to them. He also was telling of the Freescale Transistor being discussed in this thread including that he thought it was cheap and superior in function over others. He went on to say that he had built a "Backpack Amplifier" using that Transistor and had also taken it to the Dayton Hamfest and shown/demonstrated it to people at Alpha and had it tested by them, with what he thought were satisfactory results.
    I was disappointed I didn't get his call as what he had done sounded appealing to me. I looked up the product http://www.mouser.com/Semiconductor...tors/_/N-6hpe7Zlls6?Keyword=191848785&FS=True
    and the You Tube video he mentioned and then came to QRZ to see what's up and I found this thread.
    In the 50s and 60s there were home brew designs for Linear Amps. in the ARRL Hand Book, it would be nice to see something like this in there in the future.

    JIM
     
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