Welcome to the new FlexRadio Community! Please review the new Community Rules and other important new Community information on the Message Board.
If you are having a problem, please check the Help Center for known solutions.
Need technical support from FlexRadio? It's as simple as Creating a HelpDesk ticket.

PG-XL and Meffa ??

James Kennedy-WU5E
James Kennedy-WU5E Member ✭✭
edited May 2020 in Power Genius XL Amplifier
Good morning my PG-XL is the king of shack now , I didn't realize how big it is. My question is how many use MEFFA check in the PG-XL APP ? what are the PLUSES for the operator? or Help the AMP stay healthy? So very happy with the PG-XL but curious! de Jim WU5E

Best Answer

Answers

  • Doug
    Doug Member ✭✭
    edited May 2020
    It is explained is detail at the Flex site. It does not work on ssb mode but does work in other modes and changes the PGXL class of operation mode it runs in. It is a very interesting read and I would encourage you to go read up on the benefits. And BTW is you think this amp is a hunk go look at all the Alpha's and the Ameritron AL1500 etc. They weight over double of this I call compact desktop legal limit amp. 
  • bahillen
    bahillen Member ✭✭
    edited May 2020
    James I had not used Meefa since I bought the PGXL almost a year ago because it behaved a title strange with SWR. I also didn’t have an understanding how it worked. Due to RFI issues in my house I ran it at 600-900 watts. (My fire alarm would get alarmed.) With the fixes to the SWR software and resolving my fire alarm issues, I recently tried it again for FT8 and CW. I found that at 1.5 kw the temperature of the PA dropped a lot and the temperature of the harmonic load increases(doing its job) . The Meefa sets the PA bias and takes a number of transmissions to arrive at the final bias point. You will see the P.O. move around on transmission until it is zeroed in. Also you will see it takes more drive to get the P.O. you are looking for. This is software so there are a lot of things that appear to be going into the final bias points. Such as SWR, temperature, power output , Amp current and voltage. It appears to be pretty sophisticated. Your PA will run much cooler that is a particular interest for me running FT8 50% duty cycle. I would suggest trying it at 900 watts for a while then working up to full power over a few days on different bands to get familiar with what normal looks like. You will like it. Don’t forget PSK is like SSB and needs linearity not efficiency. 73 Bill W9JJB
  • Tom Porada
    Tom Porada Member ✭✭

    Meffa is real interesting and I use it most of the time. I do find that I sometimes turn it off to achieve a higher output power above 14 MHz. But it sure does allow the amp to run cooler..

  • Mark_WS7M
    Mark_WS7M Member ✭✭✭

    I have just started using meffa and I think it does keep the amp cooler as I run either CW or digital 95% of the time.

    I really can't stand loud fan things and the PGXL even with the latest firmware can get loud when it starts to warm up. But the main reason I bought it is that I can place it, my Flex 6600 and everything out in a small HVAC shed which is right where the antenna connections come in. So it's an ideal spot. It stays pretty cool since the HVAC unit is in there and it is insulated.

    So I don't have a loud amp anywhere near. A very nice feature.

  • WK2Y
    WK2Y Member ✭✭

    Is the HVAC part of the home circulation? If not, you might want something to alert you if the HVAC goes out. Small spaces can heat up really quick.

    73,

    Bob

Leave a Comment

Rich Text Editor. To edit a paragraph's style, hit tab to get to the paragraph menu. From there you will be able to pick one style. Nothing defaults to paragraph. An inline formatting menu will show up when you select text. Hit tab to get into that menu. Some elements, such as rich link embeds, images, loading indicators, and error messages may get inserted into the editor. You may navigate to these using the arrow keys inside of the editor and delete them with the delete or backspace key.