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.

Low output on 6 meters

2»

Comments

  • AH0U
    AH0U Member ✭✭

    Mark WS7M... what did you find in your test??

  • Mike-VA3MW
    Mike-VA3MW Administrator, FlexRadio Employee, Community Manager, Super Elmer, Moderator admin

    Don't forget that the FCC limits drive gain to 15db for commercial amplifiers and make sure you take this into your calculations. The PGXL is not like your grandfather's amplifier. :)

    For the PGXL, the max output is limited to about 62dbm (about 1500 watts). In order to keep the FCC happy, you will need 47dbm or about 50 or more watts to drive it to 1500 and keep the gain under 15db.

    As for heat, the Expert amps do not have Harmonic Load management as the PGXL does. In the Expert, harmonics blocked by the low pass filter just prior to the antenna port are reflected right back into the power amplifier and this can contribute to IMD products (aka, dirty signals).

    In the PGXL, the reflected energy is trapped by a high pass filter and diverted to the harmonic dummy load so that this energy does not interfere with the PA at all. When your amp heats up, it is likely due more to reflected harmonics heating up the internal 400 watt dummy load. This also results in a much cleaner transmitted signal.

    Using MeFFA also allows for a cooler running amp on constant carrier modes like RTTY, CW and FT8.

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.