Posts by DM5RM

    Meanwhile I almost believe that it won't work at all.

    On the beacon status website

    is written at the end of the page:

    "QRV: always when moon is visible with more than 10 degrees elevation at DL0SHF but only when moon declination is above 20 degrees North"

    However, Daniel, EA4GPZ, has reported that he received the beacon on May 16, 2019.…qo-100-station/#more-6594

    73 Roland


    Here is the picture of my one and only mod so far. The size resp. area of the selfadhesive copper foil depends a bit on the operating voltage.

    You should start with a tiny piece of foil and then gradually increase the area until it doesn't get any better.

    And don't forget the cover...

    Just by the way, with your power supply, you should almost be able to weld ;-)

    73+55 de

    Roland, DM5RM

    Hi, Alex and friends of BLD6G22L,

    I first tested my amplifier without any mods.

    The original bias control works very well from about 15...30V operating voltage (left PA 10...30 mA, right PA 1.23A, driver stage 0.36A, preamplifier 90...50mA).

    The gain at 2.2GHz is about 41dB, at 2.4GHz about 10dB less.

    A single small piece of copper foil on the C between W100 and the driver stage boosts the gain at 2.4GHz to 39dB.

    It is important to screw the aluminum cover on again before each measurement. Without the cover I had up to 2dB gain change and there is the danger of parasitic oscillations due to unintentional touch.

    More than about 20Watt I couldn't generate yet, because my laboratory power supply is too weak.

    Some more remarks:

    W100/W101 are not filters, but also circulators or more precisely isolators. This is easy to detect, they are slightly magnetic. I wouldn't remove them.

    In my opinion the better decoupling of the stages is more important than the possible increase in gain. This could have been a reason for the preamp problems of DB8TF.

    The input socket is MMBX.

    There are matching plugs: HUBER+SUHNER 16_MMBX-50-2-4/111_NE, e.g. from Mouser. The amplifier cover must be filed off a little so that it fits.

    The second MMBX socket is connected to the directional coupler at the amplifier output. An RF power meter could be connected there. I haven't measured this branch yet.

    The output socket is AFI.

    With an „AFI Plug PCB Bullet“ (Amphenol 920-263P-51P, also e.g. from Mouser) and some 3D printing a cable plug can be improvised.


    Roland, DM5RM