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Too Much power locks up PC

seanas3 Member, Unconfirmed
I am new to Flex radio, but upon using Flex for the first time. I noticed in 40 meter band going through my matched dipole antenna. When I am outputting about 10 to 20 watts everything is OK, but the moment I increase the power to 50 to 60 watts, I get a nasty hum coming out of my speakers, and then it locks up my USB ports and is stuck transmitting, till I hit the power button on the Radio, has anybody else experiences this.


  • Rich M5RIC
    Rich M5RIC Member ✭✭✭

    Sounds like RF getting in to the shack, Try some type 31 ferrites round the speaker and usb cables, should help.

  • Ha Gei
    Ha Gei Member ✭✭✭
    edited December 2022

    I also guess :

    Antenna too close

    Faulty connection

    Unfortunate cable lentghts (( resonances )

    we had something similar a while ago with high power and a bad ethernet cable

  • Al_NN4ZZ
    Al_NN4ZZ Member ✭✭✭

    Here are some notes on my web page when I had the RF lockup issue a few years ago.


    Regards, Al / NN4ZZ

    al (at) nn4zz (dot) com

    6600 Win10 Pro V2004 -- SSDR V3.3.33

  • KD0RC
    KD0RC Member, Super Elmer Moderator

    Hi Sean, I just had a similar problem last night on 40 CW. I did exactly as Rich suggests and put a mix 31 split ferrite bead on the USB cable from my USB hub.

    I already had one on there, but when operating my 500 W amp, I discovered that I needed an additional one.

    To find the path that the RF was taking to get into my computer, I used a clamp-on MFJ RF ammeter. It is an easy, but tedious process of clamping on to each cable connected to the computer.

    I get my mix 31 ferrite beads from Palomar Engineers. I have a bunch of old Radio Shack beads that I have replaced. They did work to an extent, but it took a bunch of them to really get rid of common-mode RF. I suspect that they are all mix 43 which is not very effective below 25 MHz.

    I also have some cheap hamfest ferrites, but they are completely ineffective at HF. I suspect that they are for VHF or UHF. In my experience, any ferrites that you find for sale that do not specify the mix are not likely to be mix 31.

  • Craig_KØCF
    Craig_KØCF Member ✭✭✭

    Snap-on mix 31 beads are great, but get BIG ones. Then you can wrap 3 or 4 turns of the cable through the bead, which greatly multiplies its effectiveness.

    73, Craig KØCF

  • WX7Y
    WX7Y Member ✭✭✭
    edited December 2022

    You Really should if possible put up to 8 MIX31 Ferrite beads for 80 through 10 Meters on your Coax before it ever enters your station **** IT AT THE SOURCE to keep the RF outside were it belongs as Craig said several wraps through the toroid the more attinuation of the RFI back into the shack so everything will be happier.

    Palomar Engenering is a excelant place to learn and purchsae toroids and kits https://palomar-engineers.com/

  • Craig_KØCF
    Craig_KØCF Member ✭✭✭

    For feed line isolation, I use manufactured "Line Isolators" from either Balun Designs or DX Engineering. I find them to be very effective. I have one at the shack side of my 4O3A remote antenna switch and another in the shack. I have zero problems with RF in the shack, and I run the legal limit with an Elecraft KPA1500.

    73, Craig KØCF

  • Erika - KØDD
    Erika - KØDD Member ✭✭✭
    edited December 2022

    All the guys who have answered the question ahead of me are notable flex operators, contesters, DXers, and active Flex contributors. The first thing I noticed with your ISSUE seanas3 is your station is locking up at 50-60 watts!!!!! That is VERY VERY low power... You do have an extreme issue with RF in the shack. I would recommend disconnecting everything in your shack and backing up to the beginning...

    I have had multiple levels of shaking out this station as... While my station is NOT a complex multi-radio multi-operator position station, LIKE SOME GUYS HAVE.... Mine is a very complex 4 monitor one computer, one radio one amplifier at a time, one tower station with multiple wire antenna station.

    The first thing you need is a good ground rod system... I recommend 8' copper clad 5/8" ground rod dedicated to your internal station.... minimum... Where my station is I'm able to go right through the floor and out an existing hole in the foundation,... a foot out the foundation is where my ground rod is located. If you have poor ground conductivity multiple rods will be required. I'd suspecting either the lack of this ground, or possibly a resonant 40m length to your ground rod.... House electrical grounding is never acceptable. DON'T CROSS THE STREAMS... I am a ghostbusters fan.

    I recommend heavy guage 4 ga copper to the rod. Mine is a pair of solid 8ga (because I have a big spool of it left over from the last station) goes right to a heavy solid copper ground buss bolted right on the operating desk. Everything making RF is grounded right to this solid copper buss. Do not rely on coax cables and their respective connectors to provide any RF or Power grounds.

    My station had issues with the monitors blinking off while power was being generated... I cured all of that by buying a kit DXE sells for making one of their over coax beam 40 bead baluns. I ended up not using that setup on an antenna but used the Beads around the shack. With my new computer I had to go back to snap on 31 big beads on the video. But the previous computer the MiniDisplay port connectors went right through the DXE beads. Though the DXE beads work on all my AC power. My desk is powered and has it's own dual 8 outlet dual duplex metal boxes bolted to the desk and fed by one source. The monitor power AC cables each use a single DXE bead secured with a loop through the DXE bead at the monitor end and cable shorten to Just nicely get to the power outlets and a new grounded plug installed. NO Cheesy plastic power strips in this house!!!!! I was aghast at Dave from QRZ's shack pictures I just saw them last week...

    The computer cleaned right up.

    But I have had loose coax connectors... I use balanced lines 600 ohm and 450 window line and I had burned through two window lines on my antennas causing the same locked transmitter issue. I had the same locked transmitter thing last week that was a quickly hand tightened antenna connector on the back of the radio. I have a nice cute Craftsman ROBO GRIP PLIERS I keep on the desk for putting a light tighten to all my coax connectors... I forgot to pick up the robo grip pliers in the heat of battle and had to shut everything down and restart the whole works. AS it did the locked transmitter thing...

    I still no matter what I try to be able to fix the EA4TX remote box coax switch used in the auto mode with a USB to the computer. I'm stuck selecting with the USB not going to the computer. Though DXE beads between the DXE 8 port switch at the tower base and a short run of shielded cable with Beads at each end to the switch... Might try next a Band Data cable between radio and EA4TX....

    Basic rules at K0DD: Keep cables of the same type together. A/C runs with A/C. DC runs with DC, RF runs with RF, grounds with grounds and use good operating practices with each separate type of cabling. Work yourself backwards from your station grounding thru all your gear to your keyer paddle and microphone... Good luck we never had these sorts of issues before computers in the shack... HAHAHA Erika DD

  • Larry _ NY8T
    Larry _ NY8T Member ✭✭✭

    mix 31 material snap-on




    1/4 id ferrites 0431167281

    1/2 id ferrites 0431164181

    3/4 id ferrites 0431173551

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