Power Supply Trouble

Discussion in 'General Technical Questions and Answers' started by KC3NYG, Jun 30, 2020.

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  1. KC3NYG

    KC3NYG Ham Member QRZ Page

    Hi all, newish ham here with a power supply issue. I just picked up 2 TYT 9800 50W quad band radios intending to use one as a base station and the other in a vehicle. For the base station I got a Pyramid PSV90 power supply. When I ran this setup on high power on the 2m and 70cm bands it seemed to work fine. On the 6m band when on high power, the power supply would "buzz" while transmitting and the radio would power off/reboot. When reducing the power to 20W, I get the same buzz from the power supply and the radio looks like it wants to shut off but just barely stays powered. 10 and 5W give no issues.

    I wanted to narrow things down to the power supply so I hooked up my second radio to it. On 6m it worked perfectly on all power settings. Here is where it gets weird. On 2m, it does the same thing the other radio did on 6m.

    I eliminated the power supply all together and ran it off a car battery. All bands worked fine at all power levels.

    I figured since it is only a 9A supply, it wasn't putting out enough power so I picked up a Pyramid PSV300 (30A) supply figuring that should fix the problems. I hooked it up to the first radio and on 6m it still buzzes and shuts down.

    I find it unlikely that I got two bad radios or that 30Amps isn't enough power to run these at 50W. I was testing the equipment after I bought it and had the antenna close by, could this be a RF issue with the power supply? It would seem strange that one radio would cause interference at only on the 50MHz band while the other would cause interference on the 144MHz band. Any ideas? Not sure where to go from here.
  2. WB8NQW

    WB8NQW Ham Member QRZ Page

    Could very well be RF getting into the power supply. Remote the antenna and try again.
  3. VE3CGA

    VE3CGA XML Subscriber QRZ Page

    how close is your antenna to the supply?
    sounds like it is getting RF into the supply due to close proximity

    have you tried the radios with the antenna further away say 25' or more
    or try lower power like 10W and see if it still messes up the power supply

    Doesnt sound like you are intending in running the final setup with the antenna that close, so see if it still does it with the antenna mounted where its supposed to go

    you might still have to install some bypass cap(s) on the output terminals of the supply
  4. K8JD

    K8JD Ham Member QRZ Page

    What's your antenna situation ? RF from the coax with a mistuned or poorly installed antenna will get into some power supplies and make themdo odd things.
    Inside antennas sitting near the radio sometimes is a RF disaster too !
    VE3CGA likes this.
  5. KP4SX

    KP4SX Premium Subscriber QRZ Page

    I agree with RF getting into the PS.
  6. W9WQA

    W9WQA Ham Member QRZ Page

    i dont know that supply but a ham friend is critical of them for ? reasons. also is that the 8900 clone?, brand x rig.
    could be a combo of problems...
  7. N3VEZ

    N3VEZ XML Subscriber QRZ Page

    Make sure that the ps is putting out the right voltage. I had a brand new Astron doing something like that. Needed new board
  8. N4MU

    N4MU Ham Member QRZ Page

    Doesn't anyone own a dummy load anymore? It can solve sooo many "problems"!
    WB5YUZ and WG8Z like this.
  9. KC3NYG

    KC3NYG Ham Member QRZ Page

    Thanks for all the suggestions.

    So it looks like it may be an antenna issue. I swapped out the antenna for the magnetic mount one I plan to put on my vehicle. Its only a 2m/70cm antenna but I ran it on 6m and there were no problems. I figure even though its not tuned for 6m, it should be able to help rule out possibilities like problems with the supply or radio itself. I guess that wouldn't rule out RFI though since if I put another tuned 6m antenna on, it may again cause issues.

    I don't have any coax yet to put the antenna up where it will be going, so for now the antenna is as far as I can get from the supply - about 15'. This was being tested in a basement which I can imagine can also cause issues with RFI. Maybe I should try testing again only sticking the antenna out the basement window. It may just be that I need a better quality antenna though. Mine is a TYT quad band antenna. What is the consensus on quad band antennas? My next step might be to invest in two seperate quality 2m/70cm and 10m/6m antennas.

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