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Al-1500 blower question

Discussion in 'Amateur Radio Amplifiers' started by KN4CTD, Jan 20, 2019.

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  1. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    That sounds way too low.

    You sure it's not reading degrees C? Even that would sound low. Should be up in the 200C range.
     
  2. KN4CTD

    KN4CTD Ham Member QRZ Page

    I’m gonna check again.
     
  3. KD2ACO

    KD2ACO Platinum Subscriber Platinum Subscriber Life Member QRZ Page

    That's what I was thinking.
     
  4. KD2ACO

    KD2ACO Platinum Subscriber Platinum Subscriber Life Member QRZ Page

    Make a cup of tea and check that thermometer out. :p
     
  5. WA7PRC

    WA7PRC Ham Member QRZ Page

    I found it easy to fabricate.
    Again, the W4ZT "socket" (actually, mounting platform) affords less airflow restriction than just opening the chassis under the tube's anode cooler. It does that while maintaining low grid-ground reactance and reducing height above chassis.
     
    KN4CTD likes this.
  6. WA7PRC

    WA7PRC Ham Member QRZ Page

    I use an IR "gun" thermometer from Harbor Fright. It produces believable numbers... a pot of boiling water shows as 212F/100C. My body temperature measures a bit high (the gun is either not quite accurate, or maybe I'm a hot guy). :p
     
  7. WA7PRC

    WA7PRC Ham Member QRZ Page

    140F = 60C, and well under the tube's specified limit. My Harbor Freight IR temperature gun can show Fahrenheit or Celsius directly.
     
  8. KN4CTD

    KN4CTD Ham Member QRZ Page

    This gun is from rural king, a local redneck store lol. I’d put it’s quality right up there with HF. I’ll check some boiling water and retest in the morning......I was using the laser feature which does seem to indicate lower temps than not using it. This gun does read in Fahrenheit and Celsius also. My readings were in Fahrenheit . That’s the problem with scientific tests, they AINT too scientific if you can’t trust your measuring equipment. A new tube is cheaper than a high dollar thermometer. I hate to be like that, but it is what it is...
     
  9. KN4CTD

    KN4CTD Ham Member QRZ Page

    I redid the test tuned for maximum output 1500 watts keydown on 20 meters because I know the band is dead here at night. I don’t have a dummy load that big. The highest temp I can read anywhere with this gun is 150 degrees Fahrenheit constant keydown on RTTY. I didn’t check the gun against a cup of boiling water but it shows “close enough” on my arm within 2-3 degrees. Thoughts?
     
  10. KD2ACO

    KD2ACO Platinum Subscriber Platinum Subscriber Life Member QRZ Page

    I’m not sure what the thermometer is seeing. Turbulent air could be a bit lower than the fin temp and anode temp. In other words, you could be a couple steps removed from the actual anode temp, which couldn’t be 60c at full power.
     

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