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Duty Cycle

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  • cqer01
    My 2m RF brick (150W) has a stated duty cycle of
    Message 1 of 7 , Jun 17, 2003
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      My 2m RF brick (150W) has a stated duty cycle of < 50%...not good.
      There is a small fan that cuts in when the amp gets warm. If it gets
      too hot (never so far in regular operation) the amp will shut down
      until it cools. My question is...how much of an improvement in duty
      cycle might I reasonably expect if I blow the large top plate heatsink
      with a big squirrel cage blower?

      Also...does anyone use a converted AM-6154/55 for WSJT. I have no idea
      what its duty cycle might be.

      Steve / VE7SL
    • Andrew T. Flowers, K0SM
      I have a Mirage 2516 (25 in for 160 out) that I run at 100% with a four inch fan blowing into the fins, and it stays *cold*. I ve been using it on WSJT, which
      Message 2 of 7 , Jun 17, 2003
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        I have a Mirage 2516 (25 in for 160 out) that I run at 100% with a four
        inch fan blowing into the fins, and it stays *cold*. I've been using it
        on WSJT, which is 30sec on/30sec off. Been doing that for 2 years now.
        I'm not saying that every amp will do this, but so far so good. I know
        some of the older bricks tend to trip the temp sensor really easily, so
        you can give it a try. If it's uncomfortable to the touch it's probably
        too much.

        Andy K0SM/2

        cqer01 wrote:

        >My 2m RF brick (150W) has a stated duty cycle of < 50%...not good.
        >There is a small fan that cuts in when the amp gets warm. If it gets
        >too hot (never so far in regular operation) the amp will shut down
        >until it cools. My question is...how much of an improvement in duty
        >cycle might I reasonably expect if I blow the large top plate heatsink
        >with a big squirrel cage blower?
        >
        >Also...does anyone use a converted AM-6154/55 for WSJT. I have no idea
        >what its duty cycle might be.
        >
        >Steve / VE7SL
        >
        >
        >
        >
        >
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        >
        >
        >
      • Steve McDonald
        Wow Andy...this is GOOD news! I may not be so bad off after all! Many thanks. Steve / VE7SL
        Message 3 of 7 , Jun 17, 2003
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          Wow Andy...this is GOOD news! I may not be so bad off after all! Many
          thanks.

          Steve / VE7SL
        • Steven Raas
          I personally wouldent use the am6154/5 for wsjt... reason being i find that durring contests n such.. that even long cw calls with the faa will tend to trip
          Message 4 of 7 , Jun 17, 2003
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            I personally wouldent use the am6154/5 for wsjt... reason being i find that durring contests n such.. that even long cw calls with the 'faa' will tend to trip the temp circut and shut down the HV for abt 45 seconds... even @ 300 w on 222... i have been trying to force more air into the ' faa' with a  blower.. it helps but not the cure all.. it still tripps from time to time  ( contest shack gets very hot ) so even the extra air i ram into it.. its still hot air... any ways... on the flip side of that coin.. i have used an 8877 on wsjt... legal limit.. no problem... still , i usually just run 1.0kW ( if i hit a burn 500w isnt going to make too much difference). But remember with any device that dissapates heat... usually the more cooling the better... i honestly dont believe in OVERCOOLING.. the cooler the better.. to a point , ( as long as u dont freeze components )
             
             
            73
            Steve Raas
            N2JDQ
             
             
            ----- Original Message -----
            Sent: Tuesday, June 17, 2003 2:24 PM
            Subject: Re: [wsjtgroup] Duty Cycle

            I have a Mirage 2516 (25 in for 160 out) that I run at 100% with a four
            inch fan blowing into the fins, and it stays *cold*.  I've been using it
            on WSJT, which is 30sec on/30sec off.  Been doing that for 2 years now.
            I'm not saying that every amp will do this, but so far so good.  I know
            some of the older bricks tend to trip the temp sensor really easily, so
            you can give it a try.  If it's uncomfortable to the touch it's probably
            too much.

            Andy K0SM/2

            cqer01 wrote:

            >My 2m RF brick (150W) has a stated duty cycle of < 50%...not good.
            >There is a small fan that cuts in when the amp gets warm. If it gets
            >too hot (never so far in regular operation) the amp will shut down
            >until it cools. My question is...how much of an improvement in duty
            >cycle might I reasonably expect if I blow the large top plate heatsink
            >with a big squirrel cage blower?
            >
            >Also...does anyone use a converted AM-6154/55 for WSJT. I have no idea
            >what its duty cycle might be.
            >
            >Steve / VE7SL
            >
            >
            >
            >
            >
            >To unsubscribe, send an email to:
            >wsjtgroup-unsubscribe@yahoogroups.com
            >Activity Periods http://www.qsl.net/wa5ufh/WSJTGROUP/WSJTGROUP.htm
            >
            >Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
            >
            >
            >




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          • Mike Lewis
            I installed a pair of 4 fans on a RF Concepts 170W brick (30 watt in) and it runs stone cold for almost a year of JT44 and FSK441 activity now. Even some EME
            Message 5 of 7 , Jun 18, 2003
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              I installed a pair of 4" fans on a RF Concepts 170W brick (30 watt in) and
              it runs stone cold for almost a year of JT44 and FSK441 activity now. Even
              some EME contacts on it to some bigger stations to inspire any readers
              interested in trying it out. Initially used a 12ft Cushcraft 10 element
              beam, though most are done now with a pair of 21ft (3WL) 10 element long
              boom yagis and an Az El rotor system.

              I recently converted a stock AM-6154 to 2M and am running over 300 watts for
              EME and except for one day when the shack was at 85 degrees, it has been
              running fine for me. It does help heat up the shack, so when temps in
              Seattle reach over 90 (as recently it has), and the amp adds more heat (lots
              of it), things can be rough. We do not have air conditioning up here :-).
              On the 90+ degree day it started to make clicking/buzzing noises like
              something in the cavity was loose and vibrating a bit. Now that things are
              cooler I have not heard that noise anymore, though I noticed my tuning is
              now different. Still investigating what is up with that. Not sure that is
              very inspiring or not :-).

              Mike, K7MDL


              > Date: Tue, 17 Jun 2003 14:24:29 -0400
              > From: "Andrew T. Flowers, K0SM" <flowersa@...>
              >Subject: Re: Duty Cycle
              >
              >I have a Mirage 2516 (25 in for 160 out) that I run at 100% with a four
              >inch fan blowing into the fins, and it stays *cold*. I've been using it
              >on WSJT, which is 30sec on/30sec off. Been doing that for 2 years now.
              > I'm not saying that every amp will do this, but so far so good. I know
              >some of the older bricks tend to trip the temp sensor really easily, so
              >you can give it a try. If it's uncomfortable to the touch it's probably
              >too much.
              >
              >Andy K0SM/2
              >
              >cqer01 wrote:
              >
              > >My 2m RF brick (150W) has a stated duty cycle of < 50%...not good.
              > >There is a small fan that cuts in when the amp gets warm. If it gets
              > >too hot (never so far in regular operation) the amp will shut down
              > >until it cools. My question is...how much of an improvement in duty
              > >cycle might I reasonably expect if I blow the large top plate heatsink
              > >with a big squirrel cage blower?
              > >
              > >Also...does anyone use a converted AM-6154/55 for WSJT. I have no idea
              > >what its duty cycle might be.
              > >
              > >Steve / VE7SL
              > >
              > >

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            • Steve McDonald
              Thanks for all the info Mike...sounds encouraging. We have the same brick amp. Not sure what I will do with the AM6155; it is unconverted so far. I take it
              Message 6 of 7 , Jun 18, 2003
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                Thanks for all the info Mike...sounds encouraging. We have the same brick
                amp. Not sure what I will do with the AM6155; it is unconverted so far. I
                take it that you do not use yours on WSJT then?

                Steve / VE7SL
              • Charles Plunk
                My 2m amp is an RF concepts 2-315 40in-170out. I run it with 50 watts drive for between 180-200 out (no element for my bird in that range yet) I have a 220v
                Message 7 of 7 , Jun 20, 2003
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                  My 2m amp is an RF concepts 2-315 40in-170out.

                  I run it with 50 watts drive for between 180-200 out (no element for my bird in that range yet)

                  I have a 220v  5" muffin fan running on 110volts on top of it at a 45 degree angle with a bracked I fashioned. The fan runs very quiet.

                  Have been running it this way for over a year on WSJT and other modes. I gets only a bit warm during a 30+ minute attempt.

                  My Astron RS-50m very warm during this time but can still hold a finger on the fins without much pain hihi.

                  I run 2  220v  5" muffin fans on my ft-847 at different angles. Also it has an internal fan. It stays rather cool.

                  Much rather burn a brick up than the rig.

                  Chuck
                  AF4O



                  At 01:10 PM 6/17/03, you wrote:
                  My 2m RF brick (150W) has a stated duty cycle of < 50%...not good.
                  There is a small fan that cuts in when the amp gets warm. If it gets
                  too hot (never so far in regular operation) the amp will shut down
                  until it cools. My question is...how much of an improvement in duty
                  cycle might I reasonably expect if I blow the large top plate heatsink
                  with a big squirrel cage blower?

                  Also...does anyone use a converted AM-6154/55 for WSJT. I have no idea
                  what its duty cycle might be.

                  Steve / VE7SL




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