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Amp cooling questions

Discussion in 'Amateur Radio Amplifiers' started by N4EYZ, Jan 18, 2016.

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  1. KM1H

    KM1H Ham Member QRZ Page

    Now you went and did it! Reality is not permitted here.
    All those who believe otherwise will now waste pages on counter theories, whining about what others post, cant read the tube manufacturers spec sheets before passing gas, ad nauseam.
    K8PG and KK4YDR like this.
  2. N4EYZ

    N4EYZ Ham Member QRZ Page

    I appreciate your reply and all the good information. You are dead on concerning the safety issues with my amp and I am aware of the hazards and plan to make up a sheet metal covering for both sides of the amp. I think it was initially rack mounted which would have addressed those issues. I have a rack but it's not a total enclosure so some side covers are needed and planned. Thanks again!

  3. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    If you have a compatible rack cabinet, just install the amp in that. You won't be able to touch anything once it's installed.

    You could add a microswitch to kill to HV if the amp is ever slid out of the rack cabinet. Those are available commercially for about twenty bucks, although it wouldn't be difficult to homebrew the same thing.
    KM1H and N4EYZ like this.
  4. KM1H

    KM1H Ham Member QRZ Page

    Desktop rack cabinets can be as low as $5-10 at some hamfests as very few use them any more, look for the ones with side and rear louvers.
    N4EYZ likes this.
  5. N4EYZ

    N4EYZ Ham Member QRZ Page

    A very good idea and one I hadn't thought of. We have a local hamfest this Saturday (Richmond, Va Frostfest). I'll add this to my shopping list. Thanks!
  6. WA4SIX

    WA4SIX Ham Member QRZ Page

    GE MASTR repeater racks are out there by the hundreds. About 3' high & perfect for your amp.

  7. KK4YDR

    KK4YDR Ham Member QRZ Page

    Dip in plate currents... I always see a dip in plate current but I tune for power regardless of plate current as long as I am putting enough load to lower my plate current and maintain acceptable power out. I consistently get 500 watts out PEP on my 811 amplifier. When I tune just plate dip I find that my power is lower, much lower in most cases.

    Since I use a tuning pulser I don't really see dips anyways. I find acceptable power and then make sure my grid isn't peaking past safe limits with a quick carrier check.
  8. KJ4YEV

    KJ4YEV Premium Subscriber QRZ Page

    Or use a rheostat, dial it in for the speed you want, then measure it and replace it with a fixed resistor close to what you want.
    N4EYZ likes this.
  9. KH2G

    KH2G Ham Member QRZ Page Handbook/ARRL 2014 Handbook Content/17.pdf This is a web page with a great write up on tubes and really gets into cooling. FWIW Dick KH2G
  10. AC8AC

    AC8AC Ham Member QRZ Page

    nice little amp . what do the home brew guys do for coating the tank coils ? I just always left mine bare copper

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