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I hate FANS

Discussion in 'Amplitude Modulation' started by W2NBC, Nov 16, 2019.

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  1. WA6MHZ

    WA6MHZ Premium Subscriber QRZ Page

    I have a Heathkit SB-230 that uses a big heatsink on the back to cool the induction tube. I used it during an operating event and it got very hot So I installed 3 muffin fans on the back and now the Heatsink runs cool. However the fans are very noisy. That was supposed to be the big selling point of the SB-230. Other ops complained about the noise. I didn't have problem with it as I used HEADPHONES during my operating. 3 muffin fans can be pretty noisy, but I prefer to keep my tube safe (UNOBTAINIUM) than worry about a little noise!
  2. N2DTS

    N2DTS Ham Member QRZ Page

    Maybe run two fans in series to move air quietly?
  3. N2EY

    N2EY Premium Subscriber QRZ Page

    It's important to read the tube data sheets in order to understand what's really being cooled by forced air.

    In the case of internal-anode glass tubes, particularly Eimac products, the real issue is often keeping the tube seals below a certain temperature, NOT cooling the anode! In many cases the cooling air must be provided whenever the filament/heater is powered.

    Read the data sheets and see.

    Conduction-cooled external-anode tubes (8873 family) were an excellent idea but never achieved enough of an amateur radio market share, and now they're rare and expensive. Same for vapor-phase-cooled tubes.

    It should be remembered that many if not most of the amateur radio amplifiers of the 1960s-70s were designed for low-duty-cycle modes such as CW and unprocessed SSB, under the old 1000-watts-DC-input rules.
    N2SR likes this.
  4. W2VW

    W2VW Ham Member QRZ Page

    Ever see a Larcan solid state transmitter operate? Pair of 5HP blowers atop the cabinets. Not quiet.

    Great to see people making use of surplus.
  5. AA7QQ

    AA7QQ Ham Member QRZ Page

    I use my 1.5KW continuous duty amp at 1.2KW PEP on SSB and about 800W PEP on AM. I made an angled plenum to use the 2 fans to feed the side of the heatsinks, with the bottom plate still in place.
    I am first & foremost a 6M junkie. Second, I am a "Repurposer" of anything & everything. Whether it be ham/automotive/home.
    My other amps came as pallets from Australia (VHF TV transmitter that works fine on 2 meters), a 2- MRF-157 (Equivelant) pallet that came from Isreal that looks almost exactly like the Ap Notes (1200W rated & run at 1KW). UHF was a 600 watt TV broadcast pallet that was simply adjusted for 70cm.
    The soda cold plate came from a restaurant that I frequent I spotted it in the back room one day.
    I use the W6PQL sequencer boards & his LPF bank for HF. the Larcan uses an ICE 2KW LPF (Very similar to the ARRL article that uses a die-cast box with brass plate/Teflon sheet & coils) for $35 at a swap. VHF & UHF filters are kit ones from Ebay.

    W2VW likes this.
  6. KF5LJW

    KF5LJW Ham Member QRZ Page

    Fans are a necessary evil for most of us using electrical and electronic gear. It is a workaround to a heat problem. It is also a very weak egg in the basket. Fans are used because it is the most inexpensive method to remove excess heat. It also takes up the least space and weight. It is a Band-Aid in the design in most cases particularity consumer grade electronics. Not so much in commercial and industrial grade equipment.

    Great examples are utilities and communications companies use a lot of Routers and Radios. You will often find the manufacture will make the same gizmo in two different versions of Standard and Hardened. Standard Cisco router uses fans, and Hardened does not. From the outside do the exact same thing. The Hardened unit is much heavier, and a little larger with heat fins on the back. The integrated circuits and components are mil spec with wider operating temperatures.

    No one cause of Blue Sky failures with radios (commercial) routers, switches, hubs, servers, ect is Fan Failure causing the unit to overheat. Or Air Conditioner fails and everything over heats when the server room or radio shelter hits 140 degrees.
  7. K5UJ

    K5UJ Ham Member QRZ Page

    Yes, cooling is only one of a few vulnerable areas. Small plate iron is one problem, another is dinky loading caps in the output network, that drift under continuous current and dinky coil stock.
  8. KV6O

    KV6O Ham Member QRZ Page

    Which is why I collect telemetry like this:


    I love data!
  9. W7UUU

    W7UUU Super Moderator Lifetime Member 133 Administrator Volunteer Moderator Platinum Subscriber Life Member QRZ Page

    Better than fanning hates :)

  10. KV6O

    KV6O Ham Member QRZ Page

    I am not a fan of flan, but fans are cool!

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