I hate FANS

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

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  1. W7UUU

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

    If you had a kitchen fire while making flan, and lacked a fire extinguisher, you could certainly try to "flan the flames".... not sure how well it would work

    Just sayin'

    N2EY likes this.
  2. KV6O

    KV6O Ham Member QRZ Page

    Flan + fire = Crème brûlée? Almost...

    I ran with the fan plan, and was panned. Canned, even. New plan, on the lam.
    N2EY likes this.
  3. W0RIO

    W0RIO Ham Member QRZ Page

    There are some really quiet fans out there.

    I used to install Comair/Rotron Sprite SU2C1 fans
    into desktop SCSI disk boxes (20+ years ago) in order to greatly reduce the noise.
    They were expensive and had relatively low air flow, but they were really quiet.

    The trick with the Sprite fans was that the leading edges of the blades had little notches, and the
    notches were in different places for each blade.
    The notches formed a spiral pattern, apparently to reduce or spread the air vorticity.
    A FANtastic design, IMHO.

    I use a Sprite fan over the 6146 final in my Harvey Wells T-90 transmitter.

    Looks like the SU2B1 is the closest thing to the SU2C1, the C1 can be found used on eBay.
    The data can be found here:

    As for the comment on the Peltier heat pump devices, the only problem with that is that you need
    an even larger fan on the hot side of the heat pump to get rid of the transported heat + the heat of the
    Peltier device. Those are fun devices, but they're probably more suited to cooling small items such as CPU chips.
  4. K4KYV

    K4KYV Premium Subscriber Volunteer Moderator QRZ Page

    The fans in my modified Gates BC1-T that I use on 160m were way too loud. I modified the circuit to run them at half-voltage and that quietened them to a whisper, but they still circulate air. Both motors are rated at 115 volts, but they are wired in series across the 230 a.c. The motors are still wired in series, but from one side of the a.c. line to neutral, so that they see only 115 volts instead of 230. That way, each motor runs at 57.5 volts nominally. I don't use any fans in my homebrew rigs.
  5. N2DTS

    N2DTS Ham Member QRZ Page

    I cool a number of things with fans and found there are some that are much quieter then others.
    Sometimes its a gentle air flow to cool 4-125/400 tubes and sometimes it is for forced air cooled tubes like the 4X150's.

    I include some speed control, just a wirewound pot in series.
    It helps to rubber mount the fan and also shield it from you (in a cabinet).

    The Flex 3000 has a nasty fan in it, bolted directly to the bottom panel to amplify the noise, a dumb design.
    (there is a flex 3000 on ebay for $500.00 buy it now which is fantastic)
    The Flex 5000 has a silent fan, a big slow turning fan instead of two fast little fans in the 3000....
  6. KM1H

    KM1H Ham Member QRZ Page

    There is more hot air on this thread than on the AM frequencies, and only one fan there is heard at a time.

    Learn how to use the proper mike and dont sit right in the air flow.
  7. N2DTS

    N2DTS Ham Member QRZ Page

    In the spirit of going quiet, I put the 3x 4D32 rig in service.

    No fans or blowers.
    Does 300 watts carrier, three 4D32 tubes in pie net modulated by 811's all at 1200 volts.
    The T368 mod transformer seems to work great in this rig.
    And everything is silent!
    W1TRY likes this.
  8. KD0DQZ

    KD0DQZ Ham Member QRZ Page

    One could implement the Clyde Clifford solution. Those of us of a certain age may remember Clyde as the host of "Beaker Street" on the Mighty 1090, KAAY Little Rock. You see, Clyde wanted to do the show himself...but union rules required an engineer to "run the board" during the show. To circumvent that requirement...and not raise the ire of the engineers...Clyde elected to do the show from an auxiliary studio at KAAY's transmitter site, thus eliminating the need for an engineer. But...an air-cooled 50kW AM rig is far from whisper-quiet. Clyde's solution was to have some music in the background during his long, thoughtful pauses between tunes. The bleepy, bloopy sounds he chose was a track titled "Cannabis Sativa" (heh) by a group known simply as "Head". (On the Buddha label, of course:)) So, all you need is some appropriate effect in the background and let the fans whir away!

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