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zapped from the knobs

Discussion in '"Boat Anchor" & Classic Equipment' started by VA7WPN, Jan 19, 2013.

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  1. VA7WPN

    VA7WPN Guest

    while tuning up my SB-100 I got a zap from the knob. This would be from a bad ground, Am I right??
  2. WA7PRC

    WA7PRC Ham Member QRZ Page

    Likely. Your PS has bypass capacitors from each side of the AC line to chassis. The PS should use a three conductor AC cord & plug. The rig should also have the chassis connected to earth ground. If you don't have any of that, expect the chassis to be above ground by half the line voltage.
  3. KM1H

    KM1H Ham Member QRZ Page

    The current shouldnt be dangerous if the AC line caps are around .015uF or less and in good condition which they should be as they are disc ceramic. A little tingle was just the way it was back then.

    The problems were when paper caps were used and they became leaky. Ive also seen stock equipment using .1 and .15uF, thats more than a tickle!

  4. W4PG

    W4PG Super Moderator Lifetime Member 279 Volunteer Moderator Platinum Subscriber Life Member QRZ Page

    Could be RF in the shack as well. What type of antenna are you using??
  5. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    Like Bob (W4PG) asked: Did this occur when transmitting, or just on standby?

    On standby, you have a leaky AC bypass cap in the power supply and an insufficient earth ground on the rig.

    If it occurs only when transmitting, that's not an electrical shock, it's an RF burn, and due to entirely different circumstances.
  6. WA7PRC

    WA7PRC Ham Member QRZ Page

    Whatever the source, RF or 60Hz, the chassis is not on ground.
  7. VA7WPN

    VA7WPN Guest

    It happened while I was tuning the transmit side for the band I was on. The antenna is a random long wire that is looped up along the ceiling of my room. The radio its self was not grounded, but the power supply is.
  8. KA9JLM

    KA9JLM Ham Member QRZ Page

    Sounds like rf burn.

    And your antenna is radiating.

    Sounds normal under the circumstances.
  9. KE3WD

    KE3WD Ham Member QRZ Page

    Unless you live in a cathedral, a wire looped up along the ceiling of your room is NOT a longwire.

    Not at HF frequencies, anyway.

    And you got zapped because there is likely RF field all over the place in there if you attempt to transmit.

  10. W9GB

    W9GB Ham Member QRZ Page

    That is a bit arrogant, RF requires RESPECT (High Voltage present, that is why insulators are used).

    Radio Frequency (RF) follows physical principles. You can not string up any HF antenna that you want ...
    or as you have found out, IT BITES.

    So let's start with some respect. Can you install an OUTDOOR antenna for HF (80-10 meters) at your QTH ??
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