n7dd 8k ultra modifications

Discussion in 'Amateur Radio Equipment Reviews' started by KB1SEL, Dec 10, 2010.

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  1. KB1SEL

    KB1SEL Ham Member QRZ Page

    Well i received my parts back today from lary n7dd

    I opened the box and noticed the poor packaging.
    So i checked out the parts and my new microy piece i had made a month earlier was broken in the middle.

    The kit contained a new plate choke new flappers and adjusment of the cap values on the plate side by changing capacitors with different value caps.

    I checked out the plate choke with my uh meter and read 90 uh almost the same of what i have now with the same size wire. A few windings had areas where the enamel had come off from being hit.So i decided this choke is not needed.

    I looked at the flappers and noticed the contact area is wider from side to side but the area front to back isnt.So basicly they do not cover the entire surface of the oposite contact in which they mate with.

    The flappers are not as long.To compensate i would have to move the 2 rows of capacitors closer to each other.

    I wont be using the flappers.

    I cannot recomend this mod to anyone.

    This mod cost me 775.00.Im out 210 plus my time for a new insulator and machine work.

    I got no refund for my damaged parts only an offer for another insulator from an older henry 8k.And false promises of insurance from usps.Even though the box has not a single blemish.
    Last edited: Dec 10, 2010
  2. AI3V

    AI3V Ham Member QRZ Page

    What was wrong with the amplifier to begin with?

    5000 watts wasn't enough?

  3. KB1SEL

    KB1SEL Ham Member QRZ Page

    I only used it at the legal limit or less.I was told by larry that the original design had flaws.And that his kit would take care of it.Expecially the arc problem they all have between the flappers and the doorknob caps on the plate side.

    Obviously he he was just trying to make a quick buck.
  4. KB1SEL

    KB1SEL Ham Member QRZ Page

    I forgot to add he had me send 2 100pf doorknob capacitors to him for the cap change.

    He never used it.Stock values 50 100 200 100 50 25.
    He changed them to 25 100 200 100 100 50

    These are the large door knob caps next to the roller

    he never used the other 100 nor did he return it nor did he return the 50.
  5. KB1SEL

    KB1SEL Ham Member QRZ Page

    I paid 50 bucks a pop for each of these caps

    The amp works flawlesly.I had both inductors rebuilt and re silver plated.This includes new contacts and new bushings for both wheels.

    I also changed the output vacuum relay with a new jennings since it was easier to get to with the small roller out.

    Over time rollers where out.So i figured i would take care of it all at once.

    I was told about n7dd and his mods so i figured i would give it a shot but i guess i made a huge mistake.I am only writing all of this to warn others so they do not do the same.
  6. KV0J

    KV0J Ham Member QRZ Page

    Just curious.... what are flappers? Do you mean air variable capacitor plates?
  7. KB1SEL

    KB1SEL Ham Member QRZ Page

    The pieces that are connected to the solonoids.They ground the doorknobs on the plate and load side to add in more capacitence when you change bands.
  8. KB1SEL

    KB1SEL Ham Member QRZ Page

    It doesnt matter anymore that 8k has since been sold.Now im selling off my other one.
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