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Crapouts are fun....

Discussion in 'Amplitude Modulation - AM Fans' started by KB3OUK, Sep 9, 2018.

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  1. KB3OUK

    KB3OUK Ham Member QRZ Page

    First pic is the offending part, can't probably see the scorch marks very well, or smell it either. Second picture is the transmitter, whoever built it did a fairly good job, except for the front panel. Notice that it is clamped to the top of the rack rather than being installed in the rack, well that's because the builder used masonite for the panel but it is slightly under 19 inches and the holes are drilled too far inward to fit on the rack but are too far outward on the panel to drill out to fit without destroying the panel. Eventually i want to replace it with a metal panel and paint it to match the rest of my gear in that rack. Third pic is the rest of the rack, the 811 modulator is bottom, then the power supply for the 807 transmitter and the Millen exciter, and the Millen 90800 exciter is the piece above the power supply.
     

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  2. W2VW

    W2VW Ham Member QRZ Page

    Thanks. You still have an indoor antenna?
     
  3. KB3OUK

    KB3OUK Ham Member QRZ Page

    Never had an indoor antenna, don't have a very high one at the moment but I'm working on it. Its a 240 foot loop, averaging about 10-12 feet above ground, the one corner dips to 3 feet because i just simply looped the wire around the yard and poked the ends in the window to hook to the matchbox. Wanted to try getting my poles up this summer (i have 4 30' poles here that are perfect for an antenna) but we haven't had enough dry days with all the rain to make digging a 5 foot hole to put these in the ground easy.
     
    W2VW likes this.
  4. N2DTS

    N2DTS Ham Member QRZ Page

    Neat looking rig.
     
  5. KB3OUK

    KB3OUK Ham Member QRZ Page

    My 1943 ARRL handbook has the article in it that this rig was built from, the picture in the article looks very much like mine. It originally appeared in the November 1940 QST. The Millen 90800 is based on the same design, if you look at the two rigs you can see the differences between the two, but then the builder of mine also made some of their own changes to the design. For example, the original design used a single B+ supply and ran a voltage divider off of that to get the 807 screen and 6L6 plate voltage. This rig has a separate low B+ that supplies the 6L6, and the high B+ supplies the 807 plate voltage and then derives 807 screen voltage from a divider. They also brought the 6L6 and 807 cathode connections out on separate connections instead of tying them together on a single connection like in the schematic for keying. This threw me off when i fired it up since the label they used is hard to read, i thought they meant that you hooked the key across the two terminals, no after closer looking i figured out that one was the 6L6 cathode, the other was the 807 cathode, and both needed to be tied to ground for the rig to transmit once it was powered up. If i were to use it for cw it does make it easy to experiment with different keying arrangements.
     
  6. N2DTS

    N2DTS Ham Member QRZ Page

    Bee cool to put a home brew receiver in that rack and have a complete station.
     
  7. K5UJ

    K5UJ Ham Member QRZ Page

    Has nothing to do with the crap out, but....I'd forget about a loop at 30 feet and focus on smaller but higher dipole. I made the same mistake around 15 years ago. Somewhere in his papers, LB Cebik basically wrote that smaller higher beats bigger lower every time. If you can get a dipole at 50' you'll be way better off.
     

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