Illegal high power HF amplifiers

Discussion in 'Amateur Radio Amplifiers' started by N8FVJ, May 20, 2019.

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  1. KA9JLM

    KA9JLM Ham Member QRZ Page

    A wire dipole will handle a lot of power before fire flies off of its ends.

    Some of the big tubes are not worth the cost of the filament power.

    I have ran over the legal limit using a dummy load. :D Made a contact once too.
    N2AMM, WQ4G and KN4CTD like this.
  2. ND6M

    ND6M Ham Member QRZ Page

    I have it from a pretty "reliable" source that a certain (SK) amateur in Mi used an AL 811 as the driver for his final amp.
    KK5JY likes this.
  3. WA7PRC

    WA7PRC Ham Member QRZ Page

    Hams often believe that 1500W is high power. When I worked in broadcast engineering, I thought the 16KW (2x 8KW) FM transmitter I maintained/repaired was high power... until I toured US Naval Radio Station, Oso, WA (aka "Jim Creek"). At that time, they were running well below maximum (1296A into 0.456Ω or 766 KW). The first stage was an old modulator from VOA, running 15 KW. Relatively speaking, 1500W is peanut power. :p
    KF5CCN, N2OTG, WW2PT and 4 others like this.
  4. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    Most of us operating "from home" couldn't run a lot more than 1500W output without a new feed from the 3-phase, 400A power.

    IMO, most of the "very big signals" on the air aren't due to power, they're due to great antenna systems.

    I remember operating from K2GL's place in NY one time 40+ years ago when I was a pretty young ham, and I was placed on 160 meter SSB where QSO rates were low and not much damage could be done.

    Before sunset, I was working several stations in Europe on 160, and almost everyone said "first North American signal!" At that time, the rig was a a full-wave delta loop with the apex at 270' above ground, atop a hill with a view of the Atlantic Ocean.

    I think the antenna + location did all the work; "power" wasn't much of a contributor. I don't remember if there was even an amp on that station.
    K4AGO, WA7PRC and K5ABB like this.
  5. N8FVJ

    N8FVJ Ham Member QRZ Page

    The high power killed the ham?
  6. N4UP

    N4UP Premium Subscriber QRZ Page

    I also believe there are relatively few who exceed the power limits.

    I routinely use an amp that is capable of more than 1500 watts ( Alpha 9500 ) but almost always operate at 1100-1400 watts and never exceed 1500 watts ( except once by accident ).

    Steve is right. Antennas can make a huge difference. I used to run near-legal limit on 160 meters and had trouble working Europe, even though I could hear them on my 900 foot beverge. Then I installed a really good 160 meter antenna ( DX Engineering Thunderbolt ) and now it is easy working Europe on 160 meters at half power. I would much rather have great antennas than big amps.

    On 30 meters I run 200 watts on CW to a 10-element LPDA at 73 feet. I do rather well on 30 meters.
  7. WA7PRC

    WA7PRC Ham Member QRZ Page

    During my tour of VLF station US Naval Radio Station, Oso, WA, the guide stated they had only one dead spot... on the opposite side of Earth. There's another station in Cutler, ME that fills-in the dead spot. :cool:

    "Jim Creek" not only runs yuuge power, the antenna system is a dozen 750MCM wirerope spans between two small mountains. :cool:
  8. AI3V

    AI3V Ham Member QRZ Page

    An ordinary oven circuit provides 240 volts and a 50 amp breaker.

    Thats 12,000 watts.

    Considering transformer losses and filament power, 10,000 watts dc imput is very possible.

    So somewhere well north of 5,000 watts rf out.

    Now you could also use the electric furnace circuit.

    100 amps at 240 volts

    A cool 24,000 watts.

    Easy peasy to put 10,000 watts into the antenna system.

    The guys you see at hamfests, with a "pole pig" on a handtruck aint buying them to run a pair of 572b

    N8ZL, KW6LA, N0NC and 3 others like this.
  9. N1OOQ

    N1OOQ Ham Member QRZ Page

    Wouldn't want to pay shipping on that power supply...:eek:
  10. AG5CK

    AG5CK Premium Subscriber QRZ Page

    People do break the law but don't assume someone with a big signal is a criminal just because they don't hear you just as well.

    My antenna is a compromise and I've still gotten some nasty comments from people that didn't like the honest signal report I gave them.
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