Illegal high power HF amplifiers

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

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  1. VE7RF

    VE7RF Ham Member QRZ Page

    LOL. I don't ever remember being on qrz..... must be losing it. BTW, I was looking through some old threads.... and saw JI posted about stuffing his 255 vac from the street into the 220 vac input of his AL-1500. Didn't know the AL-1500 even had a 220 tap. Said he's been doing it for 20 yrs. I call BS on this. Then I noticed on his home page a link to his commercial page. On his commercial site, he now makes retrofit HV lytic boards.... that hold 10 x 450 vac caps...so it's good up to 4.5 kv.
    https://www.ctrengineeringinc.com/parts-for-sale/ameritron-upgrade-boards/ Looks like a nice retrofit. That + peak reading grid meters.

    He still custom fabricates ... "sw broadcast AM" linear amps with 3x15's..+ mating B+ supplies etc. I'm sure the 41M sw bandswitch position would come in handy. There is also a 75M sw AM band....from 3900-4000 khz..... and another at just above 15 mhz

    On another note, bozo with the 3 x 4CX-15,000J's on ch-6 has good luck with 2 tubes.... but fireworks with 3rd tube plugged in..... he's got way too much stray C from the tubes..and PI net won't handle. Dunno what size line section he has, but it has a new 250 kw slug plugged in. 7.5 vac @ 160A for EACH fil. He claims 100 kw PO.
    500 mcm cu wire from 500A main panel...to HV supply.

    Bozo #2 wasn't happy with his single 3x15 ( 7600 vdc loaded at 5A )..so he decides to stuff a 2nd tube in there. 2nd socket blew up..along with sundry other stuff...like 1 tube. ( He has 400A service to his business..tower on roof)

    Then they tried wiring 2 x identical new 120 vac kooltronics blower in series...and running the pair on 240 vac. Well that didn't work out too good...one blew up.
    When T=0..... the v drops are way off, like 190-50. (Kooltronics read em the riot act). Next up was exploding plate block caps. Then they blow the vac cap in the gamma match on the yagi...wtf? Why use a gamma match these days.

    Then our mutual friend in W6 land manages to talk...'swing' 10 kw on an average reading bird 43..with a 10 kw slug...with a hb 3CX-3000A7. 6 kw cxr..talks it up 10 kw. (peaks should be 24+.... but of course get clipped off). Yeah, lets use a resistor in the CT for bias, great idea. It gets better.... 'let's put a huge lytic across the resistor..to keep the elevated (class C ) bias up higher on peaks'. ( they have turned the entire amp into a RF processor). Ok, that was last weeks news. Now they have cooked up a whole new modulation scheme...with unprecedented..'talk power'. This is a xcvr mod. This is a lot of BS to go through.... just to talk 3 states over....on a dead band. I'm gonna suggest they try CXR + one sideband..or perhaps FM. Econco does a roaring business with this stuff, esp the elevated fil V. Oh, and don't try and buy a..'big boy slug'...2 weeks before a DX contest. They usually get a run on em. A caseload of 10 kw baluns was recently shipped to the middle east...so they can have some...'headroom'..on 80-10m. Meanwhile W3xxx is happy with his 3 hole AL-811. Later... J
     
    WL7PM and KM1H like this.
  2. KM1H

    KM1H Ham Member QRZ Page

    Your last QRZ bio update was 2010 Jim. Tell us more about that new tower you were starting on and more amps.
     
  3. AA7QQ

    AA7QQ Ham Member QRZ Page

    Dang... I thought 16 2sc2879s was big in the 80s.... I guess that's just a driver nowerdays.

    Ed
     
  4. WA7PRC

    WA7PRC Ham Member QRZ Page

    I'm only 'bout 30 miles or so South. :eek:
    In some cases, it could be a predriver. When I received a private tour in the 1970s, I was thoroughly impressed by NLK (Jim Creek). It's just up the road from me.
     
  5. VE7RF

    VE7RF Ham Member QRZ Page

    For you folks with your rinky dink table top amplifiers, here's an easy way to combine the outputs of 2 -3 table top amps into one big output !


    This 1st one is made by ACOM, and splits the output of the xcvr into 3 outputs...to drive 3 x amp's inputs...... then the 3 x outputs are combined into one big output, rated for 5 kw.
    https://www.dxengineering.com/searc...-accessories&sortby=Default&sortorder=Default

    The 2nd one is made by OM Power, and will split the xcvr output into 2 outputs....to drive 2 x amps inputs...... then the 2 x amps outputs are combined into 1 big output, rated for 10 kw output.....and uses a 7-16 output connector. https://www.arraysolutions.com/amplifiers-rf/amplifier-accesories?product_id=14859 Typ use would be to drive .. and combine 2 x OM-4000 amps to 8-10 kw combined output. Easily done, since each amp only requires 20w pep for drive.

    Both units are readily available..and both sell like hotcakes. Gee, I wonder why that is ?

    Later..... Jim VE7RF
     
  6. AG5CK

    AG5CK Ham Member QRZ Page

    Why would anyone buy something like that? Buying 2 or 3 amps and then spending another $3000 to combine them seems like bad economics.
     
  7. VE7RF

    VE7RF Ham Member QRZ Page

    Agreed. Buddy's hb 3CX-6000A7 GG metal triode amp was $7k in total, for new and used parts. 12.5 kw output. Brand new tube /socket/fil xfmr was bought for $1K, from a ham who bought em new...then never went ahead with the project. 253 lb custom dahl plate xfmr was bought new for $1600.00 Both vac tune + vac load caps were bought used. Rack Cab was used. Rest of aluminum panels bought new. Tons of misc new parts bought new and used. Greenlee punches bought used. A lot of labour. The ends justify the means however. Flip side is it requires 600w of drive..which requires an ipa. The 6700 volt B+ I built years ago, used an old 4800 volt/ 10 kva / 120 lb for the plate xfmr. HB amps are one big metal work project.

    Those $3K splitter /combiner's are not cheap, just one more option. But that's what a 160-10m splitter / combiner costs these days. Point is, they are being sold....and used.
     
  8. AI3V

    AI3V Ham Member QRZ Page

    Way back, when I was playing around with uhf/shf troposcatter and vhf eme me and a buddy went to the Central States VHF Society meet in St. Louis.

    There were a couple loosers that, with great pride put on a slide show about their 6 meter eme station.

    Now this raised some eyebrows, because most of the audience were pretty savvy rf guys.

    Anyway, the slide show got to the part about their transmitter chain, and with a "wink wink, nod nod, know what I mean" they bloviated about their 2 x 3-500z driver amp.

    The audience responded with hoots of derision.

    Turns out, most of us had played professionally with REALLY BIG TRANSMITTERS :) , the challenge for amateur eme isn't building or buying a humongous amp, but instead doing it within the legal power limit.

    Like I posted earlier, I once knew a guy (wink wink, nod nod :)) who called CQ on 20 meters with a VOA class emitter, it turns out, that's about as much fun as bragging you beat a cub scout at the soapbox derby with your Buick...

    Rege
     
  9. K7KBN

    K7KBN Ham Member QRZ Page

    Ah so! Oops; make that Oso. I was there for USNR annual training in December 1967. That is enough to spend years studying, not just 14 days. My former Division Officer fron the Kitty Hawk was XO at NLK at the time
     
  10. KM1H

    KM1H Ham Member QRZ Page

    Some use a separate amp to drive different antennas especially on 80 and 160 where horizontals and verticals both get used.

    I did it for several years in the 80's on those bands, and again here starting around 91 or 92 to get a combined ~1500W out of a pair of 2x 3-500Z amps. A TS-930 and later a 940 did the honors. The result was more DX, faster pileup busting, and less QSB since all the important elevation angles were covered.

    Carl
     
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