Re: Question about Ameritron AL-1200 Amp (Uses one 3CX1200Z7 tube)
Yep. Take off the cover and get something to hold down the cover safety switch. Activate the power switch and then plug it into a live extension cable to apply the power. That way, you are holding the
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Alek Petkovic
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#37113
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Re: Question about Ameritron AL-1200 Amp (Uses one 3CX1200Z7 tube)
FWIW, keep one hand in your pocket while doodling with it. Andy? K9ATX
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DupyRail
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#37112
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Re: Question about Ameritron AL-1200 Amp (Uses one 3CX1200Z7 tube)
Being curious, what exactly is arcing? Andy? K9ATX
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DupyRail
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#37111
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Re: Question about Ameritron AL-1200 Amp (Uses one 3CX1200Z7 tube)
No, not yet Alek, I'm planning on taking the cover off it tomorrow afternoon. One guy in Idaho told me the step-start relay may be the culprit or it could need the electrolytic caps replaced. If I
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Cliff Fox (KU4GW) <cliffku4gw@...>
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#37110
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Re: Question about Ameritron AL-1200 Amp (Uses one 3CX1200Z7 tube)
Have you determined where the arc might be? Bandswitch, RF deck, power supply, power switch, transformer, filter caps, etc? 73, Alek. VK6APK
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Alek Petkovic
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#37109
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Question about Ameritron AL-1200 Amp (Uses one 3CX1200Z7 tube)
I have a Ameritron AL-1200 brought to me by the KN4UNA, P.J., who received the amp from his uncle's estate (W4WWF Dale Mash SK) and it has a problem with giving a arc when the power switch is first
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Cliff Fox (KU4GW) <cliffku4gw@...>
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#37108
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Re: Plate Blocking Capacitors again
The Marconi transmitter at BBC Wooferton used a water cooled vacuum capacitor 1nF 44kV as a coupling capacitor. https://www.youtube.com/watch?v=3-apAt9U4ZI
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Peter Voelpel
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#37107
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Re: Plate Blocking Capacitors again
shoulda? read...... with the? application? of? DC. Jim VE7RF
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Jim VE7RF
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#37106
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Re: Plate Blocking Capacitors again
Yes? I? realize? 95%? of? MW? these? days? are? SS......? I? was? referring? to the? older? tube? pa. Fixed / variable? ?vac caps? have? to? be? severely de-rated? for plate
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Jim VE7RF
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#37105
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Re: Plate Blocking Capacitors again
a linear fo AM is just a bad idea. They are 25% efficient at best. AM broadcasters largely gave them up 80-90 years ago. The Doherty version is a much more efficient option but still less efficient
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W2XJ <w2xj@...>
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#37104
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Re: Plate Blocking Capacitors again
sw broadcast TXs use vacuum caps. MW transmitters are all solid state except for the very old ones. SW TXs 50KW and under are also mostly solid state these days as well.
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W2XJ <w2xj@...>
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#37103
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Re: Plate Blocking Capacitors again
He's? got? it? mounted? on a piece? of? fiberglass.? ?He? shoulda? used? nylon? screws? to? mount the? fiberglass to the? rear? wall....and? also? another? pair? of nylon?
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Jim VE7RF
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#37102
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Re: Plate Blocking Capacitors again
I? went? through the? entire? pdf.? ?They? state the? mica? caps? are? designed? for? 100? khz? to? 3? mhz..that's? it. Then? the? graphs? depict current? ratings? from?
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Jim VE7RF
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#37101
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Re: Plate Blocking Capacitors again
Interesting that he uses one of the 'Millen HV connectors' that are supposedly only rated at 2500VDC to bring his 6500VDC in! Mod-U-Lator, Mike(y)/W3SLK From: [email protected]
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Mike Sawyer
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#37100
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Re: Plate Blocking Capacitors again
Not always: https://www.cde.com/resources/catalogs/HVOLT-CYL.pdf 73 Peter _____ From: [email protected] [mailto:[email protected]] On Behalf Of Jim VE7RF Current rating on mica's
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Peter Voelpel
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#37099
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Re: Plate Blocking Capacitors again
I'd be? more? worried? about? the? current? rating..vs? V? rating.? ?What? bands are? you? planning? to? use..and? what? tube(s) ?? ?If? u? are? using? tubes? with? typ
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Jim VE7RF
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#37098
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Re: Plate Blocking Capacitors again
Many thanks for that Peter. At 10kV peak working that capacitor looks to have a much lower rating than mine. 73s Tracey G5VU
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Tracey Gardner G5VU
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#37097
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Re: Plate Blocking Capacitors again
Seems to work https://www.qsl.net/kf8od/3cpx5000.html 73 Peter _____ From: [email protected] [mailto:[email protected]] On Behalf Of Sharalyn Koeppe Sent: Sonntag, 19. Januar 2020 23:12
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Peter Voelpel
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#37096
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Re: Plate Blocking Capacitors again
I have understood that mica is not suitable for plate blocking due to dielectric migration from the DC applied. 73,?? Roy??? K6XK
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Sharalyn Koeppe
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#37095
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Plate Blocking Capacitors again
I have an 1100pf large block shaped Dubilier mica capacitor dating from 1944. It measures approx. 3.75w x 2.25d x 3.25h inches It states on it that it was tested as follows (a) 6 amps at 300kHz for 1
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Tracey Gardner G5VU
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#37094
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