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Re: Series DC Blocking cap.
开云体育Indeed they do. The current handling / rating is usually defined by the capacitor’s Equivalent Series Resistance / ESR and its dielectric losses Dissipation Factor / loss tangent which is highly dielectric material dependent. ? High K dielectrics tend to be lossy while NPO class dielectric leaded ceramic disk capacitors generally perform much better where significant RF current is flowing. ? Leigh VK5KLT ? From:
ham_amplifiers@...
[mailto:ham_amplifiers@...]
? Capacitors have current ratings too. Voltage is one parameter and the current rating is another. Lee, w0vt On 6/27/2019 11:14 PM, jim.thom@...
[ham_amplifiers] wrote:
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Re: Series DC Blocking cap.
开云体育Capacitors have current ratings too. Voltage is one parameter and the current rating is another. Lee, w0vt On 6/27/2019 11:14 PM,
jim.thom@... [ham_amplifiers] wrote:
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Re: Series DC Blocking cap.
<Slightly off topic,? <I am using an old Heathkit antenna switch that has the control voltages riding on the coax.??The <series DC blocking capacitor in the outside box has a piece chipped out of it.??Maybe lighting, <maybe power did it.??It’s an .02 uf??1.6 KV disk. ? <I bought a .02uf??3 KV disk Vishay and installed it.??If I run a 1500 watt carrier through it for about <15 seconds, it gets warmer than lukewarm.?? Warmest on 10 meters as I would expect. ? <Would one expect the cap to be warm to hot after that amount of time????Any suggestions on <what I should put in there????Curiously, the inside control box uses two of the .02 caps in parallel, <not one as the? outside box does. ? <Jim – KR9U ##? 1500? watts? =? 5.5 amps into? 50 ohms.? That's a helluva lot of current.? The problem? with? disc ceramic caps is.... they never post any RF? current ratings on them.? ?Ideally, they should post a? ?CCS? RF? current? vs? freq chart.? ?Actual? current ratings are all over the map...and must be? determined by testing.? ##? Big difference between? a .01 uf? @ 1 kv rated cap... vs a .01uf? @ 2 kv rated cap... the 2 kv? versions are typ bigger diam, like 25mm? OD... vs the smaller diam? 1 kv units.? ?The? 2 kv versions, being bigger diam, handle more current..which testing confirms.? ?Once you get to the? 3+? kv rated units, they don't appear to handle any additional current,? just a greater V? rating.? ##? I bought 2 x doz? .01uf @ 1.3 kv? disc ceramics? from RF parts? last year.? Huge things at? 25mm? OD, and really thick.? ?These things handle loads of current, best yet so far.? ## For? your heath switch box application,? parallel a 2nd cap? in the remote switch box...then re-test.? ?Parallel a 3rd cap if required.? ?You should have zero heat..on any freq.? Dunno if the heath? box is? good up to 6m or not.? ? Jim? ?VE7RF |
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Re: International shipping of Amplifier question L4B and a NIB HF-2500 Commander
Yep, they show up on the various hot rod forums I frequent and are right at the top of their game.
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The last shipment was a comple running low mileage Ford 460 and C6 still attached going into an early pickup. That ought to smoke up the tires really good unless taller gears are used in a heavy 9" axle. I used to install gears in the 2.50 range in 50's F-100's just to get traction. Those were common in 460 Lincolns and 2.47's in several small block vehicles. Carl Back to amps but I do love to drift into vintage vehicles! Thankfully King George III isnt on here ----- Original Message -----
From: Alek Petkovic vk6apk@... [ham_amplifiers] To: ham_amplifiers@... Sent: Thursday, June 27, 2019 8:19 PM Subject: Re: [ham_amplifiers] International shipping of Amplifier question L4B and a NIB HF-2500 Commander Yeah. Lotta rev heads downunder. On 28/06/2019 2:26 AM, 'Carl' km1h@... [ham_amplifiers] wrote: Find a local freight forewarder and get quots for ship and air. They combine-- From sunny Binningup Family Businesses: SP Electrical. www.spelectrical.net.au The Velvet Fox. Smart Design Electrical. Perth Interiors. |
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Re: Series DC Blocking cap.
The choke should be doing most of the work and the cap very little. My HB and Ameritron switches all use a generic Z5 single .01 1KV right up to 1200-1500W on HF for decades of heavy use without failure.
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It often is hard to see internal choke damage but do an A:B resistance test with the other one: What is the model #? I can look tomorrow at the actual circuit. Carl ----- Original Message -----
From: kr9u@... [ham_amplifiers] To: ham_amplifiers@... Sent: Thursday, June 27, 2019 6:01 PM Subject: [ham_amplifiers] Re: Series DC Blocking cap. <<A total of .01 is more than enough, maybe a blown .02 was already removed in the past>> Thanks Carl, It's a stock box and the schematic shows it as I've described. There aren't any dissipation specs on the new cap - therefore the question. Jim - KR9U --- This email has been checked for viruses by AVG. |
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Re: International shipping of Amplifier question L4B and a NIB HF-2500 Commander
Yeah. Lotta rev heads downunder.
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On 28/06/2019 2:26 AM, 'Carl' km1h@... [ham_amplifiers] wrote:
Find a local freight forewarder and get quots for ship and air. They combine --
From sunny Binningup Family Businesses: SP Electrical. www.spelectrical.net.au The Velvet Fox. Smart Design Electrical. Perth Interiors. |
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Re: Series DC Blocking cap.
A total of .01 is more than enough, maybe a blown .02 was already removed in the past
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Carl ----- Original Message -----
From: kr9u@... [ham_amplifiers] To: ham_amplifiers@... Sent: Wednesday, June 26, 2019 10:09 PM Subject: [ham_amplifiers] Series DC Blocking cap. Slightly off topic, I am using an old Heathkit antenna switch that has the control voltages riding on the coax. The series DC blocking capacitor in the outside box has a piece chipped out of it. Maybe lighting, maybe power did it. It’s an .02 uf 1.6 KV disk. I bought a .02uf 3 KV disk Vishay and installed it. If I run a 1500 watt carrier through it for about 15 seconds, it gets warmer than lukewarm. Warmest on 10 meters as I would expect. Would one expect the cap to be warm to hot after that amount of time? Any suggestions on what I should put in there? Curiously, the inside control box uses two of the .02 caps in parallel, not one as the outside box does. Jim – KR9U --- This email has been checked for viruses by AVG. |
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Re: International shipping of Amplifier question L4B and a NIB HF-2500 Commander
Find a local freight forewarder and get quots for ship and air. They combine multi items in one container for a lower cost.
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Ive shipped several amps as well as complete vintage V8 engines that way all over the world. Australia is a hot spot for engines! Carl ----- Original Message -----
From: k9uwa@... [ham_amplifiers] To: ham_amplifiers@... Sent: Wednesday, June 26, 2019 9:17 AM Subject: [ham_amplifiers] International shipping of Amplifier question L4B and a NIB HF-2500 Commander I need to ship a Drake L4B to a ham in VK6 land. The quotes I found from FedEx DHL etc are totally nuts. The buyer isn't in a hurry but somehow we have to get the shipping to something reasonable. So I thought where better to find out than from the Ham Amplifier group? So where do we get reasonable deals. One other question. I also have a brand new in the box Commander HF-2500 with a serial number on it of 0475. It has never had a plug connected to the power cord. Yes I am selling off a local SK's ham equipment for the widow. SK is Jule Franke W9TQA link to the sales AD on QRZ.com All help appreciated. Email to me k9uwa@... thanks 73 John k9uwa --- This email has been checked for viruses by AVG. |
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Re: Econco now rebuilding Svetlana tubes !
That’s useful to know, thanks. ?I have a stock of YU204s for the 4-1000 amp and 3CX3000s for that amp but could do with a spare Thomson TH376 or two if anyone knows where to source those?
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Dave G0OIL? On Thursday, June 27, 2019, 2:46 pm, jim.thom@... [ham_amplifiers] <ham_amplifiers@...> wrote:
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Re: International shipping of Amplifier question L4B and a NIB HF-2500 Commander
Curious, how much? Bob WE6C On Thursday, June 27, 2019, 7:24:39 AM PDT, jim.thom@... [ham_amplifiers] wrote: ? ##? Drake? L4PS? ( HV supply)? ?weighs? 45 lbs. Drake L4B? RF? deck weighs? 30 lbs.? 75 lbs total weight..... not including shipping boxes.? ## You? MIGHT? be able to ship via? USPS,? using? 2 x separate boxs.?? ##? I have? 4 x L4B's.....and? ?4 x mating? L4PS? hv supplies.? ?When? new, the L4B came in one box, the L4PS in another box, and? each tube came in it's own box....? 4 x boxes in total.? ?Dunno about the? ?2 x chimneys.? ?I believe the? chimneys each had a box.?? Jim? VE7RF? ? |
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Re: International shipping of Amplifier question L4B and a NIB HF-2500 Commander
<I need to ship a Drake L4B to a ham in VK6 land. The quotes I found from FedEx DHL etc are totally nuts.? <thanks <John k9uwa ##? Drake? L4PS? ( HV supply)? ?weighs? 45 lbs. Drake L4B? RF? deck weighs? 30 lbs.? 75 lbs total weight..... not including shipping boxes.? ## You? MIGHT? be able to ship via? USPS,? using? 2 x separate boxs.?? ##? I have? 4 x L4B's.....and? ?4 x mating? L4PS? hv supplies.? ?When? new, the L4B came in one box, the L4PS in another box, and? each tube came in it's own box....? 4 x boxes in total.? ?Dunno about the? ?2 x chimneys.? ?I believe the? chimneys each had a box.?? Jim? VE7RF? ? |
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Econco now rebuilding Svetlana tubes !
? Econco is? now re-building Svetlana? tubes.? ? In the past, every tube rebuilder on the planet has tried,? (including econco)... and failed to? re-build? Svetlana tubes.? ? Apparently,? Econco removes the entire guts? from the? Svetlana? tubes.....and replaces em with 'econco'? guts. Only the anode remains as oem.? ? Econco is desperate for? 'duds'.? ?I suspect that Econco? knew how to rebuild? Svetlana tubes? all? along.? ?BTW,? Eimac also rebuilt tubes.... until? they bought out? Econco.?? I? don't get tube? prices at all.? ?Chinese 8877? from? Ameritron is? >? $1000.00? ? ? ?Eimac? 8877? from Ameritron is? >? $2800.00? ? ? ?Greenstone? (chinese) 3CX-3000A7? is still? $725.00? ? ? Henry? radio? switched to greenstone brand tubes.... 7 years before they stopped selling? ?hf? amps.? ?You can still? buy? ?3x3's? ?for? $725? from? henry radio for? $725.00? ?or any? other? greenstone? dealer.? Jim? ?VE7RF |
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Re: Hsu
<IMD is ridiculous...even at 1500W. <Screen voltage is well regulated so i am thinking IMD is from tube.? 4CX1500B swap will be possible but very <expensive ...? much more better amp is around and make here with full service support. <Dont waste a buck on this. <This is my opinion.. <Guillaume VA2NA ##? Nothing wrong with the pair of? chinese? FU-728's.? ?The? OM-4000? also uses a pair? of FU-728's, and when used with an ANAN- 8000,? IMD is? -70dbc? ? for? imd? ?3-5-7-9-11-13 .... and that's at? 4+ kw pep out.? ?But that is when .....' pure signal'? is? being used.... and the? sample is? derived from the linear .? ?KA0KA has the anan 7000 /? om-4000? setup. On the waterfall display,? on ssb / essb .... it drops off over the cliff asap.? ## But? really,? if? you want to run? 4+ kw pep? out, use a real tube, like a 3CX-3000A7.?? Jim? ?VE7RF |
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Re: Hsu
My friend VA3AQB. Alan, has one. ?He’s had his share of problems wit it. ?If you email him at his call. Yahoo.ca he can tell you much about it. ?I know he had issues. ?He fixed everything himself. ?Might want to think twice about one of them.
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On?Wednesday, June 26, 2019,?va2na@... [ham_amplifiers]??wrote:
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Series DC Blocking cap.
Slightly off topic, I am using an old Heathkit antenna switch that has the control voltages riding on the coax.? The series DC blocking capacitor in the outside box has a piece chipped out of it.? Maybe lighting, maybe power did it.? It’s an .02 uf ?1.6 KV disk. ? I bought a .02uf ?3 KV disk Vishay and installed it.? If I run a 1500 watt carrier through it for
about 15 seconds, it gets warmer than lukewarm.?? Warmest on 10 meters as I would expect. ? Would one expect
the cap to be warm to hot after that amount of time??? Any suggestions on what I should put in
there??? Curiously, the inside control
box uses two of the .02 caps in parallel, not one as the? outside box does. ? Jim – KR9U |
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Re: International shipping of Amplifier question L4B and a NIB HF-2500 Commander
开云体育PS: I'd love the Commander but I already have one. :-)On 26/06/2019 9:17 PM, k9uwa@... [ham_amplifiers] wrote: I need to ship a Drake L4B to a ham in VK6 land. The quotes I found from FedEx DHL etc are totally nuts. The buyer isn't in a hurry but somehow we have to get the shipping to something reasonable. So I thought where better to find out than from the Ham Amplifier group? So where do we get reasonable deals. -- From sunny Binningup Family Businesses: SP Electrical. The Velvet Fox. Smart Design Electrical. Perth Interiors. |
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Re: International shipping of Amplifier question L4B and a NIB HF-2500 Commander
开云体育G'day John.USPS? Pack and Send? The latter uses the same courier companies but they have big accounts, so the prices are often vastly cheaper. I don't know why it costs so much to get stuff out of North America. The same weight as a L4 amp and supply, sent from China, via DHL, etc, costs around US$80.00. I know this because I get HV transformers custom built there and they are shipped to me here in rural VK6. The VK6 ham is my good friend. He lives 9 miles from me. I suggested the L4 for him. You will not have any troubles dealing with him. He had one organised and paid for from a ham in YV but because of the political situation there, it was impounded by authorities. My mate got his money back and the last I heard, the owner is trying hard to get his amp back. 73, Alek. VK6APK On 26/06/2019 9:17 PM, k9uwa@... [ham_amplifiers] wrote: I need to ship a Drake L4B to a ham in VK6 land. The quotes I found from FedEx DHL etc are totally nuts. The buyer isn't in a hurry but somehow we have to get the shipping to something reasonable. So I thought where better to find out than from the Ham Amplifier group? So where do we get reasonable deals. -- From sunny Binningup Family Businesses: SP Electrical. The Velvet Fox. Smart Design Electrical. Perth Interiors. |
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Re: Hsu
To be honest with you guy... stay away from it.
i Know 4 owner of LA-4000, 3 got home for major repair + modification.? The last one i dont know i never spoke with the owner but i bet is power board will fry very soon. YU Lang the owner of AMPTEC, is not listen at all...not very helpfull ...he not came back to my email as i told him all the bad design he do on this piece of junk :) The way he keep the amp running using power divider on 240 volt is getting hot very fast and blow very quick. Glitch resistor value is to low and not limit often current when flashover occur...the board trace goes in smoke each time. IMD is ridiculous...even at 1500W. Screen voltage is well regulated so i am thinking IMD is from tube.? 4CX1500B swap will be possible but very expensive ...? much more better amp is around and make here with full service support. Dont waste a buck on this. This is my opinion.. Guillaume VA2NA |
Leigh Turner