On Wed, Jan 10, 2024 at 06:29 PM, Peter Voelpel wrote:
RG393 will do it easily, it is specified 25kW at 10MHz, 9.5kW at 50MHz.
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73
Peter, DJ7WW
I have found at least 1/2 oz specs for RG-393..... and they are all over the map.? ?393 only has a? small 12 ga center conductor.....(.0808").? The issue is....whatever the puny center conductor is connected too, is gonna have one helluva lot of heat on it. IE: vac relay contacts etc.? Relay contacts are sitting at 150-200C.... just from the heat from the coax.? Try running 9.5 kw cxr on 50 mhz with 393.......... been there, done that.? It's not big enough.
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SFT-600 is the Teflon version of LMR-600UF.? ?SFT-600 has a .159" center conductor? (6 ga).? The length? required from the vac load cap to the vac relay assy is very short in most cases.? It's readily available, cheap on ebay etc...and doesn't run stupid hot. Connectors are readily available, like 7-16 din etc.? ?SFT-600? works superb for stuff like rotor loops etc.?
The biggest they make in teflon? coax is SFT-900.
The fellow's website is interesting.? 100 kw pep output on ssb? from a 4x20,000C...with a 30 kva plate xfmr...dream on.?
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On that 4x10 on his site, that uses air variable tune and load caps, he uses a string of 330 uf lytics on the single phase 230 vac supply.? Those 330 uf caps only have a 1700 ma ccs ripple current rating.? Typ ripple current on the B+ supply is 2.5? X the dc plate current. You can see that in software...and also easily measured.? Those caps wont handle it, not big enough.? ?The larger value lytics always have progressively higher ripple current ratings.
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Something else to note, the actual VA power drawn from the mains is quite a bit higher than the DC input.. like a LOT higher.? But u need a true rms ammeter to measure it. If a non true rms meter is used, it will read? 20-40% on the low side when a C filter is used.?
