[Amps] Defining CCS
Roger (K8RI)
k8ri at rogerhalstead.com
Wed Jan 10 02:30:24 EST 2018
I'd need to look it up to be sure, but IIRC, exposure levels are
calculated as a 5 minute period of transmission between two 5 minute off
periods.
Out of that, CW is considered 50% duty cycle and unprocessed SSB is
considered 20%
As CW is the most demanding at 50% (neglecting digital @100%), I'd think
that would be considered to be ICAS.
Amps rated at 100% ICAS for the legal limit, are incapable of running
digital at their full ratings.
An amp capable of running a 5 minute digital transmission needs
substantial overhead compared to SSB and CW.
Depending on the thermal mass of the tube and the capability of the PS,
I "would think" most amps capable of a 5 minute digital transmission
would need to be close to CCS capable.
That PS, not only needs to be capable of supplying the voltage and
current, but the core needs to be capable of a reasonable temperature
rise and the ability to stay within that designed temperature range with
a prolonged use (contesting). IOW, 12 to 24 hours, or more, at the
equivalent of that 5 off, 5 on, 5 off, cycle.
73, Roger (K8RI)
On 12/31/2017 Sunday 6:43 PM, Jim Thomson wrote:
> Date: Wed, 27 Dec 2017 08:55:57 +0700
> From: Charles Harpole <hs0zcw at gmail.com>
> To: amps at contesting.com
> Subject: [Amps] Defining CCS
>
> <Ok, I have had it with vague sales statements. The following was used
> since at least 1955 and all amp experts know it.
>
> CCS is Continuous Commercial Service. This is true 100% duty cycle, BRICK
> ON THE KEY, rating indicating operations for 24/7/365 with no off times.
> No sales talk juggling.
>
> ICAS is Intermittent Commercial and Amateur Service. That means typical
> on-and-off ham operations without long key-down transmissions (usually 10
> minutes is called long). This is NOT 100% duty cycle but indicates use of
> full power with limited key-down times and definite key-up times.
>
> An amp can be called 100% ICAS by imaginative advertising writers, but that
> number is definitely not CCS.
>
> It is helpful to hold to old established nomenclature for clear
> communication.
> ?73?
>
> Charly, HS0ZCW
>
> ## agreed. IMO, CCS=100% duty cycle means 24/7/365 brick on key, dead cxr.
> ICAS is a 50% duty cycle. Processed ssb is no where near 50%. Then Bill orr started up the..
> IVS nonsense, intermittent voice service, non processed ssb. Terms like... 100% ICAS is
> plane misleading..and fubar at best.
>
> ## Art Bell, W6OBB came in one day and found his alph 89 on fire. His cat had fallen asleep on the
> footswitch. Art had it tweaked up to run 1.5 kw out FM on 10M band..into a flat swr. Art phones Alpha
> tech. Tech tells Art not to believe the advertising hype. Dunno if he had the optional fan on the rear apron or not.
> The 10M portion of the PI-L had turned to glop.
>
> ## IMO, both alpha + OM power are using too small a diameter for their tubing coils. The lower band torroids run way too hot.
> Buddy with the Emtron amp, he points the IR point and shoot gun at the torroid, and they were sitting at a whopping 224 deg C !
> Thats with a dead cxr.
>
> ## Alpha 9500 uses a plate xfmr thats touted as 3.5 kva CCS..and only weighs 30 lbs. I call BS on that, perhaps 3.5 kva ICAS.
> No way in hell ur gonna get 3.5 kva CCS from any 30 lb flyweight xfmr, cant be done, even in hypersil tape wound and high eff.
> A 46 lb dahl is only good for 2.7 to 2.8 kva CCS.
>
> ## melting solder on tank coil taps ? Dont solder em in the 1st place..or use correct size tank coils that dont heat up.
> The way to deal with heat is to...not generate it in the 1st place, or minimize it. I wrap the cu strap around the tubing coils,
> then a single machine screw assy cinches the tap up super tight. Taps made with cu strap. Machine screwed at the band switch.
>
> ## The story about alpha running 60 wpm dits, or in some cases, pulse tuning with a 25% duty cycle is well known. Their excuse, as
> told to me was.... they would have blown the breaker, not enough power, 240 vac line waaaay too long, no 240 available, etc, etc.
>
> ## Now it all gets worse with the latest crop of SS wonderbar amps. SPE amps use 3 x different voltages, like 48-50 vdc, then down to
> 42 vdc, then lower still to 36 vdc. For power levels of < 1500 watts, <1000 watts, < 500 watts respectively. They will auto switch to a lower
> voltage if running lower PO..thats to keep the eff high, like back up to a max of 50%. Run a 1.5 kw ss amp at just 750 watts, and eff drops to
> a lousy 35% every time, IF same higher vdc used.
>
> ## But SPE now claims NOT to used processed SSB when using 1.5 kw pep out..or the amp will kick itself down to the 42 vdc level, and tweak ur alc,
> and /or insert attenuation padS in series with the drive from the xcvr....such that amp is now 1 kw or less. The SPE wont handle 10 wpm cw at 1.5 kw
> either, kicks down to 1 kw mode. Dashes at 10 wpm, or less, with a 3:1 or 4:1 dash-dot ratio will increase short term duty cycle.
> 50% duty cycle is a time averaged thing. 1 hr on and 1 hr off and 1 hr on etc, is also a 50% duty cycle, but the amp will blow its brains out 1st.
> SO we can safely assume the SPE is not rated for..... 40% ICAS..which is all CW is anyway !
>
> ## Flex and its power genius is another doozy with its... 100% ICAS rating. I assume they mean it will actually run at 6-10 wpm ? Their u tube
> video depicts a myriad of fanS screaming in the background as soon as they start sending qsk cw. On qsk cw, you have cut off the idle current between
> dots and dashes.
>
> ## Dunno if the myriad of LP filters in these SS amps would even handle a real CCS rating. Ditto with final SS pa, and power supply, etc, etc.
>
> ## The fellow in VE6 land who builds the superb band pass filters also offers several fan options to cool em. No fan, low speed fan, high speed fan etc.
>
> ## For $7000.00 for the flex unit, and huge $$ for the SPE etc, then toss in the required, optional megabuck auto ant tuner....and you are into it for a
> lotta $$$..esp if you reside outside of the USA. Toss in the lousy IMD, and you are being sold a ... bill of goods imo. Run the SS amp at low power and imd improves,
> but eff goes to hell. But since they auto drop the vdc to a lower level to increase the eff, the IMD drops back to lousy. -30 dbc is nuts these days.
>
> ## The pre-distortion concept works..up to a point, the pre-distortion loop is not wide enough. IMD3 and IMD5 drop like a rock, but IMD7 and IMD9 only drop 10 db.
> IMD11 through IMD19 dont get any benefit or improvement at all, in fact they get worse. The only xcvr with the pre-distortion is the apache line up. And their
> latest 8000 LDE is only –30dbc, with pre-distortion dis-engaged and running only 80 watts out on 40m. So much for the touted LDMOS devices.
>
> ## None of my hb tube amps runs hot, they will all run 100% CCS key down. Pretty simple to pull that off, just use the correct sized components to begin with.
> Added cost is not much more. Long term reliability is greatly enhanced, they just run and run, nothing to blow up or overheat. IMD is superb. -59db IMD3 is
> superb, then it just gets better for the higher order products...and no pre-distortion used. A 1 tube GG triode is pretty simple. Just a tuned input,
> PI net kw output, a few meters for grid, plate, and B+, and TR relays etc, and a box. B+ supply is dead simple. Simple to trbl shoot if required.
> A $500.00 chinese 8877 is a bargain. Ditto with a chinese 3CX-3000A7.
>
>
> ## They should be using 4 of those new fangled 50 /63 vdc LDMOS devices. At 1.5 to 2.0 kw out, they would be very clean IMD wise.
> end of rant
>
> Jim VE7RF
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--
Roger (K8RI)
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