[Amps] Defining CCS

[Jim Thomson]

Date: Mon, 1 Jan 2018 19:17:44 +0000
From: Bill Turner <dezrat at outlook.com>
To: Amps group <amps at contesting.com>
Subject: Re: [Amps] Defining CCS

On Mon, 01 Jan 2018 13:58:35 +0000, Manfred wrote:

>- RTTY contesting: It's the same as above, but typically over 48 hours. 
>It's still not CCS.

REPLY 
<RTTY contesting may not be true CCS but it's not exactly  ICAS either.
<I have had many amps rated 1500 watts ICAS (Ameritron, Command, ICOM,
<SPE, ACOM and others I can't remember) and none of them hold up at
<legal limit during a RTTY contest. The only amp I have owned that does
<is an Alpha 9500, and of course my homebrew 8877 which was
<intentionally overbuilt just for RTTY.

<For what it's worth. 

<73, Bill W6WRT

##  Al-1500 wont run 1.5 kw rtty on 160m. W8JIs  excuse  was that when it was
designed, he didnt think  hams would ever run rtty on 160m.   With a 22 lb plate xfmr,
u are pushing ur luck anyway. 

##  Include  10M   FM  on the list as well.   10M is notorious for low eff on most
tube amps, like 50%  if you are lucky.  10M  rtty  and  FM  would be pushing
any tube amp to the max. 

##  The real issue is not so much defining CCS  as is this current nonsense  from
manufacturers   calling their SS amps as   100 % ICAS.   

##  Clearly, if an SPE SS amp wont handle 10 wpm CW, without kicking itself down to the
1 kw level,  and ditto with processed  ssb,   it wont handle  icas to begin with.   RTTY or FM with the
SS amp, I dont  think so, maybe for a few secs, then it too will  kick itself down to  1 kw..or less. 

##  alpha claimed 1.5 kw  CCS  CXR,   24 /7 on their older amps.   Clearly the cat falling asleep on the footswitch
proved that theory incorrect. 

##  It really is not that difficult to design a true  1.5 kw   CCS   24/7  rated amp.   Just size everything correctly. 
Use a real  3.5 kva CCS plate xfmr for the B+ supply.  Use a real tube for  the job.  An 8877 is rated for 1.5 kw CCS
diss, provided you stuff enough air through it.   I would avoid the use of torroids, unless  done right.   Use a stack of  3 x
T-225-2Bs if using torroids.  The stack ends up being 2.25 inch in diam x 3 inches long.   Each torroid is 1 inch thick..for 
the 2B version.  The 2A version is only half an inch thick.  Then some  10 gauge, or even 8 gauge teflon or polyimide wire
for winding the torroid. 

##  RL drake used  8 gauge solid tinned wire for the tank coil for 80 + 40M...on my L4B.   .25 inch OD silver plated tubing for 
20-15-10m.   Stone cold on 80 + 40m.    15m runs hot, and ditto with 10m. 

## Edge wound ribbon is the real ticket for the  160-80-40-30 lower bands, like the .25 inch, or  .375 inch variety.  You see that used in commercial 
service quite a bit.    You can even get it with a tapered pitch at one end.   Special clips slide onto the edge of the strap to make the various taps. A machine screw
cinches it up real tight.  A 2nd machine screw terminates the wire lug or strap used for the tap conductor...off to the bandswitch. 
20-17-15m use tubing like at least .25 inch, and preferably  .3125 OD..or in some cases  .375 inch od.   Tubing is cheap at home depot etc. 
For 10 + 12 M tank coils,   strap, wound flat is the ticket.   The C between adjacent turns is virtually non existent .  Then you can space adjacent turns
a lot closer.  Real easy to wind.    Strap coils, and also  edge wound ribbon coils  have a huge total circumference, which is exactly what you want. 

##  1.5 kw CCS on any band is a piece of cake really, use a real bandswitch while you are at it.   Or a double wafer bandswitch with all contacts in parallel.
End result will be bigger than the shoe box sized commercial stuff you are used to.   So what, so is my bar fridge.   If building it hb, the B+ supply can reside in its own
box, which splits the weight to manageable proportions.  

Later.... Jim   VE7RF