Date: Mon, 1 Jan 2018 19:17:44 +0000
From: Bill Turner <dezrat@outlook.com>
To: Amps group <amps@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
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|