Date: Sat, 11 Feb 2017 11:06:28 -0600
From: Kevin <kstover@ac0h.net>
To: amps@contesting.com
Subject: Re: [Amps] PowerGenius XL Video
Jim brings up a good point that didn't cross my work addled mind last night.
On 10m FM you aren't going to get 60+% efficiency. Add to that 1500W
continuous carrier on FM for lets say an hour? The Pi-L tank will be a
puddle in the bottom of the cabinet. What's an 8877 rated for in CCS
service (since ICAS is now verboten)?
On 2/11/2017 10:51 AM, Kevin wrote:
> All day, key down, maximum smoke? I doubt it.
>
> That seems to be the new standard around here. Any amplifier topology
> that can't meet that ridiculous standard isn't worthy. Oh, don't
> forget the 20:1 matching range auto-tuner so you can run all day key
> down maximum smoke on FM and RTTY (people really do that?) using crap
> antenna's, and it better not cost more than the shelled out SB-220 I
> bought 40 years ago.
R. Kevin Stover
AC0H
ARRL
FISTS #11993
SKCC #215
NAQCC #3441
## 8877 is rated for 4 kv at 1 amp CCS..provided you blow enough air through
it.
Even Dick Ehorn said you wont get more than 50% eff on any of these
bandswitched amps,
on 10 and 12 m bands. 68% on 160-80 40m. 65% on 20m. 60% on 15M. Those
are his
words not mine. But I would agree with that general statement.
## Now if you are talking about hb monoband amps, whole different ball game.
Then you can
get increased tank eff on 10m. Monoband 6m amps have good eff too.
## at one time there were several 1.5 kw CCS FM broadcast TX in the 88-108
mhz band,
that used a single 8877. Single 3CX-800A7 were used in FM broadcast at
750 w. Pairs
of 3CX-800A7 used at 1.5 kw on FM broadcast. 24 and 365.
## Its not a ridiculous standard, its what the end users specific
requirements are. IF you are a
hard core contester, and want to operate SO2R, that typ involved using 2 x
expensive xcvrs and TWO
amps. Now flex radio can do the same thing with just one xcvr, and one amp.
That just saved the
contester a pile of $$ if designing his station from scratch.
## If you are a RTTY contester, the above new power genius may well not run at
1.5 kw rtty mode,
for 48 hrs non stop. If its just for ssb and cw, the power genius will do the
trick.
## IF you dont like QSK, then qsk capability is low on the chart. I hate qsk,
so have no need for it, even though
some of my amps will function on qsk.
## IF u like 10 M FM, you will soon find out what hot is all about.
## IF you like SS amps, they typ dont do any better than 50% eff when run
maxed out,
and less, when run at lower po. Hence the lower voltage switch on some
models.
SS amps dont like swr, hence the 1-2 kw rated auto tuner. Tube amps dont
require
a myriad of half a doz kw rated LP filters, nor any type of tuner manual or
automatic.
## some tubes are instant on, some have a 3 min delay. Some like the YC-156
and YC-179
require a 6-8 min delay.
## your SB-201 is superb for general purpose operating. I would not use one
in a 48 hr
RTTY contest anytime soon. It only comes with a 500 VA CCS plate xfmr.
## The point folks were making is.. IF you are gonna shell out 7-10 grand on
a SS amp, at that
price, it had better be capable of 1.5 kw CCS FM and RTTY, and have an auto
tuner that will
handle anything you can throw at it.
Jim VE7RF
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