[Amps] New Amplifier

[Jim Thomson]

Date: Sat, 8 Apr 2017 18:04:16 -0500
From: Joe <nss at mwt.net>
To: amps at contesting.com
Subject: Re: [Amps] New Amplifier

Really makes ya think twice about home brewing up an amp with some of 
those new transistors. Like one I saw the other day was also 100% duty 
cycle 1500 Watts OUTPUT, for 250 bucks.

Then add the fact you could in reality just add whatever band pass 
filtering needed for purity standards because no output matching is 
needed when it states it can run into a 65 to 1 SWR!

Wow!

Joe WB9SBD

## dream on.  It wont run any power into a 65:1 swr.  It will just throttle back to
virtually zero watts, so it doesnt blow its brains out. Ultra fast SWR protection they state.
They dont state what power it will  run full bore..at say a 2:1  swr..or a 3:1  swr. 
Thats  what you need to know. 

No built in auto tuner either.  So you either buy an aftermarket, fully  automatic 2kw rated
tuner, or use a manual tuner.   Either way, you wont get the lightning fast  bandswitching, if the
tuner is required on both bands.   You could, if it had enough smarts to engage, or disengage the
outboard tuner, and the same tuner was tuned for just one band. 

No mention of IMD specs.  It should be fairly good, since the devices are being run at half power.  That
plus they have done it right by using 6 x  diplexers, instead of the usual  6 x LP filters.    With any LP filter, the
harmonics get reflected back to the output of the pa..making ind worse.  The harmonics dont get routed to ground, nor do they get absorbed
by the LP filter.   With a diplexer, the output of the pa is fed to both the input of a high powered LP filter, and also the input of a 
low power HP filter.   Output of lp filter is routed to ant.   Output of HP filter is routed to a 50 ohm dummy load. 
High ant  swr will make imd worse. 

100%  ICAS is pure bs.    100%  ICAS just means  it is capable of hours on end of   ssb operation, and also cw operation. 
And probably  RTTY and FM  operation, as long as the amp is not in TX mode for very long, like probably less than 30 secs.
Im not a rtty operator so will defer to Bill, as I dont know the typ overall duty cycle for typ  casual rtty ragchewing  vs contesting. 
Would be interesting to know how much po it will run, brick on key, 100%  duty cycle... which is what it really should be capable
of for $7000.00    The pair of transistors they use are fully capable of doing just that.  Any 3 kw CCS switching power supply is 
a piece of cake these days, since the telcos have been using 3 – 3.3 kw CCS switchers for 15 years or more now.   The fans,
cooling, heat sinks is another matter..whwich may be the limiting factor.  

Watch their video, you can hear the fans start  screaming,  part way through the video.   What these various amp makers
should spec, is an A weight noise spec, done from 1 meter away.   Even that doesnt tell the whole story. Fan or blower noise
at a lower pitch is more tolerable than a higher pitch. 

I would like to know what the eff is when the amp is run at lower power, like say 500-1000 watts....and if the imd is any lower,
when run at lower power. 

Jim   VE7RF