[Amps] Ampleon BLF189XR 1900W LDMOS transistor

[Jim Thomson]

Date: Tue, 18 Oct 2016 18:20:45 -0500
From: Kevin <kstover at ac0h.net>
To: amps at contesting.com
Subject: Re: [Amps] Ampleon BLF189XR 1900W LDMOS transistor
announcement

W6PQL tested the NXP BLF188XR, the device he uses in his 1KW amps, and 
came up with 1100W before hitting 1dB compression and it's a 1400W 
"peak" device.

If I was building one with the BLF189XR I'd still use two devices. Run 
each at 750W out and not stress anything. Might actually get an SSPA 
that will do full legal, any mode, no time limit as long as you can move 
the heat.

The big question is the low pass filter. The single most expensive part 
of an SSPA.


### This is my problem with these SS amps, the LP filter.  And you require
a myriad of them, not just one of em.   On a NINE band ham amp, you would
require a bare minimum of SEVEN 1.5 kw CCS rated LP filters... AND you have
to be able to switch them in / out.    You dont  require ANY LP filters on any tube amp. 

##  You also forgot the SS amps also require the fully automatic,  1.5 kw CCS rated
antenna tuner.  Again, a tube amp doesnt require a tuner. A  SS amp will blow its brains
out with swr.  None of em will operate full power into a 2:1  swr. 

##  Your typ  SS amp operates at 50% eff at best.   So for a 1.5 kw CCS  rtty / FM
signal, the heat sink would have to be able to dissipate 1500 watts  CCS.  That’s
a helluva lot of heat to deal with, which means a bunch of noisy fans.

##  can it all be made to work, sure, but its not as simple as folks are trying to make out. 
An  FM broadcast TX only requires a single LP filter, and the LP filter  does not require any
switching scheme.  The  FM broadcast TX  doesnt even require a TR relay, since its on
TX.  Nor does the FM broadcast TX require an automatic ant tuner..nor does it need to be
linear, imd is a non issue. 

## Will  2 x BLF189XRs even do 1.5 kw pep with real low IMD ??  I dont mean typ ham
junk either.  

Jim   VE7RF