[Amps] RF2K+ LDMOS linear

Jeff AC0C keepwalking188 at ac0c.com
Sun Jun 4 13:19:11 EDT 2017


I'm with Steve here.  The old saw of "build a better mouse trap and the 
world will beat a path to your door" is almost always false because it's 
hard to believe the hype surrounding stuff.  If an amp maker wants to crank 
up the sales in the US of their amps, by far the best way would be to put it 
in the hands of someone who has a good tech reputation in the community, can 
give it a serious contest workout and who also has the ability to do a basic 
IMD test.

There are many folks of that description.  Before I shovel what is going to 
be nearly 8K into a box, I really would feel a lot better if I heard that 
they lived through a couple of contests over at W3LPL, etc and Frank said 
they hummed along fine.  I'm using LPL as an example here.  My point is 
advertising and social media and endorsements from guys in EU are a lot less 
meaningful than a country local here in the US.

Made the exact same argument to a Chinese maker when he was trying to get 
going but he unfortunately just could not wrap their head around the 
marketing aspect of a product roll out.  The ham universe is pretty small - 
and an endorsement by someone objective and authoritative carries far more 
weight in this market than in others, especially given the huge financial 
investment something like this involves.

73/jeff/ac0c
www.ac0c.com
alpha-charlie-zero-charlie

-----Original Message----- 
From: Jim Thomson
Sent: Sunday, June 04, 2017 11:48 AM
To: amps at contesting.com
Subject: [Amps] RF2K+ LDMOS linear

Date: Sun, 04 Jun 2017 07:58:54 -0600
From: Steve London <n2icarrl at gmail.com>
To: amps at contesting.com
Subject: Re: [Amps] RF2K+ LDMOS linear

<I would not declare tube amplifiers dead until a legal limit, SS
amplifier repeatedly proves itself in serious contest conditions. I'm
not talking about the guy who casually makes 500 search-and-pounce
QSO's. I'm talking about the balls-to-the-walls, SO2R, all-band guy/gal
who operates close to 48 hours, running stations the entire time.
Mistakes happen under these conditions - ooops, forgot to change the
tornado tuner on the 80 when moving from 3700 to 3800, etc. Or, RF from
one amp gets into the other amp and fools it's microprocessor.

The only production SS amp that has come close to proving itself under
there conditions is the SPE line. Even they aren't perfect. See
http://www.3830scores.com/showrumor.php?arg=leadzTgmmcvix . That was an
SPE 2K. In all fairness to SPE, see
http://www.3830scores.com/showrumor.php?arg=lua4zPgqvqmsK . A pair of
SPE 1.3K's that worked flawlessly. (However, not at the legal limit.)

I would love to borrow a pair of these RF-Kit amps and put them to
serious use in one of my SO2R contest efforts.

73,
Steve, N2IC

##  High swr, so what, amp kicks offline at some pre-set threshold.
They are already in use across europe...in rtty contests.  Fans  are
pwm controlled, so heat is not an issue.   Eff is high at 65-70%.
IMD is typ –40db pep..using the newer german made LP filters.
Mark tells me these amps are 100% duty cycle rated, all modes.
If they survive a rtty contest, ssb + cw should be a lollygog.

## You are right though...  send some off to contest sites..and really beat
on em for the weekend.   Tube amps  days are numbered, the writing is on the 
wall.

Jim   VE7RF

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