Date: Thu, 11 May 2017 13:49:19 -0400
From: "Paul Christensen" <w9ac@arrl.net>
To: <amps@contesting.com>
Subject: Re: [Amps] HV MOSFETs for RF
>" ## If you think the 100w K3s paltry -23 dbc IMD3 is something to write
home about.... go for it. Ditto with the 400w yaesu FT-9000MPs ?12 dbc
IMD3. "
<<<<For the last two weeks, I've been testing the new ANAN 8000DLE. Worst-case
IMD at 200W is -75 dBc and close to -80 dBc on some bands. The PSDR mRx result
was cross-checked with an Agilent N1996A spectrum analyzer. The combination
<<<<of LDMOS, adaptive pre-distortion and a highly-isolated RF sample path back
to the receiver's sampling input all contribute to this extraordinary level of
transmitted IMD performance.
<<<<Paul, W9AC
## superb xcvr, esp with phase noise through the floor, plus other features
like a .1 PPM TCXO etc. Ok, per the ANAN forum folks, the 8000 had a 30
msec latency...which is now down to just 20 msecs. How do you monitor yourself
on headphones,
when on ssb ? I have found that anything much over 5-7 msecs sounds horrid
in the headphones. That would be a deal breaker for myself. Plan B would be to
monitor the audio, b4 it gets to the xcvr. Will the 8000 do essb ? The
8000 needs an outboard box, with a VFO and other common stuff, like the flex
offers.
## I see they used a pair of SMA connectors on the xcvr for the..... pure
signal pre-distortion jacks. If the xcvr is used stand alone, with no amp,
then a simple U cable is used between the pair of sma connectors. One sma is
the sample from the 200w pa, the 2nd sma is the main input for the
pre-distortion scheme. When a kw linear amp is used, the U link is removed,
and the sample comes from the kw amp. Apparently the sample cant be more
than 0 dbm, and no less than - 24 dbm. So you would require a big pad on the
output of the kw amp, for the sample. Dunno what type of cable is required
for the sampling, back to the xcvr ? Can you use a bnc, or something else
than a SMA...at the kw amp end ?
## A VA2 fellow from quebec has one of the other ANAN xcvrs, with the
pre-distortion scheme. His IMD3 on his pair of 3-500Zs, with pre-distortion
improved to -52 dbc. He sampled the output of the 3-500Z amp..pad, then back
to the xcvr. Looks like the typ linear amp can have its IMD improved a bunch,
like 10 - 18+ db. A 10 to 18+ db improvement.... even on a marginal amp is
a win – win.
## -75 to –80dbc IMD is not even in the same ball park as everything else
on the market..and NO class A blast furnace required. I see the new Flex
1500W SS amp has a sampled output..to be used with any xcvr that has the
pre-distortion scheme.. like the ANAN xcvrs. The current Flex xcvrs dont have
the pre- distortion scheme...yet, but at least they can see the writing on the
wall, and provided a sampled output on their 1.5 kw ss amp.
## whats needed now is to get current SS and tube amp manufactures to include
a sampled output. Plan B is to just use a T connector on the back of the
amp, and tap off the T..into a pad, then into the xcvr.
Jim VE7RF
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