Date: Mon, 8 May 2017 10:00:51 +0200 (CEST)
From: "sm0aom@telia.com" <sm0aom@telia.com>
To: jtml@vla.com, amps@contesting.com, catherine.james@att.net
Subject: Re: [Amps] HV MOSFETs for RF
<One is the output stages of modern mobile telephony base stations and
repeaters for indoor coverage.
<Several of the European type acceptance criteria actually require a -70 dB IM3
suppression in a two-tone test at the +40 dBm PEP level.
<Here, the total adjacent channel suppression is of importance, which also
includes phase noise and broadband noise,
<as well as IM products.
<73/
<Karl-Arne
<SM0AOM
## + 40 dbm = 10 watts. 10 watts in Class A would be the simplest way to
achieve low IMD products.
Perhaps Elecraft should think of doing just that with their K3 series of xcvrs.
The 10 watt version of the K3
has lousy IMD, and ditto with the 100 watt version of the K3. I think the 100w
version of the K3 uses the
same 10 W stage as a driver. If you increase the idle current on the K3, the
IMD does not improve.
## Points well taken with Phase noise + broadband noise.
## I notice that my yaesu 1000-MP-MKV, when keyed, but no audio applied..mic
gain on zero,
is a lot quieter, like by 20 db, when toggling between DSP method of ssb
generation.....and analog SSB
generation,using mech + xtal filters.
## Analog SSB is 20 db quieter. This is when listening on a 2nd MK-V, 2 foot
away, with a 2 foot wire used
for an RX ant, and both xcvrs on the same freq. With no audio applied, but
keyed, I can hear this broadband
hash, while listening and tuning + or – a bit, on the 2nd MK-V. The hash
drops like a rock, when on analog SSB.
Moot point though, since nobody can hear it. Ditto with CXR suppression.
Jim VE7RF
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