[Elecraft] IMD and supply voltage

[Matthew Cook]

Frank,

Actually No.

You can build solid state 125Wpep HF amplifiers with TX IMD figures better
than  -42dBc that operate quite happily at full power with only 11V.
Unfortunately they are typically designed and built by Military and
Commercial HF manufacturers who then have to recover their development
costs with very high transceiver prices.  I don't think most Hamsters will
want to pay for the amortised development costs, they are not insignificant.

The last commercial BJT HF amplifier design that I was involved with
required ~6 man years of development work and easily made the above
specs/grade, this was done 9 years ago.  However while the FCC and other
regulatory bodies don't make the specifications for Amateur gear better,
then there wont really be any serious developments in this area why would
you?

However there are an equal amount of poorly designed tube amplifiers c.f
solid state amplifiers on the air waves, so this phenomenon is not uncommon.

Oh the K3/K3s 100W power amplifier is certainly well above par, especially
when kept around 30Wpep; just the right amount of power to feed the KPA500
or well designed QRO tube amp.

73

Matthew
VK5ZM

On 30 October 2015 at 10:11, frank <frank at k5dkz.com> wrote:

> On Thu, 29 Oct 2015 15:21:05 -0700
> Wayne Burdick <n6kr at elecraft.com> wrote:
>
> > Yes, we made sure compression was off. We gave the unit every
> opportunity to exhibit magic properties. Alas, it did not.
> >
> > Wayne
> > N6KR
> >
>
>
> Sounds like all solid state amps offering more than about 50 watts are
> having growing pains.  It does not make much sense investing in something
> you might need to trash in a few years when someone decides to design a
> decent solid state amp or the chip designers create a magic power device.
>
> For my money its a K3S/10 and a homebrew 6146 run off a mobile power
> supply.
>
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