[Elecraft] Feasibility of KPA-1(?)

[david feldman]

Hello Jim,

The two solutions I've looked at so far are unappealing (going all the way
to the 100W level, or the hfpack-based project which includes a DC/DC
converter to run it's transistors at 28V, which has it's own efficiency 
impact.)

I have been looking for a more modest power increase, perhaps to 25-50W,
optimized for CW (no need for idling collector current), and suitable for
operation at collector voltages down to ~9V (to be consistent with K1's
input voltage range, which is a big value to me.) The Ten-Tec 405 is
a little closer (2W in gives 50W out, and consumes 7-8 amps at full output,)
but I'm not sure how it does at lower collector voltages, it's linear,
it's bulky, and in any event, it's not produced. It would be great if 
whatever
is developed could be mechanically part of the K1 (a new top cover, in space
that would be occupied by the internal battery pack, for example) and could
leverage the internal low-pass transmit filters (but for this the toroids 
may have
a saturation limit, and I doubt the band modules were ever designed with
this sort of use case in mind.)

I also had a short e-mail exchange with Wayne that ended in my suggesting
a new 3-band module covering 80 and two other bands (perhaps 40/30 or
40/20); I think something like this would be really valuable as we are now
at a lower point of the solar cycle than when the K1 was first developed.

In any event, I hope the K1 is kept "alive" in terms of product development!

73 Dave WB0GAZ wb0gaz at hotmail.com

>From: We5f at aol.com
>Subject: [Elecraft] Feasibility of KPA-1(?)
>To: Elecraft at mailman.qth.net
>Message-ID: <f6.4d9cc8b7.2f8033ff at aol.com>
>Content-Type: text/plain; charset="US-ASCII"
>
> >From Space Cadet To the Mother Ship (Elecraft):
>
>I sure enjoy my K1, s/n #01453, and use it daily.  However, there are times
>when I'm chasing DX that I'd like to be able to switch in a 10 dB boost to 
>my
>output.  Could we explore the feasibility of offering a kit amplifier for 
>the
>K1 (say a KPA-1)?
>
>I'd suggest that most owners of the K1 would immediately purchase it (1500+
>units?).  It could also make the K1 more attractive to the part-time 
>QRPers,
>like me.  The only disadvantage that immediately comes to mind is that the 
>KAT-1
>antenna tuner couldn't be used with it and would have to be removed.
>However, perhaps the KPA-1 could be plugged in its place?  Are we looking 
>at 7-8 amps
>current draw, instead of 1 amp?
>
>If you're a subscriber to this list and would like to see a KPA-1 amplifier
>kit, please join me in letting Elecraft know.
>
>R/ Jim K5HO