[Elecraft] Elecraft technology

[Lyle Johnson]

Hello Sverre!

> I received an interesting comment that it is basically the architecture
> of the K2 which is unique for a ham receiver, i.e. the single-conversion
> design and the narrow ham-band filters at the RF input -
> http://www.elecraft.com/Apps/why_is_the_k2_receiver_single.htm, and I
> agree this is key to the K2's performance. I could rephrase my question
> differently, why did it take until 1998 for this architecture to make it
> into ham receivers, why didn't it happen say ten years earlier?

Well it actually did make it into the marketplace many years ago: the early
1960's!

The Swan 175/140/120 followed by the 240 and 350 used single conversion to a
high IF with a band-switched, low-phase noise (for its day) VFO.  The Drake
TR-3 and TR-4 used a 9 MHz IF with a premixing VFO scheme (not unlike the
K1).

The Swan and perhaps the Drake used the PA Pi-Net output matching network as
the receive RF input filter, so it was even sharper than the fixed-tuned
bandpass filters of the K2.

In the early 1970s Atlas did an all solid-state update to the Swan design
(Atlas 180, then 215 and 210), and used high-level balanced mixers and
nominal 5 MHz IF.  It had band-switched bandpass filters at the input.  It's
overall design was strikingly similar to the K2, even to having a dial such
that the owners could argue about what the frequency on the dial really
meant! :-)

73,

Lyle KK7P