In article ,
"Pete KE9OA" wrote:

I think you should buy the preamp if you think you will like it. I
think that the reason nobody on this NG seems to have the Kiwa preamp
is because they all have decent receivers. With a halfway decent
receiver, you don't need a preamp. The trend in recent years has been
to use NO RF amplification ahead of the 1st mixer. In the tube days,
an RF amp was generally needed, because of the use of pentagrid
convertors, etc. Exceptions were the R390 (at least the 1970s unit I
had), which used a 6C4 1st mixer, the Squires Sanders IBS Superhet
and their amateur version (SSR-1 or SS1-R?), which used a 7360
balanced mixer. If you have a good NF, there is no need for a preamp.
A case in point...........even though the Kiwa preamp, which is very
good, has an IP3 of +34dBm, the gain that the preamp provides still
degrades the IP3 of the receiver itself by that same amount. +34dBm
is ok for a high level preamp, but it is possible to design an RF
preamp that has a +40dBm IP3. In all fairness to Kiwa, the preamp is
very reasonably priced. I once looked at a schematic of the
regenerative preamp for the Kiwa loop.............a very good design.
The things they were doing with the high performance ceramic filters
were very good. Too bad Murata decided to discontinue everything but
their 4 and 6 element ceramic filters.

The only reason I can see for a pre-amp would be a very low gain (small
size) antenna such as a small loop. A table top radio with a full size
antenna would probably not get much benefit from an amplifier. The only
other exception to this was the very low noise surroundings example
previously posted.

--
Telamon
Ventura, California