In rec.aviation.owning Jon Kraus wrote:
: Our "new" '79 M20J came with a 2 year old Garmin 430 GPS and Garmin 340
: audio panel. The backup radio is an ancient King 170B. I must say that
: the reception on the Garmin sucks compared to the 170B. Am I doing

I just flew a '77 Arrow with a 430 and a KX170B. The reception on the
170B was FAR superior to that on the 430. I think that the old-timers
that designed the 170/175 radios really had a handle on how to take care
of low signal strength inputs, while the 430 designers copied the TI
databook for a "118 to 135 MHz aircraft transmitter/receiver".

Beyond that, the antennas can make a big difference in how a receiver
performs. If the old antenna and wiring was re-used for the 430 I would
consider rewiring and replacing with new parts.
--
Aaron Coolidge