The TinEar Receiver Construction Manual
Introduction
Thank you for buying the TinEar Receiver kit. This receiver is the result of a discussion that
arose at the end of Pacificon, 2003, where an interest was expressed in a simple, discrete part
receiver design, one that “everyone” could build at Pacificon, 2004.
However, once the Ugly-style prototype of this design was built, tested, and listened to, it
became apparent that this little receiver would have appeal not only to those who could attend
the next Pacificon, but also to the QRP community at large.
Simply put, the TinEar receiver performed much better than expected. It certainly cannot be
compared to a superhet design with either a variable bandwidth IF filter, or a choice of narrow IF
filters, in terms of selectivity. However, the clean, clear audio from this simple design, coupled
with its wide tuning range, supplied by a simple, permeability tuned VFO, gives one the ability to
tune more than the entire 40 Meter band and allows one to listen to any type of signal available.
This covers the whole gamut from CW to AM, including Digital and Single Sideband.
One could certainly connect this little receiver to a computer’s sound card, and decipher any of
the modes for which sound-card related software exist, or do like one Ugly-style builder has
already done, plug an outboard audio amp and loudspeaker into it and listen to it in arm-chair
style.
The TinEar receiver is designed to operate from a 9 Volt Battery, but will certainly need more
than a simple hunk of wire as an antenna. The receiver’s input is designed for a 50 Ohm
coaxial input, and a 40 Meter Dipole, even at very low height above ground, or even a portable
whip such as a Hustler whip on a car, or a short, inductive loaded vertical and counterpoise, will
supply more than enough signal strength to provide hours of listening enjoyment.
The audio output of this little receiver was deliberately designed to be just a little on the low side,
compared to a “big rig”, both because of the type of power supply it is designed for, and
because there is no AGC circuit. However, the use of sensitive earphones or ear buds will
ensure that there will be more than sufficient audio.
Please note that some types of 9 Volt batteries can cause either motorboating (a thumping
sound in the earphones) or a heavy hissing sound in the earphones, even when no antenna is
connected. Duracell batteries, among other similar types, work well in this receiver, and give
several hours of operation.
Copyright 2004, NB6M - Unauthorized Copying or Publication Prohibited
