HearSat Frequently Asked Questions (FAQ)

1. What kind of receiver do I need?

In answer to this question there is good news and there is bad news.
First -- the good news. You can go out to your local Radio Shack store
and buy yourself the cheapest "scanner" you can find. Equipped with
this modest receiver and the whip or "rubber-duckie" antenna supplied
with the unit, you will occasionally be able to receive a few satellite
signals. Now the bad news. For serious satellite work you will need an
expensive specialized receiver.

Here are the limitations of the average scanner:

1. Low sensitivity
Scanners are designed to receive local, terrestrial signals. If they
were built with high sensitivity they would suffer from excessive
inter-modulation distortion.

2. Frequency Step
Again, scanners are designed to receive terrestrial signals. Terrestrial
band plans separate signals by fixed amounts (usually 5KHz or more).
Satellite frequencies are often separated by only 100 Hz. Unless you are
able to tune into the downlink frequency precisely, the signal will be
attenuated, distorted, or simply unreceivable.

3. Reception Mode
Many satellites transmit in either AM (Amplitude Modulation) or
FM (Frequency Modulation) modes. Scanners will receive strong satellite
signals transmitted in AM or FM. Unfortunately, many other satellites
transmit in SSB (Single Side Band) or CW (Carrier Wave) mode. The
average inexpensive scanner will not be able to receive these modes.

4. Bandwidth
The average inexpensive scanner has the wrong bandwidth for many
signals. For example, it will not permit you to receive weather pictures
from the Russian and American weather satellites (which are VERY strong
signals) because the narrowband-FM mode commonly used is not wide enough
for APT (Automatic Picture Transmission) signal decoding. Furthermore,
the wideband-FM mode found on better scanners is too wide for APT
decoding.

CONCLUSION
Do not be discouraged if you cannot afford to buy an expensive
communications receiver. You can have a lot of enjoyment with the
cheapest scanner. With a little attention to detail (such as building or
buying a better antenna) you will easily be able to receive signals
from the US Space Shuttle, the Russian Space Station Mir, weather
satellites, navigation satellites, some amateur radio satellites, and
Low Earth Orbit (LEO) communications satellites. Eventually, you may
not be able to resist the temptation to break open the piggy bank for
something a little better -- this hobby can be addictive!