Why use a car
receiver in the home?
generally have excellent FM sections and it is not uncommon for
enthusiasts to use
them as a primary or secondary tuner, connected to an external antenna
home. Car receivers offer several advantages & disadvantages over
conventional hi-fi component tuners. Long distance FM enthusiasts David
L. Pierce & Ryan L. Donaldson have gone down
this 'road'! Here we share our collective thoughts. Updated content
from Mike, Murray & Peter who have provided valuable experimental findings. We hope
will be of some use to newcomers to the hobby.
- Better selectivity
- The vast majority of component
tuners available have only two IF filters in the FM section. Furthermore, the
filters chosen are 'lossy'. They
designed to maximize fidelity, not sensitivity. Car receivers, without
exception, utilize two or three FM IF filters fed into a DSP chip or
filters for a conventional FM IF design. The number of FM IF filters
be as high as four in some models. Car receivers are designed to
selectivity due to the difficulty inherent in receiving signals in a
environment. According to independent lab tests, the Blaupunkt
Digiceiver offers at least 72 decibels of selectivity for signals
spaced 200 kHz apart. The JVC HS-IVi receiver offers at least 64
decibels, according to the chip manufacturer's lab tests. For signals
spaced 100 kHz apart, the JVC HS-IVi receiver offers at least 24
decibels of selectivity.
- Digital IF Front
End commonplace - Component tuners
featuring Digital Signal Processing
(DSP) or adaptive IF are extremely rare, while DSP car receivers are the
norm rather than the exception. Applies to models marketed from the mid 2000's
- Digital tuning - Car radios
invariably feature Digital Tuning, which is considered a prerequisite for FM DX
because of the need to know exactly what frequency you are tuned to. Many component tuners do not.
sensitivity - Car receivers are
generally coupled with a telescopic monopole antenna with no theoretical gain over a dipole. The metallic exterior of a car may act as an effective ground plane. For
reason, car radios are therefore engineered to be very sensitive, in
maximize weak signal reception. Some European manufacturers such as
Blaupunkt include dual diversity amplified antennas. Dual diversity
antenna systems may outperform a single monopole antenna.
- Inexpensive - Cheaper and more readily available than component
tuners. If buying secondhand, car receivers with a faulty CD section (which is
not necessary for DX use) can be obtained for next to nothing.
- Multi-purpose - The car
radio can be transferred between a vehicle environment and home environment as
required. Removing a car receiver is typically achieved in 15 minutes or less
with a screw driver and wrench. Some
radios, especially aftermarket ones, come with specialized tools that can
remove the radio quickly.
- RDS commonplace - Radio Data System (RDS) is a normal feature rather than
the exception. Increasingly, RDS is gaining traction in Australia as DAB Plus
coverage concurrently expands. RDS is an efficient way of identifying stations,
provided the signal strength is adequate enough to allow the receiver to
'decode' the data from the signal.
- Same tuner across
the range - In the past, many car receiver
manufacturers, including Panasonic,
Pioneer & Sony implemented the same FM section in every domestic
model. This meant that the
cheapest model offered equivalent performance to the top shelf model.
There is evidence to suggest this is no longer the case for current
- High quality amplifier built in - Just add car
speakers for a rich listening environment. If the cassette, minidisc, CD
or digital audio device input is functional, the device is useful for listening to something other
than the radio.
Audio output - Almost without
exception, car radios have conventional outputs known as RCA/phono/line out.
This means you can connect a minidisc, tape or other type of portable
recorder and be able to easily record DX on the go.
- Compact - Many of the home radio
tuners were designed to be close to the size of a DVD player. A car receiver takes up much less space in a
DXer's 'shack' & can be easily packed into a suitcase. The durability of these
units is unprecedented, they are virtually bullet proof.
unappealing - To non-DXers, it looks
quite odd to be using a car receiver in your home! Not the correct size for
placement with hi-fi components. A DXer could make a custom case to cover the car
radio in a shack to better match their other equipment,
providing they have vent holes so the radio won't overheat.
- Cumbersome to tune - Rotary tuning dials are the exception rather than
- Memory retention - The vast majority of receivers lose their preset
stations upon power off. This
important when transferring a car receiver from the car to the home.
There are exceptions including the Alpine Max Tune Professional tuner
& the Blaupunkt Digiceiver tuner. Your presets will be kept
permanently, just like a component tuner.
Powering the radio - A car radio usually needs the purchase and fitting
of a DC line socket and 12 volt 1.5amp DC plugpack so it can run on indoor
power. Cost is $25 or less. While it is generally safe as 12 volt voltages only
are used, some basic electronic knowledge or assistance is useful to determine
the yellow, black and red power leads. No soldering is required if a DC FastOn
Barewires socket (Jaycar Electronics) is used.
- Noise -
The FM section of car receivers may have slightly
poorer signal-to-noise ratios than their conventional component tuner
very weak signals. This only applies if the component tuners are being
high quality amplifiers. Poor quality amplifiers, such as 'powered
speakers' are likely to introduce more audible hiss, likely offsetting
any potential benefit to
DXers using conventional component tuners.
- 'Modding' ain't easy
- For those who like to 'fiddle'
with equipment, filter modifications can be performed on car receivers,
surface mount components, double sided Printed Circuit Boards and
accessibility make it unpleasant to do so. It takes longer to perform
modifications than it does with a conventional tuner and the likelihood
damage may be higher. Adding Filter Adder Boards would test an
patience! It is worth noting that Sony SSIR-EXA radios are extremely
easy to modify, no more difficult than your average component tuner. Kenwood K3I Clean Reception
Tuner radios are difficult to modify because of the metal shielding over the tuner module.
Discussion concerning the most selective adaptive IF car receivers, according to
real field testing by German long distance FM enthusiasts is archived here.
Highly rated FM tuners include Blaupunkt's Sharx Twinceiver, Sharx Digiceiver and
Alpine's Max Tune Pro.
Last Updated on: Wednesday, 26 October 2011