C. Crane W8JHD - Manual

August 2012 MONITORING TIMES
71
In order to maintain measurement linear-
ity, the receiver does not have automatic gain
control (AGC), so to prevent front-end overload,
a step-adjustable preamplifier/attenuator can
adjust signal gain from -16 to +45 dB. Selection
of the signal-level-dependent attenuator can
automatically switch the process on or off.
A 144 dB scaled signal is channelized to
prevent an adjacent 40 dB-stronger signal from
suppressing the weaker signal, enhancing DX
reception. Depending on the pre-amplification
chosen, the 1102S has 96-136 dB dynamic
range.
❖ The Bottom Line
Getting used to the myriad controls, some
with unfamiliar legends, will take some time, but
properly adjusted, this receiver offers outstand-
ing performance. Down-loadable updates for this
new product are available free of charge from
the manufacturer on a regular basis.
The Bonito RadioJet 1102S is available for
$699.95 plus shipping from Grove Enterprises.
E
ven though some listening hobbyists
would say that AM radio is an anach-
ronism, there are still enough folks
listening to the 530-1700 kHz broadcast band
to justify new product development.
The traditional approach to enhancing
medium frequency reception without using
an outdoor aerial is by using a loop antenna.
These can be large or small, and either an open
winding of wire or a smaller ferrite rod loop.
Some are amplified (active) and some are not
(passive).
One of the most successful loops was the
Select-a-Tenna. Roughly a foot in diameter,
it could be plugged into the external antenna
socket of a radio, or simply placed in close
proximity to the radio in order to “focus” the
desired signal to the radio’s internal antenna.
Although an excellent product, it is no longer
manufactured.
So what makes the C. Crane AM antenna
different? It is amplified and has several sepa-
rate components. Its antenna may be mounted
inside or outdoors (which may require ordering
an extension cable in 25 or 50 foot lengths).
The amplified tuner may be powered by
the AC wall adapter (included) or a nine volt
battery (not included). It will work with radios
with or without an external antenna jack.
❖ Radios without an
External Antenna Jack
Since portable radios have internal AM
antennas, the C. Crane loop must be inductively
coupled to the internal antenna. This is done by
pressing a ferrite coupling device to the cabinet
of the radio close to the internal antenna.
The tuner control is set conveniently
near the radio so that it can be adjusted by
the listener. The antenna element is placed
anywhere in a six foot radius that it picks up
signals best with minimum environmental
electrical noise.
❖ Radios with an External
Antenna Jack
If your radio receiver is equipped with an
RCA phono jack to accommodate an external
antenna, or separate antenna and ground ter-
minals as found on most home entertainment
stereo receivers, cabling and an adapter are
provided to make that interconnection. No
provision is made for radios with a 1/8 inch
phone jack or SO-239 antenna connections.
These adapters would have to be provided by
the user.
Options and accessories available
at additional cost:
Decoding software (for RTTY, CW, PSK, SSTV, FAX and time signals)
Transmitter control and encoder software (for modes listed above)
Combination transceiver control and encoder/decoder (for modes
listed above)
Project 7 RadioCom receiver/transmitter
Weather receiving software (NAVTEX, RTTY, Synopsis)
USB connected tuning wheel
16 or 32 ft. USB extension cords
Mounting bracket
Circuit Architecture And Technical
Specifications
All specifications are subject to change
without notice.
Software for Windows 7, Vista, and XP
PC-Connection and Driver installation: USB 2.0
Input Sound Samples: 48000 at 2x16 bit resolution
Output Sound Samples: 24000 at 2x16 bit resolution
Left Channel: DX-Channel +30 dB for real 48 dB in high
resolution
Right Channel: RX-Channel real -137 dBm (0.03µV) in 16-bit
resolution
Automatic channel selection: RX/DX real 144dB in 24-Bit
Resolution
A/D Converter: 2 x 16 Bit cascaded to 24-Bit high resolution
Mixer Dynamic Range: -16 to +45 dB
Technical Demodulation method: Real sampling (No I/Q-Complex)
Demodulation Modes: LSB, USB, CW, AM, FM, Stereo-DRM
IF-Filter: Variable 100-24000 Hz at +/- 5 KHz Shift
IF-Equalizer: Manually (mouse) adjusted filter for Notch and
Bandpass
IF-Recorder: Record and Playback 24 KHz / 48000 Samples
IF-Spectrum Analyzer: 24 KHz / 160 dB with 3D-LandScape and
Time Spectrum
Power consumption: 220 mA max., USB-Powered
Size/weight: 4”W x 1-1/4”H x 3-1/2”D, 7 oz.
Reception Method: Active Mixer 45.012 MHz + VFO; no AGC
Frequency range: 9 KHz – 30 MHz in 1 Hz Steps
IF-Band width: 24 KHz
IF-Filter: 15 KHz (- 3dB) crystal filter
Image rejection: >90dB / 1.IF (LO + 45MHz) >70dB / 2.IF
(In-Band -24KHz)
Dynamic range: ~96.32 dB real = () =~136.22 dB by
“Squaring the circle“
Noise floor (0.15-30MHz/2.3KHz BW): -137dBm (.03µV) -122
dBm (.18µV)
Linear processing level (0.15-30MHz/2.3KHz BW): -40 dBm
-15 dBm
Intercept Point (IP3): (7.00 & 7.20MHz) +14 dBm +29dBm
C. Crane Twin Coil Ferrite™
AM Antenna
By Bob Grove, W8JHD
❖ Setting it up
After the separate modules are intercon-
nected (you can’t mismatch connections) a weak
signal is selected on the radio – the more barely
readable, the better. With the ferrite probe set on
the portable radio top, the tuner is then switched
on.
Slowly rotating the large concentric knob,
an increase in signal should be heard at one
setting; the inner, smaller tuning knob is then
adjusted for fine tuning.
The ferrite probe is move around the radio
to find the “sweet spot” of strongest signal cou-
pling, and then the antenna element is positioned
the greatest increase in incoming signal strength.
❖ Let’s try it out
I decided to try a worst-case scenario. Us-
ing an over-the-counter AM pocket radio with
the ferrite probe against the top of the case, I
randomly selected stations that were barely
above the background hiss.
In each case the C. Crane loop brought the
signal up to 100 percent intelligibility. It must
be pointed out that tuning is quite sharp, and
although there is backlash in the main tuning
dial, it is easily resolved by adjusting the fine
tuning knob.
Success is dependent upon location and
orientation of the main antenna element. If it’s
close to interference-generating appliances or
wiring, then it’s going to amplify that noise.
But with the antenna free and clear of noxious
noise producers, and its position favoring desired
incoming signals, the ferrite loop antenna will
provide substantial signal improvement over the
radio’s internal antenna.
Twin Coil Ferrite AM Antenna, $99.95
from Grove Enterprises and some MT advertisers
and from C. Crane, 1001 Main St., Fortuna, CA.
Website: www.ccrane.com, Email rreynoza@
ccrane.com; Phone (707) 725-9000.