C-crane W8JHD Manuel d'utilisateur télécharger pdf

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.

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.

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Page 1 - AM Antenna

August 2012 MONITORING TIMES 71 In order to maintain measurement linear-ity, the receiver does not have automatic gain control (AGC),

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