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Barlow's Television Co., P.O.Box 23, New Germany, Natal, Rep. of South Africa
Barlow Wadley XCR - 30

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überarbeitet am 22.7.2010

In 1974, a portable shortwave receiver with the dimensions of a conventional travel radio got very much attention among the shortwave listeners comunity. The first time, a circuit developed by Dr. T. L. Wadley for the British commercial receiver Racal RA - 17 was used in a travel radio. The circuit was developed by Dr. Wadley who had moved to South Africa after his retirement and the set has been built by the South African home electronics manufacturer Barlow's Television Co.
In it's time, the set had the early Grundig Satellit radios, the Zenith Transoceanic, the Panasonic RF - 2200 or the Earth Orbiter CRF 5080 / 6090 as concurrents on the market. None of these sets featured a linear frequency readout with a precision better then 5 kHz and SSB reception capabilities that allowed ECSS technique (listening to the separate sidebands of an AM signal using the internally added BFO carrier instead of the carrier of the station's signal).

double conversion, IF 45 MHz, 455 kHz

analog linear dial 5 kHz

500 kHz - 30 MHz

AM, USB / LSB, (FM optional)

sensitivity

selectivity -6/-60 dB
AM 6 / 17 kHz, SSB 3 / 13 kHz

preselector, S-meter

Service Manual Service Manual with schematics: Service Manual and Schematics

This portable receiver (29.5 x 18.5 (23.5 with carrying handle) x 10cm, 4.3 kg) comes - to avoid interference within the 45-75 MHz range due to the mixing process) in a sturdy metal housing with black imitation leather coating at it's sides. On top of the set, You find a carrying handle with a amall short wave frequency chart folding up underneath. When You unscrew the back lid, You will find access to the battery compartment, where six UM-1 / mono cells will fit in.
The front panel is dominated by the two segment frequency dial. The left thumbwheel indicates the megahertz range - the one on the right the kHz steps. The distance between the 50 kHz marks with it's light green numbers and the 10 kHz lines allows to determine a frequency within the range of 5 kHz. You tune the kHz of a chosen frequency by adjusting the frequency thumbwheel on the right side of the dial window in the middle of the front plate after You have chosen the matching MHz - band.
Next to the frequency dial on the right, You find the signal strength meter moving in a small window, it's calibrated in 1 - 5 divisions. With the small metal knob below the signal-strength meter, You can adjust the oscillator exactly to the displayed frequency when receiving a station on a known and stable frequency.
Further down on the front panel, You find four large rotary knobs. The left bottom knob ist used for switching the set on and activates the volume control, th knob above operates the preselector. It has only some rudimentary marks where to look for the signal maximum once You have tuned in a station. Some preselection is made by micro switches operated with the rotation of the button.
The rotary knobs on the right are used as mode switch (USB (upper side band) / AM / LSB (lower side band); in some Pro versions, You find an additional control to choose the IF bandwidths of 6, 3 and 1,5 KHz. The knob above is used for fine tuning particularly for CW and SSB (ECSS) reception.
The antenna and earth connections are implemented as quite uncommon 3mm sockets on the left top side of the set: On it's left side, You find the sockets for a pair of headphones (3.5 mm) and for an external 9 V power supply.
The 9 cm diameter speaker in the centre of the front panel gives You pleasant audio with it's 0,4 W output power. Don't expect to find further goodies in this straughtforward constructed set like as dial lights, bass/treble control, but this will not bother You successfully tuning in shortwave stations from all around the globe.

The signal path is - like in similar receivers using the Wadley loop - design, a bit complicated: The incoming signal from the antenna socket will pass the preselector stage with its ranges 0.5 - 2/2 - 8 and 8 - 30 MHz and first amplifier stage and will be handed over to the first ring mixer, where the oscillator signal of 45,5 - 74.5 MHz is added. This signal is tuned by means of the "MHz" wheel. Thus the high first intermediate frequency of 45.2 MHz will result.
In the next mixer, an oscillator signal of 42.5 MHz is subtracted, to arrive at the intermediate frequency of 2 - 3 MHz.
After conversion to the usual second IF of 455 kHz, the signal will pass through the filter bank (in the "Pro" - version, You will find different filters here). In the original version, the passband of the intermediate filter is electronically enlarged for AM reception. Then the signal will pass a diode for AM detection, for SSB/CW a product detector is used.
This receiver layout results in a very sensitive receiver with good suppression of unwanted signals and a very useful dial accuracy (better then 5 kHz) in a reasonably priced set usind only one printed circuit board and standard components. Remember - this set has been constructed before digital readouts became affordable for the public.

The operation is not absolutely simple but can however be learned within minutes - it's similar to the one found on all other sets using the Wadley Loop circuitry. No wonder, the set has been designed by Dr. T. L. Wadley after he had settled down in South Africa after his retirement from Racal:
After switching on the set, adjust the MHZ wheel to desired MHz band. You may observe the signal strength meter and listen to the noise to find the signal maximum. With the kHZ - dial set to zero, You can tune in to the signal of the internal oscillator giving You 1 MHz marks. Set the mode switch to USB/t and tune for signal maximum and zero beat (where the whistling noise diasappears) using the tiny knob below the signal-strength meter. Now set mode switch to AM and adjust to the desired kHz setting using the right thumbwheel. With Your set on 6075 kHz, You should be able to recognize the signal of "Deutsche Welle" now, at least as You live in Central Europe. Now use the ANTENNA TRIM / preselector control withing the correct range to "peak" the receiver to maximum signal strength. In case of severe adjacent channel interference, try ECSS reception using the set in SSB mode and switching to the sideband less affected. Carefully tune the set until the voices become intelligible and the "whisling" will disappear, You also might use the "CLARIFY" control for doing this.

The Barlow Wadley offers nice audio and a good useable sensitivity to today's shortwave listener, but usually You will take a smaller less fragile set with You when You travel abroad. The somewhat inaccurate frequency readout (a detuned frequency calibration knob, wrong clarifier position won't affect the dial settings) and the slightly cumbersome tuning scheme will make the set a choice for the collector and the nostalgic shortwave listener. Battery consumption is very low compared to the later PLL synthesizer designs, so a set of batteries in Your second shortwave set will last for weeks or months.
Apparently, the final inspection at the Barlow plant seems to have sufferend from daily fluctuations, cold soldered connections, a susceptibility of the printed circuit board to hair-fine cracks can cause problems, the first HF tends to blow on static discharges from too long aerials connected to the receiver. So it's worth unplugging the external antenna when there is a risk of lightning.

The variant with the FM tuner cannot be found too frequently: the FM tuner module is attached at the top of the receiver's cabinet and is operated by a pushbutton: this feature will make the XCR-30 to become a nice holiday radio

My XCR-30 is not meant to replace my Sony 2001D, but it will always merit it's space on my shelves because of it's fascinating circuit, the inconspicuous outside and the amazing reception qualities of this oldie amongst the portable sets.

further reading:
d: Der einzige "Afrikaner": Barlow Wadley XCR-30, Nils Schiffhauer, Oldie- Kurzwellenempfänger
d: Barlow Wadley XCR-30, R. Lichte, Kurzwellenempfänger, die Qual der Wahl
d/e: www.radiomuseum.org

© Martin Bösch 20.7.2007