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Tuesday, December 3, 2013

A review of the Kaide KK-848 multi-band midget portable radio

This is a review of the Kaide KK-848, a featherweight midget 10-band radio with alarm clock. The review is based mainly on a subjective/non-technical assessment of performance, features, and operations, as tested against published specifications and not in comparison with other radios.The radio was released during 2013

Kaide Corporation, China, which produces many other radios and electronic devices, under various brand names.

AU$9.65 plus 0.99 postage from the Kangdigital Store in Hong Kong. This model is the latest to be produced. Variants are on sale through Amazon for around AU$22. Has been on sale for 585 rupees in India (about AU$11) where it has been widely used in schools.

11 cm x 7 cm x 2cm. Weighs in at 167 grams (5.9 oz) - about the same thickness as two Smartphones.

Frequency Coverage
MW 520 kHz - 1670 kHz (readout in kHz, 9 kHz channels)
FM 70 - 108 MHz (includes Ch3 - Ch5 TV audio) (readout in MHz - eg 98.1, 98.5, etc)
SW1 5750-6600
SW2 7000-8100
SW3 9360-10690
SW4 11400-12640
SW5 13580-15030
SW6 15180-16670
SW7 17490-17860
SW8 21320-23930

Tuning - by a rotating thumb-wheel

  • SW - for each band, continuous coverage, display shows frequencies in 0.1 MHz steps, such as 9.58 MHz 9.59 MHz, 9.60 MHz, etc. No Tropical band coverage, or coverage outside of the specified bands.
  • FM - continuous coverage 70 MHz to 108 MHz. The display reads out in 100 kHz increments, such as 98.1 MHz, 98.2 MHz, 98.3 MHz, etc.
  • LED - Assisted manual LED fine tuning on each band

Two AA batteries or external 3V DC. Contained in the ”Battery Room” at back, with a ribbon to help removal. Consumption less than 200 mA.

Telescopic rotatable (47 cm extended) or clip on an a long wire

Sleek silver metal frame, black plastic mouldings, black and white lettering

  • Power on-off
  • AM-FM (toggle) - start-up defaults to FM
  • SW band selector (slider)
  • Volume - rotating thumb-wheel
  • Clock and alarm settings (clock display always on) - buttons
  • Tuning - rotating thumb-wheel
  • Orange backlight on/off (press-button)
  • Display screen - black, on white background (3 cm diagonal)

FM - red
AM - green
Magic eye -  red

Internal speaker 6 cm diameter, or earphones from standard 3.5 mm jack, 0.25 W output.

Multi-page manual is 99% in Chinese

Buttons and controls are labelled in Chinese - others in English (power, volume, tuning, FM/AM selection, display on/of). Intuition needed!

Carry Strap
To hang on your wrist or belt.

Set up via front panel buttons
  • LCD display
  • Digital alarm clock (wake-up-radio and auto power-off)

Hinged plastic flap on back to sit on a table, tree stump, or other flat surface

Performance and Design
The machine is built around Phase Locked Loop (PLL) technology.

- design specs indicate that MDS (Minimum Discernible Signal) levels for a -6dB SINAD (Signal Noise and Distortion) ratio are:

  • MW  6uV
  • SW  30uV
  • FM  20uV

Design comparisons with the author’s National DR 49 receiver for a similar- 6dB SINAD ratio are

  • MW 60uV (design attenuated)
  • SW 1uV
  • FM 3.5uV

As the author does not have an RF signal generator, variable HF attenuator, or RF signal level meter, it was not possible to do a sensitivity test under controlled laboratory conditions, and the above specs for the Kaide should be used as a guide.

  • SW - Sensitivity was reasonably constant over the entire SW range.
  • FM - At a field site in West Gippsland on Dec 1 2013, with the rod antenna, nearly all FM channels were occupied - strong sigs from Gippsland, Bellarine Peninsula, Mornington Peninsula, outer east of Melbourne, and the hotch-potch of Melbourne stations.
  • MW - Good, with daytime reception out to about 150 km.

Selectivity - no specs are available. On SW and MW, at the -6dB point, selectivity would appear to be about +/- 2.5 kHz, and at the -60dB point about +/- 15 kHz. This is quite wide. On FM, about +/- 200 kHz at -35db, and +/- 400 kHz at -70 dB.

Spurious Signal Susceptibility (internal and external)

  • SW - with various single-wire antennas - minor spurious signal breakthrough observed in the 6300 kHz  to 7100 kHz region with antennas longer than about 10 m. Of note was the remarkable absence of whistles, squawks, birdies and other extraneous noises which plague many radios in the lower price range.

  • FM - from the author’s home in Mont Albert, FM was marred by overloading and cross-modulation from the cluster of transmitters located on the Surrey Hills Water Tower, about 500 m away.

  • MW - cross-modulation effects apparent from the strong signals from the group of transmitters sited at Viewbank, a few km to the north.

  • Good sensitivity on all bands
  • Light weight
  • Midget size
  • Low power consumption
  • Digital display
  • Good audio quality and level
  • Easy to transport

  • Overloading by strong local signals on FM and MW
  • Some cross-modulation on SW
  • Frequency readout 10 kHz on SW
  • Relatively broad selectivity on SW - adjacent channel performance consequently constrained
  • Tuning control abrupt - fine tuning on SW difficult
  • Band selector slider switch coarse and very small
  • No keypad
  • Instructions and labelling mainly in Chinese

This receiver would be ideal as a companion whilst travelling, camping, hiking, fishing, at the beach, at the footy/cricket, or anywhere else! It is not really suited for serious weak-signal monitoring of SW transmissions in congested bands, even though its sensitivity is assessed as good, hampered by mediocre adjacent-channel performance, Also would be useful as an emergency radio in the house.

The technology in the device is state-of-the-art, using miniaturization, demonstrating the high level of expertise which is now apparent in electronic and communications devices designed and manufactured in China.

Potential purchasers of this radio should compare the advantages and limitations shown above before making a commitment to buy.

The author is a Chartered Professional Engineer (Communications - graduate of RMIT University), located in Melbourne, Victoria, Australia.

Bob Padula, OAM
Published: 3 December 2013

>>>> You might like to watch an eight mins YouTube review (March 2013) produced by an American SWL, which describes the radio - he said "not a bad little radio for $10".

1 comment:

  1. Dear Bob,
    this simple and cheap device is one of my favourites portable radios. (Maybe your unit suffered of poor alignement).
    In summer mornings , with the help of a 2m long copper wire attached, I'm able to listen to Radio Austalia broadcast... by the way, I'm located In Madrid, Spain.

    Thanks for your reviw and best regards.