chibo c300 world band radio

This radio has been bought ca 6 years ago (2000?) and here i re-write slighly just for reference in this site

Possibly the most expensive model of the series costing € 60 contrary to its cassette size dimensions (7 x 11x2.5) .

Included with it are :

Very small metallic colored buttons ( just only thin fingers should use it!)

- Real PLL synthesis . Step/Scan up and down and 30 memories . 5 kHz steps are used in SW 0.1 MHz in FM band

- 2 timers , including alarm sleep function ( steps of 10 minutes with max 90 mins )

- Light function lighting for 15 secs as standard

- Lock key locks all buttons on the front panel

- Hi - low tone switch on the left

- Case showing ‘world receiver’ and headphones ( earbuds) - Antenna wire

- Handling bracket built in

- Instruction for use in ‘Chinglish’ IN the report there was comparison with other chibo radios , that showed on ne of them was actually showing the exact frequency even it it uses a quasi digital system . IN contrast to this , as the radio is fully digital with PLL it shown the exact freq :

FM : 87,5 -108 ≤20 µV , 100 kHz steps and stereo when using headphones

MW: 521-1620

SW: 5950-15600 continuous in 5 KHz steps -

A button is provided for selection between these SW band starting points : 7.1- 9.5 - 11.65 – 13.6 – 15.1 MHz

- Another button is provided for changing between these three bands in carousel ( MW, SW and FM) This radio has been checked for long time with the SONY ICF7600 D as reference and shown contradictory results ( as in some cases the Sony model outperformed the Kchibo and on other cases Kchibo outperformed Sony). Results from my measurements

- Very long time for changing between freqs : 1.1 sec. Step button operates also as scanning function

- Using most by thumb of the buttons produces high local oscillator noise coming into radio - Frequency indications are now exact.

- And relatively good AGC operation.( he only with some AGC??) IN case of cross-interferenced signals however there is a very high ripple - Headphone cable affects as antenna

- FM sensitivity higher regarding to 979 without the mess of overloading.

- FM Selectivity Better than 979 but not as of 7100 . Relatively better than Sony

-FM stereo audio ( via ear buds) is very good . Level as of a medium class stereo system SW/AM Sensitivity: Better than 979 . Nearly same with R75 with telescopic antenna unfolded and full preamplification( 20 db) . And relatively same level with ICF 7600 D though in some cases 7600 was better Also it is found that using wires more than 3 m overload the radio.

- Earbuds: Seem typical quality stereo earbuds. About -2db than my Philips open ear buds with ? atter audio response

- AM/SW selectivity: About 6-7 kHz . Much better than the 979 ( abt 15kHz ??) but less than 7600D ( it seems les than 4.7 kHz) . More on this in the pictures on the end . However as in result it produces pleasant audio . ON parallel listening with Sony model earbud to earbud for a given freq. range audio was in the middle .

- 3 VDC : Unkown problem with 3VDC from non stabilized adaptor showed locked all radio operations .

- Listening with its own speaker: I found that in vacant freqs the inner oscillator circuit is heard. NOw i never use its spaker , as i only use the Koss UR60 headphones for the best audio. Opening the cover : All ICs have their IDs clear and are posibly replaceable after a very lengthy usage: 1 . Suddenly , the antenna has been cut in half. This made the radio possibly lose much of its sensitivity (?)on FM but the SW eficiency is still very good : Using more than 3 m of wire it overloads itself 2. The audio in FM is still very good. It has nearly the audio of a HIfi system , with comaprison with te same headphones (UR60 Koss ) 3. AM efficiency is also quite good . Did not tested with other comaprison but also soem low power signals are audible And here are several pictures of the radio: ON the right corner clockwise : Operation LED , operation button , band button , up down freqs with cyclical buttons , mem up and down. (10 per band) Memory store , shortwave band ,sleep time (with 10 minutes steps downwards ) and background light

A close up of the radios' botons and indicatins

and left panel picture: HI low treble audio , earphones , DC in 3 V