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TESTING KCHIBO RADIOS

This article has been made with the following things on mind

1. The radio can be as low priced as possible and have SW band capability. You can consider students on the university for example or people having no fi nancial background. This is I could say the “very poor mans radio”

2. To test these so low priced radios and access results

ON the other side the recent time I have made a survey on the local market. I found that KCHIBO has a broad range of radios. Except the very low cost AM FM radios there were also a broad line of radios having also SW capability.

Here is the list of KCHIBO radios with SW and their approximate prices:

KK1099 € 10 KK999D € 18 KK634 € 8 KK979 € 20 C 300 € 60

All the above models have been tested and inspected as you will see on the next pages

Also a BOLONG model has been tested here and is found on 7th page

Notice: I totally have no connection with the company neither I advertise them. This is just a review of several models I tested

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This is the cheapest of all the models tested. ( About € 8)

The radio has MW , FM and 8 subparts of the SW band. It has a LO DX switch and a electronically controlled AM FM switch. This AM switch then is separated by a 9-pole switch for the appropriate band

Freuencies stated in the panel: ( with the results as found)

- MW: 530- 1600 (actually 521-1660. I have heard one station on 1660 ) SW1 : 5.5- 6.74 (actually 900 kHZ more! Same occurs for all other SW bands ) SW2: 6.57-7.86 SW3: 8.36-9.57 SW4: 11.1 – 12.2 SW5: 13-13.84 SW6: 14.47- 15.5 SW7: 17.15- 18.28 SW8: 20.97-21.97 (here the fres are separated by abt 300 kHz FM: 88-108 (about 87-109. I heard out of band stations on both parts )

Here are the results of testing it for several hours Reception / sensitiviy MW : poor reception SW: fair reception,., There are two very strong

radio stations on FM/VHF II causing overmod on the upper SW bands of this radio. When telescopic antenna is fully unfolded. Did not tried for over-moding

FM : good reception . Nearly all radio stations were listenable

AMP switch. Amplifi es all bands .On the model I used (S/N C9700666) the switch has bad contacts. Another unit I tested did not have this problem Using it , it produces higher audio levels and extorts the noise level too. I don’t think that it helps in getting lower signals

Tuning : Totally analog tuning with a low uality tuning knob as well as tuning capacitor. Its shaft is not correctly contacting the capacitor thus having gaps while tuning

Inside: Opening the rear side I seen something crazy . the letter stamp over the IC s surface has been rubbed , so no chip ID!!

Audio: Highly trebled audio on all bands. In FM and non condensed bands is OK but in highly condensed bands especially in SW adjacent channel RM ( up to 10 Khz far) can cause uite annoying hets Switch on by audio resistor.

Earphone socket: And something nice. The plug is stereo plug compatible.

DC 3 V socket : Is also included

Using your hands on the rear side the tuning capacitor is tuned out.

KK634

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Its main features. This is possible the smallest quasi digital radio

-Digital readout even if it is not a100% digital operation . -Frequency counter to 10 kHz ie M.kk for SW band . and 1 kHZ resolution for MW The frequency remains also

after setting it off -Time and alarm setting built in -Standing rack in the rear panel -Case and Headphones -Instructions for use And everything in a price of only € 15!!

Here is what I found while using it. ( at right what noticed in the specs sheet and then the sensitivity as listed )FM : 86.5- 109.2 !! 87-108 ≤20 µV , 100 kHz stepsMW 527-1661!! 526-1605 ≤4mV/m 1 kHz steps

SW1 5.90 –6.99 5.95-6.2 ≤100 µVSW2 7.00 - 8.13 7.1-7.3 SW3 9.30 – 10.33 9.5-9.9SW4 11.58 – 12.52 11.65-12.05SW5 13.3-13.95 13.6-13.8SW6 14.85-16.15 15.1-15.6SW7 17.50- 18.27 17.5-17.9

And here are the results after testing it:

Sensitivity: MW: relatively poor reception , but better than 634 SW: Seems to have high sensitivity but contradictions when using external wire. For example I could listen

to a station on 12172 with signal S3-4 as shown on R75 . But It could not receive AIR 10330 ( a S3 level on R75)

FM: good also reception. Nice that still some radios can receive out of band stations!

In practice , the radio has a relatively lower sensitivity over Yupiteru in SW Could not fi nd the selectivity on FM

KK999D

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Front paenl buttons

This is the fi rst model I bought before testing for use by my wife . Middle cost model ( € 13) is the nicest model from all . Unfortunately the model shown very modest specifi cation on Shortwaves. For example a strong station could be tuned in a very broad range up to 100 kHz from its main frequency.

For this reason I will make some comments here :

It is supposed to listen to VHF audio. I could not fi nd the audio channel from MTV. IN contrast the band seems to start from the 87.5MHz

Tuning: hard to tune ( very stiff knob)

Audio quality: Somehow better than other models. IN the SW bands a Turkish station had very good HiFi audio quality

AM band starts after switching on ( via the volume resistor) IN 636 Fm starts

DX switch worked properly

3 VDC socket included

Earphone socket: stereo compatible

KK1099

This is one of the little higher cost. Its price is € 20 and its resulted specifi cations seem to be a derivative of the 999D . S/N is 1841000. - As advertised it includes also TV Ch 4 band - Digital display again to 10 kHz on SW using a better tuning mechanism than 999D *( ie not so fi ne

tuning) - Clock and alarm are also included .- Case and instructions in ‘Chinglish’ Also handling bracket.

979 has been checked with C300 a, Yupiteru 7100D and partially with R75 with telescopic antenna

Measured freqs - [also var by inlet capacitors ]FM : 63.5- 109.4 !! 64-108 ≤20 µV (again also outbanders) MW 517 –1657 SW 1 54.72- 6.42 SW2 6.84-7.64 SW3 9.37-10.28 SW4 11.41-12.52 SW5 13.03-14.16 SW6 14.99-16.06 SW7 17.24-18.30

SW8 21.27-21.95

Reception / sensitiviy + MW poor to good reception ( not as C300)

Step is 1 kHz Variable ampli setting by inlet capacitor

+ SW: fair to good reception . Possibly slightly better than 999D(could not crosscheck ) a little better than Yupi 7100and nearly the same with R75/tel antenna with 10 db preamp. Two bands show noise from splatter from the local FM radio stations .Apparent heterodynes in parts of the band either from the lower side or even from the upper side. Step is 10 kHz Variable ampli setting by inlet capacitor

+ FM : fair to good reception but surely high sensitivity or low dynamic range . The radio seems to overload from the two local signals

KK979

( abt S9+40) . When using headphones , the cable can also act as antenna Variable ampli setting by inlet capacitor

LCD is nice with big numbers. When radio is turned off the radio shows the time. Tuning is abt 5kHz higher than the displayed.Tuning: It is now better than 999D , not so fi ne tuning . Selectivity: Low level Seems to be same as 999D (Spectrum analysis as shown in page 8 shows abt 15 kHz or more) Audio: very nice audio with very clear sounds Earphone socket: stereo compatibleDC in : 3 VDC with positive on shield Using headphones enhances drastically the listening eliminating the oscuilator’s noise

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Freq read out: (a forgot point) For SW bands: M.kk with 10 kHz resolution For MW band : M.kkk with 1 kHz resolution For FM band : MM.k with 100 kHZ resolution

1- Tuning : in many cases the tuning knob does not tune especially in fi ne tuning . Posibly it’s a difer-ential tuner or plastic axe is not so sensible 2- Can be tuned internally - by 4 capacitors- for change of center band freq on MW and SW amplifi cation level on MW/SW and FM . FM capacitor also effects on AM partially

3- Battery operation More than 40 hours using it 30 cm far from ears. 24 hrs continuous operation with same audio level 4. Using with full amplifi cation level MW : very strong MW sigmals have very broad freq listening

Example: signals of ERA 1044 50 kW can be heard up to 1115 , the 1179 can be hgeward up to 1245 and the University radio 1431 (100 W 500 m far) up to 1560

FM: overloaded at all band. ripled fi lter with two peaks

More on FM: Images of 21.4 mHZ lower. Lowering the FM sensitivity causes clearer signal on the lower part. This ‘problem’ diminishes when the internal amplifi cation capacitor is lowered. BUt using mains adaptor the effect continues I found that several freqs are clearer in the lower part thean their nominal freq

5. MW : Internal LCD display causes QRN to all band (as like fl uorescnt lamp)

6. Using external wire, or using it in crowded strong signals: Antenna on SW seems a litle directive , taking splatter from the local FM bands . Stronger effects are showed in the 5 lower SW bands 2 m of wire can cause severe spaltter effects in most bands

7. Nearby TV can cause severe QRM with carriers acroiss ALL AM bands

8. Playing with the bandswitch fast towards the MW band can show a M.kk indication . The normal is M.kkk . Switch on and off can corect this

9. Audio Resistor : the smoothest resistor i found ever. Very good for fi ne tune when ear in next to speaker

LONG TERM USAGE OF KK979

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 fi ngers 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’

Fore this time the freqs found are identical with what specifi ed : 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 preamplifi cation( 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 fl atter audio response

- AM/SW selectivity: About 6-7 Hz . 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

And fi nally the radio is OK with its inner part. All ICs have their IDs clear

KK C300 Freq read out: (a forgot point) For SW bands: M.kk with 10 kHz resolution For MW band : M.kkk with 1 kHz resolution For FM band : MM.k with 100 kHZ resolution

1- Tuning : in many cases the tuning knob does not tune especially in fi ne tuning . Posibly it’s a difer-ential tuner or plastic axe is not so sensible 2- Can be tuned internally - by 4 capacitors- for change of center band freq on MW and SW amplifi cation level on MW/SW and FM . FM capacitor also effects on AM partially

3- Battery operation More than 40 hours using it 30 cm far from ears. 24 hrs continuous operation with same audio level 4. Using with full amplifi cation level MW : very strong MW sigmals have very broad freq listening

Example: signals of ERA 1044 50 kW can be heard up to 1115 , the 1179 can be hgeward up to 1245 and the University radio 1431 (100 W 500 m far) up to 1560

FM: overloaded at all band. ripled fi lter with two peaks

More on FM: Images of 21.4 mHZ lower. Lowering the FM sensitivity causes clearer signal on the lower part. This ‘problem’ diminishes when the internal amplifi cation capacitor is lowered. BUt using mains adaptor the effect continues I found that several freqs are clearer in the lower part thean their nominal freq

5. MW : Internal LCD display causes QRN to all band (as like fl uorescnt lamp)

6. Using external wire, or using it in crowded strong signals: Antenna on SW seems a litle directive , taking splatter from the local FM bands . Stronger effects are showed in the 5 lower SW bands 2 m of wire can cause severe spaltter effects in most bands

7. Nearby TV can cause severe QRM with carriers acroiss ALL AM bands

8. Playing with the bandswitch fast towards the MW band can show a M.kk indication . The normal is M.kkk . Switch on and off can corect this

9. Audio Resistor : the smoothest resistor i found ever. Very good for fi ne tune when ear in next to speaker

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Inside circuitry seem

s with

handmade printout

This is a radio I received after a radio swap from a Chinese guy. I list it too because I found several interesting

q Analog tuning q FM stereo using headphones . Stereo switch included q Button lock

What I have noticed with the radio (roughly by optical ways) : Bands : MW 520 –1620 Freqs are correct with what displayed!FM 87-108 SW1 5.95-6.5SW2 6.9-7.45SW3 9.4-10.1SW4 11.5-12.2SW5 15-15.8SW6 17.53-18.1SW7 21.3-22.

Stereo - key lock - AM - FM

BOLONG HS902

Other interesting things I found:

High quality audio in all bands About 10 kHz bandwidth is apparent with low

contiguous signals Single conversion , many utes can be found

inside the band q Does not overload with long wires

Moderate sensitivity , ie 15095 (heard with C300) could not be heard

NO 3V DC socket. Freqs listed in the panel are the freqs used .

Quite accurate adjustment Two very small screws to unscrew in the rear

panel Generally more rugged and reliable than the

Kchibo models

Testing with 634 and C300 Bolong : had better audio oion FM over 634

and same as C300 Bolong has better sensitivity over 634 on MW

but lower on SW ,For FM was unmeasurable Bolong has more superhet products than

634 Also Bolong has better audio level on

headphones but the lowest corresponding speaker audio level using same headphone level. Anyway it has very low maximum audio level

Also rasdio seems very robust in all terms. For example it required 4 screws to be unscrewed before the radio opensThe inner part of the rasio seems to work as a fully tran-sistorized set hence its very nice audio. Also circuits seem to be hand designed ( as forexample circuit board is apaprently hand made )

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SOME MEASUREMENTS

Below you will fi nd a series of pictures showing freq responses of several radios

Audio response on Low and high tone level in the C300 on SW bands The higher carriers are still audible even woth low tone

Audio response on KK979 on same freq . Notice that te signal was not audible

Here with the ICF 7600 D The narowest curve of all !

Here is tha audio curve in noisy background

ie highly trebled audio!!

The sensitivity and selectivity winner ICF 7600 D

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From the 6 radios tested I have found several interesting points

1. Most of these radios seem to have fair to good sensitivity. The C300 excels from all of them having a very high sensitivity nearly same to SONY models

2. Nearly all of these radios have a low level of selectivity about 15kHZ for –3 db or posibly ‘no IF fi lter’ at all . Again C300 shows a highest level of selectivity though still not so high as SONY (prematurely self tuned enhancing its selectiv-ity . It happened after a drop )

3. For me all these models exceed their expectations in reference to their price4. Bolong stil goes farther with stereo FM that happens only on the most costlier

C300

As in result the two of the 3 radios presented here can surely cover the very basic needs for the totally non experienced user as well as the person wo canot afford to buy a more expensive radio.