Bolong radio HS902

Bolong radio HS902

New picture of the radio today 1/9

This radio has been the results of a replacement project with a Chinese friend who lived for a short time in the student residence two years ago. He used mainly that radio in offer to listen a bit to the local radio stations but also his homeland.

I give to him a Kchibo model found from the local market mainly the 515 which is a semi digital , ie having a digital readout but is fully frequency agile. More information n this radio you will find on the chibo.pdf file along with some interesting technical info also for Bolong.

Why I am writing this report , though I have already written in the pdf? This is because with the return of the PL200 back to the factory for servicing or replacement - a total of 4 weeks – and the C330 already given to my father in the country house , using big radios as 1102 and 1103 in the road is quite uncomfortable, requiring the use of cassette sized radios only in the chest pocket of the blouse which is mostly preferable for me. All that time I had the opportunity to use and test it more than previously. I also like to listen to the music when I am walking inside the city. And it impressed me very much with its audio fidelity.

Appearance

The radio is a bit thick-y with black color and metallic mesh surface over the speaker . I never use it as I prefer to use my earphones . It is a also relatively heavy compared to the C300

There are three buttons on the front face: ON button for FM one for AM , one stereo switch and onle lock switch all locatd on the bottom right position below the display . ON the top there is a 8 band sliding switch . ON the left there is a volume control a ON off switch and a earphone connector.

There is a stereo FM light and a band light( FM or AM ) and a tuning light on the top right position.

The thumbwheel is relatively small for my fingers at 1 cm of diameter and a little hard to turn . I prer it this way so that it doe not tune out for any reason .

COVERAGE

The specified coverage shown in the display are

Here are my comments:

The MW band in its specifications are for 531- 1620 kHz but as it is a analog radio its freq span is quite wider . I have heard stations on the upper MW band up to abt 1670 kHz where I can listen to the Greek pirates mostly QSOing at early to late nights and at least 3-4 channels below the 530 band ( vacant freqs every times I tested)

ON FM band it is the same. About 1-2 MHz below and 1-2 MHz above the band. These extended freqs were totally vacant . Using fully unfolded antennas Bolong shown two very poor images of 107.5 and 106.8 – at its lowest used frequency tht means 85.4 is the lowest freq

The radio has also a FM stereo /mono switch and a lock button. It’s LO seems more stable than SW

ON the SW bands it is a bit difficult to determine the accurate frequencies especially due to high LO drift.

I have an example here:

ON the 17 MB band , I can listen to 17490 kHz China Radio Intl in English service local morning to midday times at the start of the tuning band The signal is excellent so that with just erected antenna I can listen it as it was local . . However the local oscillator drifts to a great extent so that CRI sometimes is inserted in the band or even is lost outside the dial. I can assume that the LO can drift about 30 kHz above or below its main frequency!!

Performance:

This is a all stage transistor radio . as the radio , is a hard used model by the Chinese student I found that that the there are several dropouts with the sudden moves or light shocks in my pocket That possibly means soldered points are loose. In several light shocks and during Sw listening the radio was reset to the default FM band.

Audio fidelity:

• FM : One of the best sounded radios on FM with extended fidelity and trebles over any other radio including the stereo system of my wife! . Using good and high quality earphones / headphones is a pleasure. I have the same impressions of using the Degen 1103 earphones (un-sponged ) and AKG UR20 headphones ( both of high audio response)

Diversity testing with De1102 and same earphones in both radios show same bass response and trebles moving towards Bolong .Also audio is more pleasant than DE1102

• AM Modes Good audio quality reminding me the audio my old RT430 SILVER radio tape recorder ( transistor made) has.

Earphone Audio level : Quite high level . Just a little audio level can overdose the earphones. In contrast , audio output is very low .Same happens with the earphone level of C300 and PL200

Sensitivity

• FM: A little better than 1102 . I could listen to NET 88.0 with less QRN than 1102.

• MW : Its MW sensitivity is low to very low . Stations with good signals in other radios as R Skopje 810 is heard poorly in Bolong .During the nights this is a little out of question !

• SW : Parallel (earphone diversity ) testing with R75 shown a sensitivity level same or better than De1102 In a table below you will see that I several bands Bolong radio has better sensitivity or resulted audio than 1102

Selectivity

• FM: Fair levels . Good (?)levels of AGC/AFC can off tune to an stronger adjacent station during walking… Several stations that 1102 can listen , Bolong can’t especially lower signals in our crowded bands

• MW : 9-10 kHz Adjacent stations are not interfered ( except of producing QRM whistles )

• SW : About 10 kHz ,Near to 1102’s level except in near very strong adjacent signals that cover several 5 kHZ channels.

Battery usage:

The radio uses two AA batteries as most radios do today. As it is analog radio it has very low power usage . The batteries I put 1 years ago have ended recently . I can assume more than 100 hours of usage

Here is a list of tests with Bolong and DE 1102 using the diversity earphone stereo method ( 2x 1102 earphones)

Bolong >>> 0 DE1102 >>> 9

As in result in most bands Bolong seems to have a better sensitivity or total audio result than 1102 except the 50 mb . ON 50 mb there were superhet images from the lower part of the 41 mb that mixed with the upper part of the 60mb stations ( 6200 and up)

You read my review. This is a result of more than 10 hours of testing usage. Please feel obliged to send me your comments to my email address greekdx (at) otenet dot gr