Due to product quality problems within 1-3 months of receiving the product, we can replace it with a new one, but the customer pays for the logistics costs incurred. My 2021 unit present these transitory noises. I wonder if the muting system is not being enabled by the MCU firmware. Bug or hardwaredesign fault? This audio stage noise is more audible thru the speaker than on earphones, what seems to make no sense. But when looking to the circuit we see the reason. The earphones are driven thru a series RC network with 100uF and 100Ohm. Depending on the earphones impedance, the noise will be stronger for higher impedance units. However the common earphones would present 32 Ohm, a low value when compared with the series 100 Ohm resistor. Anti-interference: R-108 radio with anti-interference switch, can adapt to strong radio interference environment. AM broadband, narrowband selection. Broadband can improve the sound quality of strong signal broadcast programs, while narrowband can improve the anti-interference ability of adjacent channels.

Even when inserting a fully charged Li-Ion battery, the radio only shows 3 bars (corresponding to at least 4.1 Volt reading)for a few minutes of usage.After that it will show 2 bars (around 3.7 Volt reading) for many hours of usage.Eventually it will show just 1 bar (low 3.4 Volt reading). Some have reported that the squelch is not fast enough to unmute resulting in loss of the initial conversation. I can confirm this to be true, but it loses just a small fraction of a second, not really an issue. Functional: Alarm function, sleep mode, and the time can be set and displayed in the off state. The sleep timer setting can be automatically turned off according to your lifestyle settings. R108 radio can be placed on the bedside, get up in the morning, enjoy the wake-up service of the radio, and watch the time with an open eye. When you brush your teeth, you can listen to the radio and keep up to date with the news. I am currently located in the Northeast of Portugal, at an altitude of about 1000 meters, and I can receive radio transmission signals from the various passenger planes that fly over the area, using the telescopic antenna and being indoors at the window.Telescopic antenna - Last section (with tip) detached from the rest. Also, the antenna mounting seems to be fragile, requiring great care when rotating it, as it can break the plastic support. Looking to the publicly available pictures, extensive changes were made in the circuit diagram and PCB layout of the Receiver board. Some owners have reported a fast battery depletion even when the radio is powered off, but this seems to be a fault developed with usage or a manufacturing defect. In late 2022 a new version was quietlyreleased, despite the only visible difference to the previous versions being the use of a USB-C port instead of the older Micro-USB type. Otherwise the advertised features and performance remain the same.

The squelch also works adequately in my opinion. Set it level 1 and it will not mute the audio due to the noise floor inside house (around 12dBu), but at level 2 it would mute it; then the radio is able to unmute the audio for signals as low as 25dBu. Some report loss of sensitivity after changing betwween RF bands.This seems to be a firmware bug, as it can be fixed by doing a power off/power on sequence, or remove and insert the battery, or doing a Reset (use a clip to insert in the Reset hole). Gone is the RF front-End with the 4-Sub-Bands pre-scaler using four LC trimmers for proper alignment and better spurius strong signals rejection, being replaced by common LCR fixed values networks using SMD components. The design choice used on the D-808 was to save costs on the audio pre-amp and simply configured theCS4863's OpAmp1A andOpAmp2A with a very high bridged mode differential gain of 77 (!) If the MCU firmware is shuting down theCS4863 to avoid these nasty noises during band switching and fetching memory preset stations, as it should, then probably would be possible to fix it by following the Texas InstrumentsLM4863 datasheet.

Doingmanual tuning across RF bands results in muting/chuffing sounds when changing eachRF step.This seems to be a design characteristicof DSP based radios. In this model the volume drop can be reduced by seleccting the Slow tuning mode. A typical AVD would be between 1 and 5, maybe a mximum of 10, to contain the IC noise floor under inaudible levels. But doing so would result in very low volume levels because of the missing audio pre-amplifier stage. LW band seems to show poor sensitivity on DSP radios like this model category, due to a poor design of the RF analog passive components that favors the MW band.