Auto Shutoff = Sleep Mode?

[E_Tek]

Hi guys,

I have a question regarding the auto shut off feature. I use this almost every night because i can't goto bed without listening myself to sleep. When the unit shuts off automatically, does it go into some sort of sleep mode? I know it can't be powered back on through button presses but rather you have to cycle the power off and then back on again for boot up. What made me wonder about a possible sleep mode or if the scanner was actually "off" was one day i noticed alot of noise over the airbands of 2 receivers which i had placed close beside the 536. I thought unusual and maybe they were picking up noise from the internal oscillator or something in the 536 being so close. Of course the the 536 was off at the time due to being auto shut down the night before. I powered down the 536 via volume knob and didn't notice any difference in noise so i thought nothing of it. Today, i decided to plug in the wifi dongle to try out on an older android phone which i had found to see if the app would crash again (and of course it did...sigh) but the wifi dongle powered on as soon as i plugged it into the rear usb jack. Of course the 536 was auto shut down again and supposedly off. I powered down via volume knob and the light on the wifi dongle went out. So when the unit has been shut down by the auto shutoff feature.....the usb jack is still active, does this mean the unit is still "kinda" on and can scan in the background to the siren app with the lcd screen and leds totally off?

Thanks,

 

[Ubbe]

I haven't seen a schematic for the BCD536 but the on/off switch goes to the CPU that then signals to an electronic switch that bypasses the on/off switch to keep the power on to have time to save data to the SD card and then the CPU release the switch.

The auto shut off can then only switch off the electronics that the CPU control and put itself to sleep, but the on/off switch will still keep the power on to the whole scanner but there's no interaction with the CPU so it can't scan or do anything intelligent.

/Ubbe

 

[E_Tek]

Awesome, thanks for the explination Ubbe👍

 

[gary123]

Many devices use this type of off. TV sets, DVRs, computers etc. What your basically doing is turning off the display but the CPU and other electronics are awake and functioning.

If you suspect a RFI problem from a device the best way to check is to turn it off properly then unplug it or remove the batteries. If the problem goes away then you can look deeper to see what conditions create the RFI.

A real good example of this is dash cams. They generate all kinds of RFI and the power cable acts like an antenna radiating it all around the vehicle.

 

[E_Tek]

Thanks for the info Gary. I actually did unplug the 536 and moved it to a different room briefly but to no avail. It was probably something else in the environment causing the airband reception to be bad that particular day.

For base station use, it is a non issue for the 536 going into this "sleep" mode but for mobile applications, i could see this causing a problem with battery drain if wired to constant and users actually thinking the unit is completely off. Of course this would depend on how much more current the unit draws in this state.

I agree, some of those dashcam hardwire kits are the worst! I've had my share of troubleshooting by wrapping those little power supplies with aluminum foil, adding ferrites, trying different ground points and re-routing the wiring.

 

[gary123]

If you own a SDR and a laptop they make great signal sweepers.

 

[E_Tek]

No SDR dongle yet but one of these days 👍