BCT15X: Uniden BCT15X broadcasts/volume fades out & returns?

[Buttockup]

Hi,

I have noticed an issue with my Uniden BCT15X. Basically, I have a number of programmed frequencies relating to civil Airband, but when scanning these, the volume seems to occasionally fade really slowly to very low, & then slowly returns back to the normal volume setting?

I am not sure if it does it on other things like marine band, but when it happens on Airband, it is not exclusive to one channel/frequency, & the whole lot fade in one go?

This is a relatively new scanner. Anyone else experienced this? Might it be interference?

Many thanks,

 

[tvengr]

Slow fades are normal for aircraft in flight.

 

[jeepsandradios]

Its AM. It will fade.

 

[Buttockup]

@tvengr & @jeepsandradios Many thanks.

 

[Buttockup]

Hi again, just for the record, & in case anyone else has similar, I have also discovered that during volume "fade" out, the keyboard buttons fade out too!?! I thought it best to mention and I wondered if any more experienced techies have any thoughts?

I am running it on a supplied a/c power supply & Skyscan desktop antenna. Interestingly, the digital display/light does not fade & still scans when happening.

 

[Ubbe]

There have been some issues with power supplies that fail to deliver enough power with BCT15 scanners. Do you have anything else that can supply 11-15V and at least 800mA?

Set the squelch to 0 so that you hear noise in the speaker, turn up the volume very loud and look if the keyboard light fades that indicates that the voltage drops too low.

/Ubbe

 

[Whiskey3JMC]

I am not sure if it does it on other things like marine band,

Par for the course for AM. If you're listening to air traffic control some distance away from an airport then the tower controller will sound more "faded" than arriving or departing aircraft. Test on FM modulated signals, if it happens there then there might be something wrong internally

 

[Buttockup]

Thank you @Whiskey3JMC & @Ubbe

There have been some issues with power supplies that fail to deliver enough power with BCT15 scanners. Do you have anything else that can supply 11-15V and at least 800mA?

I have just tried what you suggest @Ubbe with volume, but no keyboard fade. I will try it again later this evening. It just seems so strange that this happens on the odd occasion? I don't have a another supply at present, but I shall keep this in mind

Thanks again both, & I will keep you updated!

 

[Ubbe]

but no keyboard fade.

Then it could be non audio related and that is the plastic film cable in these scanners that connects the front panel to the main circuit board that could develop a bad connection and needs to be re-seated in its connector. Sometimes that film are fixed with a drop of hot glue that doesn't seem to help to prevent the problem to appear.

/Ubbe

 

[Buttockup]

Hi, just a quick update & further question for @Ubbe

Basically, this issue is still happening. Last night the broadcasts seemed to get quieter & quieter, along with the keypad button tone volume, & then returned.

My question is, could something external be doing this? Before this thread I post a thread somewhere else about this issue & someone suggested interference from my PC, so I moved them further apart.

As this is still happening, I just wondered if high voltage/national grid power lines could cause this issue, but why the keypad beep volume level too?

Whilst typing this it happened again, so I increased the volume quickly & it blasted out immediately. And just to be clear, the screen does not dim when doing this.

It is as if it running out of power without the screen dimming?

Many thanks.

 

[Ubbe]

It is as if it running out of power without the screen dimming?

It sounds more like a bad connection somewhere at the loudspeaker. When you apply more sound the audio current increases and "cleans" the connection. The volume control are just a voltage regulator that sends its volume position to the CPU and then the CPU sends the volume gain to a IC that handles the volume level.

It could be the connector to the external speaker that's bad. Insert an earphone in the external speaker jack and listen if the audio change after a while and also exercise the connector by inserting the plug several times. You could also open up the scanner and check the internal speakers connector plug, if an external speaker or earphone works fine.

If you program the scanner to use recording from channels you will get audio out from the recording jack that should be good enough for an earphone and will give you sound both in the speaker and in the earphone at the same time, for comparison if the audio fade.

/Ubbe

 

[Buttockup]

Okay, thank you @Ubbe

I will try & find a suitable box & return it to seller.

They did say they will either repair or replace it.

Many thanks.