BCD436HP/BCD536HP: BCD 436 Skips Channels

[wltrsf]

Hi, I have a BCD 436HP that I purchased in August 2025 that has the latest firmware (1.28.24) that skips channels when adjacent channels are VHF and UHF. These are conventional channels, some P25 others analog.. No trunking. squelch setting is on 2. I have a 396XT and 996P2 that have identical programming and they have no issues. Here is a screenshot of the programming from Pro Scan----the channels in red are skipped over (scan direction is top to bottom)




I found a sort of fix for this, certainly not a complete or long term solution. See the image below. By programming in a "buffer " UHF and VHF frequency (shown in green) as needed I'm receiving Littleton FD, Westford PD, and Ayer PD. The "buffer" frequencies (which I don't get anything on) provide a transition from UHF to VHF and vice versa. The positive proof of this is when I reverse the scan direction Westford PD is again not received because the buffer is VHF in the reverse scan direction. I know I might be able to fix this by tedious programming but I hope there is an answer to this problem. I'm not confident in Uniden helping if I send it in.

 

[Ubbe]

Hi, I have a BCD 436HP that I purchased in August 2025 that has the latest firmware (1.28.24) that skips channels when adjacent channels are VHF and UHF.

Hold in the Avoid button while powering on the scanner and it will have a debug item in its Setting menu. Store the file to the SD card and run the debug while scanning over those VHF/UHF boundaries.

Look in that debug file and every frequency shift will start a line with PLL and then the frequency. If it says something like PLL ERROR then the scanner can be sent to Uniden to be repaired as it is a hardware problem.

/Ubbe

 

[wltrsf]

Thanks for your help. I have run the debug multiple times making sure to follow both your instructions and those in the wiki and when I open the debug files they are blank.

 

[mc48]

Set the modulation to the correct setting not auto, set audio type to correct setting, not all, and get rid of the tones they may be incorrect.

 

[Whiskey3JMC]

and get rid of the tones they may be incorrect.

Easily researchable in the RRDB...

Middlesex County, Massachusetts (MA) Scanner Frequencies and Radio Frequency Reference

Scanner Frequencies and Radio Frequency Reference for Middlesex County, Massachusetts (MA)

www.radioreference.com

 

[Ubbe]

Thanks for your help. I have run the debug multiple times making sure to follow both your instructions and those in the wiki and when I open the debug files they are blank.

So it is creating a new debug file at each time you start debug mode, and you select to save to the SD card.
I would try another SD card just to be sure that it isn't a SD card issue that creates both the empty debug files and your scanning issues.
If the new SD card are also empty then both scanning and SD card issue indicates some firmware issue.

I have version 1.26.00 on my Onedrive. You can download that and put in the firmware folder in the SD card and downgrade the 436 and see it that makes it work as it should. Then upgrade to the latest firmware again using Sentinel and try that version again.

BCD436HP_V1_26_00.bin

drive.google.com

/Ubbe

 

[wltrsf]

So it is creating a new debug file at each time you start debug mode, and you select to save to the SD card.
I would try another SD card just to be sure that it isn't a SD card issue that creates both the empty debug files and your scanning issues.
If the new SD card are also empty then both scanning and SD card issue indicates some firmware issue.

I have version 1.26.00 on my Onedrive. You can download that and put in the firmware folder in the SD card and downgrade the 436 and see it that makes it work as it should. Then upgrade to the latest firmware again using Sentinel and try that version again.

BCD436HP_V1_26_00.bin

drive.google.com

/Ubbe

OK I attempted to use a new SD card but using Sentinel it would not format. I then put in the old SD card, ran the debug and it came up with this --

 

[fxdscon]

OK I attempted to use a new SD card but using Sentinel it would not format.

When formatting an SD card......

Sentinel does not have any ability to format the SD card. First step is to download and use this formatting utility (recommended by Uniden)...

SD Memory Card Formatter for Windows Download - SD Association​

Put the scanner in "Mass Storage" mode.... or put the card in a separate card reader (much faster). When the formatter recognizes your card, a very important step here is to choose the "Overwrite format" in the formatting options section so it will detect and correct any errors on the card.

After formatting (or when using a brand new SD card), the card will still not be recognized by the scanner until you use Sentinel's "Clear User Data" function to put the necessary operating files on the card. When starting the clear user data function, be sure to check the box for "display all drives" so your SD card will show up in Sentinel. After the clear user data process completes, write your programming from Sentinel back to the SD card.

 

[Ubbe]

OK I attempted to use a new SD card but using Sentinel it would not format. I then put in the old SD card, ran the debug and it came up with this --

It's a 5 second snippet and scanner are stationary on a system. Can you let it scan for a minute or so as there are no scanning taking place during these 5 seconds. It decodes the data and those Link1 and 2 are received at each superframe of data and those Terminator are decoded at each data frame and at each 16:th of those you get Apco stop. I would say it looks normal for a system in idle mode, but are just the decoded P25 data and not the scanning function.

Let the debug run for a minute or so while scanning and post the whole file and not a screen shoot. It's important to see those PLL lines if the receiver have issues while switching between frequency bands. Format the new SD card and dump the older firmware file into the folder and run it and then check if it works, you can also do a debug run using the older firmware, and upgrade the firmware that will then clear any errors in memory, and take another debug file for comparison, if the scanner still have issues.

/Ubbe