Best microSD Card for the Uniden SDS100
Why the SDS100 Needs a microSD Card
The Uniden SDS100 uses a microSD card for two things:
- RadioReference Database (HPDB): The full nationwide trunked system database is stored on the card. Without it, you can't use the database scanning features or Location-Based Scanning. The full HPDB is under 3GB.
- Audio Recordings: When you enable recording, the SDS100 saves captured audio directly to the microSD card. A 32GB card gives you hundreds of hours of headroom.
The SDS100 does not come with a microSD card in the box. You need to supply your own.
microSD Requirements for the SDS100
| Requirement | What You Need |
|---|---|
| Card Type | microSDHC (standard micro SD card) |
| Maximum Size | 32GB (officially confirmed by Uniden) |
| File System | FAT32 — required. exFAT will not work. |
| Speed Class | Class 10 / UHS-I (U1 or U3) recommended |
| Cluster Size | 32KB recommended when formatting |
Recommended Cards
SanDisk Ultra 32GB
| Capacity | 32GB |
| Speed Class | Class 10, UHS-I (U1) |
| Read Speed | Up to 98 MB/s |
| File System | FAT32 (pre-formatted) |
| Compatibility | SDS100 confirmed ✅ |
The SanDisk Ultra is the most commonly recommended microSD card on RadioReference forums for Uniden scanners. It arrives pre-formatted FAT32 at 32GB — just pop it in and format via Sentinel. Reliable, widely available, and consistently priced under $12.
Buy SanDisk Ultra 32GB on Amazon →Samsung EVO Plus 32GB
| Capacity | 32GB |
| Speed Class | Class 10, UHS-I (U1) |
| Read Speed | Up to 95–130 MB/s |
| File System | FAT32 (pre-formatted) |
| Compatibility | SDS100 confirmed ✅ |
Samsung's EVO Plus is equally reliable and often the same price as the SanDisk. Samsung's flash manufacturing is first-party (they make their own NAND chips), giving excellent long-term endurance. A great choice if you plan to record a lot of audio — the continuous write activity is well within what this card handles.
Buy Samsung EVO Plus 32GB on Amazon →SanDisk vs Samsung — Which Should You Buy?
Honestly, you can't go wrong with either. Both are confirmed working with the SDS100, both are Class 10, both arrive FAT32 pre-formatted. Buy whichever is cheaper the day you're ordering — they trade back and forth in price.
- Buy SanDisk if you want the single most-recommended card in scanner communities with the largest body of confirmed compatibility reports.
- Buy Samsung EVO Plus if you plan to do heavy audio recording — Samsung's endurance profile is slightly better for continuous write workloads, and it's made with Samsung's own NAND flash.
How to Set Up the microSD Card in the SDS100
- Insert the card into the SDS100 microSD slot (right side of the scanner, under the rubber cover).
- Power on the scanner. It will detect the new card.
- Format via Sentinel: Connect the scanner to your PC in Mass Storage mode, open Uniden Sentinel, and use the database update tool. Sentinel will handle formatting and writing the HPDB automatically.
- Manual format option: You can also format the card in Windows — right-click the drive, choose Format, select FAT32, set allocation unit size to 32KB, and format.
Always format through Sentinel first if possible — it ensures the correct cluster size and writes the database in one step.
Frequently Asked Questions
What size microSD card does the SDS100 need?
The SDS100 officially supports up to 32GB. The full RadioReference database is under 3GB, so 16GB or 32GB is more than enough. Stick with 32GB for recording headroom. Do not use 64GB or larger cards — they default to exFAT which the SDS100 cannot read.
Do I need to format the microSD card before using it in the SDS100?
32GB SanDisk and Samsung cards typically arrive pre-formatted as FAT32, which is correct. However, Uniden recommends initiating the database update through Sentinel, which will properly prepare the card and write the HPDB in one step. If you're manually formatting, choose FAT32 with 32KB allocation unit size.
Will a 64GB microSD card work in the SDS100?
Not reliably. 64GB cards are formatted as exFAT by default, which the SDS100 cannot read. Some users have reformatted 64GB cards as FAT32 using third-party tools and reported success, but this is unsupported by Uniden and not guaranteed to work. Buy a 32GB card and avoid the headache.
Does the SDS100 come with a microSD card?
No. The SDS100 does not include a microSD card in the box. You need to purchase one separately. A 32GB SanDisk Ultra or Samsung EVO Plus (both under $12) is the standard recommendation.
What speed class microSD do I need for the SDS100?
Class 10 / UHS-I is the sweet spot. The SDS100 doesn't push cards hard enough to require the fastest U3 cards, but Class 10 ensures smooth database access and recording. Both the SanDisk Ultra and Samsung EVO Plus are Class 10 U1, which is perfect.