It’s my understanding Uniden has “dummied down” the earphone jack volume deliberately as a way of protecting your hearing, their way of eliminating lawsuits for causing damaged hearing because the owner forgot to turn down the volume when using an earbud. Previous handhelds such as the BCD396 had a simple workaround. Since the earphone jack was using a different ground value than the rest of the radio to reduce max volume, a piece of jumper wire, flattened out and wrapped around the plug’s ground, allowing it to still make contact on the jack’s end and stay in place, with the other end attached to the antenna’s ground connection in the same manner (flatten it) negated the different volume levels and gave the earphone jack the same level of volume the internal speaker enjoyed. I believe they simply added a resistor (as a stopgap measure) but in later handhelds incorporated it into the design programming. If you are handy with working on the internal components of the scanner a jumper from the internal speaker to the earphone jack may override the reduction in volume at the jack but I have no conclusive knowledge this would work, or if it would damage the scanner. Proceed at your own risk. (Those with better knowledge can advise on how detrimental this idea may be-PLEASE post here if that is the case, as stated, it’s a question I can’t give firsthand knowledge on and with the price of a SDS100, NOT something I would attempt. I too have experienced this volume reduction and use an amplified speaker, powered by a lithium battery, all carried in a small bag with a shoulder strap. Of course this will probably void any warranty so proceed with caution.
The SDS100 always had a power consumption problem with the added power hungry components added to combat simulcast, and as such, the run time of the original smaller li-ion battery pack was replaced with a larger pack and other power saving features, I suspect one of which was to lower the max volume in the audio output section of the radio, trying to squeeze as much power out of the battery for a longer run time before a battery recharge was necessary.
