sBitx Microphone Alternatives by WD0OM and W9JES

The sBitX v3, as shipped, comes with a microphone that is generally thought to produce substandard results on SSB due to it's low gain and hollow sound. Here are some ways to achieve better results.

Replace the condenser element

The chief issue with the shipped microphone is the condenser element---the actual microphone, in other words. Fortunately, an inexpensive replacement can be swapped in.

An example of an alternative is the AOM-5024L-HD-R electret condenser microphone. This microphone element is higher gain (-24db) and produces better results.

To make this replacement:

• Open up the microphone case, taking note (and possibly photographs) of the interior before you begin making changes. In particular, keep track of the polarity of the existing element's wires, and of the assembly of the PTT switch---the spring has to be placed a particular way to function!
• De-solder the old element, leaving the wire leads intact on the PCB.
• Solder the wire leads to the new element, being careful to observe the same polarity.
• Stuff some cotton batting or cotton balls loosely around the microphone element.
• Ensure everything is back where it belongs and close up the microphone case.

Use a USB microphone

If you're already using the sBitX Toolbox, you have access to a USB Microphone app that will allow many USB-connected microphones or headsets which work well with the sBitX radio software.

Use a wireless microphone

Native (Raspberry Pi) Bluetooth won't work with a Bluetooth headset, unfortunately. However, a wireless microphone or headset that uses a USB wireless receiver should.

What about other hand-mics?

The sBitx microphone interface uses a 3.5mm Tip-Ring-Sleeve (TRS) jack, with ground on the sleeve, PTT on the ring, and the mic's positive signal on the tip. Although TRS plugs are fairly common, not many radios use this configuration for mic input. You can create your own adapter cable if needed, but there are currently no direct replacements available at the time of this article.

Some had had success using TIDRadio microphones such as model TD-HM060 by replacing the 2.5mm TRSS plug with a 3.5mm TRS plug.

Several Baofeng style microphones also work. Just ensure that you have the wiring correct and swap with a 3.5MM TRS plug. You will also want to disconnect the speaker element inside the mic housing.

The wiring of the mic is: tip=mic+, ring=ptt and sleeve=ground.

Plug Base =====|GND|=====|PTT|=====|MIC+|=> Plug Tip