NOTICE: Heil HC-4 and HC-5 elements are no longer available from Heil Sound. W4RT has NO, repeat NO, HC-4 or HC-5 elements left in stock.
One BIG Punch (OBP) is a custom add-on accessory for the Yaesu MH-31 microphone that is used with the FT-817(ND), FT-847, FT-857(D), and FT-897(D). The OBP is an AF-based speech compressor specifically configured to provide remarkable increase in talk power while maintaining good audio quality (articulation) for communication purposes. Measurements using a stock FT-817 and a MH-31 containing the One BIG Punch showed that the average talk power increased by about 5 dB over the unmodified MH-31. When the optional SSB filter (Collins Mechanical Filter) for the FT-817 was used in conjunction, the talk power increased another dB or so. This information is provided for general expectations, not as a firm specification.
Want Even More PUNCH?
Then have W4RT Electronics install both the HC-4 (OBP active) & HC-5 (OBP not active) Microphone Elements in your MH-31 with the One BIG Punch! See ordering selections below. Some users like using the HC-5 on FM and the HC-4 with the OBP on HF. Overall field usage by many users determined that the HC-4 with the OBP (and with the optional SSB filter) was the best combination on HF to successfully make QSOs under marginal situations (QRP typical). NOTE: Heil is no longer offering the individual elements. W4RT Electronics has a VERY limited number of these elements left in stock.
W4RT Electronics also offers an OBP Module tha has the One BIG Punch, Heil HC-4, and Heil HC-5 microphone elements fully integrated together and ready for you to install. For those of you that just can be off the air for a few days while W4RT upgrades your MH-31, you can simply order the fully assembled MH-31A8J with the OBP Module. It just doesn't get much better than this!