Heil BM-17 Maestro

Carl N8VZ

I have a Maestro (version b) and I'm having trouble using a Heil headset with it.  I have two headsets: Heil BM-17 and Heil Proset IC.  When I plug in the earphones for either headset they work FB.  However with both of them, when I plug in the mic cord, it puts the Maestro and rig into TX.  One of these plugs has just tip and sleeve on the mic connector (ProSet IC) and the other has tip, sleeve, and ring (Heil BM-17).  Can someone tell me what would be causing this behavior?  Is there a menu setting I haven't found that I need to set to use the Mic 2 input?  Something else obvious that I'm missing.  At this point, it's a big mystery to me.  Thanks for any help you can give me.  73 de Carl N8VZ

Mike Smoot

Heil's website indicates the BM-17 uses a 1/8" mono plug for the mic audio output, and a 1/8" stereo (tip-ring-sleeve) plug for the headphone inputs.  Note that Heil also sells rig-specific adapter cables for popular rigs. I suspect if you plug the mono Mic output directly from the headset into the Maestro mic input, the (mono) plug will ground the PTT input and put it into Transmit mode.  Sounds like you need to make an adapter to float the PTT input and route it to a separate PTT switch. 

Likewise, if you mistakenly plug the TRS headphone plug into the mic jack,  one of the low-Z headphone elements will provide a current path from the PTT input to ground, likely causing it to go into Transmit mode as well.

Mike-VA3MW

In the mic settings turn off Mic 2 PTT. I am not in front of a computer at the moment but if you poke around you will find the setting. Mike

NX6D Dave

See page 11 of the Maestro User Guide:

The MIC 2 connector accepts a 1/8-inch (3.5mm) stereo (TRS) plug and provides an unbalanced microphone input with optional push to talk input.  The connector may be used with dynamic or electret microphone elements.  A software enabled 2.5V bias voltage may be applied to the Mic (+) line for electret microphones.

 
The information about disabling the MIC2 PTT is on page 137/138 which describes the Transmit Tab in the Main Menu.

Carl N8VZ

Thanks, everyone, so much.  I got it working.  I appreciate Dave's plug diagram, and Mike's description of the connectors.  All useful information.  The key for me was the other Mike's and Dave's mention of the MIC2 PTT disabling in the Transmit Tab of the Main Menu.  I had looked at that tab, but somehow missed the MIC2 PTT enable/disable function.  Being directed to it with specific instructions helped me see it and from there it was all a piece of cake!  Great community support.  I very much appreciate it!