APX public safety mic

[motorola_otaku]

1.) Does such a beast yet exist?

2.) If so, has anyone cracked one open to see how external antenna selection is handled?

I have this crazy idea that my next mobile install needs a cellphone-style cup holder on a RAM mount with connections for an external amplified speaker and antenna, but I would be much more likely to use such a contraption if I could do everything via the side accessory connector.

[resqguy911]

Impres Public Safety Microphone (PSM)
This IMPRES-enabled microphone is designed with an antenna to offer confidence in communication and increased coverage to Public Safety officials. All PSMs include 3.5mm audio jack, orange button and radio volume control. Antenna is sold separately. Public Safety Microphones are available with 700/800 MHz portables only.
PMMN4061 IMPRES Public Safety Microphone (30 inch cable) Windporting, IP55
PMMN4060 IMPRES Public Safety Microphone (24 inch cable) Windporting, IP55
PMMN4059 IMPRES Public Safety Microphone (18 inch cable) Windporting, IP55

[Tom in D.C.]

The APX and the TRBO HTs use the same programming and accessory cables, so I took a look at my 6500 TRBO HT. There does not appear to be a switch actuator for the PS mic's antenna, so I would say the sensing/changeover to the external antenna must be done inside the radio, just like it was done on the original Saber. The Saber had an internal sensor and switch, whereas the Astro Saber had a push switch as part of the accessory connector. Of course it's possible that there IS an actuator switch on the 800 mHz-capable APX radios, but the only way we can get a definite answer is to actually see if there is a push device on the PS speaker/mic.

[motorola_otaku]

There does not appear to be a switch actuator for the PS mic's antenna, so I would say the sensing/changeover to the external antenna must be done inside the radio, just like it was done on the original Saber.

I didn't figure there would be, which is why I was curious if anyone had cracked open a mic yet to see how they're wired. Not sure I'm ready to be a $115 guinea pig yet though..

[Tom in D.C.]

Come on back up to Rockville. We can have a greasy hamburger, then take Seth's APX apart and see how the PS mic works (G).

Regards,

[Karfield]

I took the class on this just a few weeks ago. Unfortunately I can't remember all of the details, however they are in the detailed service manual for the Turbo's.

There is an electronic switch in the radio that detects the type of mic you have and then changes some internal relay/diodes to modify the RF path to the PS mic antenna line. I'd have to go back through my power point presentation to give you exactly what goes on but that's it in a nutshell.

[Tom in D.C.]

Aha! Just like the old Sabers. Amazing how the older technology, if you can call it that, makes a reappearance.

[resqguy911]

I can tell you my experience has been the radio doesn't like to have the display mic connected whilst powered up. No bueno