Analog spectra DTMF mic on ASTRO spectra...

CTAMontrose · Post by **CTAMontrose** » Thu Nov 25, 2004 4:40 pm

just wanted to post that it does indeed work fine, sends DTMF in both analog and astro (NOT data 12, it sends the tone.. useless but still)...

when i inquired before about this, i was informed that "last mic i got had a tag on it saying specifically not to plug it in to an astro spectra"

i was disconnecting my analog spectra and grabbed what i thought was the the end of the standard mic that came with the astro spectra, but it turned out it wasnt...

the spectra is a 110w K band, with a W5 head, doesnt matter if the mic is plugged into the front of the head or the back...

Post by Pj » Thu Nov 25, 2004 7:22 pm

I have a spectra DTMF mic on my astro spectra.

Sends DTMF in astro...not that it sounds remotely good or not..but does work.

Why its would say "no" to hook upto the radio, I couldn't guess

ASTROMODAT · Post by **ASTROMODAT** » Fri Nov 26, 2004 1:05 pm

Pj, there is a reason why Motorola does not want their analog Spectra mic to be used on an ASTRO Spectra. The analog SPECTRA mic was designed and intended for analog FM ops only. The ASTRO mike was designed to support mixed mode ops. While the ASTRO mic and its response characteristics adequately support analog FM ops on an ASTRO Spectra, it is also tailored and enhanced to optimize the voice input to the IMBE vocoder. Keep in mind that an ASTRO Spectra runs the voice through a DSP even in FM mode (hence the delay even in FM mode), so that the voice in an ASTRO Spectra is handled differently in the FM mode than is the case with the old analog Spectra. You can verify this by taking an old analog Spectra and transmit simplex FM into a scanner. Then, transmit with an ASTRO Spectra in FM mode into the same scanner. In case 1, there is no delay. In case 2, there is a noticeable delay, due to the DSP (even with the IMBE vocoder not involved).

Motorola feels that the analog only SPECTRA mic does not sound as good as the ASTRO mic when in the IMBE mode. This is why an ASTRO Spectra comes with the ASTRO mic, whereas the analog Spectra came with a different mic.

There was an excellent technical bulletin that Motorola issued on this subject about 9 years ago that went into all of the gory details on this. I will try to find it, and post it.

larry

Post by Pj » Fri Nov 26, 2004 2:48 pm

Can't say that I have ever heard a difference between with my collection of mics on the astro radio's I have...from x9000 vintage to current ones (including the two DTMF ones I have).

This is all with DSP8 radios.

The only radio that I have heard a good difference in with, is a mod for the mic for an x9000. A local ham here changes out two little resistors, and voice quaility is almost like a nice tone remote.