I never cease to be amazed at how the simple answer to problems like this get
overlooked.
Give the FD noise cancelling microphones. The less background the mic picks
up the less distortion problem there is.
I've been on an 800 digital sytem for about 13 years now. Our earlier
purchased radios came with noise cancelling mics, that later ones didn't. OMG
what a difference. Some radios are so low in TX audio that even with the
console volume at full you have trouble hearing the troopers. Then you get
someone who's used to the noise cancelling mics using the non cancellers and
they blow you out of the console. I guess the Motherola engineers never heard
of ALC or the concept of using it on the console to keep audio levels even.
Dan Hancock N8DJP
> Re: P25 (mis)Information?
Posted by: "Steve S. Bosshard (NU5D)"
[EMAIL PROTECTED] bosshardss
Date: Thu May 29, 2008 9:10 am ((PDT))
On re-re-reading the post, I suspect the MA/COM salesman
proposes just
adding an analog trunked group to the system and calling
that group
talk-around. Just another group in the trunked system.
Any group can
be either Provoice (EDACS only) or P25 digital or Analog
FM.
To many folks in the land mobile business talk-around
refers to simplex
operation on the output frequency of a repeater station and
operation
independent of the repeater station. (hence my earlier
post about
collisions with trunked and simplex operations).
From what I understand the problem with high noise
environments and
intelligibility is due to the characteristics of the DVSI
IMBE vocoder
and how this noise is treated in quantizing. Another talk
group will
not help in building coverage issues because the trunked
system treats
all groups alike unless a group by attributes is steered to
one
particular site in a multisite system. I am most familiar
with simulcast.
I believe the problems with P25 digital are exactly that
and have
nothing to do with brand or manufacturer.
73, Steve NU5D
