[Scan-DC] TDMA for MC RE: Problems Monitoring Montgomery TRS w/ BC-796

[Rick Hansen]

Does this mean that sometime within the next year the only radio that will
monitor MC public safety is the PSR-800? 

-----Original Message-----
From: scan-dc-bounces at mailman.qth.net
[mailto:scan-dc-bounces at mailman.qth.net] On Behalf Of BLGY2K at aol.com
Sent: Sunday, January 15, 2012 3:45 PM
To: oldsdoug at hotmail.com; cathy at drzyzgula.org; racerpgt at aol.com;
scan-dc at mailman.qth.net
Subject: Re: [Scan-DC] Problems Monitoring Montgomery TRS w/ BC-796

 
sorry guys, my browser pushed all the text together.  let me try to  this 
again.
 
-------
 

I just figured it out!!! After doing a little research, I ran across  this 
interesting Communications Interoperability Plan for Montgomery County  
(July 2009). Apparently, Montgomery County is in process of upgrading the  
communications infrastructure. This all started seven months ago when the  
county issued new APX radios to Law Enforcement and Fire & Rescue  
personnel. 

-Ben G 


Radioreference.com: See Post #19  
http://forums.radioreference.com/maryland-radio-discussion-forum/213889-mont
gomery-county-apx-radios.html#post1559169
 


Montgomery County, Maryland Communications Interoperability  Plan  
http://www.montgomerycountymd.gov/content/council/pdf/agenda/cm/2009/090723/
20090723_PSMFP1-2.pdf 
 
 



Interesting articles: 

See Page 13 
"A common misconception is that  Montgomery County is moving from 800 MHz 
to 
700 MHz. This is false.  
Montgomery County was an early licensee of radio frequencies in the 821  
MHz band and was fortunate to secure 20 channels for trunked operation. As  
an 
early mover, the County secured sufficient channels to accommodate its  
public 
safety communications needs into the foreseeable future. In  accordance 
with this 
plan, P25 Phase II technology will be adopted in the  upgrade of the 
existing 
trunked radio system, doubling the capacity of the  existing channels 
through the 
use of TDMA technology. This will negate the  need for the County to 
compete for 
additional radio" 

See Page 27-28 
"The option of keeping some of the  existing system in place will be 
explored: 

1. It may be practical to maintain portions of the SmartZone 3.0 system  
that could provide an on-line hot spare backup system which could 
be  used in the unlikely case of a catastrophic failure of the newsystem. 

2. The need for Public Safety service providers Police, Fire-Rescue,  
Sheriffs, Corrections and a few others to transition to P25 
compatible  newer systems does not apply to all County radio users. 
For example, the DOT  Highway Services vehicles and the DGS 
Customer Service providers  (electricians, HVAC technicians, 
plumbers, etc.) have no such need. These  agencies could remain on 
the existing radio system for as long as the  SmartZone 3.0 system can 
be maintained or the functions might be integrated  with the new 
system. A decision to not move non-Public Safety users to the  newer 
system would be a decision to defer purchase of the newer subscriber  
radios. Another option which will be investigated and considered concerns  
the 
inter-site backbone. As described above the current system uses a hybrid  
design of 
fiber optic circuits and microwave links. This may be the optimum  for the 
new 
system, or it may not. All options should be considered."  

V. Current County Position (See Page 29-31) 
"The  existing County system has passed the last stage of software 
revisions for  Version 3 systems. System warranty and maintenance and 
expansion of the  
subscriber fleet is still provided. The current date for the end of the  
lowest level of support, radio parts and warranty, is 2016. 
The most  likely next step for an upgrade by the County is Motorola ASTRO 
25 version  8.x which is compatible with the P-25 Phase II standard and has 
an 
IP based  backbone. Version 8.x permits the use of Time Division Multiple 
Access  technology that permits a 2:1 efficiency of simultaneous talkpaths 
per  
channel, thereby increasing the utilization of the existing radio spectrum  
and 
permitting future growth. 

In summary, the County ASTRO 3.x system is in the twilight of its  useful 
and fully supported life cycle. There are no intermediate levels of  
beneficial 
upgrades available for the network due to obsolescence of certain  network 
subsystems, particularly the Motorola 6809 controllers."  


-Ben G 


In a message dated 1/15/2012 10:57:09 A.M.  Eastern Standard Time, 
oldsdoug at hotmail.com writes:



Thanks to  all... Matt, it dawned on me this morning that someone had 
mentioned  something similar and I had planned to go back and see who and 
what it 
was,  thanks for the reminder. Cathy, I hadn't thought to look at the 
attenuation  but will do so, good idea.

Everything seems to be working fine this  morning... last night it was 
un-listenable-to... I suspect that something is  going on with the county's 
radio  system.

Regards,

Doug

----------------------------------------
>  From: cathy at drzyzgula.org
> To: racerpgt at aol.com; oldsdoug at hotmail.com;  scan-dc at mailman.qth.net
> Subject: RE: [Scan-DC] Problems Monitoring  Montgomery TRS w/ BC-796
> Date: Sun, 15 Jan 2012 09:11:40  -0500
>
> I've also had problems with my Home Patrol sticking on a  channel after 
the
> transmissions have ended, leaving random signals  and static. I turned on
> the attenuation and set the squelch lower and  that has helped, but not
> completely solved the problem.
>
>  Cathy D
>