Subject: [NEXTEL-1] Re: [WFHSG] Re: more nextel woes

From: [email-masked]
Date: Sun, 10 Aug 2003 18:38:39 -0400

From:  [email-masked]
Re: more nextel woes
: "The WESH NewsChannel 2 investigation also showed Nextels -- those popular
walkie-talkie radios -- also interfere with police and fire radios, knocking them
out."
http://www.wesh.com/news/2393889/detail.html

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Actually this modification has been known to most of us since 2001. This Mod only appiles to certain MTS-2000 radios.
Others have performed modifications to System Sabers, Saber Si , XTS's to improve performence, however Motorola has
not circulated and documentation as of yet. Several departments have ordered "Narrow Band" anttens cut to their
specific operating frequencies.  The Modification described below does not always solve the problem but it helps.
Apparently in Orange County, Fl  it worked there according to the media report.

Details on the Orange County 800 MHz radio system:

The Orange County 800 MHz radio system is a Motorola Smartzone, trunked radio
system.  There are eight (8) nodes on the Smartzone system.  The main node is the Orange
County twenty-eight (28) channel, eight (8)-site simulcast system.  The other major node is the
City of Orlando?s five (5) site, twenty-two (22) channel simulcast system.  The other six (6)
nodes are single site intelligent repeater sites ranging from four (4) to ten (10) frequencies per
site. There are just over 6,000 Orange County users on the system with approximately 16,000
active ID?s system wide. The system supports 89 console positions located in seven (11)
different locations.

The modification that the report is refereing to is described below:
====================================================================================

SERVICE AND REPAIR NOTES

Bulletin

TECHNICAL INFORMATION /COMMERCIAL, GOVERNMENT & INDUSTRIAL SOLUTIONS SECTOR
8000 W. SUNRISE BLVD. / PLANTATION, FL 33322 /

If applicable, enter this information or note this bulletin number and subject material in the appropriate equipment
instruction
manuals and make necessary schematic diagram changes. Enter this bulletin in the correct MASTER and CLASSIFIED INDICES
for future reference. Labor or parts warranty reference is limited to products sold and in use in the United States,
for products sold or in use internationally this bulletin is for informational purposes only. Radios that are Agency
Approved must follow designated agency guidelines.

SRN-ISO
SRN - 1347
APC - 432, 466
Sept 2001

Memo To: SRN Mailing List
Informational Only

From: MTS2000 Subscriber Product Group

Subject: In-Band High Level Intermodulation Enhancement for MTS2000 800MHz Radios
Due to spectrum allocations that have placed commercial mobile radio service (“CMRS”) providers in the same band as
Public Safety systems, some 800MHz Public Safety radios are experiencing interference in close proximity to CMRS
sites. This interference can  result in missed calls or unintelligible audio, even though the Public Safety receivers
are operating in accordance with their published specifications.

Cause:

Intermodulation products of strong in-band signals (experienced close to CMRS sites) and the desired Public Safety
signal may
cause degraded receiver performance. APCO has published a “Best Practices” guide (available at
http://apcointl.org/afc/800bpg.htm, then click on “Best Practices Guide”) that suggests several approaches to this
problem for new and existing systems (see Best Practices Guide, pages 11-14). If the problem cannot be resolved by the
suggested methods, it is in some cases possible to improve the situation by modifying the Public Safety subscriber
radios. This bulletin details modifications that can be made to the MTS2000 portable radio to improve its performance
in high-level IM environments.

Affected Radios:
MTS2000 800MHz band radios.
Model: H01UCx9PW1xN

Modifications: The service manual referenced in this procedure is part number 68P81200C75-O.
Part numbers are referenced below in table according to selected “Modification”.
Modification # 1 - NUF6500C and older PC board modification

1. Disassemble the radio in accordance with section 6 of the manual (pg. 29 – 33); kit number is located on the bar
code label
on the
PCB as shown in Figure 1.

2. Remove Diode CR107 shown in Figure 1.

3. Place Capacitor part number 2113740A06 in place of the diode as shown in Figure 2. One end of the capacitor should
bridge two of the diode pads.

4. Re-assemble the radio in accordance with section 6 of the manual (pg. 36 - 38).
Summary Table Serial Reference Modification # 1 Modification # 2 Software Q334 Radios Shipped before July 2000 432 or
466AAMxxxx and earlier 2113740A06 None Needed Radios Shipped from July 2000 thru October 00 432 or 466AANxxxx thru
AAVxxxx 0662057A42 (R1)
0662057A73 (R5) Yes
Radios Shipped November 2000 & later 432 or 466AAWxxxx and later 0662057A42 (R1)
0662057A73 (R5) None Needed

Future MTS2000 Orders Order No Charge Option None Needed None Needed None Needed X

5. Perform basic Sensitivity and power test to verify radio’s basic functionality.

6. No firmware changes are required for this modification.

7. When NUF6500C and older PC boards are modified as described here, increased receiver Hum & Noise may be noticed
    in extremely strong signal strength areas (-15 dBm and stronger). This Hum & Noise will be audible, but will not
result in
    missed calls or unintelligible audio.

Modification # 2 - NUF6500D PC board modification

1. Disassemble the radio in accordance with section 6 of the manual (pg. 29 – 33).

2. Replace resistor R1 with part number 0662057A42

3. Remove resistor R3.

4. Place resistor R5, part number 0662057A73, in location shown in Figure 1.

5. Re-assemble the radio in accordance with section 6 of the manual (pg. 36 – 38).

6. If the radio contains firmware older than R06.50, upgrade the radio firmware to the latest release.

7. Perform basic Sensitivity and power test to verify radio’s basic functionality Future MTS2000 Orders with option
Q334 – will receive board NUF6533X PC board This board contains the enhancement as shipped from the factory.

The Moto document with pictures.
 http://f1.grp.yahoofs.com/v1/YMA2P7eZBcBr9MOTrg6R0ByeKCSKIsVqejz2YVDELc1DHtj9SGY0-ZRi6JlK7XPe3pb1ECUgIG_NdJbs/SRN1347_MTS2000_Celluar_Interference_.pdf

Harry Marnell wrote:

> Now there's a scoop (see link at bottom)...
> "Inside each emergency radio, there's a tiny part that when removed, the
> Nextel interference is eliminated."
>
> Leave it to a news reporter to solve the "Nextel problem."  I wonder which
> part it is....
>
> Harry
> http://members.cox.net/marnells/kma367-1.htm  <~~  LAPD Communications Div
> History, with some new OLD stuff
>