Aeroflex 2968 User Manual
For the very latest specifications visit www.aeroflex.com
Application
Note
The IFR 2968 TETRA Radio Test Set is the industry standard
for testing TETRA mobiles and base stations during design,
manufacture, service and repair. This application note answers
common questions concerning the capabilities and
configuration of the IFR 2968, and provides solutions to
common problems that may arise during testing.
IFR 2968 Frequently Asked Questions
by Clive Rodmell
Introduction
TETRA is a complex system with many features and a high degree
of customisation to suit the requirements of individual networks
and groups of end users. The IFR 2968 is therefore a complex
product providing configuration to match the mobiles and base
stations under test and supporting the diversity of features and
operational behaviour. Inevitably the IFR 2968 requires some user
familiarisation and experience in order to achieve the greatest
benefit from it. Further, since TETRA is a relatively new system,
some of the test methods and TETRA terminology may be unfamiliar to new users. This application note aims to distil IFR's practical experience with testing TETRA mobiles and base stations to
assist IFR 2968 customers. Note that the term 'mobile' is used as
a generic term throughout this application note to mean a radio
terminal, whether vehicle mounted or hand portable.
This application note contains details and examples of certain
procedures, but it is not a substitute for the IFR 2968 operating
manuals. You should ensure that you have obtained and read the
latest versions of these manuals relevant to the software version
in your IFR 2968. For full operating details please refer to the following publications - these are the latest versions and are relevant
to the latest Phase 3.2 software in the IFR 2968:
• 46882/324 IFR 2968 Phase 3.2 Operating Manual
TETRA Supplement, Issue 10
• 46882/274 IFR 2965A/2966A/2967/2968 Operating
Manual, Issue 13
• 46882/280 IFR 2965A/2966A/2967/2968 Programming Manual, Issue 12
Note: where references are made to specific numbered pages in
these manuals, these apply to the printed versions. Electronic versions on CD-ROM may have slightly different page numbering.
Validity of information
The information given in this application note is given in good faith
and was believed to be correct at the time of publication, August
2002. However, this information is likely to be subject to change
over time as the TETRA standard continues to develop and networks and equipment become more mature. You are advised to
periodically check our web site www.aeroflex.com for updated
information. Your assistance in informing Aeroflex of any corrections, updates or additional questions would be much appreciated (mailto:info-test@aeroflex.com).
Index to questions
Questions and answers are in the following categories:
Section 1: IFR 2968 versions and options
Section 2: Testing mobile and base station transmitters
Section 3: Testing mobile and base station receivers
Section 4: Testing the audio performance of TETRA mobiles
Section 5: Functional testing of TETRA mobiles
Section 6: Compatibility with TETRA mobiles and networks
Section 7: Signalling and protocol operations
Section 8: Testing mobiles with encryption and authentication
Section 9: Miscellaneous functions
Use the index of questions below to determine whether your
question is covered, then find the answer in the numbered
Questions and Answers section.
Section 1 Questions: IFR 2968 versions and options
Q1.1: What is the current software version for the IFR 2968? How
do I determine whether an IFR 2968 is fitted with the latest
software?
Q1.2: My IFR 2968 does not have the latest software version.
Can it be upgraded, and is there a charge for this?
Q1.3: Do I have to return the IFR 2968 to Aeroflex for the soft-
ware upgrade?
Q1.4: Is there a new version of the 2968 operating manual for
the Phase 3.2 upgrade?
Q1.5: What are the new functions in the Phase 3.2 software?
Q1.6: My IFR 2968 still has old Phase 2 software. What func-
tionality will I gain by purchasing the "2968 PHASE 3"
option?
Q1.7: What functionality will I gain by purchasing Option 32
TETRA Direct Mode?
Q1.8: Does Option 32 TETRA Direct Mode test any signalling
functions?
Q1.9: Can the IFR 2968 also set up a call to a Direct Mode
mobile?
Q1.10: Can I purchase an IFR 2968 with only one of the TETRA
system options initially and add other options at a later
date?
Q1.11: Can I purchase an IFR 2968 with none of the TETRA sys-
tem options initially and add one or more TETRA options
at a later date?
Q1.12: Can I purchase an IFR 2968 with Option 32 TETRA DM
and add Option 30 TETRA MS at a later date?
Q1.13: Does the IFR 2968 have an option for 800 MHz TETRA
systems?
Q1.14: Does the IFR 2968 have a DC supply or battery pack
option?
Q1.15: Does the IFR 2968 include automatic testing?
Q1.16: Can the IFR 2968 test other radio systems besides
TETRA?
Q1.17: Does the IFR 2968 support Tetrapol?
Q1.18: Can the IFR 2968 test US PMR/PAMR/SMR systems such
as P25, EDACS, iDEN?
Q1.19: Can I have a 2965A, 2966A or 2967 upgraded to a
2968?
Q1.20: Is there an IFR TETRA Test SIM available, as there is for
GSM?
Q1.21: Does IFR supply cables, connectors and adaptors forcon-
necting to TETRA mobiles?
For the very latest specifications visit www.aeroflex.com
Section 2 Questions: Testing mobile and base station
transmitters
Q2.1: How do I use the 2968 to control the mobile to transmit at
a particular power level?
Q2.2: Why is the mobile power level approximately 5 dB too high
or too low?
Q2.3: Can I use the 2968 to control the mobile power directly, as
with GSM?
Q2.4: How do I ensure a repeatable method for testing mobiles
on a particular power level?
Q2.5: Can I test the mobile's transmitter on different frequen-
cies?
Q2.6: Can I test the mobile's transmitter over its entire receive/
transmit frequency range?
Q2.7: Why do the TETRA mobile transmitter measurements stop
after about a minute?
Q2.8: Why does my TETRA mobile or base station exhibit exces-
sive vector error?
Q2.9: Can the 2968 measure Adjacent Channel Power (ACP)?
Q2.10: Can the 2968 power measurement compensate for cable
loss, attenuators, splitters?
Q2.11: Why does the power reading show a reverse video aster-
isk next to it?
Q2.12: Can the IFR 2968 measure directional ("through-line")
power?
Section 3 Questions: Testing mobile and base station
receivers
Q3.1: Can the IFR 2968 test the receiver sensitivity of TETRA
mobiles?
Q3.2: How do I measure receiver sensitivity using 'TT' RF
Loopback?
Q3.3: Why does the mobile drop the call while measuring receiv-
er sensitivity?
Q3.4: Why doesn't 'TT' RF Loopback work with my mobile?
Q3.5: How do I test receiver sensitivity if a mobile does not sup-
port TT RF Loopback?
Q3.6: What is the difference between 'TT' test mode and 'T1' test
mode?
Q3.7: How do I access T1 test mode in the mobile under test?
Q3.8: How do I test the mobile receiver if I have no access to TT
loopback or T1 test mode?
Q3.9: What is the difference between MER, BER and RBER?
Q3.10: Which types of T1 test signals are generated for MS test-
ing?
Q3.11: What is the content of the PRBS information generated by
the IFR 2968 T1 signals?
Q3.12: Can the 2968 generate PRBS fortesting AACH, BSCH and
SCH/HD channel types?
Q3.13: Can the IFR 2968 test base station receivers?
Q3.14: What is the synchronisation connection between the base
station and the IFR 2968?
Q3.15: How do I perform a test on a base station receiver with
the IFR 2968?
Q3.16: What is the purpose of "SYNC PULSE OFFSET" and
"AUTO SYNC PATH DELAY"?
Q3.17: Why does the base station indicate a BER measurement
of around 50%?
Q3.18: Can the 2968 signal generatorcompensate for cable loss,
attenuators, splitters etc.?
Q3.19: Why does the signal generator level setting show a
reverse video asterisk next to it?
Q3.20: Can I use the 2968 to test receiver selectivity?
Q3.21: Can the IFR 2968 be used for dynamic (fading) sensitivity
tests?
Section 4 Questions: Testing the audio performance
of TETRA mobiles
Q4.1: Can I perform audio testing whilst the IFR 2968 is in TETRA
mode?
Q4.2: Can I use an external audio source to modulate the 2968
TETRA signal?
Q4.3: How can I test the mobile's audio circuitry with the 2968?
Q4.4: What is the IFR 2968 generating when it is set to 'test
tone'?
Q4.5: Can I use the 2968 TETRA test tone for audio SINAD
measurements?
Q4.6: Can I use the 2968 to test audio at frequencies other than
1 kHz?
Section 5 Questions: Functional testing of TETRA
mobiles
Q5.1: Can the IFR 2968 test text messaging, as with SMS text
messages in GSM?
Q5.2: Can the IFR 2968 support 16-bit UCS2 and Cyrillic text
messages?
Q5.3: What is the 'commanded registration' function used for?
Q5.4: What is the 'TT test confirm' function used for?
Q5.5: What is the SYSTEM SET-UP: MOBILE PARAMETERS menu
used for?
Q5.6: Does the IFR 2968 test DGNA (Dynamic Group Number
Assignment)?
Q5.7: Does the IFR 2968 test TETRA Packet Data?
Q5.8: Why has transmission trunking behaviour changed in the
Phase 3.2 software?
Q5.9: Why has the AUTORUN PARAMETERS menu changed in
the Phase 3.2 software?
Q5.10: Why is 'TEST MODE REGISTRATION' not in System
Parameters in Phase 3.2?
Q5.11: What has happened to mobile terminated SDS types 1, 2,
3 and 4 in Phase 3.2?
Q5.12: What has happened to the mobile classmark display in
Phase 3.2?
Q5.13: When a mobile registers and attaches multiple groups,
each group identity is immediately over-written by the
next one. Is it possible to see this information?
Q5.14: When a mobile sends a text message, the IFR 2968 only
shows the first few characters. Is it possible to see the
whole message ?
Q5.15: Is it possible to change the time and date information that
is sent when the IFR 2968 sends an SDS-TL text message
to a mobile?
Q5.16: Why can't I make group calls when the mobile is regis-
tered and the PTT pressed?
Section 6 Questions: Compatibility with TETRA mobiles
and networks
Q6.1: Which TETRA mobiles can be tested by the IFR 2968?
Q6.2: How do I make an RF connection between the IFR 2968
and the mobile?
Q6.3: What is the significance of "TIP" and which version does
the IFR 2968 comply with?
Q6.4: I have a TETRA mobile that claims to be TIP compliant, and
the IFR 2968 claims to be able to test it, so why doesn't the
mobile register to the 2968 when I switch it on?
Q6.5: The essential network parameters have been set correctly
but the mobile still does not register to the IFR 2968. Is
there anything else that needs to be checked?
Q6.6: The mobile registers to the IFR 2968 but call set-up fails.
What is wrong?
Q6.7: Why is the IFR 2968 so particular about the network
parameters?
Q6.8: Why can't the IFR 2968 set the network parameters itself
automatically?
Q6.9: GSM radio test sets don't require the correct network
parameters to be set, why is this necessary for TETRA
mobiles on the IFR 2968?
Q6.10: How do I find out the network parameters for a particular
mobile?
Q6.11: How do I set up the 2968 to match the network parame-
ters of a local TETRA BS?
Q6.12: How do I convert a frequency in Hz to a TETRA channel
plan and channel number?
Q6.13: Can I test a TETRA mobile that does not conform to the
ETSI channel numbering?
Q6.14: Can I ignore channel plans and channel numbers and set
the 2968 frequency in Hz?
Section 7 Questions: Signalling and protocol operations
Q7.1: Does the IFR 2968 test signalling operations with Direct
Mode mobiles?
Q7.2: Can I see the signalling messages and parameters that the
2968 sends to the mobile and receives from the mobile?
Q7.3: Is it possible to read the individual bits of the PDU fields
that the 2968 receives?
Q7.4: Is it possible to edit the PDU fields that the 2968 sends?
Q7.5: Is it possible to view and edit the SYSINFO and SYNC mes-
sages sent by the 2968?
Section 8 Questions: Testing mobiles with encryption
and authentication
Q8.1: Can I test TETRA mobiles that use encryption and / or
authentication?
Q8.2: Does the IFR 2968 test Air Interface Encryption (AIE) or
End to End encryption (E2E)?
Q8.3: Will the IFR 2968 support encryption in a future upgrade?
Q8.4: How can I test a TETRA mobile that uses encryption?
Q8.5: The IFR 2968 has a setting for "AIR INTERFACE ENCRYP-
TION" - what is this for?
Q8.6: Can I check that the mobile attempts to perform an
encrypted registration?
Q8.7: Does the IFR 2968 test Authentication or Mutual
Authentication?
Q8.8: How can I test a TETRA mobile that uses authentication?
Q8.9: Will the IFR 2968 support authentication in a future
upgrade?
Q8.10: How can I test a TETRA mobile that uses mutual authen-
tication?
Q8.11: Will the IFR 2968 support mutual authentication in a
future upgrade?
Q8.12: Could the IFR 2968 test authentication without secure
algorithms and keys?
Section 9 Questions: Miscellaneous functions
Q9.1: Can the IFR 2968 test TETRA mobiles off-air?
Q9.2: Can the IFR 2968 receive TETRA base station signals off-
air?
Q9.3: Can the IFR 2968 perform off-air BER testing (coverage
monitoring or drive testing)?
For the very latest specifications visit www.aeroflex.com
Q9.4: Can the IFR 2968 test other base station components
besides the transceiver?
Q9.5: Can I store and recall different TETRA system set-ups on
the IFR 2968?
Q9.6: Why doesn't the store / recall facility work when I try to
store /recall TETRA settings?
Q9.7: Can I use a FLASH memory card instead of a battery
backed SRAM memory card?
Q9.8: Can I capture a 2968 screen image and use it in PC appli-
cations?
QUESTIONS AND ANSWERS SECTION
Section 1 Q&A: IFR 2968 versions and options
QQ11..11
: What is the current software version for the IFR 2968?
How do I determine whether an IFR 2968 is fitted with the latest
software?
AA11..11
: The current software version is "Phase 3.2" (version 11.20).
If you purchase a new 2968 it will have this version of software.
To determine which software version is installed in a 2968, press
the [HELP/SET-UP] hardkey then the [VERSION] softkey and check
the version numbers as follows:
The current
PPhhaassee 33..22 ssooffttwwaarree
is identified as follows:
A4 TETRA APP 11.20 16/04/02 (see note)
A6/2 MAINCODE 4M 11.20 16/04/02
TETRA application 11.20 16/04/02
The previous
PPhhaassee 33..11 ssooffttwwaarree
is identified as follows:
A4 TETRA APP 11.10 18/01/01 (see note)
A6/2 MAINCODE 4M 11.10 18/01/01
TETRA application 11.10 18/01/01
The earlier
PPhhaassee 33..00 ssooffttwwaarree
is identified as follows:
A4 TETRA APP 11.00 25/04/00 (see note)
A6/2 MAINCODE 4M 11.00 25/04/00 or version 11.01
TETRA application 11.00 25/04/00
Note: Shown only when TETRA system is selected.
QQ11..22::
My IFR 2968 does not have the latest software version.
Can it be upgraded, and is there a charge for this?
AA11..22::
Yes, it can be upgraded to Phase 3.2. If your IFR 2968 has
the previous Phase 3.1 software (version 11.10) or the earlier
Phase 3.0 software (version 11.00 or 11.01) then there is no
charge for the upgrade to Phase 3.2. If your IFR 2968 has the earlier Phase 3.0 software you can upgrade straight to Phase 3.2
without first upgrading to Phase 3.1. If your IFR 2968 has the even
earlier Phase 2 software (version 10.20 or lower) then you will
need to purchase the "2968 PHASE 3" option before your IFR
2968 can be upgraded. Please contact your local IFR sales representative or distributorto arrange for an upgrade or to purchase
the option "2968 PHASE 3".
QQ11..33::
Do I have to return the IFR 2968 to IFR for the software
upgrade?
AA11..33::
No, this is not normally necessary. The software upgrade
will normally be performed by your local IFR Approved Service
Center, either on your premises or by return to a local service center, as agreed between you and the IFR Approved Service Center.
The process takes about 45 minutes and does not require disassembly of the test set. However, if the IFR 2968 is due to be
returned to an IFR Approved Service Center for repair or routine
calibration, then the software upgrade can be requested at the
same time. If your test set is a very early unit that has never been
upgraded then it may require return to your local IFR Approved
Service Center.
QQ11..44::
Is there a new version of the 2968 operating manual for
the Phase 3.2 upgrade?
A1.4: Yes, but only the TETRA specific aspects have
changed. Current versions are:
• 46882/274 Operating Manual for
2965/2966/2967/2968: issue 13, 25 June 2001
• 46882/324 TETRA Supplement for 2968 Phase 3.2:
issue 10, 17 May 2002
• 46882/280 Programming Manual for
2965/2966/2967/2968: issue 12, 21 March 2002
If you receive a free-of-charge upgrade to Phase 3.2 from Phase
3.1 or Phase 3.0 you can also receive free-of-charge electronic
copies of the updated TETRA supplement and programming manual in pdf format. If you are purchasing the "2968 PHASE 3"
option to upgrade to Phase 3.2 from Phase 2, you will receive a
new printed copy of the TETRA supplement. You may also purchase printed copies of any of the manuals if required - please
contact yourusual IFR sales representative. If you purchase a new
2968 you will receive printed copies of all 3 manuals.
QQ11..55::
What are the new functions in the Phase 3.2 software?
AA11..55::
The following is a brief summary of the new functions in the
IFR 2968 Phase 3.2 software release with respect to the previous
Phase 3.1 release.
• TETRA Test (TT) mode registration obtains TEI, Power
Class, Receiver Class
• TETRA Test (TT) RF Loopback and TCH/S BER /
RBER / MER measurement
• Enhanced autotest with up to six configurable call set-up
and clear-down tests
• TIPv3 Compliant
• Mobile Originated SDS-TL text message, 160 characters
with destination SSI / ESN
• Mobile Terminated SDS-TL text message, 120 characters
user definable, timestamp
• Mobile Originated and Mobile Terminated 7-bit SDS-TL
text messages
• SDS-TL Short Reports sent and received
• Mobile Originated Status with destination SSI / ESN
• Multiple Group Attachments, group detachment and
group modification fully displayed
• Configurable Trunking Timers and Call Timers
• DTMF digits displayed during a call
• Mobile Originated Direct Mode call set-up and clear
down (requires Option 32)
• Direct Mode call set-up parameters displayed (requires
Option 32)
For more details refer to the IFR 2968 data sheet 46891/022
issue 9 (April 2002) and the IFR 2968 operating manual TETRA
supplement 46882/324 issue 10 (May 2002).
QQ11..66::
My IFR 2968 still has old Phase 2 software. What func-
tionality will I gain by purchasing the "2968 PHASE 3" option?
AA11..66::
The "2968 PHASE 3" option enables your IFR 2968 to be
upgraded to the latest Phase 3.2 software. The Phase 3.2
release also incorporates the enhancements introduced in the
two previous releases under the "2968 PHASE 3" option, Phase
3.0 and Phase 3.1.
Phase 3.0 was released in April 2000 with the following
enhancements w.r.t. Phase 2:
• Autotest
• TIPv2 compliant
• TCH and MCCH on different frequencies
• Transmission trunking
• Open Loop and Closed Loop power control
• Neighbour Cell Broadcast and Cell Re-Selection
• Mobile Originated Status and SDS
• Group Attachments
Phase 3.1 was released in January 2001 with the following
enhancements w.r.t. Phase 3.0:
• 800 MHz channel plan for Asia Pacific countries
• Zero offset channel plans and 410MHz channel plan with
-6.25 kHz offset
• Power reading in Watts as well as dBm
• Re-start measurement averaging
• Channel plan NO PLAN for direct entry in Hz
• Off-air capability by setting expected level -40dBm
• Pre-defined call types: Group, Private, Phone,
Emergency, User
• Mobile Terminated Phone Call with ESN
• Mobile Terminated Status and SDS
• Mobile Originated SDS-TL text message (limited length)
• Mobile Terminated SDS-TL text message (very limited)
Phase 3.2 was released in April 2002.
Refer to A1.5 above for details of the enhancements in Phase 3.2
w.r.t. Phase 3.1.
QQ11..77::
What functionality will I gain by purchasing Option 32
TETRA Direct Mode?
AA11..77::
The "TETRA DIRECT MODE" system (Option 32) is an addition to the "TETRA MOBILE" system (Option 30). When the TETRA
DIRECT MODE system is selected, the IFR 2968 does not emulate
a TETRA base station but receives and measures transmissions
from a TETRA mobile operating in direct mode. When a TETRA
mobile is set to operate in Direct Mode (DMO), it is able to transmit autonomously without synchronising or registering to the test
set, and without requesting permission to transmit. No signalling
messages from the test set are required in response to a TETRA
mobile setting up a call in direct mode, nor is any such response
expected by the mobile. Simply holding the PTT starts transmission. The format of the transmitted bursts is slightly different in
direct mode, and the burst timing is decided by the mobile, not
by the test set. The IFR 2968 transmitter measurements are modified accordingly to ensure that the direct mode transmissions are
measured according to the direct mode specification.
QQ11..88::
Does Option 32 TETRA Direct Mode test any signalling
functions?
AA11..88::
Yes, with the current Phase 3.2software. The IFR 2968 supports Mobile Originated Direct Mode Call Set-Up and Cleardown
in accordance with TTR 002 Direct Mode TIP v1.0.3. The IFR 2968
indicates when a direct mode call has been set up or cleared
down, and displays the following information sent by the Direct
Mode mobile relating to itself and the parameters of the call:
ITSI (MCC / MNC / SSI) of the mobile under test
Direct Mode power class of the mobile under test
Direct Mode call type (individual or group, clear mode or
encrypted)
Direct Mode call priority level (normal, high, pre-emptive or
emergency)
Called party ID (individual call) or called group ID (group call)
QQ11..99::
Can the IFR 2968 also set up a call to a Direct Mode
mobile?
AA11..99::
No. The IFR 2968 does not send any signalling to a Direct
Mode mobile, hence it does not support Mobile Terminated call
set-up and cleardown. This can be tested if required by using a
second Direct Mode mobile. The IFR 2968 should first be used to
determine that the transmitting Direct Mode mobile is within
specification, and to determine that the configurations and
parameters of the Direct Mode mobiles are compatible.
QQ11..1100::
If I purchase an IFR 2968 with only one of the TETRA sys-
tem options can I add other options at a later date?
AA11..1100::
Yes. The IFR 2968 can be purchased in one of the fol-
lowing configurations:
IFR 2968 + Option 30 TETRA MS + Option 31 TETRA BS +
Option 32 TETRA DM
IFR 2968 + Option 30 TETRA MS + Option 32 TETRA DM
For the very latest specifications visit www.aeroflex.com
IFR 2968 + Option 30 TETRA MS + Option 31 TETRA BS
IFR 2968 + Option 30 TETRA MS
IFR 2968 + Option 31TETRA BS
Further options can be purchased at a later date if not purchased
initially. Please contact your local IFR sales representative or distributor for a quotation.
QQ11..1111::
Can I purchase an IFR 2968 with none of the TETRA system options initially and add one or more TETRA options at a later
date?
AA11..1111::
No. At least one of Option 30 TETRA MS or Option 31
TETRA BS must be included at the time of initial purchase.
QQ11..1122::
Can I purchase an IFR 2968 with Option 32 TETRA DM
and add Option 30 TETRA MS at a later date?
AA11..1122::
No. Option 32 TETRA DM is only available as an addition
to Option 30 TETRA MS.
QQ11..1133::
Does the IFR 2968 have an option for 800 MHz TETRA
systems?
AA11..1133::
Yes, but it is not an optional extra. 800 MHz TETRA is
included as standard with its own pre-defined channel plan. The
IFR 2968 also includes as standard the ability to test any TETRA
system at any frequency from 100 MHz up to 1 GHz.
QQ11..1144::
Does the IFR 2968 have a DC supply or battery pack
option?
AA11..1144::
No, operation is only possible from AC mains power. If
you need to operate the test set from a low voltage DC supply
(e.g. in a vehicle) you are recommended to obtain an inverter with
adequate power. You may find that you can obtain a suitable
inverter intended for operating mains powered appliances in caravans. IFR has not evaluated any such inverters and is not able to
recommend particular products, therefore you should ensure that
the AC supply requirements of the IFR 2968 are satisfied.
QQ11..1155::
Does the IFR 2968 include automatic testing?
AA11..1155::
Yes. Autotest mode for testing mobiles was introduced in
Phase 3.0, and has been further enhanced in the latest Phase 3.2
release. Automatic test programs can include functional tests
(registration, call set-up, call clear-down) as well as parametric
tests (radio measurements). Phase 3.2 autotest provides the flexibility of up to six separate call set-up and clear-down tests as well
as the ability to test receiver sensitivity automatically using TETRA
Test (TT) mode RF loopback Bit Error Rate (BER) measurement.
QQ11..1166::
Can the IFR 2968 test other radio systems besides
TETRA?
AA11..1166::
Yes. GSM digital cellular, MPT 1327 analogue trunking and
automated analogue PMR testing can be added as options, either
at time of initial purchase or at a later date. Legacy analogue cellular systems (AMPS, TACS, NMT 900/450) options are also available. The IFR 2968 also provides as standard traditional analogue
radio testing capability for mobiles using FM, AM or PM modulation up to 1 GHz. Note that the GSM option only tests 900 MHz
or lower frequency GSM mobiles, or the 900 MHz band of dual
band/tri-band GSM mobiles, not the 1800 MHz or 1900 MHz
bands. Dual band and tri-band GSM mobiles are supported by the
IFR 2935 and IFR 2967 radio test sets.
QQ11..1177::
Does the IFR 2968 support Tetrapol?
AA11..1177::
No. Despite the similar sounding name, Tetrapol is not
related to TETRA. Tetrapol is a proprietary FDMA PMR system
from EADS-DSN Cogent (formerly Matra Communications) and is
a completely different system from TETRA. IFR has no plans to
provide system specific support for Tetrapol on the IFR 2968.
However, since Tetrapol is an FDMA system, many of the measurements can be made using the traditional analogue radio testing capability of the IFR 2968.
QQ11..1188::
Can the IFR 2968 test US PMR/PAMR/SMR systems such
as P25, EDACS, iDEN?
AA11..1188::
No. However, P25 (APCO Project 25) is supported on the
IFR 2975 Radio Test Set. Refer to www.p25.com for details. EDACS
is supported on the IFR 2945A and COM 120C Radio Test Sets.
iDEN is a proprietary system from Motorola which is not currently supported by any IFR Radio Test Set. IFR has no plans to support P25, EDACS or iDEN on the IFR 2968.
QQ11..1199::
Can I have a 2965A, 2966A or 2967 upgraded to a
2968?
AA11..1199::
No, these instruments cannot support TETRA.
QQ11..2200::
Is there an IFR TETRA Test SIM available, as there is for
GSM?
AA11..2200::
No. TETRA mobiles do not currently use SIMs, although a
few do include a SIM holder. Currently all TETRA mobiles have to
be configured using programming and customisation tools,
although TETRA SIMs may be used in future. Currently there is no
specification for a test version of the TETRA SIM as there is for
GSM. This situation may change in future.
QQ11..2211::
Does IFR supply cables, connectors and adaptors forconnecting to TETRA mobiles?
AA11..2211::
Yes and no. A small number of standard cables and adaptors (N-type, TNC, BNC) are available as accessories (refer to the
IFR 2968 data sheet or contact your local IFR sales representative). For a wider selection of standard types you should consult
your usual electrical distributor catalogues or specialist accessory
suppliers. For proprietary connections you will normally need to
contact the manufacturer or distributor of the mobile.
Section 2 Q&A: Testing mobile and base station transmitters
QQ22..11::
How do I use the 2968 to control the mobile to transmit
at a particular power level?
AA22..11::
TETRA mobiles use Open Loop Power Control (OLPC) in
which the mobile calculates the power level at which to transmit,
based on the strength of the signal received from the base station. A mobile that is close to a base station will receive a strong
signal, consequently it can transmit at a low power level. When the
mobile is connected to the IFR 2968, the power is determined by
the strength of the received signal, i.e. the 2968 RF Generator
Level, and by two of the parameters in the 2968 SYSTEM PARAMETERS menu, "ACCESS PARAMETER" and "MAX TX LEVEL".
The calculation is as follows:
• Take the 2968 RF GEN level, which will be in -ve dBm,
and make it +ve.
• Add the ACCESS PARAMETER, which is in -ve dBm,
range -53dBm to -23dBm.
• The result is the mobile's transmit power, subject to
some modifications.
The calculated mobile transmit poweris modified by the following
conditions:
• The mobile is not allowed to transmit at a power level
higher than MAX TX LEVEL
• The mobile cannot transmit at a power level higher than
its power does, e.g. a Class 4 Mobile has a maximum
power level of PL4 +30 dBm.
• The mobile cannot transmit at a power level lower than
its minimum, i.e. PL7 i.e. 15 dBm.
• The mobile power is quantised to defined power level
steps: PL1 +45 dBm, PL2 +40 dBm, PL3 +35 dBm, PL4
+30 dBm, PL5 +25 dBm, PL6 +20 dBm, PL 7+15 dBm.
• Some mobiles belong to an 'L' power class where their
top power level is reduced by 2.5 dB, e.g. PL4L 27.5
dBm.
QQ22..22::
Why is the mobile powerlevel approximately 5 dB too high
or too low when I have set the 2968 RF Generator Level to the
correct value for the power level required?
AA22..22::
Mobiles are permitted +/- 4 dB tolerance in measuring the
RSSI (Received Signal Strength Indication), so it is not possible to
guarantee a particular power level for a particular RF GEN level,
except when the mobile is forced to the maximum or minimum
power. If the 2968 signal generator is set at least 4 dB lower than
the calculated value for maximum mobile power, the mobile
should be using the maximum permitted power. If the 2968 signal generator is set at least 4 dB higher than the calculated value
for minimum mobile power, the mobile should be using the minimum transmit power. For the intermediate power level steps, you
can experiment with different RF Generator Level settings to
achieve the required level.
QQ22..33::
Can I use the 2968 to control the mobile power directly,
as with GSM?
AA22..33::
No. TETRA mobiles do not incorporate a direct power con-
trol mechanism, therefore the 2968 cannot directly command the
mobile to a particular power level. However, some TETRA mobiles
incorporate Closed Loop Power Control (CLPC) in which they will
respond to a command to increase or decrease their power by
one or more 5 dB power level steps. The 2968 can therefore be
used first to force the mobile to minimum or maximum power
level by using normal open loop power control, then to command
the mobile to increase or decrease power from this known starting point. However, most TETRA mobiles do not support CLPC.
QQ22..44::
How do I ensure a repeatable method for testing mobiles
on a particular power level?
AA22..44::
Use the MAX TX LEVEL parameter on the SYSTEM PARAMETERS menu to limit the mobile power to the particular power
level required. Set the RF Generator Level to a low enough level
(e.g. -100 dBm) to force the mobile to transmit at the maximum
power level permitted.
If the MAX TX LEVEL is changed, a TETRA mobile that is already
registered to the test set or active in a call may not necessarily
alter its power in response to the change, since this is not a
parameter that a mobile would expect to change on a real base
station. In this case it may be necessary to clear down the current
call or even de-register and re-register the mobile to the test set
for the parameter change to take effect. However, if the mobile is
tested in T1Test Mode using the 2968 T1 test signal, the MAX TX
LEVEL can be used to directly control the mobile's transmit power
(with RF Gen Level set to -100 dBm).
QQ22..55::
Can I test the mobile's transmitteron different frequencies?
AA22..55::
Yes. The control channel (MCCH) may have to be on a specific frequency (channel number) in order for the mobile to recognise the test set and perform registration. However, during a call
set-up, the mobile should obey an instruction from the IFR 2968
to transmit and receive on any traffic channel frequency (channel
number) within the mobile's capabilities. When the mobile is idle
on the control channel (MCCH) you can set the traffic channel
(TCH) that will be used when a call is set-up. Hence you can test
the mobile's transmitter on different frequencies by clearing down
a call, changing the traffic channel number, and setting up a new
call.
QQ22..66::
Can I test the mobile's transmitter over its entire receive /
transmit frequency range?
AA22..66::
Yes, if the mobile has a flexible RF architecture that allows
this operation. For example the 'TETRA 380 MS' channel plan can
be used to test the mobile's receiver over the range 390 to 400
MHz, and the mobile's transmitter over the range 380 to 390
MHz. However, the IFR 2968 allows you to define a reverse channel plan so the mobile's receiver can be tested over the range
380 to 390 MHz and the mobile's transmitter over the range 390
to 400 MHz. Depending on the configuration of the mobile, you
may be able to perform normal registration and call set-up with a
reverse channel plan, oryou may need to use T1 test mode to test
on reverse frequencies. For further details, refer to 'Annex B:
Configuring the IFR 2968 with a User Defined Channel Plan' in the
application note 'Testing TETRA mobiles with the IFR 2968'.
QQ22..77::
Why do the TETRA mobile transmitter measurements stop
after about a minute?
AA22..77::
The measurements do not stop, it is the mobile transmissions that have stopped. TETRA mobiles making group calls or
simplex private calls normally incorporate an autonomous transmission timer which is typically one minute in duration, so that the
mobile stops transmitting even if the user is still holding the PTT
pressed. TETRA mobiles do not normally incorporate a transmission timer when making duplex private calls or phone calls, hence
you should always set up a duplex call where possible (e.g. a
phone call) when you want to examine transmitter measurements
in detail. This also has the advantage of not requiring you to hold
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