AREMA® C&S Manual · AREMA® C&S Manual 2020 Part 24.4.3 Formatted: _____ - 1 – Formatted: No underline Justified, Don't add space between paragraphs of the same style, Tab stops:

AREMA® C&S Manual

2020 Part 24.4.3

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Recommended Ddesign Ccriteria And Bbestest pPractices For RF Filtering For Positive Train Control Rradio Iinstallations.

New 2020 (3 Pages) A. Purpose

This Manual Part recommends installation guidelines of RF interference filters for Positive Train Control (PTC) systems in effort to mitigate radio interference.

B. General

The railroads operate several types of radio communications on various frequencies. The addition of PTC radios into that environment has increased the level of RF interference related issues. This manual part offers guidance for mitigating that interference.

C. RF fFiltering Cconsiderations.

1. Interference issues can be mitigated by additional antenna separation or

radio site relocation. This option should be considered in conjunction with filter options.

2. RF Interference filters may be needed on any of the standard Railroad radio frequency bands. For example: 2. a. 160 MHz

b. 220 MHz

c. 450 MHz

3. It is recommended that filters be applied to all radios. Filtering only one radio

may not eliminate all interference. D. Performance Rrequirements

Minimum performance requirements are provided for the three radio applications. Some key criteria are as follows:.

1. 160-163 MHz band pass filter for voice radio

a. Band reject insertion loss; ≥ 60dB @ ≤ 110 MHz and ≥ 220MHz.

b. Insertion loss of .8dB or better

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d. RF power 100W

2. 217-223Hz band pass filter for PTC radio

a. Band reject insertion loss; ≥-60dB @ ≤ 160 MHz and ≥ -30dB @ ≥ 300 MHz to 2.0 GHz

b. Insertion loss of 0.9 dB or better

c. Return loss of 20dB or better

d. RF power 100W

3. 450MHz-460 MHz band pass filter for Distributed Power and EOT / HTD

radio

a. Band reject insertion loss; ≥ -60dB @ ≤ 250 MHz and ≥ 650 MHz to 1 GHz

b. Insertion loss of 1.5db or better

c. Return loss of 20dB or better

d. RF power 100W

F. Mechanical, Environmental and Structural 1. For onboard applications, a Male N connector on radio side and Female N

connector on antenna side allow operators to bypass the filter if needed.

2. Color coded labels will allow operators to easily identify filters:. Green for 220 MHz, Yellow for 450 MHz and Blue for 160 MHz.

3. For installations within the Locomotive System Integration (LSI) racks, filter maximum dimensions are 2.25” W, 7” L, and 1.4” H.

4. Filter installations should meet ANSI/IEC 60529-2004 / IP 67 standard.

G. Additional fFiltering Cconsiderations



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1. In the Northeast corridor where transits operate PTC at 217-219MHz and

freight rail operates at 220-222MHz additional filtering is required.

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2. IfWhen operating in 220-222 MHz minimum requirements are:

2.

a. Frequency Pass Band 220-222 MHz

b. Frequency Stop Band 217-219 MHz

c. Insertion Loss <2.5 dB

d. Stop Band Rejection >61 dB

e. 160 MHz, 450 MHz, 896-937 MHz Rejection>40 dB

f. Return Loss, VSWR >14 dB, 1.5:1

f.

3. IfWhen operating in 217-219 MHz minimum requirements are:

3.

a. Frequency Pass Band 217-219 MHz

b. Frequency Stop Band 220-222 MHz

c. Insertion Loss <2.5 dB

d. Stop Band Rejection >61 dB

e. 160 MHz, 450 MHz, 896-937 MHz Rejection>40 dB

f. Return Loss, VSWR >14 dB, 1.5:1

4. Mechanical

a. RF Connectors N-Type

b. Temperature Range -40°C to +70°C.

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AREMA® C&S Manual · AREMA® C&S Manual 2020 Part 24.4.3 Formatted: _____ - 1 – Formatted: No underline Justified, Don't add space between paragraphs of the same style, Tab stops: