ANSI SCTE 68-2018 pdf free download – Drop Passives: Matching Transformers 75Ω to 300Ω.
This document is identical to SCTE 68 2013 except for informative components which may havebeen updated such as the title page, NOTICE text, headers and footers. No normative changeshave been made to this document.
The purpose of this document is to specify recommended mechanical and electrical standards for broadband radio frequency(RF) devices whose primary purpose is to provideimpedance and connector match between 75Q2 coaxial type F and 300Q2 twin-lead openscrew connectorized devices.The most common use for such devices is matching coaxialinput cables from distribution systems to 300Q2 balanced screw antenna terminals on indoorreceivers.
The specification is not intended to limit or restrict any manufacturer’s innovation andimprovement. The specification may be amended in the future as deemed appropriate.2.0 MECHANICAL
2.1 RF Ports
2.1.1 All coaxial RF ports shall be type F. Female ports shall conform to the requirements of ANSISCTE 012006 while male ports shall conform to therequirements of ANSI/SCTE 123 2011.
2.1.2 300Q2 ports shall either consist of a pair of screw terminals or a short length of twin-lead cable terminated in a pair of spade lugs.
2.2 Labeling
No labeling is required for either input or output port.
3.0 ELECTRICAL
3.1 Bandwidth. All devices shall be designed to operate over a bandwidth of at least 5 to 1002 MHz.
3.2 Pass-band Response. The pass-band response of two devices connected back-to-back via their 300Q ports, and measured from one 752 port to the other 75Q2port shall notexceed ±1.0 dB relative to the slope loss of the device as measured and defined inSCTE 144 2012.
3.3 Insertion Loss. The insertion loss of two devices connected back-to-back as described in Section 3.2 shall not exceed the values specified in the following table. All measurements shall be made using the methods specified in SCTE 1442012:
3.4 Return Loss. The return loss shall be measured using a 1%, 300-Ohm resistor soldered across the 300-Ohm twin-lead cable. The resistor shall be cut to a length equal to the twin lead conductors. For screw type devices, resistors should be installed across screw terminals as closely as possible with excess lead material trimmed off. For threaded twin lead devices, resistors should be soldered across the terminals such that the terminals remain parallel as originally manufactured with excess lead material trimmed off. Measuring is accordance with SCTE 144 2012, the return loss shall be no less than 20dB across the pass-band.
3.5 Surge Withstand. The surge protection of the device when measured in accordance with ANSI/SCTE 81 2007 shall be a minimum of compliance with IEEE C62.41- 1991 Category A-3 Ring Wave 1kV, 200 Amps at the “F” port.
4.0 ENVIRONMENTAL Temperature/Humidity. The matching transformer must meet all specifications when operated in an ambient temperature ranging from +32 F (0 C) to +122  F (+50 C) and relative humidity ranging from 5 % and 99%, non-condensing.
5.0 NORMATIVE REFERENCES The following documents contain provisions, which, through reference in this text, constitute provisions of the standard. At the time of Subcommittee approval, the editions indicated were valid. All standards are subject to revision; and while parties to any agreement based on this standard are encouraged to investigate the possibility of applying the most recent editions of the documents listed below, they are reminded that newer editions of those documents may not be compatible with the referenced version.ANSI SCTE 68 pdf download.