Electronics World articles Popular Electronics articles QST articles Radio & TV News articles Radio-Craft articles Radio-Electronics articles Short Wave Craft articles Wireless World articles Google Search of RF Cafe website Sitemap Electronics Equations Mathematics Equations Equations physics Manufacturers & distributors Engineer Jobs LinkedIn Crosswords Engineering Humor Kirt's Cogitations RF Engineering Quizzes Notable Quotes Calculators Education Engineering Magazine Articles Engineering software RF Cafe Archives RF Cascade Workbook 2018 RF Symbols for Visio - Word Advertising RF Cafe Forums Magazine Sponsor RF Cafe RF Electronics Symbols for Visio RF Electronics Symbols for Office Word RF Electronics Stencils for Visio Sponsor Links Saturday Evening Post NEETS EW Radar Handbook Microwave Museum About RF Cafe Aegis Power Systems Anritsu Alliance Test Equipment Amplifier Solutions Anatech Electronics Axiom Test Equipment Berkeley Nucleonics Bittele Centric RF Conduct RF Copper Mountain Technologies Empower RF everything RF Exodus Advanced Communications Innovative Power Products ISOTEC KR Filters Lotus Systems PCB Directory Rigol RF Superstore San Francisco Circuits Reactel RFCT TotalTemp Technologies Triad RF Systems Windfreak Technologies Withwave LadyBug Technologies Wireless Telecom Group Sponsorship Rates RF Cafe Software Resources Vintage Magazines Thank you for visiting RF Cafe!
RF Cascade Workbook 2018 - RF Cafe

Intermodulation for TETRA ETSI standard - RF Cafe Forums

RF Cafe Forums closed its virtual doors in 2010 mainly due to other social media platforms dominating public commenting venues. RF Cafe Forums began sometime around August of 2003 and was quite well-attended for many years. By 2010, Facebook and Twitter were overwhelmingly dominating online personal interaction, and RF Cafe Forums activity dropped off precipitously. Regardless, there are still lots of great posts in the archive that ware worth looking at. Below are the old forum threads, including responses to the original posts.

NOTICE: The original RF Cafe Forum is available again for reading, and the new RF Cafe Blog is an active board.

-- Amateur Radio

-- Anecdotes, Gripes, & Humor

-- Antennas

-- CAE, CAD, & Software

-- Circuits & Components

-- Employment & Interviews

-- Miscellany

-- Swap Shop

-- Systems

-- Test & Measurement

-- Webmaster

 Post subject: Intermodulation for TETRA ETSI standard
Posted: Mon Mar 22, 2010 2:59 pm 
User avatar

Joined: Wed Apr 08, 2009 7:53 am

Posts: 17

Hello RF-Cafe folks!:

I have two questions regarding the ETSI TS 101 789-1 V1.1.2 (ETSI standard for TETRA Repeaters).

On point, we the Limit Values for the intermodulation Attenuation.

Te text says: “The level of intermodulation product shall be less than -60 dBc. In any case not requirement greater than -36dBm shall apply”. I can't quite understand this phrase, so I have the following two questions:

1) If I have a repeater of 2x32dBm output power. The maximum intermodulation level needed to apply ETSI is -36dBm (-68dBc) or -28dBm (32dBm-60dBc) ?

2) If I have a repeater of 2x15dBm output power. The maximum intermodulation level needed to apply ETSI is -36dBm (-51dBc) or -45dBm (15dBm-60dBc) ?

Thank you!


web: http://www.rdo-labs.com

Jose Arrina
 Post subject: Re: Intermodulation for TETRA ETSI standard
Posted: Tue Mar 23, 2010 10:59 am 
User avatar

Joined: Thu Mar 30, 2006 9:01 am

Posts: 12

The spec means your intermods have to be at least -60 dBc, and also cannot be any greater than -36 dBm in absolute power.

So your first example would produce intermods at -28 dBm when down 60 dB from the +32 dBm. That is 8 dB too high.

In the second example the intermods are at -45 dBm when 60 dB down from the +15 dBm carriers, so you're below the max absolute level of -36 dBm.

Example 1 fails, example 2 passes.

Hope that helps.



... Jose' Arrina

 Post subject: Re: Intermodulation for TETRA ETSI standard
Posted: Tue Mar 23, 2010 1:21 pm 
User avatar

Joined: Wed Apr 08, 2009 7:53 am

Posts: 17

Hello Jose, thank you for your quick response.

Your add helps a lot, but I´m still not convinced yet.

If the standard was "Intermods have to be at least -60 dBc, and also cannot be any greater than -36 dBm in absolute power" it will be more than clear.

But it says:

"...In any case not requirement greater than -36dBm shall apply", it doesn't clearly says that the absolute power can´t be greater that -36dBm, it also can be understood that they are not asking for requirement grater that -36dBm... and the question will be: what is a grater requirement? -37dBm or -35dBm???? I believe that -37dBm is a grater requirement than -36dBm.

That is why I´m not convinced yet... on one hand, I can understand what Jose said, but on the other hand I can also understand that they ask for -60dBc but that there is no need for a lower IMD than -36dBm.

What can´t be greater than -36dBm, the absolute IMD tones or the requirement?? I cant clearly understand that from the standard...


web: http://www.rdo-labs.com

Posted  11/12/2012

Innovative Power Products Couplers
Axiom Test Equipment - RF Cafe
Copper Mountain Technologies (VNA) - RF Cafe
Innovative Power Products Passive RF Products - RF Cafe
Lotus Communication Systems Modular RF Component Building Blocks - RF Cafe

Please Support RF Cafe by purchasing my  ridiculously low−priced products, all of which I created.

These Are Available for Free


About RF Cafe

Kirt Blattenberger - RF Cafe Webmaster

Copyright: 1996 - 2024


    Kirt Blattenberger,


RF Cafe began life in 1996 as "RF Tools" in an AOL screen name web space totaling 2 MB. Its primary purpose was to provide me with ready access to commonly needed formulas and reference material while performing my work as an RF system and circuit design engineer. The World Wide Web (Internet) was largely an unknown entity at the time and bandwidth was a scarce commodity. Dial-up modems blazed along at 14.4 kbps while tying up your telephone line, and a nice lady's voice announced "You've Got Mail" when a new message arrived...

All trademarks, copyrights, patents, and other rights of ownership to images and text used on the RF Cafe website are hereby acknowledged.

My Hobby Website: