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Topic: CTCSS

In the News (Wed 30 May 12)

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Pakistan

Family compact

	CTCSS, PL, Tone Squelch, and other Necessary Evils
		Amateur radios do not have this automatic feature since the CTCSS system is used to allow users to restrict what they want to listen to, not to allow several fleets of radios to operate on the same frequency.
		There are many repeaters that require CTCSS tones to activate them who welcome any and all users regardless of membership status.
		Some repeaters have part time CTCSS access turned on by the Control Operator only when he or she gets tired of listening to stations keying up their repeater while trying to access others.
	www.dra73.org /pl.html (1928 words)

	CTCSS Products
		The ARi-51 is a low current, miniature CTCSS encoder designed to fit into almost all portable and mobile radios.
		The ARi-52 is a sub-miniature, full featured 47 tone Encoder/Decoder allowing voice and data to be multiplexed with a sub-audible tone as a means of directing traffic among user groups who share a common radio channel.
		Many CTCSS modules do not filter speech, depending instead on the transmitters pre-emphasis network.
	www.ceswireless.com /ctcss.htm (149 words)

	CTCSS Tones
		The purpose of CTCSS (PL) is to reduce co-channel interference during band openings.
		CTCSS (PL) equipped repeaters would respond only to signals having the CTCSS tone required for that repeater.
		These repeaters would not respond to weak distant signals on their inputs and correspondingly not transmit and repeat to add to the congestion.
	www.uncledave.org /ham/ctcss.html (128 words)

	CTCSS on the Repeaters
		CTCSS when available is in addition to the standard 1750Hz toneburst access NOT a substitute.
		Where a repeater is fitted with CTCSS it must identify the sub-tone used by appending a word gap (7 dot spaces) and then the sub-tone identification letter to its morse identification so that all users are made aware of the sub-tone required.
		On GB3FR and GB3SO, the receiver squelch is overridden on incoming signals which have the correct CTCSS tone, this means that dropout is less likely to occur on weak or fluttery signals.
	www.fenlandrepeater.org.uk /ctcss.htm (469 words)

	CTCSS Mod.
		When user-defined CTCSS is used on the FM1100, the tone detection and generation system applies to the receiver and the transmitter, and can not be switched off individually for each of these.
		In many cases, it will be desirable to transmit user-defined CTCSS only, yet leave the receiver open to all received signals.
		The one disadvantage of this option is that the receiver is not opened when CTCSS is switched on during reception of a signal.
	home.wanadoo.nl /pmpc/ctcss_mod_.htm (353 words)

	Embedded.com - Detecting CTCSS tones with Goertzel's algorithm
		When activated, the presence of a CTCSS tone on a carrier opens the audio-squelch circuit of the receiver, allowing the signal modulation to pass through to the transmitter and be heard by the user.
		We'll be using this tone generator to test the CTCSS detector algorithm by injecting frequencies at the specific CTCSS tone frequencies and across the frequency of interest spectrum at small increments to test the response and effectiveness of the detector.
		For instance, when the amplitude of the input CTCSS tone is 5% of full scale and the block size is kept at 8,000, the relative power at that frequency is reduced to 200, and a 2% signal results in a max relative power of 80 as shown in Figure 5.
	www.embedded.com /showArticle.jhtml?articleID=186500194 (4373 words)

	CTCSS (Site not responding. Last check: )
		CTCSS / PL / subtoon, waarom, wie en hoe.
		Als de luisteraar naar zo'n relaisstation, in zijn ontvanger zijn eigen CTCSS DEcoder inschakelt, hoort deze gebruiker daarna alleen dat ene relais station.
		Aanbevelingen voor gebruik het van CTCSS in Nederland (VHF commissie).
	www.xs4all.nl /~pa0nhc/Projects/CTCSS/Dutch/index.htm (228 words)

	SERA CTCSS Plans
		CTCSS is often used as a means of solving an interference problem or preventing one.
		Some repeaters may also generate a CTCSS tone on the repeater output so that repeater users who are equipped with a radio capable of decoding sub-audible tones will not hear other interference sources on the channel that would otherwise open the squelch of the user's radio.
		The use of CTCSS may be required for a coordination to be granted if conditions so warrant, such as proximity to a co-channel repeater, or in an area where band openings frequently aggravate co-channel interference problems.
	www.sera.org /ctcss.html (381 words)

	What is this CTCSS Thing Anyway?
		CTCSS has been around for a long time in commercial radios, and there are a bunch of ISO standard frequencies that are used.
		However, if there are other users on the same channel that are either not using CTCSS or using a different tone, then you will not know, and potentially they could stop you from receiving anything on that channel if they are strong enough.
		So if you are thinking of using CTCSS then it would be worthwhile to have a listen to the channel with CTCSS turned off for a while, to see if there is anyone else already using it.
	www.hgfa.asn.au /skysailor/Issues/0510/ctcssthing.htm (517 words)

	CTCSS (Site not responding. Last check: )
		If a listener can activate a so called CTCSS Decoder in his receiver (a circuit which can detect if such a sub audible tone is received), it ONLY opens when it receives a radio signal containing that special sub audible tone.
		The pleasant result is, that other (unwanted) relay stations on the same channel (containing no tone or another sub audible tone), nor any noises like from traffic lights, gas station billing boards, computer systems or static's, can open the receiver, and will not be heard.
		Proposal for implementation of CTCSS in The Netherlands.
	www.xs4all.nl /~pa0nhc/Projects/CTCSS/English/index.htm (249 words)

	The Mississauga Amateur Radio Club (Site not responding. Last check: )
		CTCSS (Continuous Tone Coded Squelch System) is a generic trade term used by the mobile radio industry, and is used to accept desired signals and reject undesired signals on a radio channel.
		When activated, the presence of a CTCSS tone on a carrier, opens the audio squelch circuit of the receiver, allowing the signal modulation to pass through to the transmitter.
		CTCSS will not block signals arriving at your receiver at the same time as a desired signal.
	www.marc.on.ca /marc/services/serv_ctcss.asp (405 words)

	CTCSS
		With CTCSS equipped radios a sub-audible tone is transmitted along with the voice transmission.
		When the CTCSS is activated the radio will only allow received signals, which carry the correct sub-audible tone to open the squelch, i.e.
		To minimise the possibility of an operator transmitting when the frquency is in use by someone using a different CTCSS tone, most radios with CTCSS have a 'busy' indicator, which shows when the radio is receiving a signal that isn't opening the squelch.
	silkrallyradio.biz /ctcss.htm (120 words)

	What Is CTCSS? How To Decode It?
		Fleets hear only units with their own sub audible tone (CTCSS tone), and fleets using other tones on the same frequency are not heard.
		CTCSS tones are also sometimes called "interference eliminator", coded squelch, Channel Guard, Private Line or PL tones; DCS is also sometimes called Digital Channel Guard, Digital Private Line or DPL tones..
		But if you have CTCSS you would want to program the scanner with a bank of frequencies with the CTCSS tones (So you may enter the same frequency several times into the same bank, but with different CTCSS tones.
	www.scanaustralia.bigpondhosting.com /decode/CTCSS.html (754 words)

	ACBRO Team Inc 1980 - Advocates For Australian CB Radio Clubs And Operators
		Since CTCSS was introduced onto the UHF CB band a year or so ago, I have heard lots of miss-understandings and factually incorrect stuff about CTCSS so I thought this guide might help to sort out the myths from the facts.
		Therefore a nuisance operator armed with a high powered CTCSS enabled transceiver and a scanner like the 780 would be able to “break in” on your so-called “private” conversation within a matter of a few seconds of you transmitting.
		In addition, CTCSS does not give you immunity to stations going “over the top” of you if they can out-power the station you are communicating with.
	www.acbro.org /actcss.htm (1218 words)

	CTCSS Unclutters Receiver Sound
		CTCSS systems add a tone at the low end of what the human ear can hear to a transmitted signal.
		On the receiving end, a CTCSS decoder allows you to choose which signals are heard in your radio's speaker after the tone is removed.
		CTCSS also works with longer range radios, making it possible for different groups to use the same frequencies without bothering each other.
	www.wsdmag.com /Articles/ArticleID/7426/7426.html (1165 words)

	CTCSS - DCS
		CTCSS was developed into a system with numerous standard tones to choose from, often 38.
		When CTCSS is used, the audio is filtered out below about 300Hz, so that the only audio frequency energy that ends up being transmitted between 0 and 300Hz is the CTCSS tone itself (almost always any one tone between 67 and 254.1 Hz).
		CTCSS Encode DCS Decode - DCS Encode CCTCSS Decode - CTCSS/DCS ENCODE CTCSS/DCS Decode.
	www.arrg.us /pages/Tone.htm (802 words)

	CTCSS
		CTCSS was developed into a system with numerous standard tones to choose from, often 38.
		When CTCSS is used, the audio is filtered out below about 300Hz, so that the only audio frequency energy that ends up being transmitted between 0 and 300Hz is the CTCSS tone itself (almost always any one tone between 67 and 254.1 Hz).
		CTCSS 38: 39: 47: 38: 32: EIA Al.
	www.geocities.com /euro446/ctcss.html (2563 words)

	Genave Electronics - CTCSS
		In a nutshell, that's all that CTCSS really is! When you transmit on a two-way radio, a very low level hum is added to your voice.
		With CTCSS you don't hear radio transmissions of other people as they use their radios, but your own group of radios comes through just fine when they need to talk to you.
		When you transmit with CTCSS, you must monitor the channel just prior to commencing your transmission to make sure that you are not disrupting someone else's conversation.
	www.genave.com /ctcss.htm (912 words)

	Uniden Bearcat BC898 CTCSS DCS (Site not responding. Last check: )
		CTCSS and DCS are subaudible tones sometimes referred to as PL (Motorola's trademark term for Private Line).
		CTCSS and DCS are used only for FM signals and are in use by both amateur and commercial repeaters.
		CTCSS and DCS are also used in areas where interference is a factor.
	www.universal-radio.com /catalog/scanners/0898pl.html (196 words)

	KC4GZX CTCSS Frequencies
		CTCSS (Continuous Tone Coded Squelch System) enables two-way radio equipment to selectively communicate with other radios in a group.
		CTCSS, also known as 'PL' or 'Private Line' in Motorola gear, 'Channel Guard' in General Electric gear, and 'Call Guard' in E.F. Johnson gear, was developed to allow more groups of users on the same frequency.
		CTCSS is a low frequency tone that is combined with the voice signal from the radio transmitter.
	www.qsl.net /kc4gzx/kc4gzx/chrtctcss.htm (213 words)

	ST-133/ST-139 CTCSS Encoder/Decoder
		Also known as PL (Private Line®) or sub-audible tone, CTCSS is most commonly used to mute the receiver of a mobile radio or base station until an assigned tone code is received, thereby eliminating annoying chatter from co-channel users.
		CTCSS may also be used to control access to shared repeaters or to selectively call individual radios or groups of radios in a fleet application.
		The use of CTCSS allows mobile radio users to block out unwanted traffic on the same radio channel, either from a different user group on a shared repeater system, or from a foreign repeater or mobile.
	www.com-spec.com /selectone/npb/133_139/133_139.htm (646 words)

	HTX-404 DTMF and Tone Encode Defect
		The CTCSS tone decoder output is used by the IRLP interface for the receiver COS signal in order to keep repeater hang time, courtesy tones, and I.D.'s from being transmitted over the IRLP system.
		CTCSS 103.5 Hz tone of 600 Hz deviation and a DTMF tone of 3.5 kHz deviation.
		It is now obvious that the CTCSS decoders are dropping out due to the loss of received CTCSS tone during the period that the HTX-404 is over deviated.
	www.repeater-builder.com /radio-shack/htx-404/htx-404-defect.html (756 words)

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