[Repeater-Builder] Re: cor logic circuit thoughts
This sounds like the answer I need. I think Joe suggested building an op-amp comparator earlier. Can someone who has used a 741 before please check that my wiring is correct? I will buy the components this weekend. Pin 2 : Reference input 12 Vdc via trim pot (what size pot to use to approximate reference for 1 V P-P audio? Pin 3 : Audio input Pin 4 : Gnd Pin 6 : + Vdc COR output Pin 7 : + 12 Vdc in And reverse pins 2 and 3 if output swings the wrong way. Thanks Gary! Brendan --- In Repeater-Builder@yahoogroups.com, Gary Hoff [EMAIL PROTECTED] wrote: Boy, maybe I'm wrong but it sure seems like this is being made more complicated than it should be. Use a 741 or equiv. Op Amp as a DC voltage comparator. Establish a reference voltage on the + input with a pot or a couple resistors as a voltage divider. Attach the voltage that is swinging from 7V to .5 V to the - input. When the voltage on the - input goes below the reference voltage, the output swings hard. If the output doesn't go the way you want, reverse the inputs. I've been using this type of circuit for years clear back to the old tube type prog line and Motorola sensicon strips. you can move the reference voltage along the curve of the voltage swing to where ever it works the best. That's why I like to use a 10 turn pot or similar to establish the reference voltage, it gives some flexibility to the circuit. Gary - K7NEY Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
Re: [Repeater-Builder] Re: cor logic circuit thoughts
No, Brendan, my idea was to use the point you were originally using that you said went from 7V to .5 V when a carrier appeared. We are talking about purely DC voltages here, no audio is involved. a 10K pot will work fine. 1 lead to 12V and opposite to ground then take the slider (rotor) and run it to the + input of the Op Amp. Take your swinging voltage and apply it to the - input. Output should go high when + input is high relative to - input and low when it is low relative to - input. Makes a dandy DC switch and after all, that's what a COS is, a DC switch. Adjust your 10K resistor voltage divider to about 3.5 volts to start then move it one way or the other to get the best snap action by watching the output with a meter. That swinging output can then drive a mini-relay or the base of a transistor. Don't try and key the PTT line with the OP Amp, it won't sink enough current. Hope that explains it better. If you still have trouble you can contact me off line. Gary - Original Message - From: bsoutheyoz [EMAIL PROTECTED] To: Repeater-Builder@yahoogroups.com Sent: Thursday, April 01, 2004 6:39 AM Subject: [Repeater-Builder] Re: cor logic circuit thoughts This sounds like the answer I need. I think Joe suggested building an op-amp comparator earlier. Can someone who has used a 741 before please check that my wiring is correct? I will buy the components this weekend. Pin 2 : Reference input 12 Vdc via trim pot (what size pot to use to approximate reference for 1 V P-P audio? Pin 3 : Audio input Pin 4 : Gnd Pin 6 : + Vdc COR output Pin 7 : + 12 Vdc in And reverse pins 2 and 3 if output swings the wrong way. Thanks Gary! Brendan --- In Repeater-Builder@yahoogroups.com, Gary Hoff [EMAIL PROTECTED] wrote: Boy, maybe I'm wrong but it sure seems like this is being made more complicated than it should be. Use a 741 or equiv. Op Amp as a DC voltage comparator. Establish a reference voltage on the + input with a pot or a couple resistors as a voltage divider. Attach the voltage that is swinging from 7V to .5 V to the - input. When the voltage on the - input goes below the reference voltage, the output swings hard. If the output doesn't go the way you want, reverse the inputs. I've been using this type of circuit for years clear back to the old tube type prog line and Motorola sensicon strips. you can move the reference voltage along the curve of the voltage swing to where ever it works the best. That's why I like to use a 10 turn pot or similar to establish the reference voltage, it gives some flexibility to the circuit. Gary - K7NEY Yahoo! Groups Links Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
Re: [Repeater-Builder] Re: cor logic circuit thoughts
At 12:24 PM 3/31/2004 -, you wrote: Any ideas where I might find a cheap version of this circuit or basic kit to build one? ---I did a syllabic squelch for an HF remote base project a few years. It is quite easy to build on some perfboard and it works quite well: http://www.ah6le.net/hf_squelch.html Ken -- President and CTO - Arcom Communications Makers of state-of-the-art repeater controllers and accessories. http://www.ah6le.net/arcom/index.html AH6LE/R - IRLP Node 3000 http://www.irlp.net Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
Re: [Repeater-Builder] Re: cor logic circuit thoughts
Well, I am thinking that using an op-amp circuit might help you out on the audio line out with a .3-.5 blocking cap in series with a 50k pot. Op-amps demand very little current to activate, and can be reliable in rf fields by sprinkling some 0.1 tantalum caps around where there is dc bus voltages next to the components. What does this on-board squelch circuit use for it's muting limiter? bsoutheyoz wrote: I don't think a circuit such as this is going to be much good to me. This circuit looks like its intended to strip audio off an FM discriminator output and detects the noise floor level change caused by a clean carrier; then uses this to key the COR. I dont think this will work for me since the transceiver is amplitude modulated, does not have a discriminator and will not provide the changing noise levels required to key this type of logic. Hence I need to rely on the onboard squelch circuit in my radio. Obviously, using CTCSS is not an option for me either! I think what I am fishing for is a VOX type circuit as suggested by skipp here. Any ideas where I might find a cheap version of this circuit or basic kit to build one? Thanks for all the help so far. Brendan --- In Repeater-Builder@yahoogroups.com, Russ Crisp [EMAIL PROTECTED] wrote: Not to devalue any of the excellent options presented previously, but there is also a board made by Link Communications that will give you 'micor style' squelch, and cor output. It's not real expensive, and adds these functions to any receiver. All you supply is descriminator audio and DC. Plug and play solution. http://www.linkcomm.com/squelch.html 73 de K4RCC -Original Message- From: skipp025 [mailto:[EMAIL PROTECTED] Sent: Tuesday, March 30, 2004 4:28 PM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] cor logic circuit thoughts It would not be hard to add a transistor or fet stage to the cor circuit you're having so much trouble with. Even though the circuit doesn't go below ~.5 to ground, a regular series diode or two in the Emitter lead of an added transistor (with a proper series base resistor) will ensure the transistor emitter is higher than the lowest base voltage (~.5 reported). The extra transistor should then always shut/cut off. If you want to home brew a simple open squelch detected audio cor circuit, simply run the open receiver speaker audio into a 27 ohm resistor, use a simple RC high-pass network to pass audio above say... 1KHz to a basic 2 1n4148 diode rectifier circuit driving a common 2n3904 type transistor for a cor to ground logic. Use a 4.7 or higher value Non Polar Cap to Couple the audio across the 27 ohm resistor to your controller. Been doing this circuit for simple cor functions for a decade or two. cheers, skipp www.radiowrench.com Yahoo! Groups Links Yahoo! Groups Links -- 73...Clark Beckman N8PZD Pursuant to U.S. Code, title 47, Chapter 5, Subchapter II, ß227, Any and all nonsolicited commercial E-mail sent to this address is subject to a download and archival fee of $500.00 U.S.. E-mailing denotes acceptance of these terms. Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
[Repeater-Builder] Re: cor logic circuit thoughts
I don't think a circuit such as this is going to be much good to me. This circuit looks like its intended to strip audio off an FM discriminator output and detects the noise floor level change caused by a clean carrier; then uses this to key the COR. I dont think this will work for me since the transceiver is amplitude modulated, does not have a discriminator and will not provide the changing noise levels required to key this type of logic. Hence I need to rely on the onboard squelch circuit in my radio. Obviously, using CTCSS is not an option for me either! I think what I am fishing for is a VOX type circuit as suggested by skipp here. Any ideas where I might find a cheap version of this circuit or basic kit to build one? Thanks for all the help so far. Brendan --- In Repeater-Builder@yahoogroups.com, Russ Crisp [EMAIL PROTECTED] wrote: Not to devalue any of the excellent options presented previously, but there is also a board made by Link Communications that will give you 'micor style' squelch, and cor output. It's not real expensive, and adds these functions to any receiver. All you supply is descriminator audio and DC. Plug and play solution. http://www.linkcomm.com/squelch.html 73 de K4RCC -Original Message- From: skipp025 [mailto:[EMAIL PROTECTED] Sent: Tuesday, March 30, 2004 4:28 PM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] cor logic circuit thoughts It would not be hard to add a transistor or fet stage to the cor circuit you're having so much trouble with. Even though the circuit doesn't go below ~.5 to ground, a regular series diode or two in the Emitter lead of an added transistor (with a proper series base resistor) will ensure the transistor emitter is higher than the lowest base voltage (~.5 reported). The extra transistor should then always shut/cut off. If you want to home brew a simple open squelch detected audio cor circuit, simply run the open receiver speaker audio into a 27 ohm resistor, use a simple RC high-pass network to pass audio above say... 1KHz to a basic 2 1n4148 diode rectifier circuit driving a common 2n3904 type transistor for a cor to ground logic. Use a 4.7 or higher value Non Polar Cap to Couple the audio across the 27 ohm resistor to your controller. Been doing this circuit for simple cor functions for a decade or two. cheers, skipp www.radiowrench.com Yahoo! Groups Links Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
[Repeater-Builder] Re: cor logic circuit thoughts
Boy, maybe I'm wrong but it sure seems like this is being made more complicated than it should be. Use a 741 or equiv. Op Amp as a DC voltage comparator. Establish a reference voltage on the + input with a pot or a couple resistors as a voltage divider. Attach the voltage that is swinging from 7V to .5 V to the - input. When the voltage on the - input goes below the reference voltage, the output swings hard. If the output doesn't go the way you want, reverse the inputs. I've been using this type of circuit for years clear back to the old tube type prog line and Motorola sensicon strips. you can move the reference voltage along the curve of the voltage swing to where ever it works the best. That's why I like to use a 10 turn pot or similar to establish the reference voltage, it gives some flexibility to the circuit. Gary - K7NEY Yahoo! Groups Links To visit your group on the web, go to:http://groups.yahoo.com/group/Repeater-Builder/ To unsubscribe from this group, send an email to:[EMAIL PROTECTED] Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.
Re: [Repeater-Builder] Re: cor logic circuit thoughts
An earlier version of the Motorola Micom HF SSB radio system has a squelch circuit in it. The circuitry is all descrete components. I have the manual if anyone is interested. Neil - WA6KLA Ken Arck wrote: At 12:24 PM 3/31/2004 -, you wrote: Any ideas where I might find a cheap version of this circuit or basic kit to build one? ---I did a syllabic squelch for an HF remote base project a few years. It is quite easy to build on some perfboard and it works quite well: http://www.ah6le.net/hf_squelch.html Ken -- President and CTO - Arcom Communications Makers of state-of-the-art repeater controllers and accessories. http://www.ah6le.net/arcom/index.html AH6LE/R - IRLP Node 3000 http://www.irlp.net Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
[Repeater-Builder] Re: cor logic circuit thoughts
This is also good information, but at a price. The Link board is $60 in parts. The cor unit I describe $5 in parts. cheers skipp www.radiowrench.com Russ Crisp [EMAIL PROTECTED] wrote: Not to devalue any of the excellent options presented previously, but there is also a board made by Link Communications that will give you 'micor style' squelch, and cor output. It's not real expensive, and adds these functions to any receiver. All you supply is descriminator audio and DC. Plug and play solution. http://www.linkcomm.com/squelch.html 73 de K4RCC Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
