Re: [Repeater-Builder] Audio/squelch question (with audio sample)
Jeff, To my ear, it sounds like normal multipath (picket fencing) on the mobile signal may be triggering the pops, and they're being worsened by audio coupling somewhere that's passing too much low frequency audio. I've had radios that sounded like that, and also popped badly on squelch opening, when aging audio coupling capacitors became leaky. In extreme cases, if the squelch actually passes a DC bias voltage from one stage to the next, the squelch will open with a pop severe enough to damage the speaker, like putting a battery across the speaker leads. In a repeater configuration, pops can be aggravated if audio was coupled from the repeater to the controller with a cap too large in value, or a direct connection which passes DC. A low impedance receiver audio stage coupled to a much higher impedance controller audio input is an easy place to go too big on the value of the coupling cap. 73, Paul, AE4KR - Original Message - From: Jeff Lehmann To: Repeater-Builder@yahoogroups.com Sent: Tuesday, December 04, 2007 6:28 PM Subject: [Repeater-Builder] Audio/squelch question (with audio sample) Hi everyone, I'm brand new to the group, but I'm getting into a big project trying to improve one of our local repeaters. It's a Kendecom KRP-5000. It'd been having a horrible problem with popping on mobile signals, just about making the machine useless with signals that were not full quieting. Our first step was to install the RLC-MOT squelch board. This has made a big improvment with weaker mobile and handheld signals, letting them hold the machine open right down to the noise. However, it's still popping on strong, usually mobile signals. I'm wondering if we need to change how the audio is wired. Right now, it has the stock CAT-1000 controller in it, but we have an Arcom RC-210 ordered. The audio for the PL board was not coming off the discriminator from the factory. It appeared to be wired to the same tap that sends the audio to the controller. This was not disc. audio, because we originally tried the RLC-MOT on it, and it did not work. We found the disc. audio, and ran it to the RLC-MOT, but kept the actual audio wired the way it was. We changed the COR to come from the RLC-MOT instead of where it was originally. I'm wondering if when I start wiring the Arcom, if I should run the disc. audio right to the Arcom, and use the de-emphasis in the controller? I'm also planning to change the PL board's audio to disc as well. The popping does still happen with the tone is turned off though. Here's what the machine sounds like now, with a reasonable strong mobile signal, with the popping sound happening several times. http://home.comcast.net/~n1zzn/14718popping.mp3 Should I expect this to go away when I switch to the Arcom? Thanks and 73, Jeff Lehmann - N1ZZN Hanson, MA
RE: [Repeater-Builder] Audio/squelch question (with audio sample)
Jeff, I agree with Jim's assessment, that the popping might be due to an over-deviated signal coming into the repeater. Many imported radios built for the Amateur Radio market are delivered with the CTCSS deviation much too hot and causing the total deviation (voice plus tone) to exceed 5 kHz. The EIA/TIA recommended CTCSS deviation is 500 Hz for a 5 kHz channel, and 400 Hz for a 4 kHz channel. Some Ham-grade radios have CTCSS deviation as high as 1500 Hz, and it usually is not adjustable. The deviation limiter squashes the combined audio on voice peaks, distorting the CTCSS tone to where the repeater thinks the tone has gone away and mutes the audio. This effect is more pronounced in some repeaters than in others, and it matters if the repeater's receive bandwidth is not centered on the channel. Some repeater receivers have modulation acceptance that is relatively narrow, meaning that an over-deviated signal can get squashed in the receiver and thereby distorted- resulting again in muting of the receiver. I have no experience with Kendecomm repeaters, so I am simply grasping at straws here. I suggest using a known-accurate service monitor to verify that the Kendecomm receiver is centered on the channel and can demodulate a standard signal deviated 5 kHz with a 1 kHz tone without distortion. Once you have established that the receiver is handling the RF properly, you can then evaluate the squelch action. From your description of the problem, it seems as if there are two squelch circuits trying to operate at the same time. Make certain that the original Kendecomm squelch circuit is completely disabled. One final thought: Does the Kendecomm repeater have narrow-band capability? If it does, and the receiver expects a signal that is deviated 2.5 kHz, a 5 kHz signal will be severely distorted. 73, Eric Lemmon WB6FLY -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Jim Sent: Wednesday, December 05, 2007 9:32 AM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Audio/squelch question (with audio sample) Jeff Lehmann wrote: Hi everyone, I'm brand new to the group, but I'm getting into a big project trying to improve one of our local repeaters. It's a Kendecom KRP-5000. It'd been having a horrible problem with popping on mobile signals, just about making the machine useless with signals that were not full quieting. Our first step was to install the RLC-MOT squelch board. This has made a big improvment with weaker mobile and handheld signals, letting them hold the machine open right down to the noise. However, it's still popping on strong, usually mobile signals. I'm wondering if we need to change how the audio is wired. Right now, it has the stock CAT-1000 controller in it, but we have an Arcom RC-210 ordered. The audio for the PL board was not coming off the discriminator from the factory. It appeared to be wired to the same tap that sends the audio to the controller. This was not disc. audio, because we originally tried the RLC-MOT on it, and it did not work. We found the disc. audio, and ran it to the RLC-MOT, but kept the actual audio wired the way it was. We changed the COR to come from the RLC-MOT instead of where it was originally. I'm wondering if when I start wiring the Arcom, if I should run the disc. audio right to the Arcom, and use the de-emphasis in the controller? I'm also planning to change the PL board's audio to disc as well. The popping does still happen with the tone is turned off though. Here's what the machine sounds like now, with a reasonable strong mobile signal, with the popping sound happening several times. http://home.comcast.net/~n1zzn/14718popping.mp3 http://home.comcast.net/~n1zzn/14718popping.mp3 Should I expect this to go away when I switch to the Arcom? Thanks and 73, Doesn't sound like it has anything to do with the controller or how the audio is tapped. Either the user is over deviating (VERY likely), or the detector in your receiver isn't aligned right, which is also very common. It IS clipping on voice peaks! I also hear some distortion in the audio, which leads me to the detector alignment. Put a scope on the audio going into the RLC-MOT, and tune the detector coils for both max level and the CLEANEST sine wave you can get with a strong signal modulated with a 1KHz tone at 3KHz deviation. If it won't go near perfect, it means the receiver has issues, which on that brand, wouldn't surprise me very much. I'm sure there's a more detailed/better explanation on the RB site somewhere too. -- Jim Barbour WD8CHL
[Repeater-Builder] Re: 220 ACSB (Jeff D. WN3A)
Jeff you mentioned 220 ACSB. I have a question you might be able to answer about Securicor equip. Contact me off list when you get a chance. Steve, N7KP
Re: [Repeater-Builder] Audio/squelch question (with audio sample)
Hello Jeff First--There is nothing wrong with the CAT-1000 controller that comes with the Kendecom repeaters---It is a perfectly good controller capable of doing almost everything imaginable well. Now---There were a batch of Kendecom 5000 repeaters made that had a problem built in. The problem was that a Toyo inductor used in the quaduture discriminator in the receiver became unavailable and was replaced with another without other necessary circuit value changes being made to properly accept its different Q. I bought five of these repeaters and had similar initial problems in all of theme to what you describe. Wide deviation incoming signals would drive the discriminator out of linearity (maybe I should say over the edge) and if extreme, drop the squelch and the audio--- sounding a lot like your sample recording. DTMF decoding was also marginal due to excessive discriminator distortion unless the DTMF deviation was kept low. Two of us out here in the West tackled the problem with the support and encouragement of Gary at the Kendecom (now Advanced Communication Systems-ACS) factory near Haverhill in Mass. The end result was very good performance-very good audio and excellent DTMF, PL and squelch operation. Our improvements or fixes were fed back to Gary for his testing. It is my understanding that most of what we did is now in his production and we remain quite pleased with the performance of our Kendecom / ACS repeaters. A bit moreI have heard noise on repeater outputs---ours and others ---that sounded exactly like your sample that was the result in two cases of a failing antennas and in one case of bad feedlineLMR-400. And, as you might guess, there is a whole lot more detail that I can go into about the discriminator work that we did and also, you might give Gary a call. Scott, N6NXI - Original Message - From: Jeff Lehmann To: Repeater-Builder@yahoogroups.com Sent: Tuesday, December 04, 2007 6:28 PM Subject: [Repeater-Builder] Audio/squelch question (with audio sample) Hi everyone, I'm brand new to the group, but I'm getting into a big project trying to improve one of our local repeaters. It's a Kendecom KRP-5000. It'd been having a horrible problem with popping on mobile signals, just about making the machine useless with signals that were not full quieting. Our first step was to install the RLC-MOT squelch board. This has made a big improvment with weaker mobile and handheld signals, letting them hold the machine open right down to the noise. However, it's still popping on strong, usually mobile signals. I'm wondering if we need to change how the audio is wired. Right now, it has the stock CAT-1000 controller in it, but we have an Arcom RC-210 ordered. The audio for the PL board was not coming off the discriminator from the factory. It appeared to be wired to the same tap that sends the audio to the controller. This was not disc. audio, because we originally tried the RLC-MOT on it, and it did not work. We found the disc. audio, and ran it to the RLC-MOT, but kept the actual audio wired the way it was. We changed the COR to come from the RLC-MOT instead of where it was originally. I'm wondering if when I start wiring the Arcom, if I should run the disc. audio right to the Arcom, and use the de-emphasis in the controller? I'm also planning to change the PL board's audio to disc as well. The popping does still happen with the tone is turned off though. Here's what the machine sounds like now, with a reasonable strong mobile signal, with the popping sound happening several times. http://home.comcast.net/~n1zzn/14718popping.mp3 Should I expect this to go away when I switch to the Arcom? Thanks and 73, Jeff Lehmann - N1ZZN Hanson, MA
RE: [Repeater-Builder] Re: 220 repeater antennas
After spending so much time chasing the DB-224JJ information down I'd probably buy and use something else, which I have done. I'll keep the JJ Model in my mind as I pull down a few more of the Nationwide 220 ACSB Trunking Systems in the spring time. Knowing full well that Skipp may fight me on this recommendation, I'd lean toward a Sinclair SD214 or SD218 (big mama) dipole array. They're available in a split that covers 220. --- Jeff WN3A
Re: [Repeater-Builder] Motorola GM300 exciter output
I believe 100mw is the exciter PO. There are several amps that will do. David Epley, N9CZV Winchester, Indiana Has anyone had any experience taping directly into the output of a GM300 to drive an external amplifier, bypassing the GM300 PA completely. Any idea on how much drive one might expect from the exciter? Any ideas on an amp make/model that would work to watch eBay for if this is feasible? This is for a portable repeater for our local club...and the idea of bypassing the GM300 PA for a more robust external amplifier. The concept was coffee talk than anything else as this unit will see very limited use and it is doubtful that we would burn up a GM300 PA, especially with a couple of axial fans blowing on the heat sink. Mark
Re: [Repeater-Builder] Audio/squelch question (with audio sample)
Jeff Lehmann wrote: Hi everyone, I'm brand new to the group, but I'm getting into a big project trying to improve one of our local repeaters. It's a Kendecom KRP-5000. It'd been having a horrible problem with popping on mobile signals, just about making the machine useless with signals that were not full quieting. Our first step was to install the RLC-MOT squelch board. This has made a big improvment with weaker mobile and handheld signals, letting them hold the machine open right down to the noise. However, it's still popping on strong, usually mobile signals. I'm wondering if we need to change how the audio is wired. Right now, it has the stock CAT-1000 controller in it, but we have an Arcom RC-210 ordered. The audio for the PL board was not coming off the discriminator from the factory. It appeared to be wired to the same tap that sends the audio to the controller. This was not disc. audio, because we originally tried the RLC-MOT on it, and it did not work. We found the disc. audio, and ran it to the RLC-MOT, but kept the actual audio wired the way it was. We changed the COR to come from the RLC-MOT instead of where it was originally. I'm wondering if when I start wiring the Arcom, if I should run the disc. audio right to the Arcom, and use the de-emphasis in the controller? I'm also planning to change the PL board's audio to disc as well. The popping does still happen with the tone is turned off though. Here's what the machine sounds like now, with a reasonable strong mobile signal, with the popping sound happening several times. http://home.comcast.net/~n1zzn/14718popping.mp3 Should I expect this to go away when I switch to the Arcom? Thanks and 73, Doesn't sound like it has anything to do with the controller or how the audio is tapped. Either the user is over deviating (VERY likely), or the detector in your receiver isn't aligned right, which is also very common. It IS clipping on voice peaks! I also hear some distortion in the audio, which leads me to the detector alignment. Put a scope on the audio going into the RLC-MOT, and tune the detector coils for both max level and the CLEANEST sine wave you can get with a strong signal modulated with a 1KHz tone at 3KHz deviation. If it won't go near perfect, it means the receiver has issues, which on that brand, wouldn't surprise me very much. I'm sure there's a more detailed/better explanation on the RB site somewhere too. -- Jim Barbour WD8CHL
Re: [Repeater-Builder] Audio/squelch question (with audio sample)
At 12/4/2007 18:28, you wrote: Hi everyone, I'm brand new to the group, but I'm getting into a big project trying to improve one of our local repeaters. It's a Kendecom KRP-5000. It'd been having a horrible problem with popping on mobile signals, just about making the machine useless with signals that were not full quieting. Our first step was to install the RLC-MOT squelch board. This has made a big improvment with weaker mobile and handheld signals, letting them hold the machine open right down to the noise. However, it's still popping on strong, usually mobile signals. I'm wondering if we need to change how the audio is wired. Right now, it has the stock CAT-1000 controller in it, but we have an Arcom RC-210 ordered. The audio for the PL board was not coming off the discriminator from the factory. It appeared to be wired to the same tap that sends the audio to the controller. This was not disc. audio, because we originally tried the RLC-MOT on it, and it did not work. We found the disc. audio, and ran it to the RLC-MOT, but kept the actual audio wired the way it was. We changed the COR to come from the RLC-MOT instead of where it was originally. I'm wondering if when I start wiring the Arcom, if I should run the disc. audio right to the Arcom, and use the de-emphasis in the controller? I'm also planning to change the PL board's audio to disc as well. The popping does still happen with the tone is turned off though. Here's what the machine sounds like now, with a reasonable strong mobile signal, with the popping sound happening several times. http://home.comcast.net/~n1zzn/14718popping.mp3http://home.comcast.net/~n1zzn/14718popping.mp3 Should I expect this to go away when I switch to the Arcom? The only really bad thing I heard was the long squelch tail at the end. A DFQ signal should not draw a long squelch tail on a Micor squelch. The popping may be from the old squelch circuit, if the audio source you're sending to the controller is gated. I'd use the direct discriminator audio for everything. If the audio being used now is already de-emphasized (I think it is in the Kendecom RX), then you'll need to activate de-emphasis on that controller port (usually a jumper or install a capacitor). Bob NO6B
[Repeater-Builder] A couple of questions
First. I have the preamp in my MASTRII now and it's still not performing the way it should. I think that I may be having some of the receive issues mentioned on the site maybe wisker growth. What is the best way to determine if the receive side is working to full potential? Second we now have our IFR 1100S service monitor back. Today I purchased an HP 608E and an HP 608F Signal Generator from a surplus store. Can the regular signal generator be used to tune filters or does it have to be a tracking generator? Is the 8708A Synchronizer that can be added to the 608F anything close to a tracking generator? I also picked up a Micor base of some sort at the surplus store. It is a C73RTB-1106C and looking at the secret decoder ring it looks to be a VHF 100w unit. I need to know if I have all of the pieces of this thing to get it running to see if it's any good. I have the power supply, the receiver, transmitter, and card assembly, but in the pictures I have seen there is some kind of meter on the left side with a speaker and I don't have that. Do I need that for this thing to operate? Thanks, Vern KI4ONW
Re: [Repeater-Builder] help with repeater
It would be very helpful to know where my area is Randy WB0VHB I am looking for some one in my area to help build a Vhf repeater. The help would need to be hands-on.Any one that can help please let me know.
[Repeater-Builder] Motorola GM300 exciter output
Has anyone had any experience taping directly into the output of a GM300 to drive an external amplifier, bypassing the GM300 PA completely. Any idea on how much drive one might expect from the exciter? Any ideas on an amp make/model that would work to watch eBay for if this is feasible? This is for a portable repeater for our local club...and the idea of bypassing the GM300 PA for a more robust external amplifier. The concept was coffee talk than anything else as this unit will see very limited use and it is doubtful that we would burn up a GM300 PA, especially with a couple of axial fans blowing on the heat sink. Mark
RE: [Repeater-Builder] Re: 220 repeater antennas
Has anyone tried using the Austin antennas that were built for the 200Mhz ACSSB system on the ham band? There are several of them lying around on the ground here in Connecticut. Actually, I was just offered the ACSSB equipment, including the combiner, if I take it all away. I can use the wattmeter units on the Telewave combiner, but don't know what I'd do with the rest of the stuff. 73, Joe, K1ike -- Original message -- From: Jeff DePolo [EMAIL PROTECTED] After spending so much time chasing the DB-224JJ information down I'd probably buy and use something else, which I have done. I'll keep the JJ Model in my mind as I pull down a few more of the Nationwide 220 ACSB Trunking Systems in the spring time. Knowing full well that Skipp may fight me on this recommendation, I'd lean toward a Sinclair SD214 or SD218 (big mama) dipole array. They're available in a split that covers 220. --- Jeff WN3A ---BeginMessage--- After spending so much time chasing the DB-224JJ information down I'd probably buy and use something else, which I have done. I'll keep the JJ Model in my mind as I pull down a few more of the Nationwide 220 ACSB Trunking Systems in the spring time. Knowing full well that Skipp may fight me on this recommendation, I'd lean toward a Sinclair SD214 or SD218 (big mama) dipole array. They're available in a split that covers 220. --- Jeff WN3A ---End Message---
[Repeater-Builder] Sorry, it wasn't Jeff D, it was Skipp.
I read the post wrong, fortunately Skipp replied to me off list.
Re: [Repeater-Builder] Audio/squelch question (with audio sample)
Hi Jeff, I have experience similar noises on my Micor repeater that turned out to be a old antenna with minute cracks in the aluminum causing arcing during transmit that the receiver was picking up. I changed out just about everything but the antenna and STILL HAD THE NOISES!. The finial test that made me to decide to change out the antenna was a simple one. I shut down the transmitter and just listened to the input of the repeater via its receiver, no noise, pops! TX on pops, TX off gone! Also, loose and corroded parts around the antenna can also cause this arcing. Check anything near the antenna. Hope this helps! Brian, WD9HSY Your kid may be an Honor Student, Your Kid may be a Great Athlete, Your Kid may be a Doctor or a Lawyer, But My kid is in the US Air Force plays with Minuteman III ICBM's, Nuclear, Inter Continental Ballistic Missiles By the way, What is your Lat / Long? **Check out AOL's list of 2007's hottest products. (http://money.aol.com/special/hot-products-2007?NCID=aoltop000301)
[Repeater-Builder] Converting the GE MastrII Intercom switch to a Disable switch.
I was looking at the modification by N3XCC regarding the modification of the Intercom switch on the 10 volt regulator board at: http://www.repeater-builder.com/ge/gestationcontrol.html The disable is done by opening the connection between point 1 2. I am assuming that this is for a board is optioned for Decode Only. My MastrII is optioned for Encode and Decode, so I'm thinking this modification might not work properly. My idea is to replace the momentary switch with a SPST locking switch to lock it into the Intercom mode and disable the transmitter. That way, no matter how the board is optioned the switch will still disable the transmitter. I can't see any problem keeping it in the Intercom mode. It looks like all the original switch does is disable the PTT while the tech at the site talks. FWIW, has anyone ever used the Intercom feature? Am I correct? Following all the paths on the drawings (and between drawings) for the MastrII is a real pain in the butt. I wish there was a simplified overall drawing that showed how things interconnect in a base/repeater station. 73, Joe, K1ike ._,___
[Repeater-Builder] Re: 220 repeater antennas
The person Paul refers to built 2 of these antennas, from scratch, (originally called a DB-244 by Decibel Products) for our group in the early 80's. The antennas are still in operation 1500' up the broadcast tower today, one used for RX and one used for TX - no duplexer. Performance remains superb. BTW, reflecting on a discussion about the Midland 13-509 radio for repeater operation, these antennas are connected to a split apart 13-509, built at the same time as the antennas. I know this is the kiss of death, but other than a run away crystal oven (it gets very cold at 1500' in an outdoor cabinet) the Midland repeater has had no failures after 25+ years of service. We keep intending to modify a hi-band GE MVP, but as long as the Midland keeps working, the project is low on the to-do list. I have one of the factory DB 220 antennas on the ground back in Texas, and will see it in a few weeks. I can take the measurements (unless someone else in DFW wants to do it) and a few pictures. If someone really really thinks they have to this one, I can be coaxed into selling it, local DFW pick-up only, I will not ship it. Mike / W5JR / Milton GA (a suburb of Alpharetta) Posted by: Paul Finch mailto:[EMAIL PROTECTED] Re%3A%20220%20repeater%20antennas[EMAIL PROTECTED] http://profiles.yahoo.com/wb5idmwb5idm Tue Dec 4, 2007 9:07 pm (PST) I have a friend that has made his own 220 MHz version of the DB antenna, the worst problem he had was getting the harness to seal. I told him about Scotchkoat and he has not had a problem since. By the way, the Vapor Block coax does not do much for me. If the coax is sealed correctly you will never get water in it. All Vapor Block does is make it hard to work with, it still lets water migrate to the lowest point in the coax which is usually the Heliax connector. The problem with my friend right now is he is 76 years old and his mind seems to be going away. He was supposed to build me an antenna but has forgotten about it. The two antennas (1 TX, 1 RX) on his 500 foot tower have been up for about ten years with no problem. Paul
[Repeater-Builder] VXR-1000
Does anyone know if the VXR-1000U be easily converted for use on Amateur frequencies? If so, is the method documented somewhere? Does anyone have any experience using either the VXR-1000V or VXR-1000U for an Amateur Band repeater? I'm looking to setup a small portable Amateur band repeater with a UHF/VHF link; and I was considering these units. Thank-you. Vern (W6NCT)
[Repeater-Builder] 220 MHz repeaters-Midland 13-509 GE MVP (was Re: 220 repeater antennas)
At 12/5/2007 19:33, you wrote: BTW, reflecting on a discussion about the Midland 13-509 radio for repeater operation, these antennas are connected to a split apart 13-509, built at the same time as the antennas. I know this is the kiss of death, but other than a run away crystal oven (it gets very cold at 1500' in an outdoor cabinet) the Midland repeater has had no failures after 25+ years of service. We keep intending to modify a hi-band GE MVP, but as long as the Midland keeps working, the project is low on the to-do list. Ditto here. The system I maintain was built in the mid-70s by Bill Wood WB6FXJ (now W6FXJ) hasn't had any problems with the RF hardware in over 30 years. The VHF Engineering IDer died last year - probably a dried-out electrolytic capacitor. I do want to replace it with a modified MVP only because the MVP is easier (for me) to maintain interface with a multiport controller. I've received reports of problems with the front end helical filter response after modification (excessive passband ripple), so I've backed off until I get some free time to investigate this issue. Bob NO6B
