Seems like I recall at one of the VOIP conventions years past that someone stated that the APP_RPT had the micor squelch algorithm built in. I have two micor repeaters now that I set up nodes using the URI board when DSP on both COR and CTCSS. I calibrated the URI using the radio-tune-menu and I even tested the signal break point with a service monitor. Example -110 dBm is when squelch clamps down.. That is about right.. It has a hysteresis of about 5 dB which is ok, but here is the kicker.. When you are fluttering into the receiver, the app is squelching, muting and it does not allow for the extra rx unsquelched condition like the micor does when you are weak. So you end up hearing a lot of muting when the signal is useable. I know there is a delay and an attempt to remove squelch burst, but should that not be triggered by the DSP upon CTCSS decoder not seeing signal? I have heard this issue with other nodes as well, and I though all along it was a setting issue. My squelch setting is at 765, and if I lower it to 760, it them provides a long squelch burst on even strong signals. So I am looking for guidance to see if perhaps I may be doing something wrong? Or is this just the short coming of the DSP and as I would hate to revert back to the repeater CTCSS and COR signaling, I suppose I could if justified. Let me know if you have seen this and have found resolution. Thanks in advance. 73 Lu, KA4EPS Node 27870, 27869, 27875
Lu Venci, I found the same issue thought I did not measure it as you have. I reverted to good-old Micor squelch and P/L reeds because I did not feel that app_rpt DSP did as well as the Micor in either case. Sometimes 40 year old technology is still best. -- Tim :wq On Jul 25, 2011, at 11:24 AM, Lu Vencl wrote:
Seems like I recall at one of the VOIP conventions years past that someone stated that the APP_RPT had the micor squelch algorithm built in. I have two micor repeaters now that I set up nodes using the URI board when DSP on both COR and CTCSS. I calibrated the URI using the radio-tune-menu and I even tested the signal break point with a service monitor. Example -110 dBm is when squelch clamps down.. That is about right.. It has a hysteresis of about 5 dB which is ok, but here is the kicker.. When you are fluttering into the receiver, the app is squelching, muting and it does not allow for the extra rx unsquelched condition like the micor does when you are weak. So you end up hearing a lot of muting when the signal is useable. I know there is a delay and an attempt to remove squelch burst, but should that not be triggered by the DSP upon CTCSS decoder not seeing signal? I have heard this issue with other nodes as well, and I though all along it was a setting issue. My squelch setting is at 765, and if I lower it to 760, it them provides a long squelch burst on even strong signals.
So I am looking for guidance to see if perhaps I may be doing something wrong? Or is this just the short coming of the DSP and as I would hate to revert back to the repeater CTCSS and COR signaling, I suppose I could if justified. Let me know if you have seen this and have found resolution. Thanks in advance. 73 Lu, KA4EPS Node 27870, 27869, 27875 _______________________________________________ App_rpt-users mailing list App_rpt-users@ohnosec.org http://ohnosec.org/cgi-bin/mailman/listinfo/app_rpt-users
All, Just got confirmation from one of the developers that it is confirmed to be a known issue. It will be worked on later this year so I suspect in a future update, this will be corrected. In the meantime, I will just put up with it and help with testing future patches. Worse case, one can loosen up the squelch, but you will have to put up with the burst. Hmm, if we can only get a longer delay then we could rely on CTCSS decoding only . A longer delay would ensure the squelch burst would not be heard, but you might hear your own last word when you unkey LOL... Now that would be a cool temp fix. Lu KA4EPS From: app_rpt-users-bounces@ohnosec.org [mailto:app_rpt-users-bounces@ohnosec.org] On Behalf Of Tim Sawyer Sent: Monday, July 25, 2011 7:59 PM To: app_rpt list Subject: Re: [App_rpt-users] Micor Squelch like available on APP? Lu Venci, I found the same issue thought I did not measure it as you have. I reverted to good-old Micor squelch and P/L reeds because I did not feel that app_rpt DSP did as well as the Micor in either case. Sometimes 40 year old technology is still best. -- Tim :wq On Jul 25, 2011, at 11:24 AM, Lu Vencl wrote: Seems like I recall at one of the VOIP conventions years past that someone stated that the APP_RPT had the micor squelch algorithm built in. I have two micor repeaters now that I set up nodes using the URI board when DSP on both COR and CTCSS. I calibrated the URI using the radio-tune-menu and I even tested the signal break point with a service monitor. Example -110 dBm is when squelch clamps down.. That is about right.. It has a hysteresis of about 5 dB which is ok, but here is the kicker.. When you are fluttering into the receiver, the app is squelching, muting and it does not allow for the extra rx unsquelched condition like the micor does when you are weak. So you end up hearing a lot of muting when the signal is useable. I know there is a delay and an attempt to remove squelch burst, but should that not be triggered by the DSP upon CTCSS decoder not seeing signal? I have heard this issue with other nodes as well, and I though all along it was a setting issue. My squelch setting is at 765, and if I lower it to 760, it them provides a long squelch burst on even strong signals. So I am looking for guidance to see if perhaps I may be doing something wrong? Or is this just the short coming of the DSP and as I would hate to revert back to the repeater CTCSS and COR signaling, I suppose I could if justified. Let me know if you have seen this and have found resolution. Thanks in advance. 73 Lu, KA4EPS Node 27870, 27869, 27875 _______________________________________________ App_rpt-users mailing list App_rpt-users@ohnosec.org http://ohnosec.org/cgi-bin/mailman/listinfo/app_rpt-users
On 7/25/11 7:59 PM, Tim Sawyer wrote:
Lu Venci,
I found the same issue thought I did not measure it as you have. I reverted to good-old Micor squelch and P/L reeds because I did not feel that app_rpt DSP did as well as the Micor in either case. Sometimes 40 year old technology is still best.
I'm doing a hybrid of what you're doing, Tim; Scott Z built my 220 Micor bringing out both the COR signal and the discriminator audio; I use the Micor squelch circuit high for COR, and the DSP to decode the tone. In my mind, one is a go/no go, the other is something that can be inferred from simple signal processing. carrierfrom=usb ctcssfrom=dsp Gives me the best of both worlds (Micor squelch, as you say, thought 40+ years old, is the tops), and the flexibility to change tone without having to search out reeds (for testing, lid removal, etc.). I have an issue to throw out...which kind of got me scratching my head....occasionally (and non-repeatably), when keying up the repeater...I'll get a building in volume rushing noise (think raster noise like on an unoccupied TV channel that increases in volume) that peaks and then goes quiet. Incoming audio is there all the time...I was thinking it was desensing, but it is not every time I key up the machine, I've gone thru the duplexers to tweak them to >90db of notch (after cleaning up the caps and polishing the copper-to-copper mating surfaces for the coil/cap assembly...I'll send a photo if anyone is interested...) and am running only about 55w into the xmt side. Coax is 1/2" superflex out to the polyphaser, (I'm not going to admit I have some other non-recommended from the polyphaser up the pole, ok? It's in the plan to replace, I have 140' of LDF4 ready to go...just have to get up on the roof...), SWR from the radio to the amp is <1.2, from the amp to the duplexer is <1.2, loss thru the cans is 1.7db, swr out of the cans into the superflex is 1.2...all audio paths are shielded (but not ground looped, I know how to build audio channels...), no connector adapters, all silver/gold/teflon, etc. Has me scratching my head. That it's not repeatable, but happens randomly has me thinking that it's static discharge? Pole and tripod are bonded and grounded, antenna is a stationmaster-type (tram 1494 cut to length, lock screws in the center radiator are tight and lock-tighted, and it's a dc ground design, albeit with a fiberglass radome. Thinking static build up/discharge? Something else? Anyone else run into this? We can take this offline, but, seeing as we're all repeater geeks here...thought I'd throw it out for consideration. Thanks all... -- Bryan In this world, you must be oh so smart or oh so pleasant. Well, for years I was smart. I recommend pleasant. You may quote me.
Bryan, Thanks for the info on your configuration. I think I will hold off for now as I really want to help test out the patches this fall. But if it gets real bothersome, I might just loosen up the squelch. The repeater does not get much activity anyway, so an occasional bust should not be a huge deal, and that's even if I bother to open it up. As to your noise, this sounds like PIM (Passive intermodulation) that can occur when you have dirty connections, bad antenna or some other external active mixing component. If you can get me an audio sample, I would be interested in hearing this. However possible, I doubt this is static discharge. 73 Lu KA4EPS From: app_rpt-users-bounces@ohnosec.org [mailto:app_rpt-users-bounces@ohnosec.org] On Behalf Of Bryan D. Boyle Sent: Monday, July 25, 2011 9:07 PM To: app_rpt-users@ohnosec.org Subject: Re: [App_rpt-users] Micor Squelch like available on APP? On 7/25/11 7:59 PM, Tim Sawyer wrote: Lu Venci, I found the same issue thought I did not measure it as you have. I reverted to good-old Micor squelch and P/L reeds because I did not feel that app_rpt DSP did as well as the Micor in either case. Sometimes 40 year old technology is still best. I'm doing a hybrid of what you're doing, Tim; Scott Z built my 220 Micor bringing out both the COR signal and the discriminator audio; I use the Micor squelch circuit high for COR, and the DSP to decode the tone. In my mind, one is a go/no go, the other is something that can be inferred from simple signal processing. carrierfrom=usb ctcssfrom=dsp Gives me the best of both worlds (Micor squelch, as you say, thought 40+ years old, is the tops), and the flexibility to change tone without having to search out reeds (for testing, lid removal, etc.). I have an issue to throw out...which kind of got me scratching my head....occasionally (and non-repeatably), when keying up the repeater...I'll get a building in volume rushing noise (think raster noise like on an unoccupied TV channel that increases in volume) that peaks and then goes quiet. Incoming audio is there all the time...I was thinking it was desensing, but it is not every time I key up the machine, I've gone thru the duplexers to tweak them to >90db of notch (after cleaning up the caps and polishing the copper-to-copper mating surfaces for the coil/cap assembly...I'll send a photo if anyone is interested...) and am running only about 55w into the xmt side. Coax is 1/2" superflex out to the polyphaser, (I'm not going to admit I have some other non-recommended from the polyphaser up the pole, ok? It's in the plan to replace, I have 140' of LDF4 ready to go...just have to get up on the roof...), SWR from the radio to the amp is <1.2, from the amp to the duplexer is <1.2, loss thru the cans is 1.7db, swr out of the cans into the superflex is 1.2...all audio paths are shielded (but not ground looped, I know how to build audio channels...), no connector adapters, all silver/gold/teflon, etc. Has me scratching my head. That it's not repeatable, but happens randomly has me thinking that it's static discharge? Pole and tripod are bonded and grounded, antenna is a stationmaster-type (tram 1494 cut to length, lock screws in the center radiator are tight and lock-tighted, and it's a dc ground design, albeit with a fiberglass radome. Thinking static build up/discharge? Something else? Anyone else run into this? We can take this offline, but, seeing as we're all repeater geeks here...thought I'd throw it out for consideration. Thanks all... -- Bryan In this world, you must be oh so smart or oh so pleasant. Well, for years I was smart. I recommend pleasant. You may quote me.
participants (3)
-
Bryan D. Boyle -
Lu Vencl -
Tim Sawyer