My homemade RF node has no receive! Help!

App_rpt-users
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Hello! I am working on building a Allstar RF node using a Raspberry Pi 3B, a cm108 sound card, and a baofeng bf888s. I saw a few guides on how to build one so I got the parts and started working. I have it all set up and running but there is a problem.

When the BF888s gets the signal coming from my HT it doesn’t key up allstar. I can do *70 when connected to the node over DVSwitch and it will recite the node information over RF and I can hear that. So it’s activating TX on the 888s with no problems, but RX doesn’t work. I checked the COS wire so many times and it’s correctly connected, and it does go HIGH on RX like it’s supposed to. I changed carrierfrom = usbinvert to carrierfrom = usb but it had no effect.

I may have a defective cm108 sound card so I did order a new one that will be here soon. On the chance that that’s not the case, something else may be wrong. I used these two guides to build it: CM108 Sound Fob Modification and this: Baofeng BF888 Modification. If you need any more info I’m happy to give it, because I’m stumped right now. I checked everything so many times but I can’t find the issue. The wiring must be correct. All that’s left to do now is desolder all my connections and redo the whole thing from the start.

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Could you test this live and running at your COS on the sound fob for voltage when active.
What is the voltage active?
Voltage inactive ?

From a command line,
you can watch the live verbose of asterisk,

asterisk -rvvv

Perhaps it is triggering so watch that output for a check and tell us if you see action in the software on cos true.

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I was redoing everything from scratch and I accidentally destroyed 3 of the pins on the cm108 chip. I have a new one that I’ll be working on today. I think the COS line was putting out something like 2-3v when a signal was present.

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Update: After getting a new CM108 sound fob and trying again, IT WORKS! I had to put an external antenna on the bf888s because when it keyed up (in response to me transmitting), it would keep itself in a loop of waiting 5 seconds, doing the curtesy tone, then waiting 5 secs and beeping again. My guess is having the TX antenna so close to the wiring was causing a voltage to appear. Switched to a better antenna and the problem is solved!

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