STM32-DVM Duplex repeater

MMDVM_HS Hat hardware
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VA7WPN
Posts: 22
Joined: Sun May 13, 2018 3:51 am

STM32-DVM Duplex repeater

Post by VA7WPN »

Hello, I have an STM32-DVM from Repeater-Builder.Com. its an excellent board so far. It sits ontop of RPi 3+. I have pistar setup and running. My radios are a pair of CDM1250's programmed to run and Rx and Tx only devices. They are connected to the STM32-DVM as such, separate Rx and Tx devices.

Monitoring on the Tx freq using my TS2000, it is Tx'ing data. Its indicating that its Tx'ing D* data. So I am fairly sure the Tx side is okay for the most part. On the Rx side I'm not so sure.

When I use my TH-D74a, I manually entered a repeater for D*. Its not triggering the Rx radio when I key up. And when it Tx's the data stream comes thru the D74a as audio, its not decoded by it.

I'm new with programming Motorola radios, and this is my first Pi Star device.

Any help is appreciated.

Thank you!

Sent from my LG-H873 using Tapatalk

VA7WPN
Posts: 22
Joined: Sun May 13, 2018 3:51 am

Re: STM32-DVM Duplex repeater

Post by VA7WPN »

Here is how I have the two CDM1250's wired up.
MMDVM Wiring.png
MMDVM Wiring.png (10.05 KiB) Viewed 6709 times
I tried uploading my Code Plugs for the TX and RX radios, but the forum would not allow me.
VA7WPN
Posts: 22
Joined: Sun May 13, 2018 3:51 am

Re: STM32-DVM Duplex repeater

Post by VA7WPN »

It was a long night of tracing wiring, and comparing code plugs against those of working CPS Radios.

I did need to make some changes to the code plugs, but nothing that I think would cause it to not function.

NOW :

I did some further testing, with a radio just putting out an FM signal on the RX Freq of the repeater, the RX Radio lit up with full bars on reception, how ever NO lights lit up on the STM32-DVM. I expected that, as it is looking for Digital signals. Nor did it try to repeat, there was NO TX going on at all. I am in the process of looking for a DMR Radio to test the DMR out. I have Access to a Fusion Radio, and I own a D-Star Radio, so.. those should cover testing those modes.. But I DO NOT have a P25 or NXDN Radio. So... i will leave those two turned off for now.

Wish me luck, and push me in the right direction if I am NOT doing something right.

thank you again,
VA7WPN
Posts: 22
Joined: Sun May 13, 2018 3:51 am

Re: STM32-DVM Duplex repeater

Post by VA7WPN »

As a follow up to this,

I have had great success using the STM32-DVM board in duplex mode.

That being said, it seems that every time there is an upgrade/update to pi-star or the firmware I need to do some tinkering. Sometimes I lose BM connectivity, or I need to change the RX or TX inversion. Is this normal? Can someone post up their "Modem" settings from the config, or look at mine below and tell me if I have issues?

thanks a ton,
Annotation 2019-08-11 093430.png
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kf4eok
Posts: 5
Joined: Wed May 01, 2019 3:02 pm

Re: STM32-DVM Duplex repeater

Post by kf4eok »

I have built two of these and haven't gotten either one working.
One is with the zum radio board and pi-star on a raspberry pi 4
One is with the stm32 board and pi-star on a raspberry pi 4
both of them have the same results. They are connected to the internet and dashboard shows activity. you can hear digital noise on a fm radio on the output frequency but it is like the digital radio is not hearing the signal.
This happens on both setups but using the same cdm1250 radios in duplex mode. For this reason I believe that it is the programming of the code plug on the tx and rx radios that I am trying to use as the repeater.
Is anyone using the motorola cdm 1250 in a setup like this for mmdvm? If so would you be willing to share the code plugs from your working setup?
My email is [email protected]
Any ideas of what I am doing wrong.
Many thanks
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