#1 Re: General discussion » MicroDigi beta - standalone digipeater firmware » 2017-12-07 10:18:46

Hi everyone,

I have started work on exapnding a MicroDigi firmware for sending beacons.
There has been no activity either here or in the repository. Is this even still acctual?
Has anyone used this firmware "out in the wild" ?

#2 Re: Hardware » No decode while on (or next to) AC/DC converter » 2016-01-10 15:18:01

Thank You for your reply!
I will try to view signal with sound card. I have used xoscope to see changes with RC high pass filter successfully.

#3 Hardware » No decode while on (or next to) AC/DC converter » 2016-01-05 00:28:21

Replies: 3


having a (for me, at least) strange issue.
When running my Baofeng UV-B6 on battery power, microAPRS can decode packets.
When running on a car power adapter, connected to a 12V 1.5A AC/DC converter, microAPRS can not decode packets.
Also, if I leave car power adapter pluged in into the AC/DC converter and leave it next to a radio, while radio runs on battery, still no packets are being decoded.
When radio is put in charger, microAPRS decodes fine.

..? (sorry, I don't know what exactly should I ask, I am very new to electronics)

#4 Re: Hardware » MicroAPRS and APRSDroid » 2015-12-29 23:20:30


today I have used micorAPRS in KISS mode on Arduino Nano V3.0 with APRSdroid via USB serial connection (Georg Lukas has recently included this in APRSdroid, still in beta).
I have also seen these symbols, just to report this. So, apparently this issue is not tied up to blutooth...?

#5 Re: General discussion » No decode... » 2015-12-29 17:38:22

Thank You very much!
So, let's see if I got this right smile
1. De-emphasis on Baofeng sets 2200Hz level lower than of 1200Hz tone level ?
2. I should be using RC highpass filter ONLY, so that 1200Hz tone level is closer to 2200Hz tone level?
3. When using RC highpass filter, I should connect audio output from radio to both capacitor and resistor, and than draw signal from both sides of resistor to connect to modems input (to capacitor and volt divider) ?
4. Also, there is no need to ground resistor in RC highpass filter scheme?
EDIT: Ok, nevermind, I figured it out smile Indeed after placing RC HP filter packet demodulation rate has noticably improved! Thank You much for information!

Just this:
5. "Increased the volume" - using some kind of OpAmp circut or just radio volume?

#6 Re: General discussion » No decode... » 2015-12-25 14:25:39

Hallo everyone!
My name is Filip, QTH: JN95VA

I am trying to build microAPRS on an arduino nano v3.0 and so far I got the TX working allright.

But, I am also having small problems with demodulation.

I have build the modem with 3.3V reference and compiled with 3.3REF option and OPEN_SQUELCH true.
I am using a Baofeng UV-B6 for the TNC.

Setting volume knob from half to almost max volume microAPRS can decode 80-90% of packets (freely estimated, did not measured it).
I have tried using RC filter, but, as I am fairly new (noob) to electronics I am not quite sure I got that part right since only ONE packet got decoded smile
Also, I do not have ossciloscope to take correct measurments of signal coming into microAPRS.
@user11 can You please provide a schematic of that RC filter and how it connects between radio and TNC, and, what "increased the volume" exactly means in Your case?
Also, if anyone have any suggestions I would greatly appreciate it.
I hope I was clear in explaining my situation.

Thank You all in advance and for all the work and sugesstions and directions I have read so far!

I found a solution e.g. a problem with my setup. Conecting a roof antenna fixes the problem and as I can notice for now, most of packets (if not all, should monitor a bit longer) is being decoded.
Before that I had connected mobile antenna sitting in my room. So I guess the reception was bad allthough I could hear every packet clearly hmm

Performance has improved but still every 5th packet is not being decoded (rough estimate).

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