Friday, March 17, 2023

 LoRa - new Packet Radio age

This is an article about Packet Radio at Raspberry PI with LoRa modules as a TNC. It is for your own experiments. Please, share it and help with new features :) You can contact me at  honza at or on FB.

Download the Raspberry PI images:

Download image from the link on this page and unZip it.

There are TWO images:

LoRa_PR_2TNC_APRS_OK2ZAW (03/2023) is image with up to 2 TNC and APRS reporting software

LoRa_PR_2TNC_RTL-SDR_OK2ZAW (03/2023) is image with up to 2 TNC and RTL-SDR APRS

see more in text below...

Then you need to copy it to the SD card. This is for windows users :) So please download and install this software: Win 32 disk Imager

Now you can insert SD card to PC, start Win32DiskImager and open UnZipped image. Select right Device (microSD card) and press Write. If you see error, eject and insert SD card again.

After that you can insert microSD card to Raspberry PI and start it. If the Raspberry is connected to LAN you need to find its IP address. You can find it in your router (DHCP clients), using some LAN IP scanner or connect HDMI monitor.

If you use LAN connection, download and run Putty.
Write right IP address and press Open. You will see information about certificate - do agree.
Write username: pi and password: raspberry 
Now you should be logged in:

It is highly recommended to change password by: passwd
Write current one: raspberry and write your new one.

If you have bigger SD card than 4 GB you should resize partition. 
You can check free space by: df -h
Resize card: sudo raspi-config

Change your  Time zone: dpkq-reconfigure tzdata 

You can run Midnight Commandermc

Configure Raspberry PI after boot:

Resize card: sudo raspi-config

Enable SPI and I2C:
1. Select 3. Interface Options
2. Select P4 SPI (Enable, YES)
3. Select P5 I2C (Enable, YES)


There is example of schematic for two LoRa modules. You can use only one. You have to set up right PIN numbers in TNC configuration.

IRQ PIN setup: 
If you like to use two LoRa modules, you have to set up right IRQ PIN numbers.
LoRa module 1: GPIO 5
LoRa module 2: GPIO 19

TNC setup:

IZ7BOJ GitHub: there the PR version

You have to set right parameters:
- TCP_HOST and PORT (must be different for TNC1 and TNC2)
- irqPin (TNC1 = 5, TNC2 = 19 for OK2ZAW board)
- LoRa settings: Frequency and LoRa parameters.

BPQ32 setup:

Please, I am very basic user of BPQ :) Most of my settings are try-and-test... I will be very happy if someone could help me with right parameters settings!

Directory: /home/pi/BPQ
CONFIG file: bpq32.cfg
RESTART BPQ: ./bpq-config

DO NOT change config file by BPQ-config script - could break TNC configuration.

Please, change configuration to your CALL, your informations:

There are port configuration. Port one is some deffault one, port 2 is TELNET. port 3 and 4 are local TCP ports. You have to change to right PORT number (IP address) and comment.

APRS configuratio:
- there are all APRS settings. You can use it together with APRS RX gateway (RTL-SDR and direwolf)

BPQ32 web page status:

Web page access: IP:8008/Node/NodeIndex.html

EXAMPLE 1: RTL-SDR as 2m APRS gate - sending packets over LoRa:

In this case, BPQ runs as a BBS. RTL-SDR is connected to USB and Direwolf receive APRS packets at 144,800 MHz. From direwolf it is connected to BPQ and Bridged to LoRa TNC. All received packets are send to LoRa TNC too. Second Raspberry PI receive packets over LoRa TNC and sending to APRS network by configuration on BPQ.

Starting RTL-SDR with direwolf: 

rtl_fm -f 144.80M -o 4 - | direwolf -n 1 -r 24000 -b 16 -c sdr.conf -

Please, change Direwalf configuration in: /home/pi/direwolf/conf/sdr.conf

NOTE: when I moved image from Raspberry PI 4 to ZERO, Direwolf stopped working. I have to reinstall it! Error was:

Signal caught, exiting!
User cancel, exiting…
Illegal instruction

BPQ Direwolf port example:

BPQ bridging:
- this is example for bridging PORT 4 (2m APRS RTL-SDR port to ports 3 and 5 (LoRa 433 and 868 MHz)

BRIDGE 4=3 ; Bridge Direwolf port to LoRa
BRIDGE 4=5 ; Bridge Direwolf port to LoRa

RC.LOCAL start up:

There are starting commands for different softwares. you can find it in:

PATH: /etc/rc.local


# START LoRa TNC1 at localhost
sleep 2
cd /home/pi/LoRa_TNC/TNC1
sudo ./ >/dev/null &
sleep 4

# START LoRa TNC2 at localhost
sleep 2
cd /home/pi/LoRa_TNC/TNC2
sudo ./ >/dev/null &
sleep 4

#sleep 2
#rtl_fm -f 144.80M -o 4 - | direwolf -n 1 -r 24000 -b 16 -c sdr.conf - &
#sleep 2

sleep 2
cd /home/pi/BPQ
systemctl stop bpq.service
sleep 5
systemctl start bpq.service
sleep 5

# using RTC time module Tiny RTC:
sudo echo ds1307 0x68 > /sys/class/i2c-adapter/i2c-1/new_device
hwclock --hctosys


DEnable terminal in BPQ config: more there

RTC at raspberry:

There can be application where the raspberry is not connected to internet (my solar powered setup in mountains) and it is a good idea to have right time and date in system. You can use RTC board connected to my board. This is for DS3231. It is preconfigured in the IMG. You need to enable it in rc.local:

# using RTC time module Tiny RTC:
sudo echo ds1307 0x68 > /sys/class/i2c-adapter/i2c-1/new_device
hwclock --hctosys

Info (already installed in my IMG file): how to install it

Online node monitor:

There is online status monitor for BPQ: link 

Sunday, March 12, 2023

 My first F2 at 50MHz: 10th Match 2023 to OC

I left TRX switched ON. What a surprise when I look at PC in the morning. A few nice decoded lines from FK8CP. Little bit later first VK4 went through. It was easy to work VK4FNQ. VK4KEE was the second one. I did copy FK8CP again but I was not able to work him. But nice to see VK stations for 3+ hours and worked 3x DU: DU3LA, DU6/PE1NSQ and DU1/SP5APW. All these QSOs were in +- 70 °.

Friday, February 24, 2023

 February 2023 TEP 50 MHz conditions to Africa

18.2. 2023

21.2. 2023

23. and 24.2. 2023

28.2. 2023 NEW ONE FR4OO

Thursday, February 16, 2023

TROPO DUCTING at 2m and 70cm

There was nice tropo ducting after some time. I went to OL7M HF contest QTH, where I do have my remote RIG. I had to change MRF9180 transistor in my small (BY) PA. This QTH is around 300 m asl. and antenna is in 15 m but in W to NW there is a wood.

I made first DX on Sunday evening with GM4YXI with only 3 W and 12 el G0KSC at 1494 km.

OY9JD is my Tropo 2m ODX and nice surprise. He went in and out for 5 hours at distance 1961 km. With around 50 W and 12 el Yagi

70 cm remote from cottage (JN89cj):

I went to cottage on Monday evening with some things because we moved there two days later. I wanted to install simply 2 m remote there with my Adalm Pluto SDR with front ends and 7 el Yagi. But I forgot right coax cable :( But I had 70 cm 12 el DG7YBN. The front end is able to run around 4 W RF out. So I installed antenna just a meter above the ground into one small hole between other cottages. Direction around 320 deg. When I connected the antenna, there were no signal, no noise increase. Front end has got very low gain - I count with a pream in the future. Anyway I was able to made many OZ stations and even SM0DJW at 1017 km with less than 4 W and 12 el @ 1m.

Adalm Pluto SDR with the Front Ends: 4m, 2m, 70 cm

LoRa APRS 70 cm tropo:

Also LoRa 433 MHz had got some good DXes. Compare to my remote QTH in JO80CF, the conditions in 1100 m asl. were one day later compare to 300 m asl. You can see nice DX with very small power in mW but with very great LoRa modulation. OK2ZAW-13 is my tracker in car with mobile antenna. OK2ZAW-17 is solar powered DiGi.

LoRa tracker in my car
Stations heard by OK2ZAW-17 in 1100m asl.
OK2ZAW-17 copied by anothers. PWR 10 dBm + 4x dipoles