Tag: radio

SQLite database for remote radio in Max

under construction…

Max/MSP features a full implementation of SQLite using the js (javascript) object. Here we describe a database to track radio frequencies. Frequencies are stored by time, type, and mode. The frequencies can be retrieved in various ways, like with a scanner radio.

Tables can be created and maintained outside of Max using the command line (sqlite3) or database apps like SQLiteStudio.

Max patches:

(not yet available on github:

  • freqdb4.maxpat (database UI)
  • swBase3.js (SQLite code)
  • lp_radio2.maxpate (Launchpad)

DB structure:

The database is called newtestDB1

tables:

You can see the table schema in the screenshots. The tables were created using command line sqlite3 and SQLiteStudio.

freq table:

One record for each stored frequency. This table retains its state from each previous use, but new records can be added using the Max patch, or the Launchpad.

Screen Shot 2016-04-05 at 11.00.31 PM

xtime: Timestamp in UTC.

frequency: Hz.
mode:

  • usb: 0
  • lsb 1
  • cw 2
  • am 3
  • fm 4

filter: bandpass filter setting in Hz. (default is 6000)

typecodes:

0 : unknown
1 : AM/SW broadcast
2 : clock
3 : digital mode
4 : local broadcast
5 : mostly noise

zone: cq zone number

rating: 0-5 (0 = unrated)

confidence: 0-5 (0 = unknown)

tags: (general text notes)

preset table:

The preset table contains one record for each 8×8 launchpad button, for each of 3 screens.

  • screen 0: fixed presets (red) (static and persistent)
  • screen 1: time presets (green) (rebuilt with each time query)
  • screen 2: user presets (yellow) (persistent but can be modified using the Launchpad)

Data from each of theses screens is also displayed in jit.cellblock objects in the Max patch. All of the fields correspond to the fields in the freq table – except for screen, row, and col which are locators for the launchpad.

Screen Shot 2016-04-05 at 11.11.08 PM

Using the database

Launchpad presets

There are three screens of presets color coded using the Launchpad mixer button (upper right). Press it to cycle through the 3 screens.

0 fixed presets (red)

The fixed presets are static. But can be changed using SQLiteStudio. They contain commonly used radio frequencies, like the SW, Ham, and CB bands. And clock stations.

To select a preset, press its button on the Launchpad.

Currently assigned presets:

Screen Shot 2016-04-05 at 11.39.12 PM

1 Time Presets (green)

Time presets are frequencies with Timestamps that match a selected range. For example, every frequency within one hour of the current time. These can be selected with a query in the Max patch, or using default values from the Launchpad. The query will randomly match up to 64 records. If the query returns less than 64 records, you will get all matching records, but in random order.

From the Max patch:

Match hours plus/minus current time (0-12).

Type the number of hours in the number box and press the button under the delay object. This reloads the presets.

Screen Shot 2016-04-05 at 11.36.35 PM

You can view the results in the jit.cellblock:

Screen Shot 2016-04-05 at 11.39.07 PM

 

Match a specific time range:

Enter the start/end times and press the button.

Screen Shot 2016-04-05 at 11.40.51 PM

 

Selecting from launchpad

trk button: re-runs query using last set number of hours plus/minus current time. Default is one.

solo button: select one random preset using current hour range, and play it?

 

User Presets (yellow)

The user presets work like the pushbuttons on a car radio. Press to select. Hold to save the currently tuned radio frequency.

The learn button (upper left) gives feedback. If you press a pad for which no frequency has been assigned, the learn button will flash red. When you save a new preset, the learn button flashes green to indicated that the saving is done. If you press a pad for a preset that has already been saved, there will be no flash, but the radio frequency will change.

Adding new frequency records

You can add records using the Max patch or the Launchpad, or from SQLiteStudio.

Adding records from Max:

Tunning the radio fills in all of the fields except for typecode. Tune the radio. Then press one of the typecode buttons. Then press the big green button. You have added a new record.

Screen Shot 2016-04-05 at 11.55.57 PM

 

Adding records with Launchpad:

Press the Arm button (lower right) to add a record for the currently tuned frequency, using an ‘unknown typecode’

Adding records from SQLiteStudio

Just do it.

Remote radio – client

How to set up the client side of the remote radio system.

(under construction) patches have not been uploaded to github

This client works with the sever described in the previous post. We are running a MacBook Pro OSx 10.11.4. with the following:

  • logmein hamachi VPN
  • Soundjack VOIP
  • Max/MSP
  • Novation launchpad
  • DJ-Tech CDJ-101 controller

VPN

Install and set up LogMein Hamachi. It is free, for a limited number of computers.  Set up a Hamachi server on both the server and client. It should look something like this:

 

VOIP

We are using Soundjack VOIP. It is also free. Use the following parameters on the client side.

  • mic: soundflower 2ch (or something that is not currently producing input!)
  • headphone: default output (or whatever you want to listen on)

Screen Shot 2016-04-05 at 12.23.54 AM

You can ignore the rest of the settings, since we are not sending audio. Most of the configuration is done on the server side.

Max

We are using several patches, depending on which hardware controllers you are using. Make sure that the hardware controllers are connected before opening Max.

patches:
  • eagle-ui5.maxpat – User interface and main entry point for client communication and CDJ-101 abstrations

Screen Shot 2016-04-05 at 12.28.56 AM

  • freqdb4.maxpat – database handler

Screen Shot 2016-04-05 at 12.29.17 AM

  • lp_radio2.maxpat – launchpad driver

Screen Shot 2016-04-05 at 12.28.41 AM

After the max patches are loaded, you should be able to control the radio using the UI and the CDJ-101 controller. The red Mixer button in the upper right corner of the Launchpad should be lit.

Instructions:

to be continued…

Remote radio – server

How to run the server side (base station) of the remote shortwave radio system.

(Under construction) The patches have not been uploaded to github yet.

Assuming that the radio and antenna system are operating. We are using an internet connected MacBook Pro running OSx 10.9.5, with a MOTU 828 MK3 audio interface.

VPN

Install and set up LogMein Hamachi. It is free, for a limited number of computers.  Set up a Hamachi server on both the server and client. It should look something like this:

 

VOIP

We are using Soundjack VOIP. It is also free. Use the following parameters on the server side.

Local Settings:
  • mic: audio interface channel that is connected to radio audio output
  • headphone: doesn’t matter
  • volume: 0
  • audio block samples: 512
  • channels: 2
  • network packet samples 512
  • quality: high
  • userlist: manual

Screen Shot 2016-04-05 at 12.38.03 AM

User list:

UDP/IP: enter hamachi IP of client.

When Soundjack is set up on the client. Press the green start button on the right side of the user list window on the server.

If all goes well, you should hear the radio on the client. Note: The input meter under local settings should be registering audio from your radio. If not, there is a problem with the audio interface.

Max Server

The Max/MSP server exchanges CAT commands via the server serial port to the radio. The command data is exchanged with a Max patch on the client using OSC (over UDP).

Screen Shot 2016-04-05 at 12.46.02 AM

patch:

eagle-cat8.maxpat

instructions:
  • select the radio serial port from the menu (for example: usbmodem 14531)
  • initialize port settings
  • set toggle to poll the serial port

At this point you should be able to try the example commands, for instance to get the version or set frequency. If the commands are not working, it indicates a problem with the serial connection to the radio.

Next, check the IP address of the udpsend object. It should be the hamachi IP of the client.

 

Softrock SDR with DSP Radio

Mac OS software for Softrock SDR receiver

By DL2SDR

Download from: https://dl2sdr.homepage.t-online.de/

Use with “Softrock USB-Controller app: http://reactivemusic.net/?p=18285

Note: After some experimentation with various audio interfaces and sample rates, I found it difficult to get clear audio on higher sample rates, like 192k and also there doesn’t seem to be any way to adjust the IQ balance.

Remote controlled shortwave radio system

Under construction…

The first in a series describing a system for internet remote control of a shortwave radio station. Its not something new. There are commercial products that provide remote operation of amateur radio transceivers. The purpose of this project is to make it possible to use shortwave radio sounds in musical performance, without the need of an antenna system.

Features:

  • Max/MSP for USB serial control of radio, OSC remote interface, user interface, Midi device handling, and an SQLITE database of preset frequencies.
  • Low latency, good quality audio using Soundjack by Alex Carot.
  • Hardware control of radio using Midi controllers (CDJ-101 and Launchpad)
  • Bi-directional OSC and VOIP using Logmein Hamachi VPN
  • Additional hardware control of AC power and antenna selection using Arduino and a WeMo switch.
  • TouchOSC Ipad audio mixer control using MOTU Cuemix
  • TeamViewer remote desktop software for logging into to base station compuer
  • Optional radio user interface control with Ipod TouchOSC, Griffin Powermate dial, and Korg Nano-kontrol.
  • Optional VOIP backup using Mumble.

System diagram

base station:

remote-radio-sys1

remote control:

remote-radio-sys2

 

 

 

 

 

 

Hamlib and rigctl

Hamlib provides a linux command-line API for amateur radios.

Hamlib_design

Installation

On Mac OS you can install using Mac Ports:

sudo port install hamlib

Usage

Get a list of “rig numbers” for supported radios:

rigctl -l

Find available serial ports:

ls /dev/tty.*

Set the frequency to 7.2 MHz and mode to LSB on a Tentec Eagle transceiver:

rigctl -m 1608 -r /dev/tty.usbmodem14531 -s 57600 F 7200000 M LSB 0

Use a rigctl command with no commands at the end to start an interactive command shell.

Network control with TCP/IP

First start the daemon. It uses port 4532 by default, but here we are setting it explicitly:

rigctld -m 1608 -r /dev/tty.usbmodem14531 -s 57600 -t 4532 &

Then in another window, send commands to the daemon using netcat. For set example, to set the frequency to 14.247:

echo “\set_freq 14247000” | nc -w 1 localhost 4532

Max/MSP

This patch uses the mxj tcpClient object from https://cycling74.com/toolbox/tcpclient/#.Vnj_fpMrKuU by Arvid Tomayko to communicate with rigctld over TCP/IP. The patch below is a modified help file that connected to the radio using rigctld as configured above.

Screen Shot 2015-12-22 at 2.47.10 AM

Notes on grig and rpc.rigd

grig is a graphical rig front end for hamlib by Alex Csete. rpc.rigd is a daemon that allows multiple clients. I was able to get both of them sort of working together (use -m 1901 from grig) but the daemon starts streaming error messages “read_string timeout without reading a character”. Also the latency with grig over the LAN is high. Its possible that there are problems with the rig CAT file. I am using the file for the Tentec Orion – as I haven’t figured out how to add new devices. At any rate, the above methods (UDP or TCP command line) are way more responsive.

References:

 

Substituting components in parallel

Resistance and capacitance in an AM radio.

A first test to find out if its practical to ‘piggyback’ external controls on to an existing radio. The reason for doing this is to leave an original radio intact by clipping the remote components to the leads of the existing controls.

For example a varactor would be connected in parallel to the variable capacitor already in the circuit. The existing capacitor would be set low. The capacitance of the varactor would then be added to the total, using the formula for parallel capacitors.

For potentiometers, its not as easy because parallel resistors are divided:

ParallelWiderstaende

Formula:  Rtotal = R1×R2/(R1+R2)

For example if R1 is 10K, R2 would need to be 100K to get a total resistance of 9K. To get 99% of the existing resistance, the piggyback resistor needs to be 100 times the value of the existing resistor. 1 MegOhm if matched with 10K.

Practical considerations

What happens when the radio is not being controlled remotely?

  • For capacitance, the remote capacitor (varactor) should be set to 0.
  • For resistance, the remote resistor should be set as high as possible.

Conversely, how should the physical controls on the radio be set when operating remotely?

  • Variable capacitors should be set as low as possible.
  • Potentiometers should be set as high as possible. For a volume control this actually means turning the volume all the way down.

Switches

SPST switches can be considered as a form of potentiometer with infinite resistance. A piggybacked switch will only work if the existing switch is in the ‘off’ position. And vice-versa.

Double-Throw and Rotary switches present more difficulties as multiple states are maintained by the same device.

I don’t think multiple throw switches can be piggybacked. Two possible solutions:

  • mechanical connection to manual control (servo)
  • internal relays – requiring modification of the radio, so that the existing control and the remote control operate the same relays
  • Hybrid approach: Operate the switches manually while operating other controls remotely.

Testing

I piggybacked a tuning capacitor from an AM radio onto the tuning capacitor of a vintage Radio Shack Globe Patrol (regenerative receiver).

 

Regenerative receiver design

Notes and circuits

Screen Shot 2015-04-30 at 1.30.02 AM

 

“The regenerative circuit (or regen) allows an electronic signal to be amplified many times by the same active device

From Wikipedia: http://en.wikipedia.org/wiki/Regenerative_circuit

In other words it uses feedback.

Charles Kitchin, N1TEV

“High Performance Regenerative Receiver Design”, QEX Nov/Dec 1998: http://www.arrl.org/files/file/Technology/tis/info/pdf/9811qex026.pdf

A Shortwave Regenerative Receiver Project”, http://www.electronics-tutorials.com/receivers/regen-radio-receiver.htm

A two part video presentation: https://youtu.be/gcr7hSjTqd8

Google search, kitchin regenerative receiver, https://www.google.com/?gws_rd=ssl#q=kitchin+regenerative+receiver

Derivatives

Makota, 7N3WVM

Derivatives

Circuit Salad

http://circuitsalad.com

By Ray Ring

More…

SSTV in Max

Slow scan television simulation using Jitter.

See this Cycling 74 forum post for an explanation of how frame rate is limited by audio sample rate and  horizontal resolution: https://cycling74.com/forums/topic/jit-poke-vertical-bars-at-high-scan-frequencies/

Download

https://github.com/tkzic/max-projects

Screen Shot 2015-04-09 at 7.24.11 PM

Folder: sstv

Patches:

  • raster-scan4.maxpat (original)
  • raster-scan5.maxpat (better frame rate by lowering screen resolution to 160 x 120)
  • raster-poly-wrap5.maxpat (even better frame rate – up to 15 fps – by up sampling to 384 KHz)

Note – set your audio sample rate to 96KHz if possible, to get the results described above.