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Configuring the RemHam Server

Configuring the RemHam Client

Radio Engineering Associates

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Configuring the RemHam Server

This page is under construction, but is hopefully reasonably complete!

Starting and Configuring the RemHam Server

To start RemHam in Server Mode, use the -s option when starting RemHam from the command line, or click on the RemHam Server Mode shortcut that is created during the installation procedure.

Once RemHam is started in server mode, the server mode menus and functions will be active.

Adding Remote Users

Before a RemHam client can connect to a RemHam server, you must add at least one remote user. Use the "File" menu, and select "Add / Edit a Remote User...". Usernames are case insensitive, however the password IS case sensitive. If the remote user is allowed to transmit, check the "Transmit Allowed" checkbox.

Server Settings Menu

  • Set Network Buffer Level... Allows setting of the network buffers. The default is 10, and is typically sufficient.
  • Set Transmit Hang Time... When used, once the remote user changes to receive mode, RemHam will keep the transmitter in transmit mode until the configured hang time is completed. This feature is very useful when there is latency in the transmitter itself, or when there is latency in the audio equipment that feeds the transmitter. Allows the audio to be transmitted before the transmitter is changed to receive mode. Delay time: 0ms = no hang time. Up to 3000ms of hang time can be configured.
  • Server Uses Live Monitor Audio for Client Backfeeds when Transmitting When more than one client is connected to a RemHam server, the audio from the client that is transmitting is sent to the other connected clients. If no external monitor is configured, the audio from the transmitting client is simply "repeated" to the other clients. If a live monitor is configured, the live monitor audio is used to feed the non-transmitting clients.
  • Display Transmit Audio Phase (display only - do not flip) Do not flip the audio phase, but do display it.
  • Flip Transmit Audio to always use Phase A (or Phase B) The server will determine the audio phase coming from the transmitting client, and will flip the phase of the audio (if necessary) to the desired phase.
  • Use Verbose Logging Use more verbose logging. Good for debugging issues.
  • Choose Input Device... Used to select the audio input device and configure the device for use by RemHam. Audio from this device is sent to RemHam clients. This device is generally connected to the receiver output. If a live monitor is also used, when transmitting, this device is connected to the live monitor (usually a modulation monitor) output. A relay is often used for this purpose, to switch between the receiver output and the monitor output.
  • Choose Output Device... Used to select the audio output device for use by RemHam. Audio received from RemHam clients is sent to this device. The output is typically connected to the transmitter or transmit audio processing chain.
  • Choose Com Port... Selects the com port to be used. Usually this is connected to the station or transmitter's transmit/receive system or virtual com port (see below).

Network Access to RemHam

If you want to access your RemHam server from the Internet, it will be necessary to, in your router, forward UDP ports 7802 and 7803 to the computer running the RemHam server.

If you allow access to your RemHam server from the Internet, be sure to use a good, hard to guess password.

Connecting RemHam to the Transmitting Equipment

Ultimately, RemHam must be able to control the transmitter. The exact connection will vary, depending on the equipment in use. Typically, there is some kind of master Transmit/Receive switch or connection. Many pieces of modern, computer-based or computer-interfaced equipment will allow T/R control via a virtual com port.

Controlling Modern Equipment such as SDRs

RemHam can control modern equipment through a Virtual com Port. RemHam asserts DTR when transmitting. Equipment such as the Flex series of SDR units and many others can accept transmit/receive control via a Virtual com port. No external hardware com port would be needed with this type of connection.

Controlling equipment that requires a physical, wired connection for T/R

For equipment that requires physical, wired Transmit/Receive control, RemHam uses a standard hardware COM port for external control. If the computer does not have a COM port, one can be added using a USB COMM port. These work very well, and are not expensive.

A simple interface should be constructed between the "raw" RS232 COM port output and the transmitter equipment. A relay control circuit (shown below) is generally the most practical way to accomplish this.

A solid state control (example: an open collector transistor) can also be used if the transmit control uses low voltage and current, and is ground referenced. Since the RS232 output swings from approximately -12v to +12v, the RS232 output can drive the base of a transistor through a diode and a resistor.

Note: Only the RS232 control lines (CTS, RTS, DTR, etc) are used. The RS232 data lines are not used by RemHam.
Also Note: Some computers "toggle" the RS232 control lines several times during the boot process. This can key up the transmitter if the transmit control line is one of the lines toggled. A delay circuit should be used if this is the case. One such circuit is shown below.

Here are some RS232 to PTT interface circuits. I use the delay version