KC6HUR(-L)

APRIL 19, 2003 KC6HUR The TH-F6a may not be as suitable for node use as originally thought. This is due to the fact that the CTCSS setting has no effect on the COS output; therefore, it is possible for signals without the correct CTCSS to cause your node to send dead air to the Internet. The CTCSS does control the muting of the audio so that no extraneous noises will be heard, just a dead "carrier".

The TH-F6a hand-held is quite possibly one of the best radios to use when it comes to setting up a micro-node. What makes this small, versatile radio so ideally suited is that all the signals needed to connect the radio to the node computer are brought out to connectors that can simply be plugged into.

In order to connect a radio to a node computer, the following signals are needed: RX and TX audio, COS and PTT. RX audio being that audio received from the airwaves to be transmitted over the Internet. TX audio is that audio received from the Internet and then transmitted over the airwaves. COS is a signal from the radio indicating that there is something being received by the radio. PTT is the signal from the node computer telling the radio that there is something to be transmitted. As can be seen in Figure 1 above, all of these signals are present or can be used by the TH-F6a. Don't see it? Let me translate: RX = TNC RX; TX = TNC TX; COS = TNC DCD.

The TH-F6a must be configured to provide the necessary signal. The default settings for the SP/MIC jacks are for SP/MIC operation. In order to use the TH-F6a as an IRLP node radio, it must be placed into TNC mode. The steps a show below:

Don't forget to select 1200 baud operation. If you select 9600 baud operation, you will receive discriminator audio and your TX audio will go straight to the modulator. If you wish to use 9600 mode, you will need to deemphasize the RX audio; otherwise the other nodes will hear you as being very tinny. You will also have to pre-emphasize your TX audio; otherwise, everyone else will sound very bassy to you.