by 5B4AIY » 15 Jun 2014 06:33
Good Morning, Erich,
There may be a number of reasons why you are unable to communicate with the TRX-2. First, the KX3 USB cable (Elecraft reference: KXUSB) does not use standard RS-232 voltage levels. The RS-232 standard defines logic 1/Mark as a voltage between -3V and -18V; it defines logic 0/Space as a voltage between +3V and +18V. The voltage between +3V and -3V is undefined. The Elecraft USB-RS232 adaptor uses +12V for the logic 0/Space, and 0V for logic 1/Mark. If your TRX-2 serial port is working correctly it may well work with these non-standard voltage levels. I have a KX3 and the Elecraft USB cable, and I can get my TRX-2 to work with this cable.
You should first verify that your TRX-2 RS-232 port is working properly. Connect a 3.5mm stereo patch lead to the port, and measure the voltage at the tip, this is TX Data, and in the idle state it should be -9V. If it is any lower, then you have a serial port problem that you need to fix. To verify that you can communicate with the TRX-2, connect its RS-232 port to a PC running a terminal program, set the TRX-2 port protocol to the TEST mode, and use the built-in serial test suite to verify the communication.
In any case, if you are using the original TRX-2 firmware the only way to work with a CAT program is to set the TRX-2 port protocol to the Yaesu FT-817 emulation mode. Since the TRX-2 is not a Yaesu, the emulation is only partial. If you were to change to my latest firmware you would also have a choice of the Kenwood emulation as well, but let's verify that your serial port is OK before trying anything else.
PA-100D
The input VSWR of the PA-100D depends upon the input attenuator setting. At maximum gain (G4) the input VSWR is about 2.2 on 160m, 2.1 on 80m, 2.5 on 40m, 2.4 on 30m, 2.0 on 20m, 1.8 on 17m, 1.6 on 15m, 1.5 on 12m, and 2.0 on 10m. When using G1, the lowest gain, the input VSWR is less than 1.3 across the range from 160m - 10m. The reason for this is the non-linear input impedance of the transistors, (The input VSWR was measured on my PA-100D using a swept antenna analyser, a RigExpert AA-230pro.)
The power gain of the amplifier in the high gain setting (G4) is nominally 15dB, that is, for 100W output you should only need a drive power of about 3W. At the lowest gain setting (G1) for 100W output you will need an input power of about 12W. Normally when using the TRX-2 as a driver, the gain should be set to G2/G3 if the TRX-2 is set to about 10W. The power meter in the PA-100D is less accurate at low power settings, so when using the PA-100D in the STANDBY mode (Straight through) the power meter will read slightly lower than the 'real' input power from the TRX-2. You would normally set the PA-100D to the STANDBY mode, and then match the antenna using the TUNE mode of the TRX-2. Once a match has been achieved, then switch the PA-100D to the OPERATE mode.
If you are using the original firmware with the PA-100D, yes, the SWR warning will beep if the SWR is excessive. If you use my firmware you can set a delay time to mask a transient SWR during tuning.
If you intend to use your TRX-2 in combination with the PA-100D AND use the logging program, then you will have to operate the PA-100D in the Frequency Sense mode for automatic band changes, or in the manual mode. The TX/RX switching is automatic, the TRX-2 supplies a +12V logic signal via the RF input connection to the PA-100D to switch the linear into transmit.
Finally, if you use the latest version of my PA-100D firmware then I have included in this a KX3 option that allows you to use the automatic band selection of the PA-100D controlled from the KX3. You would have to make a 'Y' cable from the KX3 serial port so that the PA-100D could 'listen' to the KX3's transmit data line. (Details are included in the User Manual which is in the ZIP archive containing the new firmware.)
73, Adrian, 5B4AIY