The main station transceiver is a Yaesu FTDX 1200 which includes a multiband, multimode transmitter providing up to 100 Watts on the 160-6 meter bands, and a general coverage receiver from 30 kHZ to 56 MHz. The FTDX 1200 allows operation on SSB, CW, AM (25 Watts carrier), FM and Digital modes and uses a 32-bit high speed floating point DSP. A built-in 4.3-in TFT full colour high resolution display provides the usual indicators as well as a 20 kHz to 1 MHz Spectrum Scope, Audio Frequency FFT Scope, RTTY/PSK31 Encode/Decode and CW Auto Zero-in Decode.
The FTDX 1200 is used as the exciter for an Ameritron AL-811H linear amplifier running four fully neutralized 811A transmitting tubes that is capable of providing a maximum power of 800 Watts PEP and 600 Watts CW output on the 160-15 meter bands (including WARC bands). It has also been modified to provide 12 and 10 meter band operation on the auxiliary band switch position.
As an Amateur Advanced License holder, I am currently restricted to a maximum output power level of 400 Watts PEP (pX) and 120 Watts CW (pY) under Australian amateur radio licensing conditions. 20 Watts drive from the FTDX 1200 is all that is required to produce 400 Watts output from the AL-811H amplifier. This means both the FTDX 1200 and the AL-811H can be run at drive levels well within their specified output power limits.
An Ameritron ARB-704 relay buffer sits between the FTDX 1200 and the AL-811H and provides isolation between the transceiver TX GND output and the linear amplifier Relay input. ALC is also fed back via the ARB-704 from the amplifier to the transceiver and I have the level adjusted so that the amplifier output power doesn’t exceed 400 Watts.
Antenna matching and switching is performed with an LDG Electronics AT-1000ProII Autotuner which provides fully-automatic and semi-automatic antenna matching across the 160-6 meter bands at power levels up to 1000 Watts (250 Watts on 6m). I also have the optional M-1000 analogue meter which is more precise than the tuner LED bargraph when adjusting the load and plate controls on the AL-811H linear amplifier.
The AT-1000ProII has a built-in 2-port antenna switch with 2,000 memories for each port. An initial full tuning cycle may take anywhere from 0.2 to 15 seconds for a frequency and antenna that hasn’t yet been matched and had the settings saved. A memory tuning cycle only takes 0.2 seconds when the settings from a previous match are recalled and the tuner checks that an acceptable SWR level exists using those memorised settings.
I have a MFJ-993 IntelliTuner that I used previously before acquiring the linear that tunes any balanced or unbalanced antenna automatically and handles 300 Watts PEP and 150 Watts CW. It is a comprehensive automatic antenna tuning centre complete with SWR/Watt-meter, antenna switch for two antennas and a 4:1 current balun for balanced lines.
A secondary station transceiver is a Yaesu FT-897D which is a multiband, multimode portable transceiver providing coverage of the 160-10 meter bands, including the U.S. 60m (5 MHz) band, plus the 6m, 2m and 70cm bands. The FT-897D allows operation on SSB, CW, AM, FM and Digital modes and features a 0.5 ppm TCXO Unit. The FT-897D is capable of 20-Watt portable operation using internal batteries, or up to 100 Watts when using an external 13.8-volt DC power source.
A Manson SPA-8330 continuous switch mode power supply is used to power the FTDX 1200, FT-897D, MFJ-993 and other 13.8 VDC station accessories. This supply can provide a total current of 33A which is adequate at this point in time.