I use the Yaesu MD-100A8X microphone and run the mike gain at 50 with the processor turned on with the level set at 50. I purchased a 10 pin DIN cable from W7YEN on eBay that connects to the Linear jack on the back of my FTDX-1200 and has RCA outputs for the relay and ALC.
Tuning the amplifier properly is very important in order to have a clean signal. The amplifier must always be tuned using maximum output power, not at reduced output.
With the amplifier turned off, set the ALC control on the back of the amplifier fully counter clockwise when looking at the back of the amplifier. This only needs to be done once.
Set the carrier level to 65 watts output when in the RTTY mode on the FTDX-1200.
Set the band switch to the correct band on the amplifier. Turn on the amplifier and set the ALC SET control on the front of the amplifier to 1. Tune for maximum power output just to get you in the ballpark for resonance.
Now, set the ALC SET control on the front of the amplifier to 4 and tune for maximum output power. This corresponds to about 130 ma of grid current, 400 ma of plate current and about 55 watts of output power from the FTDX-1200. This should produce about 700 watts of output power from the amplifier. Note that you should never exceed 700 watts of key down output, if you do, reduce the power output from the FTDX-1200.
If everything is correct, setting the ALC SET on the front of the amplifier higher than 4 should cause no change in grid current, plate current or power output from the amplifier.
Once the amplifier has been tuned properly at maximum power, reduce the ALC SET control on the front of the amplifier to 3.5 - this keeps everything just below the maximum limits for the 3-500Z, about 120 ma of grid current and 390 ma of plate current and about 50 watts of output power from the FTDX-1200.
The FTDX-1200 ALC meter should indicate that everything is within the proper range (the blue area of the ALC meter) when operating on SSB under normal speaking conditions.
These settings will produce about a kilowatt on voice peaks as registered by the AT2K peak reading meter.
I use the following switch settings on the bottom of the MD-100A8X microphone:
- MAIN set to THRU.
- HIGH EMPHASIS set to ON.
- LOW CUT set to OFF.
I have also changed the following SSB menu settings on my FTDX-1200:
- Menu item 101: SSB HCUT FREQ set to OFF.
- Menu item 104: SSB TX BPF set to TTBF.
There is a secret "Power On" function built into the FTDX-1200 that allows the rig to transmit from 50Hz to 4kHz. It is called "TTBF" which stands for Total Transmit Bandwidth Frequency. Once enabled, it will extend your transmit bandwidth to 4kHz.
In order to use the "TTBF" setting, do the following:
- Turn the power off.
- Find the "CS" and "TXW" buttons just left of the frequency dial.
- Push and hold "CS" and "TXW" buttons in while powering on the radio via the "ON/OFF" switch.
- Select menu item 104 and you will see that "TTBF" has replaced "3000WB".
Here is something that I found that really helps out with the readability of received signals:
- Menu item 108: RX DSP CONTOUR LEVEL set to 10.
Press the "CONT/APF" button on the front of the radio. Adjust the "CONT/APF" control to 1500 (or to your liking) and you will be amazed how the signals just seem to pop out of the noise and are so much easier to copy.
I do not use the IPO on 160, 80, 60 and 40 meters and as needed on the other bands. I set the RFLT (roofing filter) to 3kHz and the AGC is set to MID.
These settings may or may not be to your individual taste but they sure work FB for me!