Using The K7DYY SuperSenior AM Transmitter: The microphone connections are the same as for the K7DYY Senior transmitter, although the level will need to be reset. Pin 1 is ground, Pin 2 is audio (600 ohms at 0 dbm nominal). Pin 3 is +8 Vdc to power the audio processor and Pin 4 is push to talk, which is activated by a switch closure to ground.
The MUTE/PTT connector on the rear panel has single pole double throw relay contacts for receiver muting and another PTT connection. Pin 1 is ground, Pin 2 is PTT, Pin3 is normally closed mute contact, Pin 4 is the pole, and Pin 5 is the normally open contact. The mute relay contacts are rated for 120 V at 1 A maximum.
The SuperSenior has peak limiting at about 1500 watts PEP. This is provided to protect the transmitter and should not be reached under normal use. It is expected that the external audio source will provide suitable compression or limiting which should be set below the transmitters limiting threshold. Otherwise, distortion and splatter can result, similar to negative overmodulation.
I have also provided additional overmodulation protection that will latch the transmitter off if extreme overmodulation is detected. Extreme overmodulation is reached when something catastrophic happens like losing a microphone ground or feedback that might cause damage to the SuperSenior. The SWR protection display HIGH SWR and will also latch the transmitter off. Both error conditions can be reset by cycling AC power.
The carrier power should not be set above 375 watts. Because the peak power cannot exceed 1,500 watts, the carrier would not be set above 375 watts for 100% modulation. If you are asymetrically modulating the SuperSenior you should also allow for higher audio peaks when setting your carrier power output. If you exceed the preset peak level, distortion will result.
The transmitter has wide audio bandwidth, in excess of 10 khz. It is essential that the external audio source provide the proper overall audio bandwidth limits.
Take care not to block the airflow into the fans or out of the back of the transmitter.
The FREQ switch sets the operating frequency from 1805 to 1995 khz and 3605 to 3995 khz in 1 khz steps on the 160/80 meter model. It set the operating frequency in 1 khz steps from 3605 to 3995 khz and 7130 to 7295 khz on the 80/40 meter model. Band change occurs automatically as the frequency is increased or decreased beyond the band edge. Frequency can only be changed in receive mode.
The SPOT switch provides a signal that can be heard in the receiver but not transmitted. When the SPOT and XMIT switches are both on, approximately 80 watts are provided for tune up purposes.
