VOA Radiogram is a Voice of America program experimenting with digital text and images via shortwave broadcasting. It is produced and presented by Dr. Kim Andrew Elliott.
In response to questions about the transmission of VOA Radiogram from the Edward R. Murrow Transmitting Station in North Carolina, here are some details.
What kind of transmitter is used?
We are using GE 4BT250A1 250-kW transmitters for the VOA Radiogram programs. It is one of the original transmitters installed at the station in 1962.

What is the actual transmitted power?
The transmitter output power is 80 kW.
What type of antennas are used?
The 5745 kHz and 6095 kHz programs are using a simple dipole with a bearing of 10 and 190 deg:

The 17860 kHz and 15670 kHz programs are using a curtain antenna with a bearing of 45 degrees, This antenna has a forward gain of about 17 dB:

Any other interesting details?
There is no audio processing used in the audio chain between the program source and the transmitter for the Radiogram program.
There is less than 1 dB of loss between the transmitter and the antenna.
See also BBG press release, 2 May 2012, with a link to a video about the transmitting station.