New Horizons was said to be able to communicate at ~1kbit/s at Pluto and 38kbit/s at Jupiter.
Communication with the spacecraft is via X band. The craft had a communication rate of 38 kbit/s at Jupiter; at Pluto's distance, a rate of approximately 1 kbit/s per transmitter is expected. Besides the low data rate, Pluto's distance also causes a latency of about 4.5 hours (one-way).
However the Voyager 1 which was decades older can transmit 1.4kbit/s around 2018 at a much larger distance
Termination of Data Tape Recorder (DTR) operations (limited by ability to capture 1.4 kbit/s data using a 70 m/34 m antenna array; this is the minimum rate at which the DTR can read out data)
The Voyager 2 is also faster at Jupiter's distance (~115.2kbit/s)
Communications are conducted over the S-band (about 13 cm wavelength) and X-band (about 3.6 cm wavelength) providing data rates as high as 115.2 kilobits per second at the distance of Jupiter, and then ever-decreasing as the distance increased, because of the inverse-square law
Why is that?