HAMTV from the ISS - HAMTV Transmitter Information
Whilst the transmitter has a number of possible configurations, it is anticipated that most transmissions will be:
- RF: 2395 MHz, RHCP.
- Modulation: 2.0 Msymbols/second, QPSK, DVB-S, FEC 1/2
- Content: MPEG-2 video with MP2 audio.
Other possible frequencies are:
- 2395 MHz (main operating frequency)
- 2369 MHz
- 2422 MHz
- 2437 MHz
The HAMTV transmitter produces 10 watts RF, however this is then fed through a series of interconnecting cables and bandpass filter before passing through the ISS Columbus module external wall.
Estimated power at the antenna is approx. 2 watts.
Polarisation is RHCP.
DVB-S modulation
- Symbol rates: 1.3 Ms/s or 2.0 Ms/s (2.0 Ms/s is normally used)
- FEC : ½
- Rolloff: 35%
TS format
- MPEG-2 Video, approx. 1.5 Mbits/s, PID 256
- MP2 Audio, approx 64kb/s, PID 257
- Null padding, PID 8191
- NTSC
- SIF resolution: 352×240 or D1:720×480, 29.97fps
MPEG-TS Recordings of previous transmissions can be found at live.ariss.org/media/HAMTV Recordings/
ISS HAMTV antenna
The HamTV transmission runs relatively low power on 2395MHz to antenna 41 on the ISS which is a simple patch antenna.
This patch antenna is located on the earth facing side of the ISS but there are many other items that project below the antenna and may cause reflections. These include the solar panels, thermal radiator panels, sometimes, two or more visiting vehicles and robotic arms. Depending upon your location in respect to the ISS, these projections may result in strong reflected signals as well as the one from the patch antenna itself. They may cause disturbances to the signal level you receive.
The ISS also “flies” slightly nose down to protect the cupola windows from space debris and so the RF performance, particularly when it is rising from the west, is slightly unpredictable.
The transmissions are right hand circular polarised (RHCP)