Note: When the VHF-1 transmitter is Running, the Amateur Radio receivers in the 2-meter band will go deaf (Receiving on 145, 490, 145.200, 145.990). This is because the Transmitting antenna for VHF-1 is less than 50 feet away from the Amateur Radio antennas.
The VHF-1 transmitter is usually left running for a few hours at a time for ground stations to test against. If you wish to test this theory, just try to ping the Amateur radio packet station ISS during a VHF-1 transmitter test.
When VHF-1 is transmitting, you will not see any packet activity, other than internally generated Beacons on 145.800 (down 145.800, uplink 145.990). When VHF-1 shuts down, normal packet access will resume.
Marex discovered this problem with the Mir Amateur Radio station. We then custom designed a filter by DCI, to resolve the issues. No such filter exists on ISS.
http://www.marexmg.org/documents/DCIFilterProject1.doc
WF1F, www.marexmg.org
--- On Wed, 7/14/10, Bob Christy [email protected] wrote:
From: Bob Christy [email protected] Subject: [amsat-bb] ISS - Mission Control Comm Check To: [email protected] Date: Wednesday, July 14, 2010, 4:47 AM Today's ISS crew schedule shows VHF comm checks from the Russian segment while over North America. Ground stations are at White Sands and Wallops.
The pass is from 20:00 UTC (west coast) to 20:15 UTC (east coast).
VHF-1 is 143.625 MHz FM, there may also be something on VHF-2 at 130.167 MHz.
Bob Christy _______________________________________________ Sent via [email protected]. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb