Hey everybody.

Just walked in this evening (14-June-2019) & happened to catch the ISS at decent elevation around 2230 UTC. The packet digipeater sounded great and I had a quick exchange of digipeated 'Message' packets with W4TBD who happens to be just on the other side of town.

As the ISS tracked NW to SE, I stood by to see who else might be around. I keep the FM radio's squelch open & volume up a little to judge how the downlink packets are sounding.

All of a sudden, there was a dead carrier on (or at least near) the 145.825 ISS packet downlink. Sounded like a neighbor keying up to mess with me - except for the fact that I don't have any neighbors.

I quickly spun another radio to the area of 145.825 and set it to USB to see if I could recognize what that jamming carrier was. Turns out it wasn't a dead carrier at all, but a tone sweeping back and forth. Someone else needs to check me (since you can't ever be sure from a single observation), but from the SUBJECT line of this post you know that the offending tone appeared to be from XW-2D which was passing directly overhead at the same time. Here is a link to a screen shot of their orbits when this happened:

https://www.qsl.net/k/k4kdr//images/iss-xw2d.png

... so, if this VERY strong 2-meter signal was in fact from XW-2D, you might want to keep track of where that satellite is located just as a point of reference. There have been previous posts about XW-2D's transponder not working correctly.

If you have uplink or downlink trouble with anything that operates in the 145.800 - 145.900 range, this might be the cause if I'm guessing correctly.

73,

-Scott, K4KDR