[amsat-bb] LilacSat-2 Ground Interference Resolved (hopefully!)

[Scott]

Hello everyone.

By the quirk of the orbital pattern, for several months I've found myself
at home -and- on the radio during some high, usually weekend evening passes
of LilacSat-2 (CAS-3H).  Seems like I often get a good pass around 6pm or
so on the East Coast Fri/Sat/Sun.

It's bad enough that you never really know when LilacSat-2's FM transponder
might be active (144.350 up; 437.200 down; no tone), but it seemed like
every time I did catch it active there would be obvious ground stations
getting into the uplink.   You could still make contacts, but it was tough
squeezing in between stations that had no idea they were being
retransmitted across the entire country.

I never could catch a call sign, but suspected they might be centrally
located since the conversations often lasted from AOS to LOS.

Well, last week I finally got a partial call sign.  After searching on QRZ,
I thought I might be on the right track & sent an email to Mark, AA0YY.
Right there on his QRZ page was mention of an AllStar node set to 144.250!
Not EXACTLY the uplink freq of LilacSat-2, but in the ballpark.  AND, he's
located in Missouri which is pretty close to the center of the continental
U.S.

Mark was super helpful and copied his reply to Dan, KE0OZU, who
collaborates with him on their AllStar system.  That nailed it.  Dan
replied that while Mark's AllStar node was on 144.250, it was actually
Dan's own AllStar node that was set square on 144.350.

I didn't mention anything to either of them about changing frequency...
didn't have to.  Dan immediately replied that he would change his system's
frequency to avoid the conflict with LilacSat-2.

I've only been around for a couple of passes since Dan made the change, but
so far no more ground repeater conversations on the uplink.  There's some
general static noise on LilacSat-2 when no one transmits, but otherwise the
signal can often be absolutely crystal clear.

So, only time will tell if that was the ONLY ground repeater getting into
LilacSat-2's uplink, but hopefully it was an isolated case.  The up/down
status of the FM Transponder is still a hit or miss proposition, but since
the other FM sats are often crowded, folks might want to check to see if
this one is active when you have a high pass.

-Scott,  K4KDR