OK. I guess there is some consolation in the fact that I am not alone...
Both adapters work now:
ug 28 15:11:10 tvburk tvheadend[4552]: http: 192.168.1.4: using ticket F40D7572A1DADFECC00EB13949AF85848A1A01C0 for /stream/channel/4411270327a9c6646c48096869b552aa
Aug 28 15:11:10 tvburk tvheadend[4552]: mpegts: 138MHz in MCA - tuning on Silicon Labs Si2168 : DVB-C #0
Aug 28 15:11:10 tvburk tvheadend[4552]: subscription: 004A: "HTTP" subscribing on channel "Nelonen MP4", weight: 100, adapter: "Silicon Labs Si2168 : DVB-C #0", network: "MCA", mux: "138MHz", provider: "MCA", service: "Nelonen MP4", profile="pass", hostname="192.168.1.4", client="VLC/2.2.1 LibVLC/2.2.1"
Aug 28 15:11:29 tvburk tvheadend[4552]: http: 192.168.1.4: HTTP/1.1 GET /1_0_1_130_B_1_FFFF0000_0_0_0.png -- 1
Aug 28 15:11:32 tvburk tvheadend[4552]: http: 192.168.1.4: using ticket 968BD59242AC76F6D977BB44BC49880D110B9DAF for /stream/channel/85a80c57c1990828c6b5f71202f4f271
Aug 28 15:11:32 tvburk tvheadend[4552]: mpegts: 162MHz in MCA - tuning on Panasonic MN88473 : DVB-C #1
Aug 28 15:11:32 tvburk tvheadend[4552]: subscription: 004B: "HTTP" subscribing on channel "TV3", weight: 100, adapter: "Panasonic MN88473 : DVB-C #1", network: "MCA", mux: "162MHz", provider: "MCA", service: "TV3", profile="pass", hostname="192.168.1.4", client="VLC/2.2.1 LibVLC/2.2.1"
Aug 28 15:11:34 tvburk tvheadend[4552]: TS: MCA/162MHz/TV3 Transport error indicator (total 1)
Aug 28 15:11:34 tvburk tvheadend[4552]: TS: MCA/162MHz/TV3: TELETEXT @ #948 Continuity counter error (total 1)
Aug 28 15:11:34 tvburk tvheadend[4552]: TS: MCA/162MHz/TV3: MPEG2VIDEO @ #772 Continuity counter error (total 1)
even if I see this:
Aug 28 14:21:23 tvburk tvheadend[4552]: mpegts: 130MHz in MCA - tuning on Panasonic MN88473 : DVB-C #1
Aug 28 14:21:23 tvburk tvheadend[4552]: linuxdvb: Panasonic MN88473 : DVB-C #1 - failed to tune [e=Invalid argument]
Aug 28 14:21:23 tvburk tvheadend[4552]: mpegts: 202MHz in MCA - tuning on Panasonic MN88473 : DVB-C #1
Aug 28 14:21:23 tvburk tvheadend[4552]: subscription: 0018: "epggrab" subscribing to mux "202MHz", weight: 4, adapter: "Panasonic MN88473 : DVB-C #1", network: "MCA", service: "Raw PID Subscription"