Re: QUAD Inverto Black Ultra LNB

Markus Kempf

Ernst, you could try an increased supply voltage for the lnb. Some tuners allow this setting. You can also measure the nominally 13/18V at the LNB. Too low a voltage could be a reason. Second guess is a bad capacitor in the lnb. Third guess a suboptimal circuit design of the switch matrix. I own a single Inverto black ultra lnb with approx 30m of cable run and two quad lnb for Astra/Hotbird with in-house Switches. 

Am 16. Aug. 2020, 13:44 +0300 schrieb Ernst Lobsiger via <ernst.lobsiger@...>:

Dear All

I attach an schematic layout of a typical QUAD LNB. The only difference
from a SINGLE or TWIN LNB is the multiswitch (matrix) at the right side.

SINGLE: 4 x 1
TWIN   : 4 x 2
QUAD  : 4 x 4

So the effect I observed lately should also be seen on a TWIN LNB.
Assuming you have e.g. a TWIN Inverto Black Ultra LNB with two TC
receivers of any kind (Router like SR1, TBS PCIe card or USB-box).
If a first receiver is running (e.g with BASIC + HVS-1) and you
now start and tune the second receiver (e.g. HVS-2), does this
produce a burst of missed packets on the first TC receiver?

If this is a problem of the multiswitch maybe someone uses an
external multiswitch and has observed a similar effect. Switching
on one channel would give a burst of missed packets on a running
TelliCast receiver on a different cable?

My four 25m cables run in a plastic tube of about 1'' diameter. But
they have shielding > 100dB and I cannot think of a DC powering of one
cable can affect IF frequencies in another cable. HAMs might comment.

Best regards


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