Converter definition for C-BAND LNBs

[ik8xld]

Hi Simon,
after our messages on twitter, here I am to better describe converter definition needed for the C-band LNBs.
Currently UP or DOWN converters definitions are working subtracting or adding the local oscillator value (OFFSET) from the frequency: (FREQUENCY - OFFSET)
For C-BAND LNBs converter definition calculation should be:
OFFSET - FREQUENCY
an example:
Desired frequency 3623 MHz (to shown on software)
LNB offset 5150 MHZ (settable offset)
calculation: 5150-3623=1527 MHz (1527 SDR Frequency)

TNX in advance

[Simon G4ELI]

Ah,

Now I understand.

[ik8xld]

Tnx Simon,
of course I'm available for any info and test

[ik8xld]

Hi Simon,
I think that a custom converter definition that can be configured in this way can satisfy all requests.
In attach also a classic C-BAND LNB spec.
73 Rocco IK8XLD

[Max]

Hi Simon,
I think that a custom converter definition that can be configured in this way can satisfy all requests.
In attach also a classic C-BAND LNB spec.
73 Rocco IK8XLD

Rocco

A question to you in my ignorance:

What is the reason for running the LO in the LNB at 5150 and not 2450?

73

Max

[ik8xld]

Hi Max,
I do not imagine the reason but they are all like this.
Have the oscillator at 5150 MHz.

73 Rocco Labella IK8XLD

[Max]

OK Rocco thank you. Seems odd as one might imagine the frequency stability is harder at the higher frequency!

73

Max

[ik8xld]

A possible explanation could be that a 2450 MHz OL would be too close to the IF. (950 - 1750 MHZ)

73 Rocco Labella IK8XLD