Sunday, June 2, 2019

The Ellies Dual Port LNB modification for QO-100

The Ellies Dual Port LNB modification.

I want to modify the Ellies Dual Port LNB so that the output frequency would be ether on 70cm 435Mhz or 2M 145Mhz so that it can be used on the QO-100 Satellite directly to VHF/UHF SSB rigs.

Here is an opened LNB.

Opend LNB

Here you can see the two local filters to the two ports.

The Main Mixer and PLL LO seem to be Rafael Micro RT320n
Top View
The Mixer and LO and PLL seem to be Rafael Micro RT320n
Rafael Micro RT320n

It seem Like the Local Crystal is 25Mhz
Crystal is 25Mhz



What this mean if I change the LO Crystal frequency I should be able to force the IF to the required Output to ether on 70cm 435Mhz or 2M 145Mhz


I have created a Spreadsheet to calculate the required IF frequencies so you can listen to QO-100 on the required Ham band.

I did some calculations and the LO to Crystal frequency = LO / 390
see calculated values

Blue / Red is crystal frequency for your LO in LNB
 

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