Re: It's gone very quiet. Is no one Microwaving (other than their (porridge)

John Fell

Looking at the Labgear pic it seems to allow a DC path through each branch of the split ports .
This implies that there is no DC blocking cap to stop Volts arriving at the input to the 618MHZ  RX . 
A basic USB dongle may well have an input DC blocking cap , but several of the more advanced SDR devices allow selectable DC output to antenna pre-amps . Damage could occur if the 12V+DC injected for the LNB got into this other source.

A bias T would normally insert a DC blocking Cap in the 618MHZ port to prevent the above and a suitable choke in the DC injection port to stop the wanted 618MHZ going into the DC feed circuit , causing attenuation .


On Thu, 22 Nov 2018 at 20:55, Mike G4TVP <mike_cat_taylor@...> wrote:
Thank you for the advice John much appreciated. Some it went over my head a little, but we will see where I get to.

I seem to have a two way splitter (Labgear FBS402s), which I must of used in the past. Is there any benefit/drawback on this approach rather than using a biasT?

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