RE: [linrad] xpol question

[Leif Åsbrink <leif.asbrink@xxxxxxxxxxxxxxxxxxxx]

Hi Jurgen,

> I am using direct conversion(2x SBL1 and signalgenerator) from 144 Mhz to
> 2,5Mhz(rx2500).
> Just finished a steep bandpass 142Mhz 148Mhz -50dB and putted it all
> together.Still over 40dB gain in front of mixer. It looks to  much for the
> Delta 44, so I have to play around with the gain distribution in the Rx
> chain
OK.

In case you do not have an amplifier between SBL-1 and RX2500 I suggest
you run the Delta 44 at max gain. Then the NF at the RX2500 input will
be about 9dB so you will have NF=15dB at the mixer input. Suitable
gain will be 25 to 35 dB depending on whether you want low system NF
or high dynamic range. 

73

Leif / SM5BSZ



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