RE: [linrad] xpol question

[postmaster@xxxxxxxxxxxxxxxxxxx]

Thanks Leif,

I need definately low system NF , and with the stepattenuator  I can go for the High
dynamic range if needed.

Jurgen PE1LWT


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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