Re: VC-Tune for SUB receiver?? Why??


33 73s
 

Hi Kees,  There is just one point to note which is certainly not very detrimental on the low bands, but on the high bands it reduces the NF perfs of this beautiful machine, it is that this VC-Tune itself has a fairly high insertion loss... (probably around 10dB ..)
This loss of INS from this "agile" filtering is masked by a high level LNA at the filtering output to mask the degradation due to high INS (so not all).
Admittedly, this is not optimal, but making a more efficient VC-T filter costs ... and above all would take up a lot more space ... So the manufacturer has done its best.
It is moreover not recommended to use it VC-Tune on the higher bands, if it is not necessary.

73s
Sylvain F6CIS


Le mardi 7 juillet 2020 à 22:36:10 UTC+2, PA7TWO - Kees <pa7two@...> a écrit :


Hi Sylvain,

Thanks for sharing these test results, appreciated. It concludes my earlier stated findings on VC-Tune usage here in the shack The attenuation to strong nearby frequencies especially on the low bands is absolutely fantastic.

Vy 73, de Kees - PA7TWO - M5TWO

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