[Hallicrafters] Tech Tip - SX-117 XTAL Options

[Duane Fischer, W8DBF]

Hello Al,

The SX-117 allows the user to install four auxiliary xtals, if they so
desire.

The manual cautions against using crystals between 5000 and 7000 Khz. I am
not sure why this is, possibly harmonics?

The first I.F. is 50.75 Khz, the tuneable second I.F. is 6.0-6.5 Mhz and
the third I.F. is 1650 Khz.

Can you explain to me what the rationality is for avoiding xtals between
5000-7000 Khz? Thank you very much Al.

Duane Fischer, W8DBF


Duane,

1st IF is 6.0-6.5 variable, 2nd is 1650, 3rd is 50.75.
They say to avoid 5.5 to 7 mc xtals to stay away from the 1st IF, with a
500kc "safety", and probably to avoid heterodynes with the VFO which could
fall into the 1650 IF.
they do use a 6.5 xtal for the VLF range of abt 85kc to 500kc.
other than that there's no reason to use a xtal between 5.5 & 7

Al, W8UT


Duane Fischer, W8DBF - WPE8CXO
E-Mail: dfischer at usol.com
Hallicrafters web site: www.w9wze.net
HHRP web site: hhrp.w9wze.net