[Hallicrafters] SX-117 USERS - HELP

[Paul Graham]

I have come into possession of a very fine SX-117. I
have studied the manual and schematic. Hallicrafters
made it possible with this receiver to be able to tune
frequencies which lay outside the HF bands at the time
when the unit was new. But they also did not provide,
as stock, crystals for three segments of 10 meters,
nor for 10 MHz WWV, although these are provided for
with crystal sockets and bandswitch positions.

I hope I may trouble other SX-117 users to confirm the
following observations:

1.) I can tune WWV by installing a 16.0 MHz CR-18/U in
the WWV crystal socket, selecting WWV on the
bandswitch and tuning to 10 MHz (red scale).

2.) I can complete coverage of 10 meters by installing
34.5 MHz, 35.5 MHz, and 40.0 MHz crystals (all
CR-23/U) in crystal sockets Y4, Y2, and Y1
respectively. (Y3 has the provided 35.0 crystal for
the 28.5-29 MHz portion of the band.) 

3.) I can cover 30 meters by installing a 16.5 MHz
CR-18/U in Xtal Osc socket 2 (select Band 7 and Xtal
Selector 2, tune on black scale).

4.) I can cover 17 meters by installing a 24.5 MHz
CR-23/U in Xtal Osc socket 3 (select Band 21 and Xtal
Selector 3, tune on black scale).

5.) I can cover 12 meters by installing a 31.0 MHz
CR-23/U in Xtal Osc socket 4 (select Band 28 and Xtal
Selector 4, tune on red scale).

This leaves Xtal Selector position 1 unused. Anyone
got an idea what to use it for?

If all this is right, it remains necessary only to
find said crystals. Perhaps you old Hallicrafters
hands can give me a tip.

I really appreciate the help! 

Highest regards - Paul G.