[Milsurplus] BC348Q Usage / art-13 operator's vs maintenance manual on CFI

[Mike Morrow]

>I have fixer's book on art-13.  Table in last post must be from
>another source.

It's information found in *every* calibration book, operation manual, or maintenance manual for the ATC or AN/ART-13(*).
 
>Let me quote from pg 4-9 of tm 11-692b-1
>
> A regen freq. divider ckt. is employed in "CFI" to obtain a 50kc
> fundamental...

That information is in all the maintenance manuals for the AN/ART-13.

>The last-post table multiplies this by the factor employed to produce output
>per settings in book.  Like 2-3 mhz multiplies HF pto x 2 & hence the
>2 x 50 kcs = 100kc blips heard on the sidetone ckt.  
>
>Another way to say this is the blips heard are @ 50 kcs intervals & the 
>dial readings are watcha get after selected freq. multiplication.

That's it.  That's why there are *no* calibration points spaced at 50 kc.

The MF/HF frequencies of the AN/ART-13 are generated by a VFO that operates from 1000 to 1510 kc.   The calibration audio signal is produced by beating the 50 kc harmonics of the CFI against the fundamental output of this VFO, not the output after the multiplier stages.  The actual transmitter output is always some multiple of this fundamental VFO, thus the calibration points occur at 50 kc times that multiple of the VFO, as shown below:

  Frequency       VFO Dial A    VFO Multiplier        Cal Interval
 2.0 to  3.0 mc       1 or 2           2                   100 kc
 3.0 to  4.0 mc       3 or 4           3                   150 kc
 4.0 to  6.0 mc       5 or 6           4                   200 kc
 6.0 to  9.0 mc       7 or 8           6                   300 kc
 9.0 to 12.0 mc      9 or 10          9                  450 kc
12.0 to 18.1 mc      11 or 12          12                   600 kc

Mike / KK5F