[Milsurplus] TCS loading coils

[WA5CAB at cs.com]

OK.  It took about two hours in the shack to check all of this, first 
dismounting and disassembling the 47205 Loading Coil and then the same with the 
transmitter,  The RMCS is correct in that Switch Position 6 is minimum 
inductance in the 47205 External Loading Coil.  In my defense, I normally keep my 
TCS-14 transmitter tuned up on 3885 and connected to the 45' wire.  A few 
weeks ago I needed the wire for something else but needed the TCS too (local 
signal) and basically loaded it up into the loading coil and forgot I had 
done it.  I ran out to the shack, saw the switch set to 0, and came back in and 
wrote the previous.

However, on the internal rotary inductor, I didn't say max what or min 
what.  And in practice it wouldn't matter, regardless of what I was thinking 
when I wrote it.  Crank it from lock to lock key down.  If you don't get an RF 
Ammeter reading, unkey and go to the next step on the external coil and try 
again.  Perry is correct of course in that 43 on the rotary inductor dial is 
minimum inductance and 0 is max.

Something sorta good did come out of this though, not that it is of major 
international importance.  NAVSHIPS 900,291 is the final revision manual on 
the TCS-7, 9, 10. 11 and 12.  Figure 97 is the drawing on the 47205.  There 
are three errors on it.  The front view drawing shows the switch at Position 
3.  Normally, one would expect all the other drawings to be consistant.  The 
Electrical Circuit drawing shows it in Position 4.  Section A-A shows it in 
Position 2.  And Section B-B incorrectly shows which terminals the wires 
from the coil go to.  The terminal on the right side of the switch, shown as 
unused, actually connects to the right end of the coil and the right-hand 
front panel post.  The rest of the wires also need to move one terminal to the 
right, leaving two unused on the left side of the switch.  Now I know why 
that drawing always bothered me.  It never seemed to make sense.  And it 
doesn't.  I'm not sure that with the TIF editor tools I have I can fix it neatly. 
 So I added correction comments for future reprints.  Anyone who has the 
manual, whether from me or an original, should as the typical Navy Temporary 
Change Notice might say, make pen and ink corrections as indicated above.  I 
have not yet checked whether the same or a similar drawing is in the thin 
Preliminary manuals that were done on the TCS-12. 13, 14 and 15 and if so 
whether it has the same error.  If you have one of those manuals and they have a 
similar drawing and the Electrical Circuit diagram shows switch wipers 
going to coil terminals numbered 2 and 4 and the front panel drawing shows the 
knob pointed at 3, then they are also wrong.

In a message dated 4/30/2010 8:30:06 PM Central Daylight Time, 
w8au at sssnet.com writes: 
> At 05:39 PM 4/30/2010, WA5CAB at cs.com wrote:
> >I suspect a lot of RM's when tuning the transmitter, instead of 
> >turning the external loading
> >coil to 0 (minimum inductance) and running the internal loading coil to
> >max, then click the external to coil and go back to min on the 
> >internal, and so
> >forth, which is the proper way to do it if you haven't a clue where the 
> two
> >controls need to be, would first turn the external coil up until an 
> ammeter
> >reading showed up and then fine tune it with the variable.  The 
> transmitter
> >really doesn't care.  And it's quicker.  But the receiver suffers.
> 
> Interesting.... all of the TCS sets I've used, including my own have the
> minimum inductance at the high number end, not zero.  Also the external
> loading coil is minimum L or bypass at position 6, not 0.
> 
> Always thought that was odd, but I adapted to it.:-)
> 
> (no I wasn't standing on my head when tuning them)
> 
> Perry w8au
> 

Robert & Susan Downs - Houston
wa5cab dot com (Web Store)
MVPA 9480