[Elecraft] K1 with internal battery

[Stephanie Maks]

>
> The KBT1 should have been made easily removable so that the  
> compromises associated with having it installed need only be  
> suffered when absolutely needed.  The KBT1 *should* attach via a  
> cable with a polarized two-pin female connector to a male connector
>  *anchored* on the RF board.  This would allow easy removal at any  
> time.  The current design has the connections made by soldered  
> connections, and even if you jury-rig in a connector in the power  
> leads, one side of the connector will then be floating ar
> ound creating potential shorts when the KBT1 is removed.
>
> 73,
> Mike / KK5F

I got the KBT1 kit but haven't really used it yet.   I have made some  
modifications though that will make using it much easier, including  
adding my own jack on the RF board so that I can add / remove the  
entire battery kit without soldering.

Where the two solder points are to wire in the auxiliary 12 volts,  
the + point is directly under the switch, but the - point was next to  
the switch. I got a 3-pin female socket, similar to the one you get  
with the ATU - it's a 0.1" spacing 3 conductor socket.  Anyhow I  
drilled a hole in the RF board, and mounted the 3-pin socket there.   
The two outside pins are both ground, and the centre one is for +12  
volts.  (not quite as good as a polarized plug, but I just used the  
parts I had laying around). I used the special diode they supplied  
with the KBT1 to go from the centre pin of my 3-pin connector, to the  
power switch - rather than having the diode being part of the KBT1  
assembly itself, this means the diode is right on the RF board, on  
the bottom.  Finally, I used some hot-melt glue on the top side to  
provide additional strength to the 3-pin socket.

For the wiring from the KBT1 bracket I used the supplied red and  
black wiring, and just terminated it on a 3-pin header.

The last thing I changed was rather than using discrete AA sized  
rechargables, I had a battery pack assembled.  This allowed me to use  
the larger diameter AA type cells.  Without the plastic battery  
holder there is more room for batteries.  So I have a 9.6v 2000 mAh  
battery pack made up.  On its terminals I added a '9-volt' style snap  
connector, and to the KBT1 switch I put another '9-volt' style snap  
connector.  This lets me easily pull the battery pack out and drop it  
into my Maha quick charger, without removing the KBT1 bracket etc.    
I still have the 8-AA plastic holder of course, and with another 9- 
volt style snap connector on that, I can just as easily drop that in  
and load it with off the shelf AAs if needed.

In the meantime, I also used two small strips of brass to add a  
little 'lip' to the stock K1 top cover, because I like the ease of  
opening it with just the two knurled thumbscrews at the back.

So now the whole process of switching from the 'normal' K1 to the  
battery powered unit takes me under a minute - just unscrew the  
thumbscrews, remove the stock lid and speaker, drop in the KBT1  
bracket, plug in the speaker, plug in the power cable, and put on the  
KBT1 lid and screw it down.  No tools required at all.

73 de
Stephanie
va3uxb