[Elecraft] A couple of questions re: toroids

[Kevin Cozens]

Greetings.

1. In the SSB Carrier Null Notes by AB7MY there is an additional note from 
N6KR at the bottom which states (in part):

There's some signal leakage *around* the BFO attenuator, which puts a 
lower-limit on how far down you can go. This leakage can be reduced by 
about 10 dB by changing the BFO inductor  (L33) to a toroid (45 turns of 
#28 on a T44-8/90 , which can be purchased from our parts department, 
support@elecraft.com ). This will improve carrier suppression on sideband. 
The toroid should be mounted securely underneath the PCB, and you'll have 
to re-run CAL FIL. (Write down your present BFO frequencies before making 
the change.)

Is this a note related to older K2's using a solenoidal inductor for L33 
compared to the toroids that were used later on?


2. One of the mod notes says suggests RFC11 should be replaced with a 
FT37-43 toroid. The closest I can get to that is either an FT37-61 or 
FT50-43. Would I need to adjust the number of turns used if I used the 
FT37-61? Having moved recently, my ARRL Handbook is in storage so I can't 
check the toroid information and formula re: changes in turns from one core 
material to another.

Cheers!

Kevin.  (http://www.interlog.com/~kcozens/)

Owner of Elecraft K2 #2172        |"What are we going to do today, Borg?"
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