Note On L10 And C43 - Ten-Tec 1253 Assembly And Instruction Manual

Detail 3-44: Note on L10 and C43
These two components are additions to the original circuit: the
receiver works quite well without them. Adding L10 and C43
results in a significant boost in receiver sensitivity to weak
signals but also requires somewhat more careful adjustments of
the Regeneration Control. If this is your first experience with
regenerative receivers, we suggest that you omit L10 and C43
for now and gain real familiarity with the receiver's operation.
Consider adding these parts later if your listening interests begin
to include looking for weak CW or SSB signals on bands which
are nearly deserted because of time of day or sunspot conditions.
If those same bands are busy with strong signals, the receiver
works fine without L10 and C43, to the extent that the RF Gain
control setting will need to be reduced considerably.
The extra sensitivity offered by this circuit addition also can
permit the use of shorter antennas such as telescoping whips for
portable operation.
Adding L10 and C43 later will require a major dismantling of the
receiver, including removal of the subpanel installed in Step 3-36.
However, an easier approach is possible which also permits you
to try out the increased regeneration sensitivity without
committing to it permanently. For now, install C43 in the normal
manner. By itself, it will have no effect on receiver operation.
ln the position marked on the board for L10, solder two bare
wires extending about 1/2" above the board. Whenever you
wish, L10 can be soldered to these two wires after removing
only the top cover shell and battery shelf . This will allow you to
compare receiver performance with and without C43 and L10.
Inductor L10 is a 100 μH RF choke resembling the smaller
electrolytic capacitors but with no polarity stripe or one lead
being longer than the other. C43 is a .01 μF ceramic disc type.
Return to step 3-34 after deciding about L10 and C43.
1253 - 26