> 1. Why is the TiCK side tone when in programming mode so much lower than
> the regular sidetone from the chip when transmitting? The programming
> tones have to bee less than half the volume. Yes I did play with the
> value of R 17? and it made not difference in the sidetone volume. (My
> first clue?).
The reason is because the original circuit paralleled the sidetone circuit
with the receive mixer during receive, loading the sidetone circuit. This
was not a problem without the Tick chip because sidetone was only needed in
transmit mode. With the Tick chip, sidetone is used in receive mode for
keyer programming info. The solution is a mod suggested by Brad of Tick
chip fame. I don't have the exact text of his solution here, but the idea
is:
**************
Do the normal Tick mod per original instructions. Then make an additional
change. This involves one additional trace cut and adding a 4.7k resistor.
The normal Tick mod connects the tick sidetone to the left side of R17 (see
schematic) and cuts U4 pin 3 out of the circuit. The additional change
disconnects C32 from R19 at the point marked "A" on the schematic. Then it
connects C32 through a NEW 4.7K resistor to U5 pin 6. The old way had the
sidetone just paralleled with the receiver audio. The new way sums the
sidetone into the op-amp virtual ground input.
I don't have a board with me here, so I can't tell you exactly where to
cut, but it is fairly easy to figure out when you know what you want to do.
You need to break the connection between C32 and R19 without breaking the
connection between R19 and C15. That is one cut.
Next, add a resistor from the end of C32 that you just disconnected to U5
pin 6. I just added this fly-wire style on the top of the board. By
tracing the connections to U5, you can probably find a convenient point to
connect to closer than U5 itself.
I hope I haven't confused everyone.
Just remember that you want to connect C32 to U5 through its own 4.7k
resistor, not the one that is already there, and then figure out how to do
that.
************
> 2. I wonder if the receiver is giving me all it should be. I can hear
> stuff and get white noise and hiss and yes the noise goes up when that
> antenna is attached, but it still seems kinda muted or deaf according to
> the other reports that I have heard. I did jump R 24 and the audio out
> did increase a little, but not by much.
Hard to tell. The rig is no ear-blaster, but an S9 signal should cause you
to want to turn down the RF gain from max. Do you get two peaks when you
adjust TC1? If not, you may not be able to tune to 10 MHz and may need to
adjust the transformer toroid.
> 3. Thump thump. Yes mine does thump a LOT. I would like to kill some of
> this, bu the receiver is the first order of business.
Yep. I think it will not be easy to get rid of. If you used sockets, you
may be able to try different 4066 ICs and use the quietest one.
Mike K1MG
[
QRP-L Archive |
]
[
1993 |
1994 |
1995 |
1996 |
1997 |
1998 |
1999 |
2000
]