Matt (and anybody else)
I didn't feel like drawing all the symbols, so I just used text. It
should be fairly obvious.
Hopefully it didn't get screwed up in your viewr
+9V DC
o-----------*--------*----------*--------
| | | |
R1 | R3 L1
47K | 33K 15-22Uh
| C | |
--------*------B Q1-2N3904 | *--------C5----*---L3---*-----o
| | E | | 0.01uF | 2.2uH | ant
| C1 | | | | |
| 100pF | | | C6 C7
X1 | | | C | |
| *--------*----C3----*-----B Q2-2N3904 ---------*------
--*--- | | 82pF | E | |
| | C2 R2 L2 | gnd |
C12 C13 100pF 1.5K 100uH | |
1nF 40pF | | | | |
| | | | *-------*----*-----*----------o Key o--
| | | | | | | |
* /* | | C4 R4 | |
/ | | 1000pF 10K | | 10uF
| | | | | D1 C8 --C9+-
--------*--------*----------*-------* 1N914 0.1uF | |
S1 | | | | | |
gnd C10 | | | |
10uF | | 8 1
Audio
+ |
------2 Out
| | LM386
5--+C11--o
+9V DCo-----R5---*----* ------3
10uF
1K | | 4 6
| gnd------ |
| |
--------------------
I just text-ized the K5FO drawing from the QRP-L archives, and changed
the little things I modified on mine.
All inductors are molded chokes. C9, C10 and C11 are electrolytic, so
note the polarity. The circuit will NOT work if any are reversed (trust
me, I know).
The original schematic called for a 0.05uF cap at C4, but I had to
change to 1000pF to avoid an aweful sawtooth waveform. I also changed
the output filter: both caps are 1000pF, and the inductor is 1.5uH. I
only did this because I didn't have any 820pF's.
Of course, there's only one ground, but I couldn't draw it like that.
Finally, the K5FO drawing doesn't have C12 & C13 below X1. Another
writeup I saw suggested those tied to a switch to make it have a manual
TR offset. I haven't tried this, but it should work, I think. I drew
it in any case. You can omit S1, C12 & C13, and the rig works fine.
Mine's on a 1.5" square perfboard, but I have quite a bit of room free.
It should fit on a 1" square if you have nimble fingers. Of course,
using SMD, you could make it smaller still....
I haven't tested mine in any way, I've just build it and listened to
it. It's been a GREAT learning experence for me, and I think I'll
modify this or brew up another rig now. What fun!
As far as mods, I'm going to try a higher power PA, sidetone, RIT, VXO,
different bands and anything else I can think of. I'm not ready to try
to make my own mods for my 38S yet, but I'm getting close...
Good luck! Let me know how it goes...
Mark Arvidson
KB0SPQ
[
QRP-L Archive |
]
[
1993 |
1994 |
1995 |
1996 |
1997 |
1998 |
1999 |
2000
]