"Way to go Dave"
Since I built my first Rock-mite and burnt three traces right off the pcb
I've tried to build a manhatten version without decent results. I have built
the entire tranceiver twice. Once with some of the mods (i.e. a 2n2219
for Q6 and a 5 ohm resister subbed for R18) the results were less than
satisfactory. So I figured to stick with the receiver should I succeed
with it then I could proceed with the transmitter portion. Well I'm still
building the receiver, and rebuilding the receiver a least a half dozen
times so far ( I've stopped counting) the results have been the same.
The schematic is copyrighted by K1SWL and ARRL,
so is not available
here BUT the article is available from QST (SEE HEADER )
When I hook the antenna to the right side of Y1 I am able to receive the
audio from two stations, at the same time. The first is a LOCAL STATION
AT 1310 AM, the other I can only assume is a SWBC as day time it broadcasts
as S.N.R. NEWS playing Christian Gospel Music presently Christmas Music
( I didn't realize that there were so many versions) and at night for a
while a spanish station that sounded like RADIO MARTI from Washington D.C.
(Cuban). It's in the 39-40 meter portion of the band. The audio is strong
enough to drive a small 2" 8 ohm speaker and it has no distortions on it.
But if I hook the antenna to the left (antenna ) side of Y1 I receive nothing,
zip, NADA. This boggles my mind, as all solder joints and parts have been
triple checked the results never vary.
The receiver strip
I have even added the tuned antenna tank circuit with no change in the results.
Here is the receiver strip with the antenna tuned tank circuit added.
Now I don't expect anybody to look at these pictures and trouble shoot it,
but your thoughts as to why/how this is happening will be of assistance
to me. Please note that this is not a part of my web page and will never
be posted. It WILL be removed on Jan 1 after you have had a chance to review
it. It's just easier to put my thoughts together this way.
The crystals case was not grounded because I was swapping 3 different ones
in and out. They were: #1) 10.106mhz; #2) 7.112mhz #3) 7.040mhz.No signals
were heard on these frequencys, not even the LOCAL OSCILLATOR from my regular
station receiver. The only signals that are heard are those that are overloading
(swamping, for lack of a better word) the frontend of the receiver. There are
some longish leads because of point to point wiring and the fact that after
trimming some leads down it became difficult to salvage parts to reuse them,
and I have already depleted the three local Radio Shacks of these parts.
December 20, 2002
I am estatic! After waiting all WEEK, my days off finally arrived and I could
get back to work on this project.Chuck (W5USJ) Carpenter pointed out that by
building just the receiver circuits I was neglecting the LOCAL OSCILLATOR input
from Q4 which is injected into U1 on pin 6 (point B ) which originates from the
emitter of Q4 between R13 and R14 (point B )and is mixed in U1 to produce the audio
signals, tonight I built the local oscillator portion of the transmitter from the
junction of R9 /D5 through to C12 on the base of Q5, hooking up point B transmitter
to point B receiver. At first NO JOY so started checking and found that R9 was 47K
instead of 4.7K I changed this out and looked for more. I also found a bad connection
on the emitter of Q4's pad. I re-did this solder connection and a couple of others
hooked up the power. I almost fell out of my chair! I COULD HEAR THE LOCAL OSCILLATOR!
Not just in my Omni but also in my Rock-mite RM-40 that was exersising a battery.
Unhooked power the tones went away, applied power again nice and pretty at 7.0403mhz
I could hear a W6 calling CQ, all this on my SW antenna
Here are three pictures of the receiver strip with Local oscillator Q4 added.
Note that the pcb has been salvaged from a previous attempt to do this manhattan
version of a 40m Rock-mite, Q5 Q6 and the PIC keyer I will try to get this week.
here's Q4, Q5, Q6 I did sub the 2N2222A (Q6) with a 2N3053 and R18 ( 10 ohm )
with a 6.8. I also checked again the Local Oscillator again for continued operation.
Next up the output tank circuit, Q2, Q3, and the PIC keyer...
FINISHED!!!! COMPLETED FINALLY I'M PROBABLY BALD FROM PULLING MY HAIR BUT I DID IT!!!!!
AND IT WORKS!!!! I CAN HEAR THE TONES IN MY EARS FROM TWO DIFFERENT FREQUENCIES WHEN I
KEY THE SWITCH, I CAN HEAR THE SIDE TONE IN THE HEAD SET!!!! THERE IS ENOUGH AUDIO POWER
TO DRIVE A SMALL SPEAKER. I CAN HEAR THE KEYER CHANGE SPEEDS. I AM ABLE TO HEAR THE LOCAL
OSCILLATOR IN MY STATION RECEIVER ON TWO DIFFERENT FREQUENCIES
Yes I know it looks like something a stray dog left in the yard. But think about what it means you.
If you have a schematic, you can build it!. These shots were taken after I finished and I used the
12x lens to point the digital camera
Actually I did not decide on a case. I added a front and a back so I could mount the antenna connector,
power connector and the on/off switch. front the key jack, phone jack and the switch. I deceided on the
U frame because it should makeit easier to do mods, and trouble shoot should it need to be done
72/71 de "RC"KC5WA