T
(the dipshit)
Guest
I apologize if this topic is outside the limits of the group; I would be
very receptive and appreciative of any suggestions dealing in the nature
of the following context `cat <<EOF` ...
I have been trying to build a basic diode/crystal set radio. Initially I
was trying to use the 741 as a pre-amplifier with a 10k pot connected to
the lm386 (non-inverting input (pin 3)). I have been bread-boarding any
and all circuits I have been able to find of this nature for like
several months - not a single one works.
I decided that rf electronics is out of my league and `quit`. Shortly
after I started using the lm 386 directly without a preamp stage. Diode
detector hooked to lm386 - pin2. I also connect the ``earth ground'' (a
screw on my light switch) with the lower antenna/coil to pin 3 - I was
trying to keep the ground rail clean and prevent any back leakage into
lm386 via pin4 `circuit ground'. (some how the 741 does this split
non-inverting and spit out of pin5 reversing/re-phasing the ground strip
or something - I dropped the circuit and now have no idea what the hell
I did.)
Anycase, the basic circuit that I am using for rf-power-amplification
was copied from the electronics for dummies (pg 316), the only exception
is that neither pin3 nor pin4 pull from ground. Needless to say this
bitch oscillates so bad that I'm re-soldering my speakers once a weak.
To me it just makes more sense to use an opamp and float the ground with
a split power supply - just use pin four as ground reference. The only
other option I know of is to use audio isolation transformer(s)/[relays].
Well, I decided to quit once again. While browsing the world wide web^1
I discovered an/the interesting idea of using a local oscillator to beat
the `band frequency' with a `constant as possible with an option for
VFO' oscillations, my thoughts being that the local oscillator would add
4 MHZ to the full band. Being that I happen to have an ls04 I used it to
modulate a 4 MHZ crystal (also marked 18pf) and then ``mixed''/passed
the amped signal through the germanium diode and actually got non-bbc
radio (unless there is a spanish bbc station).
Then the state sought intervention and recommended an excellent re-hab.
Anyway I've started using again; a pathetic attempt at making a 455cps
IF from a PNP NTE100 and NPN NTE101. I do not have test equipment (like
a scope or frequency meter, etc.) so I hooked it this IF oscillator to a
transformer (no I do not have the specs for it) and blew 700 kh off of
my local radio.
Just some questions:
1. slew of opamp is bad, slow, and noisy - lm386 is sensitive but likes
to have a chassis ground and I am not sure using split supply for the
little guy is doing it any good (it's had better sounding days).
2. How do I learn about signal phase identification and 180^0 flips with
a breadboard, RF-containment, and what the fuck a ground is - I've been
running three. I though that using two split supplies from isolated
breakers was a good idea - it's not.
3. (This is a real question), any good books or web sites on building
superhets without the use of the magic TDA/mka/etc .
a. Any books on building test equipment for LC tanks and air
induction coils. I got those green ones but I rarely see them
in the store...
^1) the ls04 oscillator I found on circuits-lab.com or
electronics-lab.com. I forget the designer's name (or idea architect
(see I can be a business person)).
very receptive and appreciative of any suggestions dealing in the nature
of the following context `cat <<EOF` ...
I have been trying to build a basic diode/crystal set radio. Initially I
was trying to use the 741 as a pre-amplifier with a 10k pot connected to
the lm386 (non-inverting input (pin 3)). I have been bread-boarding any
and all circuits I have been able to find of this nature for like
several months - not a single one works.
I decided that rf electronics is out of my league and `quit`. Shortly
after I started using the lm 386 directly without a preamp stage. Diode
detector hooked to lm386 - pin2. I also connect the ``earth ground'' (a
screw on my light switch) with the lower antenna/coil to pin 3 - I was
trying to keep the ground rail clean and prevent any back leakage into
lm386 via pin4 `circuit ground'. (some how the 741 does this split
non-inverting and spit out of pin5 reversing/re-phasing the ground strip
or something - I dropped the circuit and now have no idea what the hell
I did.)
Anycase, the basic circuit that I am using for rf-power-amplification
was copied from the electronics for dummies (pg 316), the only exception
is that neither pin3 nor pin4 pull from ground. Needless to say this
bitch oscillates so bad that I'm re-soldering my speakers once a weak.
To me it just makes more sense to use an opamp and float the ground with
a split power supply - just use pin four as ground reference. The only
other option I know of is to use audio isolation transformer(s)/[relays].
Well, I decided to quit once again. While browsing the world wide web^1
I discovered an/the interesting idea of using a local oscillator to beat
the `band frequency' with a `constant as possible with an option for
VFO' oscillations, my thoughts being that the local oscillator would add
4 MHZ to the full band. Being that I happen to have an ls04 I used it to
modulate a 4 MHZ crystal (also marked 18pf) and then ``mixed''/passed
the amped signal through the germanium diode and actually got non-bbc
radio (unless there is a spanish bbc station).
Then the state sought intervention and recommended an excellent re-hab.
Anyway I've started using again; a pathetic attempt at making a 455cps
IF from a PNP NTE100 and NPN NTE101. I do not have test equipment (like
a scope or frequency meter, etc.) so I hooked it this IF oscillator to a
transformer (no I do not have the specs for it) and blew 700 kh off of
my local radio.
Just some questions:
1. slew of opamp is bad, slow, and noisy - lm386 is sensitive but likes
to have a chassis ground and I am not sure using split supply for the
little guy is doing it any good (it's had better sounding days).
2. How do I learn about signal phase identification and 180^0 flips with
a breadboard, RF-containment, and what the fuck a ground is - I've been
running three. I though that using two split supplies from isolated
breakers was a good idea - it's not.
3. (This is a real question), any good books or web sites on building
superhets without the use of the magic TDA/mka/etc .
a. Any books on building test equipment for LC tanks and air
induction coils. I got those green ones but I rarely see them
in the store...
^1) the ls04 oscillator I found on circuits-lab.com or
electronics-lab.com. I forget the designer's name (or idea architect
(see I can be a business person)).