shortwave receiver schematics
John Lundgren
> I'm looking for the schematics for a decent, albeit simple, shortwave
> receiver. I've searched the net (probably in the wrong place, Mark<g>)but I'm
> coming up empty-handed. If anybody knows of a half-decent plan on the net
> I'd appreciate directions to it. Thanks.
> ed
Decent and simple are mutually exclusive.
Try some of the magazines at the library or bookstore. I have seen
several receivers in the better ham pubs like QST and 73.
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ellio...@my-dejanews.com
receiver. I've searched the net (probably in the wrong place, Mark<g>)but I'm
coming up empty-handed. If anybody knows of a half-decent plan on the net
I'd appreciate directions to it. Thanks.
ed
-----== Posted via Deja News, The Leader in Internet Discussion ==-----
http://www.dejanews.com/rg_mkgrp.xp Create Your Own Free Member Forum
Ira 'Crash' Knorr
> receiver.
Check flea markets and ham radio swapmeets for used SW receivers at
good prices. Also consider the kits sold by MFJ and Ramsey. That said,
here's a diagram that was posted to a ham radio mailing list a few years ago.
View with a monospaced font such as Courier.
-- Crash Knorr
http://members.xoom.com/mediumwave/
**********************************************************************
SCHEMATIC DIAGRAM -- REGENERATIVE RECEIVER
Designed by Charles Kitchin, N1TEV
LM386 Audio amplifier added by Paul Harden, NA5N
Original circuit: August 18, 1994 EDN magazine
and December 1994, "CQ" Magazine
See also 1995 Radio Amateur's Handbook "Beginners Regen. Receiver"
See NOTES at bottom of schematic
Detector Diode
D1 C5
---->I-----||-----> to Audio Amplifier
Ant | 1N914 .01 to Q2-base (below)
| |
| 2-5pF | coll Q1 2N2222 REGENERATIVE
---||--*-----*-----------\ (NPN) RF STAGE
C1 | | \ I base
--- C L1A >I---------*------
C2 ---> C / I | |
250p | C 1000p /emitter C4 | +9V to
variable | *--||-----* 1000pF R3 -->audio
gnd C C3 | | 100K | amps
C R1 gnd | |
Hand wound-> C L1B 1K *---R14----*-----*
coil | | | 150K | |
(See Note 1) | *----- | +C10 switch
| R2 | | 33uF |
| 150K <-- REGEN | | (+) 9V
| POT Control | gnd BATTERY
| | | (-)
| gnd | D2 D3 D4 |
*------------------------------*-->I-->I-->I----*
| | 1N914's |
C8 +C9 gnd
.01 33uF
| |
gnd gnd
Modified Audio Stages --->+9V
|
-------------*---R5----*--------R8-----
| | 2K 100 |
| | +C10 *--.1--gnd
R4 coll*--------||------ |
470K / 10uF | | LM386
from | baseI / | ########## C11
D1/C5----*-------I< VOLUME R6 # 6 1#--+10uF--|
Audio in Q2 (NPN) I \ Control 10K<----#3 # |
2N2222 \emitter POT # 8#---------|
| | gnd-#2 # +C12
gnd gnd # 4 7 5#---||----
########## 10uF |
| | |
gnd C13 8-ohm Speaker
.1 or phones
| |
gnd gnd
NOTES:
1. Most components are junk box items; most values not critical.
2. L1: Wind with #22 hookup wire on a plastic 35-mm film can or
pill bottle. L1A=8 turns, L1B=4 turns. Experiment with windings
to obtain different frequency ranges (more windings = lower freq.)
3. C3 and C4 can be more or less than 1000p, but should be same value.
(Higher value = lower frequency)
4. Audio coupling capacitors, C10+C12, can be any electrolytic in the
range 4uF to 20uF (higher value, lower audio response).
5. Volume control R6 can be any pot from about 2K to 100K.
6. C2 tuning capacitor, can be old open-air variable capacitor or
mini film variable capacitor (Radio Shack part), or salvaged from
any AM transistor radio.
7. C11 optional. It increases the audio gain of the LM386. Without
C11, gain will be 20dB. C11 can be 2uF or higher.
8. Audio amplifier Q2 can be omitted with lower audio gain and some
"pulling" of the receiver. Connect D1 directly to C10.
9. I recommend using a transistor socket for Q1; experiment with
different transistors you might have for best performance. Judge
based on ease of oscillation and overall gain.
10. Do not mount inside a metal enclosure. The metal cover will lower
the Q of L1 and can keep it from oscillating.
11. D2-D4 form a simple voltage regulator to keep 1.5v on Q1-base.
Any small signal diode will work for D1-D4.
Cost of parts is $10-15. At Radio Shack, a couple of 2N2222's are $1;
an LM386 about $3; a mini tuning cap $3; small speaker $2.
OPERATION:
Regenerative receivers have a "romance" of their own and it takes a
little experience and patience for optimum performance.
Turn on power and advance regeneration control R2 until the circuit
oscillates (squeels). Back off to the point where oscillation just
stops. This is the highest gain and highest selectivity. Now tune
around until you hear a station. You will have to carefully adjust
the REGEN control to the critical point (just before oscillation)
after even small changes in tuning. For voice modulation, such as
the BBC London, adjust REGEN control for best sounding audio. For
CW/SSB transmissions, advance REGEN control just slightly into
oscillation for proper detection/audio sound. It takes some practice,
but once properly tuned and REGEN set, you'll be amazed at the short
wave stations you'll hear and fairly good sounding audio.
If possible, try to use a tuning cap (C2) that has a gear-reduction
scheme; very small changes in C2 can be 10-20 KHz. A smaller variable
cap, say 5-50pF, can be added across C2 for a "fine tune" control.
For calibration, it is best to make a "log scale," that is, a dial that
points to numbers 1-10. Then, as you identify stations and the
operating frequency, you can make a table or chart that shows what
logging number equals what frequency.
For the 5-10 MHz range, you will hear powerful international broadcast
stations around 6-6.5 MHz, 7.2 MHz and 9.5-10 MHz. Using virtually
the circuit above, I have heard the BBC London, Radio Netherlands,
NHK Tokyo, R. Havana Cuba, HCJB Quito Ecuador and others with a
modest antenna (a 30 foot long wire).
Once you get it working, experiment with it. Wind different coils for
different frequency ranges. Have fun. Great club project.
72, Paul NA5N (pha...@nrao.edu)
--------------------------------------------
This circuit is being issued to the QRP-L mailing list in response
to the numerous requests received. It is intended for the use of the
QRP-L subscribers. Not to be published or electronically distributed
without citing originating credit. This information will appear as an
article in the September 1995 issue of "Low Down," Colorado QRP Club.
Thereafter, the article may be freely reproduced in any QRP journal.
(Camera ready copy will then be available to QRP editors upon request).
Read the prospectus carefully before you invest or send money.
Past performance does not guarantee future yields.
ellio...@my-dejanews.com
through some old boxes of Ham Radio Horizons, QST, 73, etc.,...still got a way
to go, but I'll keep looking!
ed
In article <360AB2...@mail.rancho.cc.ca.us>,
NOlundg...@mail.rancho.cc.ca.us wrote:
> ellio...@my-dejanews.com wrote:
>
> > I'm looking for the schematics for a decent, albeit simple, shortwave
> > receiver. I've searched the net (probably in the wrong place, Mark<g>)but
I'm
> > coming up empty-handed. If anybody knows of a half-decent plan on the net
> > I'd appreciate directions to it. Thanks.
>
> > ed
>
> Decent and simple are mutually exclusive.
>
> Try some of the magazines at the library or bookstore. I have seen
> several receivers in the better ham pubs like QST and 73.
>
> --
-----== Posted via Deja News, The Leader in Internet Discussion ==-----
ellio...@my-dejanews.com
mediu...@hotmail.com (Ira 'Crash' Knorr) wrote:
> > I'm looking for the schematics for a decent, albeit simple, shortwave
> > receiver.
>
> Check flea markets and ham radio swapmeets for used SW receivers at
> good prices. Also consider the kits sold by MFJ and Ramsey. That said,
> here's a diagram that was posted to a ham radio mailing list a few years ago.
> View with a monospaced font such as Courier.
>
> -- Crash Knorr
> http://members.xoom.com/mediumwave/
>
> **********************************************************************
>
> SCHEMATIC DIAGRAM -- REGENERATIVE RECEIVER
> Designed by Charles Kitchin, N1TEV
Thanks for the reply, Crash. This looks very much like the "Neophyte
Receiver" that I began sticking together last night, though these plans look
a bit more refined, I'll look at it tonight and see what changes were made to
it.
I've got an old friend that's a pastor of a little church here that has
showed interest in SWL. My intentions are to build him a little rig to "fan
the fires" and also brush up on my building/soldering skills...two birds with
one stone, and all that jazz. :)
Thanks again for the schematic!
ed
John Lundgren
>
> > I'm looking for the schematics for a decent, albeit simple, shortwave
> > receiver.
>
> Check flea markets and ham radio swapmeets for used SW receivers at
> good prices. Also consider the kits sold by MFJ and Ramsey. That said,
> here's a diagram that was posted to a ham radio mailing list a few years ago.
> View with a monospaced font such as Courier.
>
> -- Crash Knorr
> http://members.xoom.com/mediumwave/
[regen schematic snipped]
Jeez, I thought regen receivers went out with toobs. Regen receivers
were meant to be used for really low cost projects. Remember that
these regens are the same receiver that is used for those two for $9.95
Radio Crap CB walkie talkies that put out as much RF while receiving as
when they're sending. They're pretty sad. I mean, they are beneath the
dignity of just about everyone nowadays. No offense, but today, it's
just as simple and cheap, and a lot better performance if you use a chip
like the NE602 or whatever. I bet you didn't know the H-P made a regen
receiver, or was it superregen? Anyway, it received up to VHF.
Ira 'Crash' Knorr
NOlundg...@mail.rancho.cc.ca.us wrote:
> Jeez, I thought regen receivers went out with toobs.
Hams who are into low-power simple equipment (QRP) seem to like regen
circuits because they can copy SSB and CW. They are appropriate
technology in some peoples' eyes.
And whaddaya mean "went out with toobs," wasn't it you who suggested
making mediumwave pirate gear with toobs because they don't go "pop"
when exposed to high VSWR? Valves haven't gone out, just ask any
audiophile. I wish I could afford one of those CD players with tube
amplifier built in.
John Lundgren
> In article <360B77...@mail.rancho.cc.ca.us>,
> NOlundg...@mail.rancho.cc.ca.us wrote:
> > Jeez, I thought regen receivers went out with toobs.
> Hams who are into low-power simple equipment (QRP) seem to like regen
> circuits because they can copy SSB and CW. They are appropriate
> technology in some peoples' eyes.
Heh, yeah, like Radio Shaft's eyes. I say 'went out with tubes' because
when tubes were popular, the project builder would try to get as much
out of a single tube as possible. Today, there is no need and no point
in compromising receiver quality to get simplicity. It's not a problem
to use a single chip with almost everything the decent receiver needs on
it except capacitors and a few inductors. The power output is enough to
drive a small speaker.
> And whaddaya mean "went out with toobs," wasn't it you who suggested
> making mediumwave pirate gear with toobs because they don't go "pop"
> when exposed to high VSWR?
I don't believe I suggested making mediumwave gear with them, mainly
because the tube ham gear that's available is cheap and easily
obtainable at the swap meets. So roll-your-own is not really cost
effective.
The tube finals in ham gear will take a whole lot more abuse caused from
mistuning and high VSWR than transistor gear will, unless your
transistorized final has a SWR monitoring circuit that will shut down or
throttle the final when there's a high VSWR condition. I highly
recommend using some protection for the final whether it's fire bottles
or transistors.
> Valves haven't gone out, just ask any
> audiophile. I wish I could afford one of those CD players with tube
> amplifier built in.
Seems a bit off the deep end to me. Like I go into some of the thrift
stores to see some of the old audio equipment that's been recycled.
Almost everything is solid state, seldom are tubes to be seen. And this
is equipment that is not new. I really don't think that 99+ percent of
the population has the money to buy new tube equipment, whether it's
high end audio or not. Because the quantity of tube equipment
manufactured today is so low, it can't be sold for the low consumer
prices of today. So tube equipment is just about dead as far as the
average person is concerned.
jnsg
there have been a lot reports on public radio and such suggesting that the
time will come when analog radio and television signals will die. i guess
that we can expect to have one big internet pipline providing radio, t.v.,
and phone in the future. i expect car radios will be upgraded to
communicate with satellites. this technology has just been made available
for cell phones. i imagine, however, that bandwidth will again be limited
when the internet starts coming through satellites...any thoughts.
so i guess what i'm trying to say is that the future of radio is on the
internet now. maybe we should give up attempting to legalize the airwaves
and instead lobby to keep the government off the internet.
this leads me to my real question, which is: what do i need to get set up
for internet broadcast. specifically, I want to know the software and
where i can get it and the cost, and the hardware....
my best to everyone listening.
joshua
BIAS COMMS
We think it's quite funny the way that "audiophiles" are duped into buying
poorly designed valve-based (US: "Tube-based") audio equipment, which will
invariably have poorer specs than even the cheapest and nastiest transistor
amplifier!
However, we'll keep selling our valve-based audio processor for those digital
studios that need to "dirty up the sound" - it's a great seller, and they keep
coming back for more!
This is a bit off the original topic!
The ARRL website has a couple of schematics for simple receivers. There's a
direct conversion job that uses an NE 612 (or 602) and an LM 386, which gives
endless fun to an 8 year old kid we know....
BIAS COMMS
Everything gets easier with practice, except getting up in the morning!
ellio...@my-dejanews.com
NOlundg...@mail.rancho.cc.ca.us wrote:
> Ira 'Crash' Knorr wrote:
>
> > In article <360B77...@mail.rancho.cc.ca.us>,
> > NOlundg...@mail.rancho.cc.ca.us wrote:
>
> > > Jeez, I thought regen receivers went out with toobs.
>
> > Hams who are into low-power simple equipment (QRP) seem to like regen
> > circuits because they can copy SSB and CW. They are appropriate
> > technology in some peoples' eyes.
>
I'm the culprit who started this thread so let me explain what I'm doing. A
very old and dear friend of mine(grew up together in grammar school), who
happens to a small church pastor, asked me about shortwave radio receivers
the other day. He was interested in getting one. Well, he hasn't got the
funds to get one right now so I figured I'd try to throw something together
to keep him interested. He runs a hardware store so I went and bought some
PVC fittings the yesterday to install the radio in....I figure it'll be a
suprise to him and the pvc fitting enclosure will be up his alley.<g>
Plus...it helped me practice up on my soldering skill. I ended up building
the "Neophyte Receiver" which is regenerative, though I got the schematics of
the "improved circuit" a day late (though I might mod it before I send it to
him). With the basic rig I'm picking up "Deutsch(sic) Radio", "Radio
Havana", LOTS of Asian and Spanish speaking stations. Pretty good little
receiver for junk-box parts. Now it's done got me interested in building a
multi-band xtal receiver.<grin>
Anyhow, I know it's an old circuit...but for someone "without" it might just
be a magic box...er, pipe. :)
ellio...@my-dejanews.com
bias...@aol.com (BIAS COMMS) wrote:
> The ARRL website has a couple of schematics for simple receivers. There's a
> direct conversion job that uses an NE 612 (or 602) and an LM 386, which gives
> endless fun to an 8 year old kid we know....
>
> BIAS COMMS
>
> Everything gets easier with practice, except getting up in the morning!
>
Howdy Bias, could you give me a good address of the plans? I logged onto the
site but undoubtedly overlooked the schematic section. Thanks!\