开云体育

开云体育

Ok, last off topic post from me on this subject... I completed the
dismantling of the monitor and posted the pictures on my web page at
. Just look at
this long list of all the nice components I found inside! There's enough
here to build a very nice CW transceiver and other useful stuff!

73 Hans G0UPL



Integrated Circuits:

LM324 Quad Operational Amplifier (SMD)
KA358 Dual operational Amplifier
74HCF4011 Quad 2-input NAND gate (SMD)
74HCT02 Quad 2-input NOR gate (SMD)
74HC86 Quad 2-input XOR gate (SMD)
74HCT74 Dual D-type Flip Flop (SMD)
74HCF4053 Tripple 2-channel multiplexer (SMD)
UC3842 Current mode PWM controller
TDA9105 Deflection processor
LM1283 140MHz RGB Video Amplifier
MAS9181 Eight discrete 8-bit Digital-Analogue converters in one IC, I2C
programmed
CVA4401 Triple 400MHz buffer
CR6727 Triple hybrid video amplifier
LM2940 12V 1A Voltage Regulator
7805 12V 1A Voltage Regulator
Several other custom IC's which I couldn't find datasheets for on the
internet

Other semiconductors:

SLA5038 5-MOSFET array
Several LARGE rectifier diodes
Several zener diodes
Numerous small signal diodes, look like 1N4148, both SMD and normal
Numerous small transistors, both SMD and normal
Several IRF-series TO220 MOSFET's, e.g. IRF620
Several BD-series bipolar power transistors e.g. BD135
5mm green LED

Other components:

Numerous resistors, both SMD and normal, various power ratings
Numerous capacitors, both SMD and normal, including many useful
electrolytics
Notable LARGE 330uF 385V smoothing capacitor in the mains rectifier
Two small neon bulbs, used as spark gaps
8MHz quartz crystal, HC49 case
Numerous inductors and transformers, but no toroids
12V Relay, dual pole changeover
Numerous preset potentiometers
Five small push buttons
Approx 10 metres of shielded cable, i.e. 5 shielded conductors in the cable



-----Original Message-----
From: Hans Summers
Sent: 08 February 2005 17:57
To: 'BITX20@...'
Subject: RE: Recycling monitors



P.S. For those who don't get attached pictures, they're also in the group
photos under G0UPL/recycle

73 Hans




-----Original Message-----
From: Hans Summers
Sent: 08 February 2005 17:56
To: 'BITX20@...'
Subject: OT: Recycling monitors



Latest news, following Paolo's influence: I have commenced dismantling of
the previously mentioned 19-inch DELL monitor, which the IT department
failed to remove from the cupboard next to my desk here in the office!

Inside I found a secondary RF shielded box made from thin sheet metal. Very
difficult to remove. Attached are the pictures so far. You can see that I
managed to open 1 side of the RF shield box and see the back of the PCB.
Still haven't glimpsed the front of the PCB. I will make a page on my site
about this, following Paulo's example, and list the useful things I find
inside! Later, I will add links to that pages, to other projects on my
website, to show where I used the parts. Recycling is fun! I've been using
old recycled parts for all of my electronics hobby since I was 5 or 6 years
old. Now it's time to document this side of things!

73 for now

Hans G0UPL


-----Original Message-----
From: Paolo Cravero as2594 [mailto:pcravero@...]
Sent: 03 February 2005 17:52
To: BITX20@...
Subject: Re: [BITX20] Stability?



Hans Summers wrote:

> IT department still haven't taken it, I might be found harvesting
> useful components from the monitor for homebrew projects! The wire in
> the field deflection coils are useful for winding coils from. There
> must be other useful stuff in there too!

Been there! :-) And written about it. See


Also featured: VCR, CD-ROM and laptop. One day I will add TV and
floppy-disk drives as well.

Paolo IK1ZYW

PS: when I dismantled that monitor I was not yet into winding coils, so
I just kept the inductors, which I am now using as wire source.

PPS: hot-air guns are a great tool for part scrounging! (but you MUST do
it in open-air and dry WX ;-) )



Yahoo! Groups Links

__________________________________________________
Do You Yahoo!?
Tired of spam? Yahoo! Mail has the best spam protection around
http://mail.yahoo.com

Ok, last off topic post from me on this subject... I completed the
dismantling of the monitor and posted the pictures on my web page at
. Just look at
this long list of all the nice components I found inside! There's enough
here to build a very nice CW transceiver and other useful stuff!

73 Hans G0UPL



Integrated Circuits:

LM324 Quad Operational Amplifier (SMD)
KA358 Dual operational Amplifier
74HCF4011 Quad 2-input NAND gate (SMD)
74HCT02 Quad 2-input NOR gate (SMD)
74HC86 Quad 2-input XOR gate (SMD)
74HCT74 Dual D-type Flip Flop (SMD)
74HCF4053 Tripple 2-channel multiplexer (SMD)
UC3842 Current mode PWM controller
TDA9105 Deflection processor
LM1283 140MHz RGB Video Amplifier
MAS9181 Eight discrete 8-bit Digital-Analogue converters in one IC, I2C
programmed
CVA4401 Triple 400MHz buffer
CR6727 Triple hybrid video amplifier
LM2940 12V 1A Voltage Regulator
7805 12V 1A Voltage Regulator
Several other custom IC's which I couldn't find datasheets for on the
internet

Other semiconductors:

SLA5038 5-MOSFET array
Several LARGE rectifier diodes
Several zener diodes
Numerous small signal diodes, look like 1N4148, both SMD and normal
Numerous small transistors, both SMD and normal
Several IRF-series TO220 MOSFET's, e.g. IRF620
Several BD-series bipolar power transistors e.g. BD135
5mm green LED

Other components:

Numerous resistors, both SMD and normal, various power ratings
Numerous capacitors, both SMD and normal, including many useful
electrolytics
Notable LARGE 330uF 385V smoothing capacitor in the mains rectifier
Two small neon bulbs, used as spark gaps
8MHz quartz crystal, HC49 case
Numerous inductors and transformers, but no toroids
12V Relay, dual pole changeover
Numerous preset potentiometers
Five small push buttons
Approx 10 metres of shielded cable, i.e. 5 shielded conductors in the cable

开云体育

Hi Ruud,

First of all; hartelijk dank voor alle info, leuk om ham uit PA-land
hier te ontmoeten!
I really appreciate the good information you provided. Had a quick
look at your interface drawings which look very profi. I am in the
early stage of building the rig. I choose for the 18MHz WARC band
because I do not have equipment for this part of the spectrum yet and
i do not know what to expect (which is exciting). I finished PSU, LF
amp, (mechanics and part of electronics) for VFO which I think is not
stable enough yet (shortterm drift of 300Hz); so next step is to
include the huffandpuff circuit ("bijsloffer") from om pa0ksb in
order to obtain a drift less than 10 Hz (optimistic??). I started
with this module yesterday; found a nice 32MHz local oscillator on an
old PC board for reference oscillator which works fine. Rest of
hufenpuf components to be shipped in next week.
OK about PSK... I have very nice experience with MixW2.1 with
digimodes (rtty, psk31) and cwget and cwtype running on an old
Celeron 266 MHz pc ;i coupled this pc to a Kenwood TS515 from 1972
with tubes and made lots of qso's past year (on 80-40-20-15m) and cw
qso on a homebrew 30m xtal trscvr. I will keep all your good advice
in mind when i will be working on the interface, but first things
first. I am surprised you are using the vxo on 24 MHz. Did you
already make a qso with your bitx? Or are you still in the building
phase?
Bye for now and till next time,
Ron
PA2RF


--- In BITX20@..., "Ruud Jongeling" <pe2bs@t...> wrote:

Hi Ron,

Although al bit late I may have some suggestions for PSK. I also
build a BITX20 for PSK. Last weekend I completed the interface from
the TRCV to the soundcard. The schema is uploaded as a PDF file in
the file-box.

Some remarks:
- To avoid "earthloops" effects I used two tr's 1:1 from an old
computerswitchingsupply. I also used an optocopler from the same
supply. You can recognize the optcoplers by the DIL6 package. (pin

1

Anode D, pin 2 Cathode D, pin 3 NC, pin 4 Emitter T, pin 5

Collector

T, pin 6 Base T).
- You can easily check for low frequency sounds (earthloop and
others, special lower than 500 Hz!!) by using the waterfalldiagram

in

HamScope. No lines no sound. To avoid every possibility I used 3u3
capacitors between the stages of LF. The low frequency's below

500Hz

are almost blocked. (See picture HamScope in picture box).
- The signal send to the computer by Line in comes back by Line

out.

To my suprise came peaks of the signal through T6 and T5 to T4.
Oscillation was the result. T3 was added as a switch.
- When I used SpectrumAnalyzer I saw a peak in the signal I first
could not explain (see picture in the picture box). After a while I
discovered that the output impedance of the LM386 did not match

with

Tr2. First I added a variable resistance. The value had great

affect

on the frequency spectrum! Check with SpectrumAnalyzer. R18=33 ohm
was the best in my situation.
- The oscilator in my BITX20 will (if possible) be a VXO on 24MHz.
The reason for this is simple: lots of cristals in the junkbox and

a

good supression of the signal by the Pi-filter. I can vary tot 5

kHz

when I use three crystals. But the frequency of the oscilator also
goes about 5 Kc up when a crystal is added!
The VXO is not ready yet. I still have to work for enough output

for

the balance mixer.
With CWGet it is possible to decode CW in the first part of the

band.

When everything is working well iI wil order a special crystal for
PSK.

73,

Ruud
PE2BS


--- In BITX20@..., Ron Brink <pa2rf@y...> wrote:

Dear bitx20 homebrewers,
I intend to build the BITX for the 17m WARC band (18.068-18.168

MHz). My ultimate goal will be to work psk31 with this splendid

rig.

Has anyone suggestions to convert bitx20 to bitx17. VFO must be
changed of course and RF filters... I intend to keep my progress
updated on my website (see below).

73 de Ron
PA2RF
pa2rf@y...





---------------------------------
Do you Yahoo!?
Yahoo! Search presents - Jib Jab's 'Second Term'

Hi Ron,

Although al bit late I may have some suggestions for PSK. I also
build a BITX20 for PSK. Last weekend I completed the interface from
the TRCV to the soundcard. The schema is uploaded as a PDF file in
the file-box.

Some remarks:
- To avoid "earthloops" effects I used two tr's 1:1 from an old
computerswitchingsupply. I also used an optocopler from the same
supply. You can recognize the optcoplers by the DIL6 package. (pin 1
Anode D, pin 2 Cathode D, pin 3 NC, pin 4 Emitter T, pin 5 Collector
T, pin 6 Base T).
- You can easily check for low frequency sounds (earthloop and
others, special lower than 500 Hz!!) by using the waterfalldiagram in
HamScope. No lines no sound. To avoid every possibility I used 3u3
capacitors between the stages of LF. The low frequency's below 500Hz
are almost blocked. (See picture HamScope in picture box).
- The signal send to the computer by Line in comes back by Line out.
To my suprise came peaks of the signal through T6 and T5 to T4.
Oscillation was the result. T3 was added as a switch.
- When I used SpectrumAnalyzer I saw a peak in the signal I first
could not explain (see picture in the picture box). After a while I
discovered that the output impedance of the LM386 did not match with
Tr2. First I added a variable resistance. The value had great affect
on the frequency spectrum! Check with SpectrumAnalyzer. R18=33 ohm
was the best in my situation.
- The oscilator in my BITX20 will (if possible) be a VXO on 24MHz.
The reason for this is simple: lots of cristals in the junkbox and a
good supression of the signal by the Pi-filter. I can vary tot 5 kHz
when I use three crystals. But the frequency of the oscilator also
goes about 5 Kc up when a crystal is added!
The VXO is not ready yet. I still have to work for enough output for
the balance mixer.
With CWGet it is possible to decode CW in the first part of the band.
When everything is working well iI wil order a special crystal for
PSK.

73,

Ruud
PE2BS


--- In BITX20@..., Ron Brink <pa2rf@y...> wrote:

Dear bitx20 homebrewers,
I intend to build the BITX for the 17m WARC band (18.068-18.168

MHz). My ultimate goal will be to work psk31 with this splendid rig.
Has anyone suggestions to convert bitx20 to bitx17. VFO must be
changed of course and RF filters... I intend to keep my progress
updated on my website (see below).

73 de Ron
PA2RF
pa2rf@y...





---------------------------------
Do you Yahoo!?
Yahoo! Search presents - Jib Jab's 'Second Term'

P.S. For those who don't get attached pictures, they're also in the group
photos under G0UPL/recycle

73 Hans

Latest news, following Paolo's influence: I have commenced dismantling of
the previously mentioned 19-inch DELL monitor, which the IT department
failed to remove from the cupboard next to my desk here in the office!

Inside I found a secondary RF shielded box made from thin sheet metal. Very
difficult to remove. Attached are the pictures so far. You can see that I
managed to open 1 side of the RF shield box and see the back of the PCB.
Still haven't glimpsed the front of the PCB. I will make a page on my site
about this, following Paulo's example, and list the useful things I find
inside! Later, I will add links to that pages, to other projects on my
website, to show where I used the parts. Recycling is fun! I've been using
old recycled parts for all of my electronics hobby since I was 5 or 6 years
old. Now it's time to document this side of things!

73 for now

Hans G0UPL

Is it possible for someone to post a picture of the FAR BITX PCB ?
Or is there a website that shows it ? I would like to see what it
looks like before ordering one.
Thanks,
Steve
K1EL

Hi agn!
I just added circuits of the LA4185 audio amplifier and ( intend to
build) pa0ksb huff & puff to the Photo directory. Audio amp is
working fine now. Still waiting for the huff&puff components
(Conrad... wakie-wakie !.
Demolished a defective AV-unit from akai yesterday (found the box
near a carbage lit) and there were a lot of nice components in it
like three nice ring-cores, LEDs, relais, cooling profile, cinch
busses lots of screws and washers and so on .
Bye
Ron
PA2RF

Paolo

I just uploaded a corrected file. Sorry about the confusion. That
error came from my use of a then new CAD program, not from anything on
K8IQY's web page, so it was my mistake.

Arv
_._

--- In BITX20@..., Paolo Cravero as2594 <pcravero@a...> wrote:

Hi (Arv)
While browsing through the files repository for BITX20 I found a

mistake

in "K8IQY RIT Circuit.png" at


D2 and D3 are zeners, which are drawn backwards in the diagram, or am I
wrong?

73,
Paolo IK1ZYW

Hello,

This email message is a notification to let you know that
a file has been uploaded to the Files area of the BITX20
group.

File : /MODIFICATIONS/RIT-K8IQY.png
Uploaded by : k7hkl_arv <arvevans@...>
Description : RIT Circuit from K8IQY's Web Page

You can access this file at the URL:


To learn more about file sharing for your group, please visit:


Regards,

k7hkl_arv <arvevans@...>

Hi (Arv)
While browsing through the files repository for BITX20 I found a mistake in "K8IQY RIT Circuit.png" at

D2 and D3 are zeners, which are drawn backwards in the diagram, or am I wrong?

73,
Paolo IK1ZYW

__________________________________________________
Do You Yahoo!?
Tired of spam? Yahoo! Mail has the best spam protection around
http://mail.yahoo.com

Jim,

We used to make non inductive resistors specially for some clients in the '80's. In general purpose carbon or metal film resistors, the body is spiral cut at least 60% of the body length. Less than 60% cuts results in lower temperature stability. This is not a problem in low values, so we slowed the cutting spindle and allowed the blade to spiral less than one turn.. this means that the path of least resistance was a straight line.. therefore minimum inductance. We used to charge a lot for them because the production was slow.

Actually there was a magical smoke test on the final paint line. We applied a brief 250V pulse to the resistors, defective ones went up in a flash.

A bit of trivia, in small resistors the major cost is the copper leads! the end user cuts most of it and discards.

73 Raj vu2zap

On Feb 5, 2005, at 10:58 AM, Raj wrote:

Nope, I was in the resistor manufacturing field. I was managing a
factory some years ago.. from the time the resistive element is put on to
the end of painting the value on it.. the orientation of clockwise or
anticlockwise is lost.

Where I work, we have a problem w/ some fiber optic transceivers so we're hand-testing parts for one customer to provide parts that work just for them, and binning the rest by performance numbers. I think it's by 0.1 dB on one component of RGB, but I'm just the technical writer.

Where we're at in amateur radio, we essentially hand sort EVERY part, and I think it'd be fun to pick through a batch of surplus resistors, turn them this way and that, and install them in the best direction and orientation for the application at hand.

You ARE right -- if your manufacturing process delivers a wire-wound resistor core that can be turned either way in its final enclosure, and it's not specified for inductance or direction of winding, then there's no reason to care.

For wire-wound resistors used as RF chokes, like the Ohmite Z-series resistors used for parasitic suppression in sweep-tube RF amplifiers in the 1960s and 1970s, the winding orientation did not matter because they were not close enough to anything to induce coupling.

It's really good to know that we have people on this group who know what's inside our electronic components.

Besides that magical smoke ...


72/73

Jim N6OTQ

Jim,

Nope, I was in the resistor manufacturing field. I was managing a factory some years ago.. from the time the resistive element is put on to the end of painting the value on it.. the orientation of clockwise or anticlockwise is lost.

On wire wounds of certain types. The wire is clearly visible below the paint and it may be possible to determine whether its going clockwise or not and allow you to select them accordingly..

73 Raj vu2zap

On Feb 4, 2005, at 1:12 AM, Paolo Cravero as2594 wrote:

I'd like to remind you a simple study I made on two
100ohm 5W resistors found in a PC monitor PSU.

See (part
of the page is in Italian, ROS=SWR in tables)

Basically those "inductive" resistors can be used to form cheap QRP *HF*
dummy loads, with SWR <1.3:1 at 30MHz.

I installed my RF voltage probe on that load, and that is the way I
measure (ehm, estimate) my circuits' output power.

A wonderful idea!

I suspect that if you wired the resistors in parallel on a 50-ohm stripline PC board with the connectors X-ed on opposite sides of the board, you could cancel out a lot of the inductance. It would also be theoretically possible to add a variable capacitor to cancel out the inductive reactance and get a higher usable frequency at lower SWRs, at the penalty of making the load frequency-dependent.

An indexed dial for the variable capacitor would fix that. If it were a fixed-frequency load. tune it once and forget it.

Jim N6OTQ

开云体育