|
Ron,
This is probably because of ceramic capacitors being used the oscillator stages. Components that determine frequency must be ultra-stabe. Use NP0 caps, brown ceramics with a black top. You can also use polystyrene, they are transparent plastic with a silver foil visible inside. They were only available in the old days in small pF values less than 5Kpf.
I usually pour bees wax on top of oscillator components to keep them thermally isolated and keep them from shaking.
Avoid ceramic caps in audio stages, it causes microphonics. Tap them and you will hear a thump in the speaker/transmission. Use mylar/polyester.
Do not use mylar/polyester type caps in RF stages for bypass, instead use ceramic. Polyester work well in audio for coupling.
Ceramic = brown round disks
Polyester/Mylar = green like a chewing gum with leads.
Hope I have not confused you..
73 Raj
vu2zap
toggle quoted message
Show quoted text
MHz IF will give the proper range) Frequency range seems to be ok but
stability is bad. After 20 minutes waiting freq shift of 1 KHz still
exists. I think I will order some components for a HuffAndPuff
circuit for stabilizing purposes.
|
I really appreciate your quick reply Raj,
No you did not confuse me.
This forum is alive !  Yes I used the ceramic ones for initial trails. I have some polysterene ones (old!! from Philips radios) in my junkbox and will do some trials coming days.
What is your feeling about making the 2 transistor vfo as shown in the original schematics working with a freq. drift of 10Hz or less (this is a tough requirement for digimodes like psk31).
Is there experience with the bitx working with digimodes (rtty, psk31...) as far as you know?
?
73 and again tnx fer advice!
Ron
Raj wrote:
Ron,
???????? This is probably because of ceramic capacitors being used the
oscillator stages. Components that determine frequency must be ultra-stabe.
Use NP0 caps, brown ceramics with a black top. You can also use
polystyrene, they are transparent plastic with a silver foil visible
inside. They were only available in the old days in small pF values less
than 5Kpf.
???????? I usually pour bees wax on top of oscillator components to keep
them thermally isolated and keep them from shaking.
???????? Avoid ceramic caps in audio stages, it causes microphonics. Tap
them and you will hear a thump in the speaker/transmission. Use
mylar/polyester.
???????? Do not use
mylar/polyester type caps in RF stages for bypass,
instead use ceramic. Polyester work well in audio for coupling.
???????? Ceramic = brown round disks
???????? Polyester/Mylar = green like a chewing gum with leads.
???????? Hope I have not confused you..
73 Raj
vu2zap
>MHz IF will give the proper range) Frequency range seems to be ok but
>stability is bad. After 20 minutes waiting freq shift of 1 KHz still
>exists. I think I will order some components for a HuffAndPuff
>circuit for stabilizing purposes.
Do you Yahoo!?
Yahoo! Search presents -
|
?
Ron
?
In
case you are not aware of my very simple Huff & Puff VFO stabiliser designs,
you can read about them here: ?.
The 2-chip design uses common and cheap IC's 74HC4060 and 74HC74, an ordinary
32.768KHz watch crystal, and a 5mm red LED for tuning. This design works well
and has been successfully replicated by at least 5 different
constructors.
?
73
Hans G0UPL
http://www.HansSummers.com
toggle quoted message
Show quoted text
I really appreciate your quick reply Raj,
No you did not confuse me.
This forum is alive ! Yes I used the ceramic ones for initial trails. I have some polysterene
ones (old!! from Philips radios) in my junkbox and will do some trials coming
days.
What is your feeling about making the 2 transistor vfo as shown in the
original schematics working with a freq. drift of 10Hz or less (this is a
tough requirement for digimodes like psk31).
Is there experience with the bitx working with digimodes (rtty, psk31...)
as far as you know?
?
73 and again tnx fer advice!
Ron
Raj wrote:
Ron,
????????
This is probably because of ceramic capacitors being used the
oscillator
stages. Components that determine frequency must be ultra-stabe.
Use NP0
caps, brown ceramics with a black top. You can also use
polystyrene,
they are transparent plastic with a silver foil visible
inside. They
were only available in the old days in small pF values less
than
5Kpf.
???????? I usually pour
bees wax on top of oscillator components to keep
them thermally isolated
and keep them from
shaking.
???????? Avoid
ceramic caps in audio stages, it causes microphonics. Tap
them and you
will hear a thump in the speaker/transmission. Use
mylar/polyester.
????????
Do not ! use mylar/polyester type caps in RF stages for bypass,
instead
use ceramic. Polyester work well in audio for
coupling.
???????? Ceramic =
brown round disks
????????
Polyester/Mylar = green like a chewing gum with
leads.
???????? Hope I have
not confused you..
73 Raj
vu2zap
>MHz IF will give the
proper range) Frequency range seems to be ok but
>stability is bad.
After 20 minutes waiting freq shift of 1 KHz still
>exists. I think I
will order some components for a HuffAndPuff
>circuit for stabilizing
purposes.
Do you Yahoo!?
Yahoo! Search presents -
|
Dear Hans, Nice website with great designs Hans. I intend to build a huff-and-puff circuit (design by om Spaargaren PA0KSB) when i do not get sufficient stability from the circuit as shown in the original bitx circuitry. Do you know if succesful qso's have been made with digimodes (psk31, rtty) using the bitx (without huff & puff circuit). Regards es 73 de Ron pa2rf --- In BITX20@..., Hans Summers <Hans.Summers@t...> wrote:
Ron
In case you are not aware of my very simple Huff & Puff VFO stabiliser designs, you can read about them here:
<> . The 2-chip design uses common and cheap IC's 74HC4060 and 74HC74, an ordinary 32.768KHz watch crystal, and a 5mm red LED for tuning. This design works well and has been successfully replicated by at least 5 different
constructors.
73 Hans G0UPL
] Stability?
|
Hi Ron
Thanks for the nice complements about my website :-) I had a look around
your website this morning, you have some very interesting projects there. I
sent an email to a fellow who I know is interested in panoramic adapters and
has been corresponding with me about my spectrum analyser (
)
If you are going to build one of the earlier designs, I have most of the
Huff Puff articles in my reference library for download, see
. In performance
terms, I think my 2-chip simplification should perform as well as the
original Huff Puff designs. For the ultimate performance, G7IXH's "fast"
stabiliser is slightly more complex but performs best.
I do know that people have used BITX20's for PSK31 very successfully. But
don't forget that your VFO for 17m is twice the BITX20 VFO's frequency,
therefore it is bound to be less stable (all other things being equal).
73 Hans G0UPL
toggle quoted message
Show quoted text
-----Original Message----- From: pa2rf [mailto:pa2rf@...] Sent: 03 February 2005 12:11 To: BITX20@... Subject: [BITX20] Re: Stability? Dear Hans, Nice website with great designs Hans. I intend to build a huff-and-puff circuit (design by om Spaargaren PA0KSB) when i do not get sufficient stability from the circuit as shown in the original bitx circuitry. Do you know if succesful qso's have been made with digimodes (psk31, rtty) using the bitx (without huff & puff circuit). Regards es 73 de Ron pa2rf --- In BITX20@..., Hans Summers <Hans.Summers@t...> wrote:
Ron
In case you are not aware of my very simple Huff & Puff VFO stabiliser designs, you can read about them here:
<> . The 2-chip design uses common and cheap IC's 74HC4060 and 74HC74, an ordinary 32.768KHz watch crystal, and a 5mm red LED for tuning. This design works well and has been successfully replicated by at least 5 different
constructors.
73 Hans G0UPL
] Stability?
Yahoo! Groups Links
|
Thanks for advice dear Hans,
Sure the instability of the vfo will increase the the frequency increase.
I was amazed by the one-chip huff&puff circuit on your site with the 32MHz xtal.
Effective and very simple! I knew that zenerdiodes could be used as varicaps, but led's that's new for me.
Try this one if you are interested in homebrew Panoramareceivers:
Have fun,
Ron
Hans Summers wrote:
Hi Ron
Thanks for the nice complements about my website :-)? I had a look around
your website this morning, you have some very interesting projects there. I
sent an email to a fellow who I know is interested in panoramic adapters and
has been corresponding with me about my spectrum analyser (
)
If you are going to build one of the earlier designs, I have most of the
Huff Puff articles in my reference library for download, see
. In performance
terms, I think my 2-chip simplification should perform as well as the
original Huff Puff
designs. For the ultimate performance, G7IXH's "fast"
stabiliser is slightly more complex but performs best.
I do know that people have used BITX20's for PSK31 very successfully. But
don't forget that your VFO for 17m is twice the BITX20 VFO's frequency,
therefore it is bound to be less stable (all other things being equal).
73 Hans G0UPL
Do you Yahoo!?
Yahoo! Mail - Easier than ever with enhanced search.
|
?
Hello
Ron
?
The
crystal is 32KHz not MHz! Well, 32.768KHz to be precise, which is an ordinary
watch crystal. The 1-chip stabiliser is a little sensitive to adjustment. The
resistor ratios in the VFO gating (mine show 56K and 10K) and the differentiator
time constant (22pF with 10K) need to be chosen (i.e. adjusted) quite carefully
to get it to work. Nevertheless, it does work. Arv K7HKL and I have both
succesfully built the 1-chip stabiliser. The 2-chip stabiliser?is neat
because the spare half of the 74HC74 behaves as VFO. The 2-chip design is easy
to get working, it is not sensitive to ultra-precise choice of component values.
?
Thanks
for the panoramic adapter link, I will forward it to my correspondent who is
interested in building such a device.
?
73 and
good luck
?
Hans
G0UPL
toggle quoted message
Show quoted text
Thanks for advice dear Hans,
Sure the instability of the vfo will increase the the frequency
increase.
I was amazed by the one-chip huff&puff circuit on your site with the
32MHz xtal.
Effective and very simple! I knew that zenerdiodes could be used as
varicaps, but led's that's new for me.
Try this one if you are interested in homebrew Panoramareceivers:
Have fun,
Ron
Hans Summers
wrote:
Hi
Ron
Thanks for the nice complements about my website :-)? I had
a look around
your website this morning, you have some very interesting
projects there. I
sent an email to a fellow who I know is interested in
panoramic adapters and
has been corresponding with me about my spectrum
analyser (
)
If
you are going to build one of the earlier designs, I have most of
the
Huff Puff articles in my reference library for download, see
. In performance
terms, I think my 2-chip simplification should perform
as well as the
original Huff Puff designs. For the ultimate performance,
G7IXH's "fast"
stabiliser is slightly more complex but performs
best.
I do know that people have used BITX20's for PSK31 very
successfully. But
don't forget that your VFO for 17m is twice the BITX20
VFO's frequency,
therefore it is bound to be less stable (all other
things being equal).
73 Hans G0UPL
Do you Yahoo!?
Yahoo! Mail - Easier than ever with enhanced search.
|
Ron,
????????Reminds me
of the old days as a youngster building Valve VFO, enclosing it in a box
etc.. For PSK: I suggest that you take this requirement to the another
extreme and build a DDS VFO !!! Not Joking, its actually the best of both
worlds.. Its tough to make a VFO with 10Hz stability.
????????Try
replacing the 56pf next to Q5 with polystyrene.. it should give your
major improvement.
????????No recent
experience with digital. I used to run a bbs till some years
ago..
73 Raj vu2zap
At 03/02/2005, you wrote:
toggle quoted message
Show quoted text
I really appreciate your quick
reply Raj,
No you did not confuse me.
This forum is alive
!
Yes I used the ceramic ones for initial trails. I have some polysterene
ones (old!! from Philips radios) in my junkbox and will do some trials
coming days.
What is your feeling about making the 2 transistor vfo as shown in the
original schematics working with a freq. drift of 10Hz or less (this is a
tough requirement for digimodes like psk31).
Is there experience with the bitx working with digimodes (rtty, psk31...)
as far as you know?
?
73 and again tnx fer advice!
Ron
Raj wrote:
- Ron,
- ???????? This is probably
because of ceramic capacitors being used the
- oscillator stages. Components that determine frequency must be
ultra-stabe.
- Use NP0 caps, brown ceramics with a black top. You can also use
- polystyrene, they are transparent plastic with a silver foil visible
- inside. They were only available in the old days in small pF values
less
- than 5Kpf.
- ???????? I usually pour bees
wax on top of oscillator components to keep
- them thermally isolated and keep them from shaking.
- ???????? Avoid ceramic caps
in audio stages, it causes microphonics. Tap
- them and you will hear a thump in the speaker/transmission. Use
- mylar/polyester.
- ???????? Do not use
mylar/polyester type caps in RF stages for bypass,
- instead use ceramic. Polyester work well in audio for
coupling.
- ???????? Ceramic = brown
round disks
- ???????? Polyester/Mylar =
green like a chewing gum with leads.
- ???????? Hope I have not
confused you..
- 73 Raj
- vu2zap
- >MHz IF will give the proper range) Frequency range seems to be ok
but
- >stability is bad. After 20 minutes waiting freq shift of 1 KHz
still
- >exists. I think I will order some components for a
HuffAndPuff
- >circuit for stabilizing purposes.
|
?
Ron,
Raj...
?
I have
a simple DDS design too, which doesn't need microprocessors: ?.
It would be possible to replace the DIP switches with up/down counters, driven
perhaps by an optical shaft encoder. Not an optical encoder you buy very
expensively! There are two in every computer mouse, available usually as free
scrap. Just a little work required to convert it into a shaft encoder.
?
Personally though I am still nervous about the noise and spurious outputs
from DDS generators. I'm Ok with using it in a transmitter but I'd worry about
using it in a receiver and degrading performance. Perhaps I'm just paranoid.
Mine is currently driving my QRSS beacon ?which
is currently QRV on 10,140,050 MHz with 250mW to an indoor attic
dipole.
?
73
Hans G0UPL
toggle quoted message
Show quoted text
Ron,
????????Reminds
me of the old days as a youngster building Valve VFO, enclosing it in a box
etc.. For PSK: I suggest that you take this requirement to the another extreme
and build a DDS VFO !!! Not Joking, its actually the best of both worlds.. Its
tough to make a VFO with 10Hz
stability.
????????Try
replacing the 56pf next to Q5 with polystyrene.. it should give your major
improvement.
????????No
recent experience with digital. I used to run a bbs till some years
ago..
73 Raj vu2zap
At 03/02/2005, you wrote:
I really appreciate your quick
reply Raj,
No you did not confuse me.
This forum is alive !
Yes I used the ceramic ones for
initial trails. I have some polysterene ones (old!! from Philips radios) in
my junkbox and will do some trials coming days.
What is your feeling
about making the 2 transistor vfo as shown in the original schematics
working with a freq. drift of 10Hz or less (this is a tough requirement for
digimodes like psk31).
Is there experience with the bitx working with
digimodes (rtty, psk31...) as far as you know?
?
73 and again tnx
fer advice!
Ron
Raj
wrote:
- Ron,
- ???????? This is probably
because of ceramic capacitors being used the
- oscillator stages. Components that determine frequency must be
ultra-stabe.
- Use NP0 caps, brown ceramics with a black top. You can also use
- polystyrene, they are transparent plastic with a silver foil visible
- inside. They were only available in the old days in small pF values
less
- than 5Kpf.
- ???????? I usually pour bees
wax on top of oscillator components to keep
- them thermally isolated and keep them from shaking.
- ???????? Avoid ceramic caps in
audio stages, it causes microphonics. Tap
- them and you will hear a thump in the speaker/transmission. Use
- mylar/polyester.
- ???????? Do not use
mylar/polyester type caps in RF stages for bypass,
- instead use ceramic. Polyester work well in audio for
coupling.
- ???????? Ceramic = brown round
disks
- ???????? Polyester/Mylar =
green like a chewing gum with leads.
- ???????? Hope I have not
confused you..
- 73 Raj
- vu2zap
- >MHz IF will give the proper range) Frequency range seems to be ok
but
- >stability is bad. After 20 minutes waiting freq shift of 1 KHz
still
- >exists. I think I will order some components for a HuffAndPuff
- >circuit for stabilizing purposes.
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|
|
|
Ron, Raj...
Let me add another comment to Hans' response suggesting the use of optical encoders from dead mice (the computer kind!) to tune a DDS system.? You can also remove stepper motors from disk drives (floppy and/or older hard disk types) and use these to derive up and down stepping pulses for your DDS system.? The head position motors in newer hard disk drives are not suitable because they are not real step motors and do not rotate the full 360 degrees.
Arv K7HKL
_._
On Thu, 2005-02-03 at 08:45, Hans Summers wrote:
toggle quoted message
Show quoted text
?
Ron, Raj...
?
I have a simple DDS design too, which doesn't need microprocessors: ?. It would be possible to replace the DIP switches with up/down counters, driven perhaps by an optical shaft encoder. Not an optical encoder you buy very expensively! There are two in every computer mouse, available usually as free scrap. Just a little work required to convert it into a shaft encoder.
?
Personally though I am still nervous about the noise and spurious outputs from DDS generators. I'm Ok with using it in a transmitter but I'd worry about using it in a receiver and degrading performance. Perhaps I'm just paranoid. Mine is currently driving my QRSS beacon ?which is currently QRV on 10,140,050 MHz with 250mW to an indoor attic dipole.
?
73 Hans G0UPL
-----Original Message-----
From: Raj [mailto:ggrk@...]
Sent: 03 February 2005 15:04
To: BITX20@...
Subject: Re: [BITX20] Stability?
Ron,
????????Reminds me of the old days as a youngster building Valve VFO, enclosing it in a box etc.. For PSK: I suggest that you take this requirement to the another extreme and build a DDS VFO !!! Not Joking, its actually the best of both worlds.. Its tough to make a VFO with 10Hz stability.
????????Try replacing the 56pf next to Q5 with polystyrene.. it should give your major improvement.
????????No recent experience with digital. I used to run a bbs till some years ago..
73 Raj vu2zap
At 03/02/2005, you wrote:
I really appreciate your quick reply Raj,
No you did not confuse me.
This forum is alive !
Yes I used the ceramic ones for initial trails. I have some polysterene ones (old!! from Philips radios) in my junkbox and will do some trials coming days.
What is your feeling about making the 2 transistor vfo as shown in the original schematics working with a freq. drift of 10Hz or less (this is a tough requirement for digimodes like psk31).
Is there experience with the bitx working with digimodes (rtty, psk31...) as far as you know?
?
73 and again tnx fer advice!
Ron
Raj wrote:
Ron,
???????? This is probably because of ceramic capacitors being used the
oscillator stages. Components that determine frequency must be ultra-stabe.
Use NP0 caps, brown ceramics with a black top. You can also use
polystyrene, they are transparent plastic with a silver foil visible
inside. They were only available in the old days in small pF values less
than 5Kpf.
???????? I usually pour bees wax on top of oscillator components to keep
them thermally isolated and keep them from shaking.
???????? Avoid ceramic caps in audio stages, it causes microphonics. Tap
them and you will hear a thump in the speaker/transmission. Use
mylar/polyester.
???????? Do not use mylar/polyester type caps in RF stages for bypass,
instead use ceramic. Polyester work well in audio for coupling.
???????? Ceramic = brown round disks
???????? Polyester/Mylar = green like a chewing gum with leads.
???????? Hope I have not confused you..
73 Raj
vu2zap
>MHz IF will give the proper range) Frequency range seems to be ok but
>stability is bad. After 20 minutes waiting freq shift of 1 KHz still
>exists. I think I will order some components for a HuffAndPuff
>circuit for stabilizing purposes.
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*** IMPORTANT: Do not open attachments from unrecognized senders ***
Yahoo! Groups Links
- To visit your group on the web, go to:
?
- To unsubscribe from this group, send an email to:
BITX20-unsubscribe@...
?
- Your use of Yahoo! Groups is subject to the .
|
?
Arv
?
That's
right! I remember reading about that too. Works very well apparently. I've never
tried it. Neither have I ever tried it with the computer mouse, though I've
thought about it several times and got as far as opening some mice up. There are
some websites about converting computer mice and stepper motors into shaft
encoders. If I have time to dig them up I'll let you know, otherwise, Google
should find them.
?
In
fact, I have a dismantled one here on my office desk right now. It was on the
cupboard next to my desk, along with a keyboard and a big old 19-inch monitor,
which I was using for something else for a couple of months. So I called the IT
department 5 times to take this rubbish away from here, because I don't like my
view being spoiled by looking into the back of an old CRT. Since I got no
respone I dismantled the mouse. Next time I saw someone from IT I showed them
the inside of the mouse. I told them that next to go was the keyboard. After
that, if they still hadn't removed it, the monitor was going to get dismantled.
So, in a few days (or weeks) time when my arbitrary time limit has expired and
if the 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!
?
73
Hans G0UPL
toggle quoted message
Show quoted text
Ron, Raj...
Let me add another comment
to Hans' response suggesting the use of optical encoders from dead mice (the
computer kind!) to tune a DDS system.? You can also remove stepper motors
from disk drives (floppy and/or older hard disk types) and use these to derive
up and down stepping pulses for your DDS system.? The head position
motors in newer hard disk drives are not suitable because they are not real
step motors and do not rotate the full 360 degrees.
Arv
K7HKL
_._
On Thu, 2005-02-03 at 08:45, Hans Summers wrote:
Ron, Raj...
?
I have a simple
DDS design too, which doesn't need microprocessors: ?.
It would be possible to replace the DIP switches with up/down counters,
driven perhaps by an optical shaft encoder. Not an optical encoder you buy
very expensively! There are two in every computer mouse, available usually
as free scrap. Just a little work required to convert it into a shaft
encoder.
?
Personally though I am still nervous about the noise and spurious
outputs from DDS generators. I'm Ok with using it in a transmitter but I'd
worry about using it in a receiver and degrading performance. Perhaps I'm
just paranoid. Mine is currently driving my QRSS beacon ?which
is currently QRV on 10,140,050 MHz with 250mW to an indoor attic
dipole.
?
73 Hans G0UPL
-----Original
Message-----
From: Raj [mailto:ggrk@...]
Sent: 03 February 2005 15:04
To:
BITX20@...
Subject: Re: [BITX20]
Stability?
Ron,
????????Reminds
me of the old days as a youngster building Valve VFO, enclosing it in a
box etc.. For PSK: I suggest that you take this requirement to the another
extreme and build a DDS VFO !!! Not Joking, its actually the best of both
worlds.. Its tough to make a VFO with 10Hz
stability.
????????Try
replacing the 56pf next to Q5 with polystyrene.. it should give your major
improvement.
????????No
recent experience with digital. I used to run a bbs till some years
ago..
73 Raj vu2zap
At 03/02/2005, you wrote:
I really appreciate your quick reply Raj,
No
you did not confuse me.
This forum is alive !
Yes I used
the ceramic ones for initial trails. I have some polysterene ones (old!!
from Philips radios) in my junkbox and will do some trials coming days.
What is your feeling about making the 2 transistor vfo as shown in
the original schematics working with a freq. drift of 10Hz or less (this
is a tough requirement for digimodes like psk31).
Is there
experience with the bitx working with digimodes (rtty, psk31...) as far
as you know?
?
73 and again tnx fer
advice!
Ron
Raj
wrote:
Ron,
????????
This is probably because of ceramic capacitors being used the
oscillator stages. Components that determine frequency must be
ultra-stabe.
Use NP0 caps, brown ceramics with a black top.
You can also use
polystyrene, they are transparent plastic
with a silver foil visible
inside. They were only available in
the old days in small pF values less
than
5Kpf.
???????? I
usually pour bees wax on top of oscillator components to keep
them thermally isolated and keep them from
shaking.
????????
Avoid ceramic caps in audio stages, it causes microphonics. Tap
them and you will hear a thump in the speaker/transmission.
Use
mylar/polyester.
????????
Do not use mylar/polyester type caps in RF stages for bypass,
instead use ceramic. Polyester work well in audio for
coupling.
????????
Ceramic = brown round
disks
????????
Polyester/Mylar = green like a chewing gum with
leads.
????????
Hope I have not confused you..
73
Raj
vu2zap
>MHz IF will give the proper range)
Frequency range seems to be ok but
>stability is bad. After
20 minutes waiting freq shift of 1 KHz still
>exists. I
think I will order some components for a
HuffAndPuff
>circuit for stabilizing purposes.
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Yahoo! Groups Links
- To visit your group on the web, go to:
?
- To unsubscribe from this group, send an email to:
BITX20-unsubscribe@...
?
- Your use of Yahoo! Groups is subject to the .
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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 ;-) )
|
????????I fixed a
ICOM735 encoder with LED parts from an old hi-res mouse. The LED inside
the encoder was identical to the one in the mouse.
????????I have
seen some enterprising chaps make TV's out of old monitors. Throwing away
things goes against the grain in India.
73 Raj vu2zap
At 03/02/2005, you wrote:
toggle quoted message
Show quoted text
?
Arv
?
That's right! I remember
reading about that too. Works very well apparently. I've never tried it.
Neither have I ever tried it with the computer mouse, though I've thought
about it several times and got as far as opening some mice up. There are
some websites about converting computer mice and stepper motors into
shaft encoders. If I have time to dig them up I'll let you know,
otherwise, Google should find them.
?
In fact, I have a dismantled
one here on my office desk right now. It was on the cupboard next to my
desk, along with a keyboard and a big old 19-inch monitor, which I was
using for something else for a couple of months. So I called the IT
department 5 times to take this rubbish away from here, because I don't
like my view being spoiled by looking into the back of an old CRT. Since
I got no respone I dismantled the mouse. Next time I saw someone from IT
I showed them the inside of the mouse. I told them that next to go was
the keyboard. After that, if they still hadn't removed it, the monitor
was going to get dismantled. So, in a few days (or weeks) time when my
arbitrary time limit has expired and if the 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!
?
73 Hans G0UPL
- -----Original Message-----
- From: Arv Evans
[
mailto:arvevans@...]
- Sent: 03 February 2005 17:13
- To: BITX
- Subject: RE: [BITX20] Stability?
- Ron, Raj...
- Let me add another comment to Hans' response suggesting the use of
optical encoders from dead mice (the computer kind!) to tune a DDS
system.? You can also remove stepper motors from disk drives (floppy
and/or older hard disk types) and use these to derive up and down
stepping pulses for your DDS system.? The head position motors in
newer hard disk drives are not suitable because they are not real step
motors and do not rotate the full 360 degrees.
- Arv K7HKL
- _._
- On Thu, 2005-02-03 at 08:45, Hans Summers wrote:
- Ron, Raj...
- ?
- I have a simple DDS design too, which
doesn't need microprocessors:
. It would be
possible to replace the DIP switches with up/down counters, driven
perhaps by an optical shaft encoder. Not an optical encoder you buy very
expensively! There are two in every computer mouse, available usually as
free scrap. Just a little work required to convert it into a shaft
encoder.
- ?
- Personally though I am still nervous
about the noise and spurious outputs from DDS generators. I'm Ok with
using it in a transmitter but I'd worry about using it in a receiver and
degrading performance. Perhaps I'm just paranoid. Mine is currently
driving my QRSS beacon
which is
currently QRV on 10,140,050 MHz with 250mW to an indoor attic
dipole.
- ?
- 73 Hans G0UPL
- -----Original Message-----
- From: Raj
[
mailto:ggrk@...]
- Sent: 03 February 2005 15:04
- To: BITX20@...
- Subject: Re: [BITX20] Stability?
- Ron,
- ??????? Reminds me of the old days
as a youngster building Valve VFO, enclosing it in a box etc.. For PSK: I
suggest that you take this requirement to the another extreme and build a
DDS VFO !!! Not Joking, its actually the best of both worlds.. Its tough
to make a VFO with 10Hz stability.
- ??????? Try replacing the 56pf
next to Q5 with polystyrene.. it should give your major
improvement.
- ??????? No recent experience with
digital. I used to run a bbs till some years ago..
- 73 Raj vu2zap
- At 03/02/2005, you wrote:
- I really appreciate your quick reply Raj,
- No you did not confuse me.
- This forum is alive
!
- Yes I used the ceramic ones for initial trails. I have some
polysterene ones (old!! from Philips radios) in my junkbox and will do
some trials coming days.
- What is your feeling about making the 2 transistor vfo as shown in
the original schematics working with a freq. drift of 10Hz or less (this
is a tough requirement for digimodes like psk31).
- Is there experience with the bitx working with digimodes (rtty,
psk31...) as far as you know?
- ?
- 73 and again tnx fer advice!
- Ron
- Raj wrote:
- Ron,
- ???????? This is probably
because of ceramic capacitors being used the
- oscillator stages. Components that determine frequency must be
ultra-stabe.
- Use NP0 caps, brown ceramics with a black top. You can also use
- polystyrene, they are transparent plastic with a silver foil visible
- inside. They were only available in the old days in small pF values
less
- than 5Kpf.
- ???????? I usually pour bees
wax on top of oscillator components to keep
- them thermally isolated and keep them from shaking.
- ???????? Avoid ceramic caps
in audio stages, it causes microphonics. Tap
- them and you will hear a thump in the speaker/transmission. Use
- mylar/polyester.
- ???????? Do not use
mylar/polyester type caps in RF stages for bypass,
- instead use ceramic. Polyester work well in audio for coupling.
- ???????? Ceramic = brown
round disks
- ???????? Polyester/Mylar =
green like a chewing gum with leads.
- ???????? Hope I have not
confused you..
- 73 Raj
- vu2zap
- >MHz IF will give the proper range) Frequency range seems to be ok
but
- >stability is bad. After 20 minutes waiting freq shift of 1 KHz
still
- >exists. I think I will order some components for a
HuffAndPuff
- >circuit for stabilizing purposes.
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Good idea and simple too, the digital activity is in a narrow part of the spectrum on 20M. A VXO should be good enough. 2 xtals should cover sub-band confortably..
I expect that the VFO coil can be replace with a xtal and it should work with minor change of values.
Farhan?
73
Raj
toggle quoted message
Show quoted text
And how about a VXO?
Chris.
For PSK: I suggest that you take this
requirement to the another extreme and build a DDS VFO !!!
|
OK Hans,
Tnx for advice. Nice dds design, but i will first try what is possible with the 4-ic huff and puff (2x 74hc4060, 74hc74+opamp). I do not want to make things too fancy for a starter. Maybe later.
Yesterday i inserted some polysterene cap's and glued (bizon kit!) ?the fixed value coil to the pcb. Stability really improved. A trial of one hour showed about 300 Hz drift. Adding the huff and puff circuitry should further improve the situation. Maybe soldering a box from unetched pcb material around the vfo helps too.
Good homebrewing and best wishes from Holland  Ron
PA2RF
Hans Summers wrote:
?
Ron, Raj...
?
I have a simple DDS design too, which doesn't need microprocessors: ?. It would be possible to replace the DIP switches with up/down counters, driven perhaps by an optical shaft encoder. Not an optical encoder you buy very expensively! There are two in every computer mouse, available usually as free scrap. Just a little work required to convert it into a shaft encoder.
?
Personally though I am still nervous about the noise and spurious outputs from DDS generators. I'm Ok with using it in a transmitter but I'd worry about using it in a receiver and degrading performance. Perhaps I'm just paranoid. Mine is currently driving my QRSS beacon ?which is currently QRV on 10,140,050 MHz with 250mW to an indoor attic dipole.
?
73 Hans G0UPL
Ron,
????????Reminds me of the old days as a youngster building Valve VFO, enclosing it in a box etc.. For PSK: I suggest that you take this requirement to the another extreme and build a DDS VFO !!! Not Joking, its actually the best of both worlds.. Its tough to make a VFO with 10Hz stability.
????????Try replacing the 56pf next to Q5 with polystyrene.. it should give your major improvement.
????????No recent experience with digital. I used to run a bbs till some years ago..
73 Raj
vu2zap
At 03/02/2005, you wrote:
?
- attachments from unrecognized senders? ***
Do you Yahoo!?
Yahoo! Search presents -
|
Thanks Paolo!
Reading your web page has inspired me to bring forward my imaginary deadline
to the IT department! The monitor is now on death row, awaiting demolition.
Those IT boys now have very little time remaining to rescue their monitor
and transport it to safety... I will let you know what I find inside!
73 Hans G0UPL
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Show quoted text
-----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
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