?
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.
*** eSafe scanned this email for malicious content ***
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|
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.
|
?
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.
|
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.
|
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
|
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?
|
Dear Ashhar,
It is an honour to me? to chat to the designer of the bitx ! Compliments for the extensive info on the internet. I like the KISS (keep it simple stupid) principle a lot. I appreciate all your good advice.  I have made some notes behind each of your hint&tip: . make all the components connect to each other with short leads and without any 'jiggly' wires.
--That's what i did
2. put an epoxy glue over the coil and stick the coil to the board with a drop of expoy.
-- here i can made an improvement ! Now the fixed value coil floats above the pcb
3. put a sheild around the vfo (i know it is too much work).
--message understood. Yes shielding?improve the situation?
4. Are u connecting to the tuning capacitor with flexible wire? use a short stiff copper wire or a resistor tail end.The ground end should be directly in contact with the chassis.
--yes i used a short thick copper wire to the capacitor's hot end. The ground end is directly soldered onto the pcb
5. Make sure that your regulator is actually regulating. Check the diode (i have often mistakend 1N4148s for other zeners).
--yes it is a stable voltage is measured after the zener.
?
I have used ceramic capacitors and will replace them the the polysterne ones for better performance.
What is your opinion about working with digimodes (like rtty and psk31) with the bitx, Ashhar? Is there any experience in this field ? A 10 Hz stability requirement for psk31 is very though!! (altough i managed to get an old kenwood ts515 with tubes working on psk31..)
Ron
pa2rf
http://home.versatel.nl/laar60
Ashhar Farhan wrote:
the 1 Khz drift is more of a construction problem that a design problem.
I would suggest that you try the following:
1. make all the components connect to each other with short leads and
without any 'jiggly' wires.
2. put an epoxy glue over the coil and stick the coil to the board with a
drop of expoy.
3. put a sheild around the vfo (i know it is too much work).
4. Are u connecting to the tuning capacitor with flexible wire? use a
short stiff copper wire or a resistor tail end.The ground end should be
directly in contact with the chassis.
5. Make sure that your regulator is actually regulating. Check the diode
(i have often mistakend 1N4148s for other zeners).
Unfortunately, an open VFO on a work-bench is rarely stable. Especially,
if your coil has an low permeability like the tap washers.
- farhan
On Thu, 3 Feb
2005, pa2rf wrote:
>
>
> Thanks for advice dear Chris,
> Saw on the forum that the BITX17 already? seems to exist!
> OK, past couple of days I started to setup the power supply unit
> capable of delivering the required voltages.
> Also did some trials with a VFO working from 8.060 - 8.180 MHz. (+ 10
> 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.
> Or maybe a FET Hartley oscillator. We'll see.
> Bye for now and till next time.
> Dank voor je reactie Chris. Leuk om te zien dat andere om druk met de
> bitx in de weer zijn.
> 73 de Ron
> pa2rf
>
>
> --- In BITX20@..., "vdberghak" wrote:
>>
>> Dear Ron,
>>
splended idea to make it for 17 mtrs.
>> In your message you asked for suggestions, you want to have more
>> suggestions then all the postings in this newsgroup, including
>> Photos, Files etc?
>> Can you be more precisely what else you need?
>> By the way, you can show your progress in this newsgroup, you do
> not
>> need an other website for it.
>> Best regards,
>> Chris.
>>
>>> 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'
>
>
>
>
>
>
> Yahoo! Groups Links
>
>
>
>
>
>
>
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 -
|
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,
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.
|
From the mouths of babes...
i was fooling around with a direct conversion receiver in my shack today when my four year old daughter came in with her friends to play 'wheelie train' (a noisy sport where each participant sits in an office chair holding onto the next one's chair and the front engine pulls everyone around the room).
i was just about to ask them to go out to play, to let me play my thing, when i was offered ... a polo. the mint with a hole.
it immediately went into the direct conversion receiver as a VFO coil. quite stable.
now, a single roll will be enough to build the entire BITX, although I am not sure of the losses. You will have to cover it with some epoxy paint/glue to make sure that ants dont eat up your rig.
i will report back from the toroid sucking convention soon.
- farhan
|
the 1 Khz drift is more of a construction problem that a design problem.
I would suggest that you try the following:
1. make all the components connect to each other with short leads and without any 'jiggly' wires.
2. put an epoxy glue over the coil and stick the coil to the board with a drop of expoy.
3. put a sheild around the vfo (i know it is too much work).
4. Are u connecting to the tuning capacitor with flexible wire? use a short stiff copper wire or a resistor tail end.The ground end should be directly in contact with the chassis.
5. Make sure that your regulator is actually regulating. Check the diode (i have often mistakend 1N4148s for other zeners).
Unfortunately, an open VFO on a work-bench is rarely stable. Especially, if your coil has an low permeability like the tap washers.
- farhan
toggle quoted message
Show quoted text
On Thu, 3 Feb 2005, pa2rf wrote:
Thanks for advice dear Chris,
Saw on the forum that the BITX17 already seems to exist!
OK, past couple of days I started to setup the power supply unit
capable of delivering the required voltages.
Also did some trials with a VFO working from 8.060 - 8.180 MHz. (+ 10
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.
Or maybe a FET Hartley oscillator. We'll see.
Bye for now and till next time.
Dank voor je reactie Chris. Leuk om te zien dat andere om druk met de
bitx in de weer zijn.
73 de Ron
pa2rf
--- In BITX20@..., "vdberghak" <vdberghak@z...> wrote:
Dear Ron,
splended idea to make it for 17 mtrs.
In your message you asked for suggestions, you want to have more
suggestions then all the postings in this newsgroup, including
Photos, Files etc?
Can you be more precisely what else you need?
By the way, you can show your progress in this newsgroup, you do
not
need an other website for it.
Best regards,
Chris.
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'
Yahoo! Groups Links
|
Thanks for advice dear Chris, Saw on the forum that the BITX17 already seems to exist! OK, past couple of days I started to setup the power supply unit capable of delivering the required voltages. Also did some trials with a VFO working from 8.060 - 8.180 MHz. (+ 10 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. Or maybe a FET Hartley oscillator. We'll see. Bye for now and till next time. Dank voor je reactie Chris. Leuk om te zien dat andere om druk met de bitx in de weer zijn. 73 de Ron pa2rf --- In BITX20@..., "vdberghak" <vdberghak@z...> wrote:
Dear Ron,
splended idea to make it for 17 mtrs.
In your message you asked for suggestions, you want to have more
suggestions then all the postings in this newsgroup, including
Photos, Files etc?
Can you be more precisely what else you need?
By the way, you can show your progress in this newsgroup, you do
not need an other website for it.
Best regards,
Chris.
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'
|
Dear Ron, splended idea to make it for 17 mtrs. In your message you asked for suggestions, you want to have more suggestions then all the postings in this newsgroup, including Photos, Files etc? Can you be more precisely what else you need? By the way, you can show your progress in this newsgroup, you do not need an other website for it. Best regards, Chris. 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'
|
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
?
http://home.versatel.nl/laar60 
Do you Yahoo!?
Yahoo! Search presents -
|
New file uploaded to BITX20
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 : /MFJ-9420-CW-module-1.gif
Uploaded by : vu3wjm <vu3wjm@...>
Description : MFJ Trvelradio CW section that may be adapted for BITX
You can access this file at the URL:
To learn more about file sharing for your group, please visit:
Regards,
vu3wjm <vu3wjm@...>
|
HI!? Farhan and friends,
?
With BITX having become so popular CW operations I assume was simply matter of time. Over years many kits have evolved the same route.
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Among the commercial products Travel radio by MFJ is one such popular kit here are the ckts for the CW section including CW keying. Surprisingly the design is in keeping with the the discreet simplicity of BITX.
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Hope the attachment comes thru else I load under files section .
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73
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Rahul VU3WJM
Ashhar Farhan wrote:
How does one go about with full QSK on BITX20?
There is very little switching around.
the most crucial point to me is that the receiver input needs to switch
from the linear amp's output to input. that makes for possible feedbacks
if not isolated properly.
on TX, the bitx's output has to be routed to the linear's input and the
linear's output to the antenna. we should assume that this is how it is
permanently wired. during tx, the linear amp's output should not get back
into input via the electronic switching that will connect the bitx
directly to the antenna.
any ideas?
- farhan
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How does one go about with full QSK on BITX20?
There is very little switching around.
the most crucial point to me is that the receiver input needs to switch from the linear amp's output to input. that makes for possible feedbacks if not isolated properly.
on TX, the bitx's output has to be routed to the linear's input and the linear's output to the antenna. we should assume that this is how it is permanently wired. during tx, the linear amp's output should not get back into input via the electronic switching that will connect the bitx directly to the antenna.
any ideas?
- farhan
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Re: BITX 20 Ver 2 PCB tested
--- In BITX20@..., "vu3wjm" <vu3wjm@y...> wrote: Hi Rahul Here we have completed 2 BITX 20s. We used the ver. 2 layout for
PCB. PCB is thankfully without any mistakes however Pin 2 of LM386
also needs to be grounded to ground plain nearby to avoid ground
loop. (Will correct and upload corrected PCB shortly) Look's really nice, can't wait to make one.!! 73 de OZ2AFY
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Re: Assembling Far bitx boards
paul,
the PCBs have been printed component side! to mark the correct side, i had put the letters BITX in the middle of the PCB as a reminder so that it reads properly.
I guess the fault is partly mine, I am used to imagining the circuit from topside, so i designed it from component side. This is my first PCB and i designed it using the Microsoft Paint program. I should have flipped the entire image over before uploading it. I felt that the builder would figure out the correct side looking at the "BITX" text.
Now, there are two resolutions:
1) for the existing boards, put the LM386 on the foil side.
2) bend all the IC legs by 180 degress so that they are all pointing up rather than down, then flip the IC over and solder it in place on the component side.
The new boards will have take care to flip the circuit around.
It might be a good idea for those buying from FAR to be refered to the BITX20@... for updates and help with assembling the board.
- farhan
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