Date   
Re: ver, 3.0

wbdmxbaileybobbuttercup
 

I have the xfrmers with the caps installed in the board now, but I also have the ones with the caps removed and they tested with a L of 5 to 9 depending on the slug all the way in and all the way out.


From: Raj
Sent: Tuesday, May 27, 2008 12:29 AM
To: BITX20@...
Subject: Re: [BITX20] ver, 3.0


I am sure you can make your own or substitute with 10.7 IFT's salvaged from an
old radio.

guess I can scrap that idea if parts are not available here. what a waste of time and money.
--
Raj, vu2zap
Bengaluru, South India.

Re: ver, 3.0

wbdmxbaileybobbuttercup
 

well, I am not giving up yet, I have 20 of the 10 mhz xtals that need to be used some where.

the IF transformers I have have a L of 7.4 and a C of 30 built in, so maybe I can just add one external to get it to 14 Mhz.
I already have all the other parts to build the version 3 including a HB pc board all drilled and ready to assemble


From: Arv Evans
Sent: Tuesday, May 27, 2008 12:55 AM
To: BITX20@...
Subject: Re: [BITX20] ver, 3.0


Bob

I used standard US available 10.7 MHz IF transformers in my first BITX20
build. These came from an older AM/FM transistor radio (junk box
parts). Like Raj said, these had an internal capacitor (you can see it
from the bottom of the IF can) which can be disconnected by breaking it,
or by cutting one lead. With the internal capacitor disconnected I
added 39 pf externally to allow tuning to 14.25 MHz.

In my second BITX20 I used 10.7 MHz IF transformers from
DansSmallPartsAndKits.com. These did not have the internal capacitor
and required a 39 pf externally for resonance on 14.25 MHz. When I
converted this rig to 40M I changed the external capacitors to 150 pf
for resonance on 7.2 MHz.

Another alternative might be to wind a toroid for 2.7 uH and use an
external trimmer capacitor to peak it's tuning.

Yet another alternative might be to use the plastic faucet washers (tap
washers) as formers and wind your own 2.7 uh inductors as was done in
the original BITX20 design. Again, you would need external trimmer
capacitors to peak them to resonance.

Part of the magic in the BITX20 design is that it can be assembled from
readily available surplus or from junk box parts. However, this does
require that one think about what is needed, where it might be obtained,
or how it might be built. The first hundred or so BITX20 units were
constructed using Manhattan or Ugly Construction style and were totally
made from locally available parts. Since these were assembled by hams
in many parts of the world, there were many variations in components
between each of our BITX20 builds...yet the all worked (some required a
bit more troubleshooting than others!).

Don't give up too easily if you cannot find the exact component that
might be specified. There is plenty of room for innovation in this design.

Arv
_._

bob bailey wrote:

guess I can scrap that idea if parts are not available here. what a
waste of time and money.

From: Rahul Srivastava
Sent: Monday, May 26, 2008 11:46 PM
To: BITX20@... <mailto:BITX20%40yahoogroups.com>
Subject: Re: [BITX20] ver, 3.0

Coils provided with V3 boards are FM 10.7 IF transformers. Here in
India these are manufactured by a firm Rosy. They are available in 2
types one is tuned with external 82pf cap, second one is tuned with
internal 68pf cap. Both the coils are specificaly made to be used with
Philips TEA5591 chip.
&nbsp;
Former variety is supplied with the kit as the inductance&nbsp; is
quite close to recomended value at 2.7uH. There is no inbuilt cap
inside these.
&nbsp;
At times we also use the later ones but we parallel the original
internal cap with another 82 pf and it tunes nicely on 7Mhz.

Since 10.7 is a lower frequency the internal cap will have to be
reduced to bring it up on 14Mhz.
&nbsp;
Think its time to assemble one LC meter.

From: wb7dmx <wb7dmx@... <mailto:wb7dmx%40hotmail.com>>
Subject: [BITX20] ver, 3.0
To: BITX20@... <mailto:BITX20%40yahoogroups.com>
Date: Tuesday, 27 May, 2008, 4:22 AM

can anyone give me a part number for the if cans used for l1, l2, and
l3 in the version 3 bitx20 ?

also do you remove the internal cap inside the can ?

I have already bought 10 of the 10.7 IF's and cannot retune them for 14
mhz, any ideas on how to do this ?
maybe I bought the wrong ones.

Unlimited freedom, unlimited storage. Get it now, on
http://help.yahoo.com/l/in/yahoo/mail/yahoomail/tools/tools-08.html/
<http://help.yahoo.com/l/in/yahoo/mail/yahoomail/tools/tools-08.html/>





--
======================================
Web: http://K7HKL.homelinux.net
http://bitx20a.livejournal.com
http://home.earthlink.net/~arvevans/
http://www.geocities.com/k7hkl_arv/
======================================

Re: ver, 3.0

Arv Evans
 

Bob

I used standard US available 10.7 MHz IF transformers in my first BITX20
build. These came from an older AM/FM transistor radio (junk box
parts). Like Raj said, these had an internal capacitor (you can see it
from the bottom of the IF can) which can be disconnected by breaking it,
or by cutting one lead. With the internal capacitor disconnected I
added 39 pf externally to allow tuning to 14.25 MHz.

In my second BITX20 I used 10.7 MHz IF transformers from
DansSmallPartsAndKits.com. These did not have the internal capacitor
and required a 39 pf externally for resonance on 14.25 MHz. When I
converted this rig to 40M I changed the external capacitors to 150 pf
for resonance on 7.2 MHz.

Another alternative might be to wind a toroid for 2.7 uH and use an
external trimmer capacitor to peak it's tuning.

Yet another alternative might be to use the plastic faucet washers (tap
washers) as formers and wind your own 2.7 uh inductors as was done in
the original BITX20 design. Again, you would need external trimmer
capacitors to peak them to resonance.

Part of the magic in the BITX20 design is that it can be assembled from
readily available surplus or from junk box parts. However, this does
require that one think about what is needed, where it might be obtained,
or how it might be built. The first hundred or so BITX20 units were
constructed using Manhattan or Ugly Construction style and were totally
made from locally available parts. Since these were assembled by hams
in many parts of the world, there were many variations in components
between each of our BITX20 builds...yet the all worked (some required a
bit more troubleshooting than others!).

Don't give up too easily if you cannot find the exact component that
might be specified. There is plenty of room for innovation in this design.

Arv
_._


bob bailey wrote:


guess I can scrap that idea if parts are not available here. what a
waste of time and money.

From: Rahul Srivastava
Sent: Monday, May 26, 2008 11:46 PM
To: BITX20@... <mailto:BITX20%40yahoogroups.com>
Subject: Re: [BITX20] ver, 3.0

Coils provided with V3 boards are FM 10.7 IF transformers. Here in
India these are manufactured by a firm Rosy. They are available in 2
types one is tuned with external 82pf cap, second one is tuned with
internal 68pf cap. Both the coils are specificaly made to be used with
Philips TEA5591 chip.
&nbsp;
Former variety is supplied with the kit as the inductance&nbsp; is
quite close to recomended value at 2.7uH. There is no inbuilt cap
inside these.
&nbsp;
At times we also use the later ones but we parallel the original
internal cap with another 82 pf and it tunes nicely on 7Mhz.

Since 10.7 is a lower frequency the internal cap will have to be
reduced to bring it up on 14Mhz.
&nbsp;
Think its time to assemble one LC meter.

From: wb7dmx <wb7dmx@... <mailto:wb7dmx%40hotmail.com>>
Subject: [BITX20] ver, 3.0
To: BITX20@... <mailto:BITX20%40yahoogroups.com>
Date: Tuesday, 27 May, 2008, 4:22 AM

can anyone give me a part number for the if cans used for l1, l2, and
l3 in the version 3 bitx20 ?

also do you remove the internal cap inside the can ?

I have already bought 10 of the 10.7 IF's and cannot retune them for 14
mhz, any ideas on how to do this ?
maybe I bought the wrong ones.

Unlimited freedom, unlimited storage. Get it now, on
http://help.yahoo.com/l/in/yahoo/mail/yahoomail/tools/tools-08.html/
<http://help.yahoo.com/l/in/yahoo/mail/yahoomail/tools/tools-08.html/>





--
======================================
Web: http://K7HKL.homelinux.net
http://bitx20a.livejournal.com
http://home.earthlink.net/~arvevans/
http://www.geocities.com/k7hkl_arv/
======================================

Re: ver, 3.0

 

I am sure you can make your own or substitute with 10.7 IFT's salvaged from an
old radio.

guess I can scrap that idea if parts are not available here. what a waste of time and money.
--
Raj, vu2zap
Bengaluru, South India.

Wanted Bitx Pictures From Hams

Sunil Lakhani <freedomworld123@...>
 

I am looking out for pictures for Bitx, from Hams who are constructing
it,so that I can post them on my blog http://wwww.cqbitx.blogspot.com

Interestingly Cq bitx gets around 100 hits or more a day.
So it would be a good action on your part to submit your Bitx pics and
see your Bitx get noticed among Radio Amateurs world- wide.

Happy home-brewing

73's

Sunil Lakhani VU3SUA

Re: ver, 3.0

wbdmxbaileybobbuttercup
 

guess I can scrap that idea if parts are not available here. what a waste of time and money.


From: Rahul Srivastava
Sent: Monday, May 26, 2008 11:46 PM
To: BITX20@...
Subject: Re: [BITX20] ver, 3.0


Coils provided with V3 boards are FM 10.7 IF transformers. Here in India these are manufactured by a firm Rosy. They are available in 2 types one is tuned with external 82pf cap, second one is tuned with internal 68pf cap. Both the coils are specificaly made to be used with Philips TEA5591 chip.
&nbsp;
Former variety is supplied with the kit as the inductance&nbsp; is quite close to recomended value at 2.7uH. There is no inbuilt cap inside these.
&nbsp;
At times we also use the later ones but we parallel the original internal cap with another 82 pf and it tunes nicely on 7Mhz.

Since 10.7 is a lower frequency the internal cap will have to be reduced to bring it up on 14Mhz.
&nbsp;
Think its time to assemble one LC meter.

From: wb7dmx <wb7dmx@...>
Subject: [BITX20] ver, 3.0
To: BITX20@...
Date: Tuesday, 27 May, 2008, 4:22 AM

can anyone give me a part number for the if cans used for l1, l2, and
l3 in the version 3 bitx20 ?

also do you remove the internal cap inside the can ?

I have already bought 10 of the 10.7 IF's and cannot retune them for 14
mhz, any ideas on how to do this ?
maybe I bought the wrong ones.

Unlimited freedom, unlimited storage. Get it now, on http://help.yahoo.com/l/in/yahoo/mail/yahoomail/tools/tools-08.html/

Re: ver, 3.0

Rahul Srivastava
 

Coils provided with V3 boards are FM 10.7 IF transformers. Here in India these are manufactured by a firm Rosy. They are available in 2 types one is tuned with external 82pf cap, second one is tuned with internal 68pf cap. Both the coils are specificaly made to be used with Philips TEA5591 chip.
&nbsp;
Former variety is supplied with the kit as the inductance&nbsp; is quite close to recomended value at 2.7uH. There is no inbuilt cap inside these.
&nbsp;
At times we also use the later ones but we parallel the original internal cap with another 82 pf and it tunes nicely on 7Mhz.

Since 10.7 is a lower frequency the internal cap will have to be reduced to bring it up on 14Mhz.
&nbsp;
Think its time to assemble one LC meter.


From: wb7dmx <wb7dmx@...>
Subject: [BITX20] ver, 3.0
To: BITX20@...
Date: Tuesday, 27 May, 2008, 4:22 AM






can anyone give me a part number for the if cans used for l1, l2, and
l3 in the version 3 bitx20 ?

also do you remove the internal cap inside the can ?

I have already bought 10 of the 10.7 IF's and cannot retune them for 14
mhz, any ideas on how to do this ?
maybe I bought the wrong ones.
















Unlimited freedom, unlimited storage. Get it now, on http://help.yahoo.com/l/in/yahoo/mail/yahoomail/tools/tools-08.html/

ver, 3.0

wbdmxbaileybobbuttercup
 

can anyone give me a part number for the if cans used for l1, l2, and
l3 in the version 3 bitx20 ?

also do you remove the internal cap inside the can ?

I have already bought 10 of the 10.7 IF's and cannot retune them for 14
mhz, any ideas on how to do this ?
maybe I bought the wrong ones.

Re: Latest BitX ? ?

Leonard <bitx@...>
 

--- In BITX20@..., "Charles Darley" <charles@...> wrote:

Hi All

For me and another friend who are both building the BITX from the
original I
would like to see an up date from to the original schematic. We
have made
our variations but were thinking how to we submit them without up
setting
the originator who had put in so much work originally ... and
anyway are
our changes already those done by others.



So could we have the ORIGINAL one updated.



Another question ...what is the expected output is it 6 watts as
mentioned
"An easy to build 6 watts SSB transceiver for 14MHz" as we can only
manage 2
W !!!
My Far Circuits Boards, http://golddredgervideo.com/bitx20/index.htm
put out a little over 4 watts. You can see the PA videos at the link
above. These boards were almost the original circuits. The main mods
I made were in the mike amp to get rid of the 2nd harmonic of the
modulation problem that is also documented on the site. The other mod
I made was adding relay switching in the linear for receiver and
transmitter isolation.
Leonard

Re: Latest BitX ? ?

Charles Darley
 

Hi All

For me and another friend who are both building the BITX from the original I
would like to see an up date from to the original schematic. We have made
our variations but were thinking how to we submit them without up setting
the originator who had put in so much work originally ... and anyway are
our changes already those done by others.



So could we have the ORIGINAL one updated.



Another question ...what is the expected output is it 6 watts as mentioned
"An easy to build 6 watts SSB transceiver for 14MHz" as we can only manage 2
W !!!



Regards Charles G4VSZ



From: BITX20@... [mailto:BITX20@...] On Behalf Of
Leonard
Sent: 26 May 2008 22:00
To: BITX20@...
Subject: [BITX20] Re: Latest BitX ? ?



--- In BITX20@... <mailto:BITX20%40yahoogroups.com> , "Greg
W:-)" <onegammyleg@...> wrote:

Hi all..

I don't know about anyone else in here , but I would like to see a
revised and updated schematic with all of the changes that have been
made over the time that the group has been up.

I am soon coming to a time when I will be free of my current
projects
and am looking for something to do.k, and I'de like to do a Bitx20
,,but with all the revisions up to date.---- not build something ,
then have to do fixes.

Regards

gregW:-) OH2FFY
You are going to have to be far more specific when you talk about a
bitx. Do you mean the original circuit, a bitxkit, or a version 3?
There may be even more out there. These are the one's I'm familiar
with.
I occasionally get a question about a bitx and the first question I
have to ask is which one?
Leonard

Leonard



No virus found in this incoming message.
Checked by AVG.
Version: 8.0.100 / Virus Database: 269.24.1/1468 - Release Date: 26/05/2008
15:23

Re: Latest BitX ? ?

Leonard <bitx@...>
 

--- In BITX20@..., "Greg W:-)" <onegammyleg@...> wrote:

Hi all..

I don't know about anyone else in here , but I would like to see a
revised and updated schematic with all of the changes that have been
made over the time that the group has been up.

I am soon coming to a time when I will be free of my current
projects
and am looking for something to do.k, and I'de like to do a Bitx20
,,but with all the revisions up to date.---- not build something ,
then have to do fixes.

Regards

gregW:-) OH2FFY
You are going to have to be far more specific when you talk about a
bitx. Do you mean the original circuit, a bitxkit, or a version 3?
There may be even more out there. These are the one's I'm familiar
with.
I occasionally get a question about a bitx and the first question I
have to ask is which one?
Leonard

Leonard

Re: Follow along on troubleshooting a bitx kit.

Leonard <bitx@...>
 

--- In BITX20@..., "wimmie262000" <jowijowi@...> wrote:

Hi, Leonard,
Good stuff. Also a nice idea to use the scope as high input impedance
pre-amp for the SA. I just bought a 2nd hand Tektronix scope and found
it has an output as well.
In your experience, how good is such a pre-amp on distortion and
intermod when you look at the SA screen?

Cheers,

Joop
I would guess that as long as your scope preamp has the bandwidth and
you aren't exceeding the limits of the crt display as far as amplitude,
what comes out of the signal out jack is a very good replica of the
scope input signal. The preamp I have is a 7A26 which is good to 200
MHz and the 7904 mainframe is good to 500 MHz. It should be reproducing
the input very faithfully.

I use the Sig Out jack whenever I need to use my scope pulgins as a
signal conditioner. One special one I have is a 7A22.
http://www.barrytech.com/tektronix/tek7000/tek7a22.html#specs

What it has that is special is a 10uv/div range. Also it is good only
to 1 MHz but it has adjustable -3db upper and lower cutoff points. This
works great for looking a mike outputs. I can set up a bandpass filter
at almost any frequency up to 1 MHz.

I love the old 7000 series Tektronix scopes. The 7904 will hold 4
plugins and the plugins are cheap on ebay. Usually less then $30.00.
Leonard

Re: Latest BitX ? ?

Greg W:-) <onegammyleg@...>
 

SNIP

OR ....might I suggest a maintained and dated text file placed in the
groups files section with links to other files with the errata or mods
in it., in a complete and clear way.

At least that way we can track mods that work and apply them with
ease., instead of hunting through years worth of posts to find what we
are after.

gW:-)

Latest BitX ? ?

Greg W:-) <onegammyleg@...>
 

Hi all..

I don't know about anyone else in here , but I would like to see a
revised and updated schematic with all of the changes that have been
made over the time that the group has been up.

I am soon coming to a time when I will be free of my current projects
and am looking for something to do.k, and I'de like to do a Bitx20
,,but with all the revisions up to date.---- not build something ,
then have to do fixes.

Regards

gregW:-) OH2FFY

BiTX20 Indian PCB pack....

iw1axr
 

Link of photos

PCB, coils and package of indian PCB

http://digilander.libero.it/danaxr/info/packbitx.pdf

73! Dan

BiTX20 PCB from India ....

iw1axr
 

BiTX20 PCB from India...


BITX VERSION 3 PCB Coils And 2570 ... 22$

http://cqbitx.blogspot.com/2008/04/pictures-of-bitx-home-brewed-by.html

http://cqbitx.blogspot.com/2008/01/new-bitx-pcb.html


Complete FREQUENCY COUNTER KIT... 20$

http://cqbitx.blogspot.com/2008/04/frequency-counter-kit.html


Shipping status...

http://cqbitx.blogspot.com/2008/04/frequency-counter-kit.html



Pay with paypal at Mar 26, shipped at apr 04, received PCB, coil ect.
at apr 12 ...


73! Dan

Re: Follow along on troubleshooting a bitx kit.

wimmie262000 <jowijowi@...>
 

Hi, Leonard,
Good stuff. Also a nice idea to use the scope as high input impedance
pre-amp for the SA. I just bought a 2nd hand Tektronix scope and found
it has an output as well.
In your experience, how good is such a pre-amp on distortion and
intermod when you look at the SA screen?

Cheers,

Joop

Re: Follow along on troubleshooting a bitx kit.

Arv Evans
 

Leonard

Fantastic! DC voltage, AC voltage, and stage-by-stage gain
documentation is something that we have all needed for some time. With
that we will have met and exceeded Heath Kit level documentation for our
BITX20 construction. Thanks for making the effort, and for making this
information available on-line.

Arv
_._


Leonard wrote:


I began troubleshooting a kit board for a friend and in the process
went back to check and compare levels on mine. I had used mine to
make most of my videos and had left it in good working condition a
couple of months ago. Now though, it didn't want to put out much
power. I wasn't getting enough drive level to R83. My previous notes
called for 1.25-1.5 volts of drive with 50mv's input modulation.
After watching all of my videos again, looking at the notes penciled
on my master schematic I thought, "This would be a great time to
attempt to document signal waveforms and levels on my web page so if
you had one that didn't work, you could just compare signals to help
isolate the trouble area." Thats a great idea but it would work a
whole lot better if you had a good one to make the measurements to
start with, which I didn't. Lacking that, I began measuring each
stage and comparing the results with the gains written on the
schematic. I had done this before and verified that they were at
least in the ballpark. This time will be different though as I am
documenting them photographically as I go.

You can see a page describing the equipment setup at
http://golddredgervideo.com/kc0wox/bitxkitsigtrace/photosetup.htm
<http://golddredgervideo.com/kc0wox/bitxkitsigtrace/photosetup.htm>

There may be easier ways to do it but this seems to work with the
equipment that I have. The troubleshooting page begins at

http://golddredgervideo.com/kc0wox/bitxkitsigtrace/signaltrace.htm
<http://golddredgervideo.com/kc0wox/bitxkitsigtrace/signaltrace.htm>

It's not completed yet. I seem to have identified the problem area
but I currently don't have the time to isolate it to component
level.

This troubleshooting is done using a spectrum analyzer. It is a lot
easier because you can isolate out desired frequencies and ignore
the rest. I will add a page on the same process through the stages
after I get mine and the other one I'm working on, fixed.
Leonard
kc0wox

--
======================================
Web: http://K7HKL.homelinux.net
http://bitx20a.livejournal.com
http://home.earthlink.net/~arvevans/
http://www.geocities.com/k7hkl_arv/
======================================

Follow along on troubleshooting a bitx kit.

Leonard <bitx@...>
 

I began troubleshooting a kit board for a friend and in the process
went back to check and compare levels on mine. I had used mine to
make most of my videos and had left it in good working condition a
couple of months ago. Now though, it didn't want to put out much
power. I wasn't getting enough drive level to R83. My previous notes
called for 1.25-1.5 volts of drive with 50mv's input modulation.
After watching all of my videos again, looking at the notes penciled
on my master schematic I thought, "This would be a great time to
attempt to document signal waveforms and levels on my web page so if
you had one that didn't work, you could just compare signals to help
isolate the trouble area." Thats a great idea but it would work a
whole lot better if you had a good one to make the measurements to
start with, which I didn't. Lacking that, I began measuring each
stage and comparing the results with the gains written on the
schematic. I had done this before and verified that they were at
least in the ballpark. This time will be different though as I am
documenting them photographically as I go.

You can see a page describing the equipment setup at
http://golddredgervideo.com/kc0wox/bitxkitsigtrace/photosetup.htm

There may be easier ways to do it but this seems to work with the
equipment that I have. The troubleshooting page begins at

http://golddredgervideo.com/kc0wox/bitxkitsigtrace/signaltrace.htm

It's not completed yet. I seem to have identified the problem area
but I currently don't have the time to isolate it to component
level.

This troubleshooting is done using a spectrum analyzer. It is a lot
easier because you can isolate out desired frequencies and ignore
the rest. I will add a page on the same process through the stages
after I get mine and the other one I'm working on, fixed.
Leonard
kc0wox

Build notes

 

Where could I locate the "Complete enhanced build notes, ver. 5") mentioned by Jonathan, 2E0TFE ?
Lee, WA8QFE