Date   
Re: PA 15W modfications??

Juan Carlos Berberena Glez <jcberberena@...>
 

Hi Dean
Thank you for your help
Here you can see the diagram in the attachment
Please check it out and give e hint
73's
Jc

2011/1/29 Dean Blake <dsblake1@...>


More power is easily available on the PA with higher voltage. You can run
a separate supply to feed just the finals...and 13.8v for the rest of the
radio.
BUT remember the matching network/filter impedances will have to be
resolved as the source impedance is much lower. I found that
the Bitx20a can do 10w to 15w PEP with a 4A...13.8v DC supply... thats
plenty for my QRP rig..higher than this quits being a QRP rig.

K4DSB
Dean

To: BITX20@...
From: jcberberena@...
Date: Sat, 29 Jan 2011 14:59:58 +0000
Subject: [BITX20] PA 15W modfications??




























Hy Guys

Happy Weekend for Everybody

I found a PA modification to get 15W with only one IFR510 in the photos
section made by E20EHQ/E21QJU.

Please I need more details to reproduce it.

Thanks in advance

Jc



WJ6C ex/CO6BG






















------------------------------------

Yahoo! Groups Links



--
Juan Carlos Berberena

Re: PA 15W modfications??

k4dsb
 

More power is easily available on the PA with higher voltage. You can run a separate supply to feed just the finals...and 13.8v for the rest of the radio.
BUT remember the matching network/filter impedances will have to be resolved as the source impedance is much lower. I found that
the Bitx20a can do 10w to 15w PEP with a 4A...13.8v DC supply... thats plenty for my QRP rig..higher than this quits being a QRP rig.

K4DSB
Dean

To: BITX20@...
From: jcberberena@...
Date: Sat, 29 Jan 2011 14:59:58 +0000
Subject: [BITX20] PA 15W modfications??




























Hy Guys

Happy Weekend for Everybody

I found a PA modification to get 15W with only one IFR510 in the photos section made by E20EHQ/E21QJU.

Please I need more details to reproduce it.

Thanks in advance

Jc



WJ6C ex/CO6BG

PA 15W modfications??

Juan Carlos <jcberberena@...>
 

Hy Guys
Happy Weekend for Everybody
I found a PA modification to get 15W with only one IFR510 in the photos section made by E20EHQ/E21QJU.
Please I need more details to reproduce it.
Thanks in advance
Jc

WJ6C ex/CO6BG

Re: Hendricks BitX17A almost alive thanks to KC0WOX's videos..

Leonard
 

An important thing to remember on my waveforms is I'm using a 10x probe, The voltages displayed on the screen are correct as displayed on the screen, You don't have to multiply x 10. The big difference is the capacitive loading. For a x1 probe, it is around 110pfd to ground where a x10 probe is around 15 pfd. It can make a big difference in voltage displayed depending on the circuit. If the voltages you measure are dramatically different, that is a good area to check out. I've checked a lot of btx20's and the ones that worked properly had at least 800 mv's of drive.

Leonard

--- In BITX20@..., "William" <k6whp@...> wrote:



Arv, et al,

Well, the most I could get out of the little beast is about 5 watts which would make sense given the 200 mV drive coming out of the bandpass filter. I also seem to have some difficulty now obtaining a minimum out of the balance modulator. Whereas I seem to remember my traces last night looking like Leonard's.

Also, the rig draws less than two amps. This kind of all makes sense given the five watts, etc. However, I am still mystified as to why so little power.

As before, a good night's sleep, browsing the archived messages here, and a clear mind tomorrow my help.

Any ideas or suggestions greatly appreciated.

72,

Bill, k6whp

--- In BITX20@..., Arv Evans <arvid.evans@> wrote:

Bill K6WHP

I don't recall that anybody has made an input versus output chart..
..etc.

G6LBQ PCB Corrected

Sunil VU3SUA <freedomworld123@...>
 

Kindly find pictures of the new and updated PCB for G6LBQ Multiband PCB.
The schematic as well as the Q4 placement has been corrected on the PCB.
Also the new pcb are in stock.

Link to pictures of new pcb G6LBQ Bitx

http://groups.yahoo.com/group/BITX20/photos/album/1342218047/pic/249316694/view?picmode=&mode=tn&order=ordinal&start=1&count=20&dir=asc

Thanks..

best of 73s
de
VU3SUA

member approval

Harya Sidharta
 

Thank You for approving as member of BITX yahoogroup
 
 
Regards
 
 
 
Harya S

Re: Bitx Ver.1 Original -40 m???

Yannick <yannick.devos@...>
 

Hi guys,

I don't know if you are aware of AA1TJ's works about CFL.
http://www.aa1tj.com/dasderelicht.html

Here more about CFL parts :
http://www.pavouk.org/hw/lamp/en_index.html

73,
Yan.
---
Yannick DEVOS - XV4TUJ
http://capheda.wordpress.com/ (Blog in french)
http://www.qsl.net/xv4tuj/ (web page in english)

--- In BITX20@..., "iam74@..." <iam74@...> wrote:



--- In BITX20@..., "iam74@" <iam74@> wrote:



--- In BITX20@..., Arv Evans <arvid.evans@> wrote:

John

Can those green VLF cores from CFL lamps be used to make RFCs for use at
HF frequencies?

Arv
_._

I doubt it. That thing is designed to operate at about 150-200 KHz. Try putting a SW receiver next to one and see what you get.

I just put a receiver next to one (23W) and got responses at 180 KHz, 270 KHz and 360 KHz plus a lot of RF noise around 400 KHz.

The circuit is nothing more than a simple flyback switching power supply, similar to but much less sophisticated than that in computer power supplies. They have a transistor oscillator, a transformer, a boost coil, and a fast diode to provide a surge voltage through a coil to bring it up to speed. The "CFL" is really just a fluorescent tube and operates like any of its much larger brethren in the kitchen.

I would doubt that they have more than .5cc of mercury in them though. That is not enough to do any serious harm, but mercury accumulates in the body and getting any in your system is not a good idea. It causes effects like muscular dystrophy. (this coming from one who played recklessly with it as a child and a chemistry major. HI HI)

That green core probably saturates at about 1 MHz.

The most interesting thing in there is the fast schottky diode. In the larger power supplies there are dual diodes and I have wondered how those "hot carrier" diodes would work as varactors.


john
AD5YE

Oops! Sorry about that Arv. You did say "RFC" and my mind registered "broad-band transformer".

As I said below they might make good chokes in the mH range. And they might work as XFO coils. Experiment and find out. I should think that they are best applied around 40m and below, though.


john

Re: Bitx20V3 Update

hamfm1000
 

Bill,
I've resting the soldering iron at the moment and doing the thinking!
My current plan is to check the drive level of the main board to see if it is within Leonards scope images. 
Next plan is to find an RF signal generator and test the PA board.  If I can't get hold of one,
I might have a 14.060MHz crystal somewhere to make an oscillator/buffer chain to an appropriate drive level.
The ham operator in me wants to get the kit finished and operating on the air.
The electronic hobbyist in me is enjoying testing, tinkering and above all learning about the BITX in detail.
It does get a little frustrating, but its a chance to play with the oscilloscope.
 
73
Tony

--- On Wed, 26/1/11, William <@k6whp> wrote:


From: William <@k6whp>
Subject: [BITX20] Re: Bitx20V3 Update
To: BITX20@...
Date: Wednesday, 26 January, 2011, 16:06


 





Tony,

My Hendricks BitX17A is experiencing the same symptoms: My VFO, the input to and output from the bandpass filter is about 1/3rd what KC0WOX's videos show for his Bitx20A. Of course, try as I might, I cannot coax more than 5 watts out of the rig.

Check my most recent thread; Arv suggests that the VFO components may determine the output of the VFO.

That being said, like yours, my kit still has a way to go before the evil nasty is found and the raw unadulterated power of the machine can be unlocked.

72,

Bill

--- In BITX20@..., "Tony" <hamfm1000@...> wrote:

Hi all,

Latest on the Bitx20V3 is that I seem to have a problem in the TX path. RX section is working well - thanks!










[Non-text portions of this message have been removed]

Re: Bitx20V3 Update

William <k6whp@...>
 

Tony,

My Hendricks BitX17A is experiencing the same symptoms: My VFO, the input to and output from the bandpass filter is about 1/3rd what KC0WOX's videos show for his Bitx20A. Of course, try as I might, I cannot coax more than 5 watts out of the rig.

Check my most recent thread; Arv suggests that the VFO components may determine the output of the VFO.

That being said, like yours, my kit still has a way to go before the evil nasty is found and the raw unadulterated power of the machine can be unlocked.

72,

Bill

--- In BITX20@..., "Tony" <hamfm1000@...> wrote:

Hi all,

Latest on the Bitx20V3 is that I seem to have a problem in the TX path. RX section is working well - thanks!

Re: Hendricks BitX17A almost alive thanks to KC0WOX's videos..

William <k6whp@...>
 

Arv, et al,

Well, the most I could get out of the little beast is about 5 watts which would make sense given the 200 mV drive coming out of the bandpass filter. I also seem to have some difficulty now obtaining a minimum out of the balance modulator. Whereas I seem to remember my traces last night looking like Leonard's.

Also, the rig draws less than two amps. This kind of all makes sense given the five watts, etc. However, I am still mystified as to why so little power.

As before, a good night's sleep, browsing the archived messages here, and a clear mind tomorrow my help.

Any ideas or suggestions greatly appreciated.

72,

Bill, k6whp

--- In BITX20@..., Arv Evans <arvid.evans@...> wrote:

Bill K6WHP

I don't recall that anybody has made an input versus output chart..
..etc.

Re: Bitx Ver.1 Original -40 m???

John Backo
 

--- In BITX20@..., "iam74@..." <iam74@...> wrote:



--- In BITX20@..., Arv Evans <arvid.evans@> wrote:

John

Can those green VLF cores from CFL lamps be used to make RFCs for use at
HF frequencies?

Arv
_._

I doubt it. That thing is designed to operate at about 150-200 KHz. Try putting a SW receiver next to one and see what you get.

I just put a receiver next to one (23W) and got responses at 180 KHz, 270 KHz and 360 KHz plus a lot of RF noise around 400 KHz.

The circuit is nothing more than a simple flyback switching power supply, similar to but much less sophisticated than that in computer power supplies. They have a transistor oscillator, a transformer, a boost coil, and a fast diode to provide a surge voltage through a coil to bring it up to speed. The "CFL" is really just a fluorescent tube and operates like any of its much larger brethren in the kitchen.

I would doubt that they have more than .5cc of mercury in them though. That is not enough to do any serious harm, but mercury accumulates in the body and getting any in your system is not a good idea. It causes effects like muscular dystrophy. (this coming from one who played recklessly with it as a child and a chemistry major. HI HI)

That green core probably saturates at about 1 MHz.

The most interesting thing in there is the fast schottky diode. In the larger power supplies there are dual diodes and I have wondered how those "hot carrier" diodes would work as varactors.


john
AD5YE

Oops! Sorry about that Arv. You did say "RFC" and my mind registered "broad-band transformer".

As I said below they might make good chokes in the mH range. And they might work as XFO coils. Experiment and find out. I should think that they are best applied around 40m and below, though.


john

Re: Bitx Ver.1 Original -40 m???

John Backo
 

--- In BITX20@..., "Mark" <huitmarmottes@...> wrote:

Yeah,

It's on my desk at home so I didn't have the number handy -- I thought John could illuminate us on the type of part...

Cheero,

Mark.
--- In BITX20@..., Arv Evans <arvid.evans@> wrote:

Mark

If that unknown part has a label on it, try doing a Google search for
"datasheet nn" where nn is the label on that part.

Arv

Well, Arv, would'ya look at that. Give 'em an inch and they want to take...back half an inch. HI HI.

Now that you ask, naturally I can't find the specific diodes that I have saved. There has to be some semblance of disorder in the junkbox, anyway.

But all you have to do is google "Schottky dual Diode" and you will find all the information you want. That is because these parts are presently in commercial use everywhere and lots of manufacturers have them available. For instance, just at random, "Sanyo SBR200 series" or "ST STPR1020 Ultra-Fast Recovery Diodes".

Incidentally, I hope that when you find these data sheets you are saving them in your computer (like in a folder called "Datasheets") because you will want them later for one reason or another.

If you have an obsolete part, then the going gets a lot tougher. Googling usually brings up a lot of automatic references to sales reps...er, brokers...who will guarantee to find it for you if you need 10000 parts or more, and who usually don't have a clue as to where to get them.

You will have better luck at one of the datasheet archives. Two of the best (since they include a lot of obselete parts as well as current ones) are:

www.alldatasheet.com

www.datasheetcatalog.com

These are usually maintained by the manufacturers to benefit the engineering community and provide hassle-free service.

If, after all that, you still can't find a reference, try looking around at the on-line forums for everything under the sun. Some group somewhere has probably gotten into whatever it is you have and may provide some information.

Beyond that, it is likely that you have a common part with a house number or a specialized part which is of no use to you anyway. Throw it away. Unless you suspect it may be a 12 bit AD converter or something like that. Most (99%+) of the unmarked transistors you come across will be PN2222's or an equivalent. Most of the power transistors you find will be MOSFETs of one kind or another. One of the principal things that digital devices can do is switch. There are digital switches everywhere and MOSFETs fill that application better than anything else.

Did you know that the IRF510 was originally used in automobiles for such things as turn-signal control?

As for that green toroid, I wouldn't be too quick to toss it; if nothing else it would probably make the core of a dandy RF choke, or maybe a puller for an XFO (the coil in the BFO of the BITX for example).



john
AD5YE

Re: Bitx Ver.1 Original -40 m???

Mark <huitmarmottes@...>
 

Yeah,

It's on my desk at home so I didn't have the number handy -- I thought John could illuminate us on the type of part...

Cheero,

Mark.

--- In BITX20@..., Arv Evans <arvid.evans@...> wrote:

Mark

If that unknown part has a label on it, try doing a Google search for
"datasheet nn" where nn is the label on that part.

Arv
_._


On 01/25/2011 12:42 PM, Mark wrote:

Ooops,

Well if all those cfl inductors are designed for the KHz range then
the cores won't be very good for the BITX board. Probably even the
dumbell core will saturate at 10MHz huh?

John, what is the dual diode you mentioned? Besides the five 1n4007s
in mine I had an unknown diode (small blue) on mine. The pcb had what
looked like a back-to-back diode symbol for that one?

Thanks and cheers!

Mark.
--- In BITX20@... <mailto:BITX20%40yahoogroups.com>,
"Mark" <huitmarmottes@> wrote:

Thanks for the link Arv :-)

My cfl had a pretty good parts supply too:

5 x 1n4007
5 x mix of film capacitors
1 x 200V electrolytic (can't remember value just now)
1 x dumbell core with a lot of magnet wire just like in the BITXver3
kit (could just solder in bitx bfo and remove a few turns maybe)
2 x transistors (still need to find specs)
1 x ac transformer (didn't check windings yet but obviously low power)
7 x smd resistors and a couple caps
1 x small green toroid

Not too bad :-)

Cheers,

Mark.


--- In BITX20@... <mailto:BITX20%40yahoogroups.com>, Arv
Evans <arvid.evans@> wrote:

Mark & Juan Carlos

<http://qrp.webhop.net/Hints_and_Tips/cflampsurplusandsalvage.html>

shows some information regarding what you may find inside a CFL
light bulb.

Arv
_._


On 01/24/2011 05:40 PM, Mark wrote:

Sure Carlos!

Also, if you can get it out without breaking the bulb, I've
heard that
compact fluorescent light bulbs also have a toroid in them. I
have a
dead one at home I will try to break open its base tonight and see.

73's

Mark.

--- In BITX20@... <mailto:BITX20%40yahoogroups.com>
<mailto:BITX20%40yahoogroups.com>, Juan
Carlos Berberena Glez <jcberberena@> wrote:

Thank You Mark
I am sending them a L/C meter to find the inductance more easy
At this time I am not sure what will be resource available for
them, but
it's(LPF) not a big deal
Maybe in the the Russian radio receiver they can pick it up
73's
Jc

2011/1/24 Mark <huitmarmottes@>



Hi Carlos,

I'm not sure of the supply in Cuba, but if they can find a
supply
of dead
computers, there are normally a few toroid cores on the
motherboards. Their
permeability will vary as sometimes they are powdered iron and
sometimes
different kinds of ferrite, but they could try to find a
batch of
scavenge
all the same kind. Sometimes you can tell by the number of
windings
(typically there will be less turns on the ferrite core types).

Then they would just have to experiment around a bit with
winding
to find
the correct inductance. Certainly it will be a lot less
windings
than tap
washer coils!

Cheers!

Mark.


--- In BITX20@...
<mailto:BITX20%40yahoogroups.com> <mailto:BITX20%40yahoogroups.com>
<BITX20%40yahoogroups.com>, Juan Carlos
Berberena Glez <jcberberena@> wrote:

Thanks John

The reason for that is to follow the original idea to
avoid use
toroides
I am helping some Cuban Amateur to build it, and it is the
best
project
for
them meanwhile the economical situation go up.
73's
WJ6C exCO6BG



2011/1/24 iam74@ <iam74@>





--- In BITX20@...
<mailto:BITX20%40yahoogroups.com>
<mailto:BITX20%40yahoogroups.com> <BITX20%40yahoogroups.com>
<BITX20%
40yahoogroups.com>, Juan Carlos

Berberena Glez <jcberberena@> wrote:

Hi Every one
I want to run the original design in 40m,
What will be the best combination L/C for the LPF
using the tap
washer
(120pF-4uH)
I was thinking to double the number of turn and the total
capacity
until
reach 120pF.
Any suggestion?




<BITX20%40yahoogroups.com>

--
Juan Carlos Berberena
Juan,

You have to keep the same relative impedances when you
change to
another
band. If your original is for 20m or 14 Mhz, then double
the
values of
all
your components and the system should work for 40m or 7
Mhz.
It is easy
to
do that with capacitors, but inductance does not double
with a
simple
doubling of the turns.

However, you will know the target inductance that you need,
and you
should
be able to find it experimentally. It will probably be
somewhere around
70%
more turns for 40m than for 20m, but that is not
guaranteed for
tap-washer
scramble wound coils.

john
AD5YE




--
Juan Carlos Berberena


[Non-text portions of this message have been removed]



--
Juan Carlos Berberena


[Non-text portions of this message have been removed]

[Non-text portions of this message have been removed]


Re: Bitx Ver.1 Original -40 m???

Arv Evans
 

Mark

If that unknown part has a label on it, try doing a Google search for
"datasheet nn" where nn is the label on that part.

Arv
_._

On 01/25/2011 12:42 PM, Mark wrote:

Ooops,

Well if all those cfl inductors are designed for the KHz range then
the cores won't be very good for the BITX board. Probably even the
dumbell core will saturate at 10MHz huh?

John, what is the dual diode you mentioned? Besides the five 1n4007s
in mine I had an unknown diode (small blue) on mine. The pcb had what
looked like a back-to-back diode symbol for that one?

Thanks and cheers!

Mark.
--- In BITX20@... <mailto:BITX20%40yahoogroups.com>,
"Mark" <huitmarmottes@...> wrote:

Thanks for the link Arv :-)

My cfl had a pretty good parts supply too:

5 x 1n4007
5 x mix of film capacitors
1 x 200V electrolytic (can't remember value just now)
1 x dumbell core with a lot of magnet wire just like in the BITXver3
kit (could just solder in bitx bfo and remove a few turns maybe)
2 x transistors (still need to find specs)
1 x ac transformer (didn't check windings yet but obviously low power)
7 x smd resistors and a couple caps
1 x small green toroid

Not too bad :-)

Cheers,

Mark.


--- In BITX20@... <mailto:BITX20%40yahoogroups.com>, Arv
Evans <arvid.evans@> wrote:

Mark & Juan Carlos

<http://qrp.webhop.net/Hints_and_Tips/cflampsurplusandsalvage.html>

shows some information regarding what you may find inside a CFL
light bulb.

Arv
_._


On 01/24/2011 05:40 PM, Mark wrote:

Sure Carlos!

Also, if you can get it out without breaking the bulb, I've
heard that
compact fluorescent light bulbs also have a toroid in them. I
have a
dead one at home I will try to break open its base tonight and see.

73's

Mark.

--- In BITX20@... <mailto:BITX20%40yahoogroups.com>
<mailto:BITX20%40yahoogroups.com>, Juan
Carlos Berberena Glez <jcberberena@> wrote:

Thank You Mark
I am sending them a L/C meter to find the inductance more easy
At this time I am not sure what will be resource available for
them, but
it's(LPF) not a big deal
Maybe in the the Russian radio receiver they can pick it up
73's
Jc

2011/1/24 Mark <huitmarmottes@>



Hi Carlos,

I'm not sure of the supply in Cuba, but if they can find a
supply
of dead
computers, there are normally a few toroid cores on the
motherboards. Their
permeability will vary as sometimes they are powdered iron and
sometimes
different kinds of ferrite, but they could try to find a
batch of
scavenge
all the same kind. Sometimes you can tell by the number of
windings
(typically there will be less turns on the ferrite core types).

Then they would just have to experiment around a bit with
winding
to find
the correct inductance. Certainly it will be a lot less
windings
than tap
washer coils!

Cheers!

Mark.


--- In BITX20@...
<mailto:BITX20%40yahoogroups.com> <mailto:BITX20%40yahoogroups.com>
<BITX20%40yahoogroups.com>, Juan Carlos
Berberena Glez <jcberberena@> wrote:

Thanks John

The reason for that is to follow the original idea to
avoid use
toroides
I am helping some Cuban Amateur to build it, and it is the
best
project
for
them meanwhile the economical situation go up.
73's
WJ6C exCO6BG



2011/1/24 iam74@ <iam74@>





--- In BITX20@...
<mailto:BITX20%40yahoogroups.com>
<mailto:BITX20%40yahoogroups.com> <BITX20%40yahoogroups.com>
<BITX20%
40yahoogroups.com>, Juan Carlos

Berberena Glez <jcberberena@> wrote:

Hi Every one
I want to run the original design in 40m,
What will be the best combination L/C for the LPF
using the tap
washer
(120pF-4uH)
I was thinking to double the number of turn and the total
capacity
until
reach 120pF.
Any suggestion?




<BITX20%40yahoogroups.com>

--
Juan Carlos Berberena
Juan,

You have to keep the same relative impedances when you
change to
another
band. If your original is for 20m or 14 Mhz, then double
the
values of
all
your components and the system should work for 40m or 7
Mhz.
It is easy
to
do that with capacitors, but inductance does not double
with a
simple
doubling of the turns.

However, you will know the target inductance that you need,
and you
should
be able to find it experimentally. It will probably be
somewhere around
70%
more turns for 40m than for 20m, but that is not
guaranteed for
tap-washer
scramble wound coils.

john
AD5YE




--
Juan Carlos Berberena






--
Juan Carlos Berberena





Re: Hendricks BitX17A almost alive thanks to KC0WOX's videos..

Arv Evans
 

Bill K6WHP

I don't recall that anybody has made an input versus output chart for
the BITXxxA RF PA stage.
Probably Leonard's scope indications are the best we have to go from in
that area. Maybe
someone with a working BITXxxA could make input versus output voltage
readings and post
that on this discussion group. It could be valuable for those who are
experiencing power
output problems.

In the early BITX20 years I found that scrounging parts and using ugly
construction was more
educational than all the books read and all the kits that I have built.
Having room to experiment
with modifications and "found" parts makes the hobby so much more
interesting. Yes, those
early BITX units looked ugly, but they worked quite well. If they
didn't we just re-built them
until the did work as desired.

73's

Arv K7HKL

On 01/25/2011 09:41 AM, William wrote:



Arv,

Thank you for the insight; short-term really, really dumb question: is
the 120 mV input to the PA adequate enough for that stage? Short-term
really, really dumb answer: try the PA drive adjustment/tune-up
procedure and find out.

Seriously Arv, if it gets me 10 watts or so, I am fine with that. I'll
finish the frequency display, button up the rig, and call it a day.
But! I am not done with BitX work per se. The other variants (Sunil's
boards and mini-kits and/or the Far Circuit boards) look inviting and
have more room to play around in. Armed with the general insights that
you, Charles, Jim, and Leonard have provided, it would be fun to
tackle a 20m version..

..and -- who knows? -- a 40m version.

There's method in my madness. I have a couple of ham friends who
wanted to get into building and getting the boards and scrounging the
parts would enrich their experience. They are not CW types and the
prospect of building an SSB rig might appeal to them.

Thanks again. Will keep you posted.

Bill, k6whp

--- In BITX20@... <mailto:BITX20%40yahoogroups.com>, Arv
Evans <arvid.evans@...> wrote:

Bill

Design of the BITXxxA VFO is such that the output is dependent on
the resonant loop impedance of the frequency determining
components. This means that if you use a very small capacitor for
C-37 it will decrease the amount of oscillator feedback and thus
reduce the VFO output.

Re: Bitx Ver.1 Original -40 m???

Mark <huitmarmottes@...>
 

Ooops,

Well if all those cfl inductors are designed for the KHz range then the cores won't be very good for the BITX board. Probably even the dumbell core will saturate at 10MHz huh?

John, what is the dual diode you mentioned? Besides the five 1n4007s in mine I had an unknown diode (small blue) on mine. The pcb had what looked like a back-to-back diode symbol for that one?

Thanks and cheers!

Mark.

--- In BITX20@..., "Mark" <huitmarmottes@...> wrote:

Thanks for the link Arv :-)

My cfl had a pretty good parts supply too:

5 x 1n4007
5 x mix of film capacitors
1 x 200V electrolytic (can't remember value just now)
1 x dumbell core with a lot of magnet wire just like in the BITXver3 kit (could just solder in bitx bfo and remove a few turns maybe)
2 x transistors (still need to find specs)
1 x ac transformer (didn't check windings yet but obviously low power)
7 x smd resistors and a couple caps
1 x small green toroid

Not too bad :-)

Cheers,

Mark.


--- In BITX20@..., Arv Evans <arvid.evans@> wrote:

Mark & Juan Carlos

<http://qrp.webhop.net/Hints_and_Tips/cflampsurplusandsalvage.html>

shows some information regarding what you may find inside a CFL light bulb.

Arv
_._


On 01/24/2011 05:40 PM, Mark wrote:

Sure Carlos!

Also, if you can get it out without breaking the bulb, I've heard that
compact fluorescent light bulbs also have a toroid in them. I have a
dead one at home I will try to break open its base tonight and see.

73's

Mark.

--- In BITX20@... <mailto:BITX20%40yahoogroups.com>, Juan
Carlos Berberena Glez <jcberberena@> wrote:

Thank You Mark
I am sending them a L/C meter to find the inductance more easy
At this time I am not sure what will be resource available for them, but
it's(LPF) not a big deal
Maybe in the the Russian radio receiver they can pick it up
73's
Jc

2011/1/24 Mark <huitmarmottes@>



Hi Carlos,

I'm not sure of the supply in Cuba, but if they can find a supply
of dead
computers, there are normally a few toroid cores on the
motherboards. Their
permeability will vary as sometimes they are powdered iron and
sometimes
different kinds of ferrite, but they could try to find a batch of
scavenge
all the same kind. Sometimes you can tell by the number of windings
(typically there will be less turns on the ferrite core types).

Then they would just have to experiment around a bit with winding
to find
the correct inductance. Certainly it will be a lot less windings
than tap
washer coils!

Cheers!

Mark.


--- In BITX20@... <mailto:BITX20%40yahoogroups.com>
<BITX20%40yahoogroups.com>, Juan Carlos
Berberena Glez <jcberberena@> wrote:

Thanks John

The reason for that is to follow the original idea to avoid use
toroides
I am helping some Cuban Amateur to build it, and it is the best
project
for
them meanwhile the economical situation go up.
73's
WJ6C exCO6BG



2011/1/24 iam74@ <iam74@>





--- In BITX20@...
<mailto:BITX20%40yahoogroups.com> <BITX20%40yahoogroups.com> <BITX20%
40yahoogroups.com>, Juan Carlos

Berberena Glez <jcberberena@> wrote:

Hi Every one
I want to run the original design in 40m,
What will be the best combination L/C for the LPF using the tap
washer
(120pF-4uH)
I was thinking to double the number of turn and the total
capacity
until
reach 120pF.
Any suggestion?




<BITX20%40yahoogroups.com>

--
Juan Carlos Berberena
Juan,

You have to keep the same relative impedances when you change to
another
band. If your original is for 20m or 14 Mhz, then double the
values of
all
your components and the system should work for 40m or 7 Mhz.
It is easy
to
do that with capacitors, but inductance does not double with a
simple
doubling of the turns.

However, you will know the target inductance that you need,
and you
should
be able to find it experimentally. It will probably be
somewhere around
70%
more turns for 40m than for 20m, but that is not guaranteed for
tap-washer
scramble wound coils.

john
AD5YE




--
Juan Carlos Berberena


[Non-text portions of this message have been removed]



--
Juan Carlos Berberena




[Non-text portions of this message have been removed]

Re: Bitx Ver.1 Original -40 m???

Mark <huitmarmottes@...>
 

Thanks for the link Arv :-)

My cfl had a pretty good parts supply too:

5 x 1n4007
5 x mix of film capacitors
1 x 200V electrolytic (can't remember value just now)
1 x dumbell core with a lot of magnet wire just like in the BITXver3 kit (could just solder in bitx bfo and remove a few turns maybe)
2 x transistors (still need to find specs)
1 x ac transformer (didn't check windings yet but obviously low power)
7 x smd resistors and a couple caps
1 x small green toroid

Not too bad :-)

Cheers,

Mark.

--- In BITX20@..., Arv Evans <arvid.evans@...> wrote:

Mark & Juan Carlos

<http://qrp.webhop.net/Hints_and_Tips/cflampsurplusandsalvage.html>

shows some information regarding what you may find inside a CFL light bulb.

Arv
_._


On 01/24/2011 05:40 PM, Mark wrote:

Sure Carlos!

Also, if you can get it out without breaking the bulb, I've heard that
compact fluorescent light bulbs also have a toroid in them. I have a
dead one at home I will try to break open its base tonight and see.

73's

Mark.

--- In BITX20@... <mailto:BITX20%40yahoogroups.com>, Juan
Carlos Berberena Glez <jcberberena@> wrote:

Thank You Mark
I am sending them a L/C meter to find the inductance more easy
At this time I am not sure what will be resource available for them, but
it's(LPF) not a big deal
Maybe in the the Russian radio receiver they can pick it up
73's
Jc

2011/1/24 Mark <huitmarmottes@>



Hi Carlos,

I'm not sure of the supply in Cuba, but if they can find a supply
of dead
computers, there are normally a few toroid cores on the
motherboards. Their
permeability will vary as sometimes they are powdered iron and
sometimes
different kinds of ferrite, but they could try to find a batch of
scavenge
all the same kind. Sometimes you can tell by the number of windings
(typically there will be less turns on the ferrite core types).

Then they would just have to experiment around a bit with winding
to find
the correct inductance. Certainly it will be a lot less windings
than tap
washer coils!

Cheers!

Mark.


--- In BITX20@... <mailto:BITX20%40yahoogroups.com>
<BITX20%40yahoogroups.com>, Juan Carlos
Berberena Glez <jcberberena@> wrote:

Thanks John

The reason for that is to follow the original idea to avoid use
toroides
I am helping some Cuban Amateur to build it, and it is the best
project
for
them meanwhile the economical situation go up.
73's
WJ6C exCO6BG



2011/1/24 iam74@ <iam74@>





--- In BITX20@...
<mailto:BITX20%40yahoogroups.com> <BITX20%40yahoogroups.com> <BITX20%
40yahoogroups.com>, Juan Carlos

Berberena Glez <jcberberena@> wrote:

Hi Every one
I want to run the original design in 40m,
What will be the best combination L/C for the LPF using the tap
washer
(120pF-4uH)
I was thinking to double the number of turn and the total
capacity
until
reach 120pF.
Any suggestion?




<BITX20%40yahoogroups.com>

--
Juan Carlos Berberena
Juan,

You have to keep the same relative impedances when you change to
another
band. If your original is for 20m or 14 Mhz, then double the
values of
all
your components and the system should work for 40m or 7 Mhz.
It is easy
to
do that with capacitors, but inductance does not double with a
simple
doubling of the turns.

However, you will know the target inductance that you need,
and you
should
be able to find it experimentally. It will probably be
somewhere around
70%
more turns for 40m than for 20m, but that is not guaranteed for
tap-washer
scramble wound coils.

john
AD5YE




--
Juan Carlos Berberena


[Non-text portions of this message have been removed]



--
Juan Carlos Berberena





Re: Hendricks BitX17A almost alive thanks to KC0WOX's videos..

William <k6whp@...>
 

Arv,

Thank you for the insight; short-term really, really dumb question: is the 120 mV input to the PA adequate enough for that stage? Short-term really, really dumb answer: try the PA drive adjustment/tune-up procedure and find out.

Seriously Arv, if it gets me 10 watts or so, I am fine with that. I'll finish the frequency display, button up the rig, and call it a day. But! I am not done with BitX work per se. The other variants (Sunil's boards and mini-kits and/or the Far Circuit boards) look inviting and have more room to play around in. Armed with the general insights that you, Charles, Jim, and Leonard have provided, it would be fun to tackle a 20m version..

..and -- who knows? -- a 40m version.

There's method in my madness. I have a couple of ham friends who wanted to get into building and getting the boards and scrounging the parts would enrich their experience. They are not CW types and the prospect of building an SSB rig might appeal to them.

Thanks again. Will keep you posted.

Bill, k6whp

--- In BITX20@..., Arv Evans <arvid.evans@...> wrote:

Bill

Design of the BITXxxA VFO is such that the output is dependent on
the resonant loop impedance of the frequency determining
components. This means that if you use a very small capacitor for
C-37 it will decrease the amount of oscillator feedback and thus
reduce the VFO output.

Re: Bitx Ver.1 Original -40 m???

John Backo
 

--- In BITX20@..., "iam74@..." <iam74@...> wrote:



--- In BITX20@..., Arv Evans <arvid.evans@> wrote:

John

I was thinking more of increasing L (decreasing turns requirement) by
increasing
mutual inductance with 360 degrees or more of core coverage. You do
bring up
an interesting point about the inductance clumping effect.

Arv
_._


Yeah; remember that all the good effects are in a UNIFORM magnetic field. Stray inductance disrupts that uniform field.


john
AD5YE
Another thought.

You can measure quite easily the efficiency of your toroid: Build an oscillator with it and move a piece of iron around the coil, listening for variation in frequency. The closer you have to get to the coil to make things change, the better your toroid effect is.



john

Re: Bitx Ver.1 Original -40 m???

John Backo
 

--- In BITX20@..., Arv Evans <arvid.evans@...> wrote:

John

I was thinking more of increasing L (decreasing turns requirement) by
increasing
mutual inductance with 360 degrees or more of core coverage. You do
bring up
an interesting point about the inductance clumping effect.

Arv
_._


Yeah; remember that all the good effects are in a UNIFORM magnetic field. Stray inductance disrupts that uniform field.


john
AD5YE