Date   
BTX20A Simple FET MIC amplifier

qrpjl1kra
 

Re: low volume

Ashish
 

thank you Asharr Farhan

I am not getting any ham band signals after connecting antenna(half
wave center fed dipole).I m getting some local radio stations.I m
getting pretty hihg volume now.

The base voltage in transistors in BFO is about 5V.(both transistors)
Is that the problem?

Re: low volume

Ashhar Farhan <farhan@...>
 

get a 14.318 MHz crystal. it is probably the most common crystal
because it is used in every PC. make an oscillator out of it and try
using that as a signal source.

Once you have tuned it in, peak the RF coils. then you should set the
carrier oscillator such that as you tune up to the crystal, the tone
should start as high pitch, become mellow and then drop out and
entirely vanish (or become very feeble) as you keep tuning past it. If
the tone again rises in pitch at the same volume, then move your
carrier lower down (increase the preset's capacitance).

After this, connect about 40 feet of wire and tune around in the
evening and do some SWL-ing.

- farhan

On Sun, Apr 27, 2008 at 1:16 AM, Ashish <geniusashish85@...> wrote:






I have just assembled a bitx on copper clad board.I have not made an
antenna yet.So with a wire connected as antenna I can hear noises.But
the volume is too low.I dont have an oscilloscope.so i couldn't check
the output of each stage.only thing I m having is a digital multi
meter.can any one suggest me how to check each stage?

Re: problems

wbdmxbaileybobbuttercup
 

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

Bob

My mistake. I thought you had referred earlier to the Laserjet
method
of making PCBs.
no mistake, I have always used the positive transperceny method to
make boards, but never had tryed the iron method, and today after
you mentioned I did one, used a glossy photo paper in the laserjet
printer and ironed it to a board, the paper came of ok but the
glossy photo paper left a thin film of what seamed to be almost
plastic, took most of the day with tweasers and the board in a water
tray to get all that film off the board, it was the worst mess I
have ever tried, but the board did come out ok and ready to etch.
I did the one that is in the version 3 collection and is the bottom
trace, after checking everything, I could see no reason to do the
top layer as it is just a ground plane, anyway I am going to
tinplate it and build it as a experience project.

planning on ordering the one from qrpkits when my stemulas check
comes, then I will have built everything he sells, no not yet got to
get the digital dial too.

just finished the frequency standard referance from kits and parts,
that is a nice gadget for the bench.

Re: problems

Arv Evans
 

Bob

My mistake. I thought you had referred earlier to the Laserjet method
of making PCBs.

The laserjet method of making PCBs involves printing a dark laserjet
copy of your PCB in reverse on paper that has a clay surface content.
Then using your XYL's clothing iron, remelt the xerography toner (it is
actually plastic micro-balls) onto the copper surface. Once the print
is securely fastened to the PCB material by melted toner, you soak the
whole thing in soapy water to dissolve the paper, leaving melted plastic
as resist for etching. This can do a fair job of making PCBs but it
does take a bit of experimenting and practice to get it right.

Arv
_._


wb7dmx wrote:


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

Bob WB7DMX

There are a number of image editors available that do allow you to
scale
image size for printing. I use "gimp" (Graphical Image
Manipulation
Program), but other programs work as well and may be less complex
to
learn and use. A trick you can use is to add a pair of marks
along the
outside edge of your image that are intended to be exactly "n"
inches
apart. Then print a test copy and measure this distance to verify
that
your scaling is correct. If you can get it correct to within 0.1
inches
in a 3 inch distance, then all your parts should be close enough
to
mount properly.

Accurate registration of front side versus back side for double-
sided
home etched PCBs can be accomplished by marking matching drill
spots in
opposite corners of your PCB layouts, then pre-drilling these
holes to
use as placement marks for your iron-on patterns. Do this in the
perimeter ground plane, or just outside it, so that the marks will
not
interfere with populating your finished board. Iron your pattern
onto
one side of the blank PCB material...drill the alignment holes,
then
iron your other pattern onto the opposite side (making sure it
matches
the alignment holes).

Designing your own PCB layout would allow you to add modifications
that
you specifically want for your rig. Alternatively, you might want
to
build your first BITX20 using Manhattan or Ugly construction
method.
This makes it easy to try different components and different
modifications.

A schematic for the BITX20A Kit from qrpkits.com is available as
part of
the down-loadable instruction manual on Doug's web site
<http://www.qrpkits.com <http://www.qrpkits.com>>, and at various
other places on the
BITX20
group and on my blog site <http://bitx20a.livejournal.com/
<http://bitx20a.livejournal.com/>>. Doug
does
not make just the PCB layout for the BITX20A Kit available because
he
spent a significant amount of money in developing that and now
must sell
enough kits to recover that expense. Giving away that particular
PCB
layout would make it difficult for him to recover his costs.

Arv K7HKL
_._
thank you very much, I just printed the image and then scanned it
and imported it to paint shop pro, where I was able to do the resize
and crop of the image, then printed it, all came out the correct
size.
thank you for the help.

now the next question, you said iron on, well I have never used that
method yet, so clue me in as to what material do I print the image
to that will allow it to be ironed on to the pc board, I will give
it a try.

thank you
bob
WB7DMX

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

Re: VXO

Stanley Grixti
 

Hi guys

spent a few hours playing with the bitx again this evening.

i managed to get the 8.1mhz xtal to move from 8099 to 8100.15 and stay there reliably

the beacon is going to be on 17meters simply due to available xtals

so the resultant design is 10mhz + 8.1 and i have op exactly on 18.100.15 right on the psk31 segment of 17mtrs

thanks to eveyone for their help & suggestions

What I would like to ask now is....

I have arrived onto the driver stage and soon the outboard pa...i don't have any 'tv balun' cores.

i do however have a selection of toroids as an alternative

could someone guide me to T3 on the pre-driver and T2 on the PA

Also any other suggestions/experiences with a 17mtr version would be appreciated.

thanks again to all..this is a really helpfull group!

best 73

stan 9h1lo
p.s. uploaded some more photos on 'photos' section of group under '9H1LO' the shot of the spectrum analyser was taken before it put the BPF in circuit !

Ashhar Farhan wrote:


the bitx vxo is quite a bad circuit for a receiver local oscillator. it
functions well as a BFO though. this is because it has a heavily clipped
output. which is fine for a bfo as the harmonics (which are quite strong)
are filtered out by the crystal filter. if you use it in the open part of a
receiver (before the crystal filter), you may get a number of undesired
birdies and spurs.
it is better to use a vxo that has a tuned tank in the output and buffer it
well enough just like a VFO. the lighter you load a VXO the more it will
pull.

- farhan

On 4/26/08, Juanjo Pastor <ec5aca@... <mailto:ec5aca%40wanadoo.es>> wrote:

Of course, Stan, you have to tune out all the undesired mixing products.
I
thought it was understood... I think that the 12 MHz is possible to be
tuned
20 KHz or even more under its nominal frequency and the 16 MHz rock
can be
lifted over its nominal frequency with a simple adjustable capacitive
trimmer. Some years ago I tuned a 19.6608 crystal to 19.670 MHz with
only a
65 pF trimmer (the big plastic yellow one) in a 40 to 11 metres
receiving
converter with a S042P (it is in my site, but it is written up in
Spanish...).

On the other hand, I will not mention all of you, but you are a really
stunning bunch. I declare myself a fan to you and the group is the one I
like best! I stay tuned as always...

73, 72 de Juanjo, EC5ACA. EA-QRP #104, G-QRP #9742, QRP-L #1662,
FP #899.

Juanjo Pastor
C/San Roque, 4-1�
46460 Silla
SPAIN

e-mail: ec5aca@... <mailto:ec5aca%40gmail.com>
<ec5aca%40gmail.com>
web: http://es.geocities.com/ea5chq <http://es.geocities.com/ea5chq>
web del club: http://www.eaqrp.com <http://www.eaqrp.com>
Tel.: +034 96 120 17 67
Movil: 651 35 35 11
----- Original Message -----
From: "Stanley Grixti" <stanley@...
<mailto:stanley%409h1lo.net> <stanley%409h1lo.net>>
To: <BITX20@... <mailto:BITX20%40yahoogroups.com>
<BITX20%40yahoogroups.com>>
Sent: Saturday, April 26, 2008 12:55 PM
Subject: Re: [BITX20] Re: VXO

i am now considering the 16-12 solution...

would you think it would be best to have a 4mhz BPF after the mixer
before the 10+4mhz mixer??



Juanjo Pastor wrote:

Hello everybody as this is my first post to the group.

Stan, what about vxoing or supervxoing the 4.096 MHz standard
crystals?
If
you can't find them in Malta, send me your address and I will send a
couple
of them to you. 26 KHz down is quite a lot with a 4 ish MHz rock
but it
could be doable. Another option would be heterodining two crystal
frequencies, like 8 and 12 convinently pulled, I see 8 should be
pulled down
and 12 up. Or even better, 12 and 16, I am sure that with the
corresponding
pulling you could get the 4.070 mix easily. Anyway I am not into
other
digimodes but CW, and I really think it is possible to get a stable
enough
VFO covering from 4 to 4.350 MHz to work all the band. The huff
& puff
FLL
is also interesting, and would made a good VFO even better. I
will stay
tuned to hear your results. Best wishes to all the BiTXers!

73, 72 de Juanjo, EC5ACA. EA-QRP #104, G-QRP #9742, QRP-L #1662,
FP #899.

Juanjo Pastor
C/San Roque, 4-1�
46460 Silla
SPAIN

e-mail: ec5aca@... <mailto:ec5aca%40gmail.com>
<ec5aca%40gmail.com> <mailto:
ec5aca%40gmail.com <ec5aca%2540gmail.com>>
web: http://es.geocities.com/ea5chq
<http://es.geocities.com/ea5chq> <http://es.geocities.com/ea5chq <http://es.geocities.com/ea5chq>>
web del club: http://www.eaqrp.com <http://www.eaqrp.com>
<http://www.eaqrp.com <http://www.eaqrp.com>>
Tel.: +034 96 120 17 67
Movil: 651 35 35 11
----- Original Message -----
From: "wimmie262000" <jowijowi@...
<mailto:jowijowi%40gmail.com> <jowijowi%40gmail.com><mailto:
jowijowi%40gmail.com <jowijowi%2540gmail.com>>>
To: <BITX20@... <mailto:BITX20%40yahoogroups.com>
<BITX20%40yahoogroups.com> <mailto:
BITX20%40yahoogroups.com <BITX20%2540yahoogroups.com>>>
Sent: Friday, April 25, 2008 5:38 PM
Subject: [BITX20] Re: VXO

--- In BITX20@...
<mailto:BITX20%40yahoogroups.com> <BITX20%40yahoogroups.com> <mailto:
BITX20%40yahoogroups.com <BITX20%2540yahoogroups.com>>,
"Mike W" <mike@...> wrote:

Duh, why did'nt I see that too Joop:-)
obviously the old grey matter is diminishing.
a very good idea as the 24Mhz CPU xtals are readily
available for a
few pence
each. However, is'nt the PSK31 mode sideband depemdent though?,
high
side
injection will mean swapping the CIO insertion.
73 Mike G8NXD
Well I see I am wrong in my calculation of the ppm's (quiete a bit
higher), but you got the idea. And I am not sure about the PSK
sensitivity. Could the sideband "orientation" LF not be chosen
with
the right BFO frequency?


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

Yahoo! Groups Links


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

Yahoo! Groups Links




Re: antenna and baluns

Charlie Ivermee <charlie@...>
 

Ashish wrote:
Thank you Raj...

Do u have any idea about how to make a balun for bitx?or can u give me some links of websites which gives information about building a balun?
will the reciever work with out the balun?



Baluns:

http://www.bcdxc.org/balun_information.htm#Ed,%20WA2SRQ

http://www.io.com/~n5fc/balun_1-1.htm

http://www.hamuniverse.com/balun.html

http://www.dxzone.com/catalog/Antennas/Baluns/

Regards,


Charlie.

--
M0WYM
www.radiowymsey.org

Wymsey - Ten years Old!
www.wymsey.co.uk

Re: antenna and baluns

Ashish
 

Raj can u pls give me more information on rotary dipole?

low volume

Ashish
 

I have just assembled a bitx on copper clad board.I have not made an
antenna yet.So with a wire connected as antenna I can hear noises.But
the volume is too low.I dont have an oscilloscope.so i couldn't check
the output of each stage.only thing I m having is a digital multi
meter.can any one suggest me how to check each stage?

Re: crystals in BITX

Ashish
 

thank you guys...thanks a lot...

Re: antenna and baluns

Ashish
 

Thank you Raj...

Do u have any idea about how to make a balun for bitx?or can u give me
some links of websites which gives information about building a balun?
will the reciever work with out the balun?

Re: problems

wbdmxbaileybobbuttercup
 

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

Bob WB7DMX

There are a number of image editors available that do allow you to
scale
image size for printing. I use "gimp" (Graphical Image
Manipulation
Program), but other programs work as well and may be less complex
to
learn and use. A trick you can use is to add a pair of marks
along the
outside edge of your image that are intended to be exactly "n"
inches
apart. Then print a test copy and measure this distance to verify
that
your scaling is correct. If you can get it correct to within 0.1
inches
in a 3 inch distance, then all your parts should be close enough
to
mount properly.

Accurate registration of front side versus back side for double-
sided
home etched PCBs can be accomplished by marking matching drill
spots in
opposite corners of your PCB layouts, then pre-drilling these
holes to
use as placement marks for your iron-on patterns. Do this in the
perimeter ground plane, or just outside it, so that the marks will
not
interfere with populating your finished board. Iron your pattern
onto
one side of the blank PCB material...drill the alignment holes,
then
iron your other pattern onto the opposite side (making sure it
matches
the alignment holes).

Designing your own PCB layout would allow you to add modifications
that
you specifically want for your rig. Alternatively, you might want
to
build your first BITX20 using Manhattan or Ugly construction
method.
This makes it easy to try different components and different
modifications.

A schematic for the BITX20A Kit from qrpkits.com is available as
part of
the down-loadable instruction manual on Doug's web site
<http://www.qrpkits.com>, and at various other places on the
BITX20
group and on my blog site <http://bitx20a.livejournal.com/>. Doug
does
not make just the PCB layout for the BITX20A Kit available because
he
spent a significant amount of money in developing that and now
must sell
enough kits to recover that expense. Giving away that particular
PCB
layout would make it difficult for him to recover his costs.

Arv K7HKL
_._
thank you very much, I just printed the image and then scanned it
and imported it to paint shop pro, where I was able to do the resize
and crop of the image, then printed it, all came out the correct
size.
thank you for the help.

now the next question, you said iron on, well I have never used that
method yet, so clue me in as to what material do I print the image
to that will allow it to be ironed on to the pc board, I will give
it a try.

thank you
bob
WB7DMX

Re: problems

Arv Evans
 

Bob WB7DMX

There are a number of image editors available that do allow you to scale
image size for printing. I use "gimp" (Graphical Image Manipulation
Program), but other programs work as well and may be less complex to
learn and use. A trick you can use is to add a pair of marks along the
outside edge of your image that are intended to be exactly "n" inches
apart. Then print a test copy and measure this distance to verify that
your scaling is correct. If you can get it correct to within 0.1 inches
in a 3 inch distance, then all your parts should be close enough to
mount properly.

Accurate registration of front side versus back side for double-sided
home etched PCBs can be accomplished by marking matching drill spots in
opposite corners of your PCB layouts, then pre-drilling these holes to
use as placement marks for your iron-on patterns. Do this in the
perimeter ground plane, or just outside it, so that the marks will not
interfere with populating your finished board. Iron your pattern onto
one side of the blank PCB material...drill the alignment holes, then
iron your other pattern onto the opposite side (making sure it matches
the alignment holes).

Designing your own PCB layout would allow you to add modifications that
you specifically want for your rig. Alternatively, you might want to
build your first BITX20 using Manhattan or Ugly construction method.
This makes it easy to try different components and different modifications.

A schematic for the BITX20A Kit from qrpkits.com is available as part of
the down-loadable instruction manual on Doug's web site
<http://www.qrpkits.com>, and at various other places on the BITX20
group and on my blog site <http://bitx20a.livejournal.com/>. Doug does
not make just the PCB layout for the BITX20A Kit available because he
spent a significant amount of money in developing that and now must sell
enough kits to recover that expense. Giving away that particular PCB
layout would make it difficult for him to recover his costs.

Arv K7HKL
_._





wb7dmx wrote:


I am looking at building the btx-20,it looks like it would be a fun
rig to play with.

the only problem I am running into it that there are so many
fifferant versions out now and many differant pc board tracks.

I have a limit of pc board size right now of a 4 X 6. unless I buy a
bigger one, which I am willing to do.

I print the track to a transfer film with my laser jet printer for
all the pc boards I make.

the board that is 3 X 5 looks like one I would try, but I cannot
find the schenatic for that one.

also I like the newer version 3 circuit, but does it have to be a
double sided board ?

another problem I am having is when I print out the track, the size
is off enough that I don't want to make the board that way, I can't
seam to be able to print the correct size so the parts will fit
correctly. let alone the matching of a double sided board.

I could also just give up and buy the kit, but that would be the
last choice.

I already have a lot of the parts, I think, I bought 20 of the 10mhz
xtals and 10 of the if cans, hope there the correct ones.

confused
bob
WB7DMX

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

Re: problems

Greg W:-) <onegammyleg@...>
 

Hi Bob.

Yeup , thats the problem when art is saved as a JPG.

PS , or even BMP will scale or preserve the original dimensions
correctly , but JPG wont.

Fortunately the only critical parts in the bitx20 where size is
important is the 8 pin dip IC , but that will be good enough if you
drill with big holes.

If you use transformer cans for your coils , thats even harder again.

I recommend to anyone doing further artwork to make sure its in a
format that doesn't distort the shape when scaling.

Of course nothing is impossible to get OK , it just take as lot of time.


Regards

gregW:-) OH2FFY
http://groups.yahoo.com/group/CB2HAM

=====================================================================

--- In BITX20@..., "wb7dmx" <wb7dmx@...> wrote:
SNIP
another problem I am having is when I print out the track, the size
is off enough that I don't want to make the board that way, I can't
seam to be able to print the correct size so the parts will fit
correctly. let alone the matching of a double sided board.
SNIP

confused
bob
WB7DMX

problems

wbdmxbaileybobbuttercup
 

I am looking at building the btx-20,it looks like it would be a fun
rig to play with.

the only problem I am running into it that there are so many
fifferant versions out now and many differant pc board tracks.

I have a limit of pc board size right now of a 4 X 6. unless I buy a
bigger one, which I am willing to do.

I print the track to a transfer film with my laser jet printer for
all the pc boards I make.

the board that is 3 X 5 looks like one I would try, but I cannot
find the schenatic for that one.

also I like the newer version 3 circuit, but does it have to be a
double sided board ?

another problem I am having is when I print out the track, the size
is off enough that I don't want to make the board that way, I can't
seam to be able to print the correct size so the parts will fit
correctly. let alone the matching of a double sided board.

I could also just give up and buy the kit, but that would be the
last choice.

I already have a lot of the parts, I think, I bought 20 of the 10mhz
xtals and 10 of the if cans, hope there the correct ones.

confused
bob
WB7DMX

Re: VXO

Ashhar Farhan <farhan@...>
 

the bitx vxo is quite a bad circuit for a receiver local oscillator. it
functions well as a BFO though. this is because it has a heavily clipped
output. which is fine for a bfo as the harmonics (which are quite strong)
are filtered out by the crystal filter. if you use it in the open part of a
receiver (before the crystal filter), you may get a number of undesired
birdies and spurs.
it is better to use a vxo that has a tuned tank in the output and buffer it
well enough just like a VFO. the lighter you load a VXO the more it will
pull.

- farhan


On 4/26/08, Juanjo Pastor <ec5aca@...> wrote:

Of course, Stan, you have to tune out all the undesired mixing products.
I
thought it was understood... I think that the 12 MHz is possible to be
tuned
20 KHz or even more under its nominal frequency and the 16 MHz rock can be
lifted over its nominal frequency with a simple adjustable capacitive
trimmer. Some years ago I tuned a 19.6608 crystal to 19.670 MHz with only a
65 pF trimmer (the big plastic yellow one) in a 40 to 11 metres receiving
converter with a S042P (it is in my site, but it is written up in
Spanish...).

On the other hand, I will not mention all of you, but you are a really
stunning bunch. I declare myself a fan to you and the group is the one I
like best! I stay tuned as always...

73, 72 de Juanjo, EC5ACA. EA-QRP #104, G-QRP #9742, QRP-L #1662,
FP #899.

Juanjo Pastor
C/San Roque, 4-1º
46460 Silla
SPAIN

e-mail: ec5aca@... <ec5aca%40gmail.com>
web: http://es.geocities.com/ea5chq
web del club: http://www.eaqrp.com
Tel.: +034 96 120 17 67
Movil: 651 35 35 11
----- Original Message -----
From: "Stanley Grixti" <stanley@... <stanley%409h1lo.net>>
To: <BITX20@... <BITX20%40yahoogroups.com>>
Sent: Saturday, April 26, 2008 12:55 PM
Subject: Re: [BITX20] Re: VXO

i am now considering the 16-12 solution...

would you think it would be best to have a 4mhz BPF after the mixer
before the 10+4mhz mixer??



Juanjo Pastor wrote:

Hello everybody as this is my first post to the group.

Stan, what about vxoing or supervxoing the 4.096 MHz standard crystals?
If
you can't find them in Malta, send me your address and I will send a
couple
of them to you. 26 KHz down is quite a lot with a 4 ish MHz rock but it
could be doable. Another option would be heterodining two crystal
frequencies, like 8 and 12 convinently pulled, I see 8 should be
pulled down
and 12 up. Or even better, 12 and 16, I am sure that with the
corresponding
pulling you could get the 4.070 mix easily. Anyway I am not into other
digimodes but CW, and I really think it is possible to get a stable
enough
VFO covering from 4 to 4.350 MHz to work all the band. The huff & puff
FLL
is also interesting, and would made a good VFO even better. I will stay
tuned to hear your results. Best wishes to all the BiTXers!

73, 72 de Juanjo, EC5ACA. EA-QRP #104, G-QRP #9742, QRP-L #1662,
FP #899.

Juanjo Pastor
C/San Roque, 4-1º
46460 Silla
SPAIN

e-mail: ec5aca@... <ec5aca%40gmail.com> <mailto:
ec5aca%40gmail.com <ec5aca%2540gmail.com>>
web: http://es.geocities.com/ea5chq <http://es.geocities.com/ea5chq>
web del club: http://www.eaqrp.com <http://www.eaqrp.com>
Tel.: +034 96 120 17 67
Movil: 651 35 35 11
----- Original Message -----
From: "wimmie262000" <jowijowi@... <jowijowi%40gmail.com><mailto:
jowijowi%40gmail.com <jowijowi%2540gmail.com>>>
To: <BITX20@... <BITX20%40yahoogroups.com> <mailto:
BITX20%40yahoogroups.com <BITX20%2540yahoogroups.com>>>
Sent: Friday, April 25, 2008 5:38 PM
Subject: [BITX20] Re: VXO

--- In BITX20@... <BITX20%40yahoogroups.com> <mailto:
BITX20%40yahoogroups.com <BITX20%2540yahoogroups.com>>,
"Mike W" <mike@...> wrote:

Duh, why did'nt I see that too Joop:-)
obviously the old grey matter is diminishing.
a very good idea as the 24Mhz CPU xtals are readily available for a
few pence
each. However, is'nt the PSK31 mode sideband depemdent though?,
high
side
injection will mean swapping the CIO insertion.
73 Mike G8NXD
Well I see I am wrong in my calculation of the ppm's (quiete a bit
higher), but you got the idea. And I am not sure about the PSK
sensitivity. Could the sideband "orientation" LF not be chosen with
the right BFO frequency?


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

Yahoo! Groups Links


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

Yahoo! Groups Links




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Re: VXO

Juanjo Pastor
 

Of course, Stan, you have to tune out all the undesired mixing products. I
thought it was understood... I think that the 12 MHz is possible to be tuned
20 KHz or even more under its nominal frequency and the 16 MHz rock can be
lifted over its nominal frequency with a simple adjustable capacitive
trimmer. Some years ago I tuned a 19.6608 crystal to 19.670 MHz with only a
65 pF trimmer (the big plastic yellow one) in a 40 to 11 metres receiving
converter with a S042P (it is in my site, but it is written up in
Spanish...).

On the other hand, I will not mention all of you, but you are a really
stunning bunch. I declare myself a fan to you and the group is the one I
like best! I stay tuned as always...

73, 72 de Juanjo, EC5ACA. EA-QRP #104, G-QRP #9742, QRP-L #1662,
FP #899.

Juanjo Pastor
C/San Roque, 4-1�
46460 Silla
SPAIN

e-mail: ec5aca@...
web: http://es.geocities.com/ea5chq
web del club: http://www.eaqrp.com
Tel.: +034 96 120 17 67
Movil: 651 35 35 11

----- Original Message -----
From: "Stanley Grixti" <stanley@...>
To: <BITX20@...>
Sent: Saturday, April 26, 2008 12:55 PM
Subject: Re: [BITX20] Re: VXO


i am now considering the 16-12 solution...

would you think it would be best to have a 4mhz BPF after the mixer
before the 10+4mhz mixer??



Juanjo Pastor wrote:

Hello everybody as this is my first post to the group.

Stan, what about vxoing or supervxoing the 4.096 MHz standard crystals?
If
you can't find them in Malta, send me your address and I will send a
couple
of them to you. 26 KHz down is quite a lot with a 4 ish MHz rock but it
could be doable. Another option would be heterodining two crystal
frequencies, like 8 and 12 convinently pulled, I see 8 should be
pulled down
and 12 up. Or even better, 12 and 16, I am sure that with the
corresponding
pulling you could get the 4.070 mix easily. Anyway I am not into other
digimodes but CW, and I really think it is possible to get a stable
enough
VFO covering from 4 to 4.350 MHz to work all the band. The huff & puff
FLL
is also interesting, and would made a good VFO even better. I will stay
tuned to hear your results. Best wishes to all the BiTXers!

73, 72 de Juanjo, EC5ACA. EA-QRP #104, G-QRP #9742, QRP-L #1662,
FP #899.

Juanjo Pastor
C/San Roque, 4-1�
46460 Silla
SPAIN

e-mail: ec5aca@... <mailto:ec5aca%40gmail.com>
web: http://es.geocities.com/ea5chq <http://es.geocities.com/ea5chq>
web del club: http://www.eaqrp.com <http://www.eaqrp.com>
Tel.: +034 96 120 17 67
Movil: 651 35 35 11
----- Original Message -----
From: "wimmie262000" <jowijowi@... <mailto:jowijowi%40gmail.com>>
To: <BITX20@... <mailto:BITX20%40yahoogroups.com>>
Sent: Friday, April 25, 2008 5:38 PM
Subject: [BITX20] Re: VXO

--- In BITX20@... <mailto:BITX20%40yahoogroups.com>,
"Mike W" <mike@...> wrote:

Duh, why did'nt I see that too Joop:-)
obviously the old grey matter is diminishing.
a very good idea as the 24Mhz CPU xtals are readily available for a
few pence
each. However, is'nt the PSK31 mode sideband depemdent though?, high
side
injection will mean swapping the CIO insertion.
73 Mike G8NXD
Well I see I am wrong in my calculation of the ppm's (quiete a bit
higher), but you got the idea. And I am not sure about the PSK
sensitivity. Could the sideband "orientation" LF not be chosen with
the right BFO frequency?


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Re: antenna and baluns

Jim <n6otq@...>
 

--- Ashish <geniusashish85@...> wrote:

thank you Raj and Arvind...

so shall I go for bare copper wire(single strand)?and what should be
the approximate wire guage?I am having RG-59 cable.I think its 75
ohms
(pls correct me if I m wrong).Shall I use this as feed lines?Will
that
work with the BITX tranceiver whose output impedence is 50 ohm?or is
there any need of a balun?

What you'll find with a dipole is that almost anything you put up will
work. Sometimes better than other times ...

A balun is not a requirement. I've never used one and I've never
suffered any problems because of it. But since it's so easy to build a
balun for BITX power levels, I'd recommend that you consider using one.


After all, you need something to use for the center separator/ support
hanger for the dipole.

N6OTQ


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Re: VXO

Stanley Grixti
 

i am now considering the 16-12 solution...

would you think it would be best to have a 4mhz BPF after the mixer before the 10+4mhz mixer??



Juanjo Pastor wrote:


Hello everybody as this is my first post to the group.

Stan, what about vxoing or supervxoing the 4.096 MHz standard crystals? If
you can't find them in Malta, send me your address and I will send a couple
of them to you. 26 KHz down is quite a lot with a 4 ish MHz rock but it
could be doable. Another option would be heterodining two crystal
frequencies, like 8 and 12 convinently pulled, I see 8 should be pulled down
and 12 up. Or even better, 12 and 16, I am sure that with the corresponding
pulling you could get the 4.070 mix easily. Anyway I am not into other
digimodes but CW, and I really think it is possible to get a stable enough
VFO covering from 4 to 4.350 MHz to work all the band. The huff & puff FLL
is also interesting, and would made a good VFO even better. I will stay
tuned to hear your results. Best wishes to all the BiTXers!

73, 72 de Juanjo, EC5ACA. EA-QRP #104, G-QRP #9742, QRP-L #1662,
FP #899.

Juanjo Pastor
C/San Roque, 4-1�
46460 Silla
SPAIN

e-mail: ec5aca@... <mailto:ec5aca%40gmail.com>
web: http://es.geocities.com/ea5chq <http://es.geocities.com/ea5chq>
web del club: http://www.eaqrp.com <http://www.eaqrp.com>
Tel.: +034 96 120 17 67
Movil: 651 35 35 11
----- Original Message -----
From: "wimmie262000" <jowijowi@... <mailto:jowijowi%40gmail.com>>
To: <BITX20@... <mailto:BITX20%40yahoogroups.com>>
Sent: Friday, April 25, 2008 5:38 PM
Subject: [BITX20] Re: VXO

--- In BITX20@... <mailto:BITX20%40yahoogroups.com>,
"Mike W" <mike@...> wrote:

Duh, why did'nt I see that too Joop:-)
obviously the old grey matter is diminishing.
a very good idea as the 24Mhz CPU xtals are readily available for a
few pence
each. However, is'nt the PSK31 mode sideband depemdent though?, high
side
injection will mean swapping the CIO insertion.
73 Mike G8NXD
Well I see I am wrong in my calculation of the ppm's (quiete a bit
higher), but you got the idea. And I am not sure about the PSK
sensitivity. Could the sideband "orientation" LF not be chosen with
the right BFO frequency?


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

Yahoo! Groups Links


Re: [Fwd: Re: Re: VXO]

Stanley Grixti
 

I am using the xtal oscillator designed in the orignal bitx bfo...but i changed the 220pf caps to 100pf

wimmie262000 wrote:


--- In BITX20@... <mailto:BITX20%40yahoogroups.com>, Stanley Grixti <stanley@...> wrote:

very strange ...i only want to pull up just about 1.15khz!

actually i found some other 'old type' they are like hc49 but larger

i tested them in circuit...they all won't move far...only 1 or 2khz
max then dye...i even found one at 4030khz! pity!
What oscillator circuit are you using?
With small capacitances the total impedance increases to a point where
you might need more loop gain to sustain oscillation.