Date   
LED Frequency Display

Mike W <mike@...>
 

Hi folks,
I don't know if this will interest anyone. But I have just obtained a
fairly large quantity of minature multiplexed 7 segment LED displays.
They have 7 numeric characters and 7 'S' meter, like leds in a
bargraph. and fit into a standard 28 pin DIL socket.

They would be ideal for use with an OM3CPH PIC frequency display for
the BITX

see picture at
http:&#92;www.qsl.net&#92;g8nxd&#92;files&#92;LEDS.gif

I'm a little unsure about what they are worth but if anyone would
like one for 1.00 UKP plus postage to anywhere on Earth.
Then please give me a shout off list.

My BITX20 is still not finished but it will be soon. Congrats to all
builders who have finished theirs. I hope to work you on 20m soon

72/73 de Mike W, G8NXD qthr

Re: BITX20 Photos

Arv Evans <arvevans@...>
 

Pete

Congratulations on the very good looking BITX20 transceiver.  That LCD display is a good
addition.

Arv K7HKL
_._
On Sat, 2004-10-02 at 05:25, vdberghak wrote:
Looks good Pete!
First I searched in your directory but I found them in the main
directory.
Indeed building the circuit in some kind of box is may be the
hardest part.
I am still thinking about the best construction to make the dial
knob on the capacitor... ;-(
Best regards,
Chris.

--- In BITX20@..., "kaliediscope2004"
wrote:
> Greetings fellow BITX20 Builders. I have just uploaded some photos
> of my BITX20 in the newly completed homebrew enclosure. Still need
> to add the sides and top but the hard part is mostly done.
>
> This is one FB radio and I have had many enjoyable QSO's with the
> little radio. Am looking forward to a possible 2X QSO with another
> BITX20.
>
> 73's
> Pete W6JFR


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  • New file uploaded to BITX20

    BITX20@...
     

    Hello,

    This email message is a notification to let you know that
    a file has been uploaded to the Files area of the BITX20
    group.

    File : /MODIFICATIONS/Schema VXO.gif
    Uploaded by : vdberghak <vdberghak@...>
    Description : 13 MHZ VXO for BITX17

    You can access this file at the URL:
    http://groups.yahoo.com/group/BITX20/files/MODIFICATIONS/Schema%20VXO.gif

    To learn more about file sharing for your group, please visit:
    http://help.yahoo.com/help/us/groups/files

    Regards,

    vdberghak <vdberghak@...>

    Re: BITX20 Photos

    Chris van den Berg
     

    Looks good Pete!
    First I searched in your directory but I found them in the main
    directory.
    Indeed building the circuit in some kind of box is may be the
    hardest part.
    I am still thinking about the best construction to make the dial
    knob on the capacitor... ;-(
    Best regards,
    Chris.

    --- In BITX20@..., "kaliediscope2004"
    <kaliediscope2004@y...> wrote:
    Greetings fellow BITX20 Builders. I have just uploaded some photos
    of my BITX20 in the newly completed homebrew enclosure. Still need
    to add the sides and top but the hard part is mostly done.

    This is one FB radio and I have had many enjoyable QSO's with the
    little radio. Am looking forward to a possible 2X QSO with another
    BITX20.

    73's
    Pete W6JFR

    Re: Extra capacitors in your BITX...?

    Arvid Evans <arvevans@...>
     

    Dear Rahul

    Thank you for the information on RU area transceivers. It will take a
    while to translate and understand all this, but it is very interesting
    reading.

    Thanks,
    Arv K7HKL
    _._

    --- In BITX20@..., Rahul Srivastava <vu3wjm@y...> wrote:
    Dear Hans and Arv

    Hi!

    It is indeed pleasure to see some interest in ones post. I find this
    as a case of history repeating itself. Similar on the line of two
    different concept that evolved during development of a space suit one
    a 7 layered design and other in RU teritories almirah door type ones.

    Hams I see you did some serious work on the hammer/ screwdriver page
    ( This is what i comprehend from the icon). At times it appeared funny
    to see something translated like the administration is done by change
    it pressure. Ultimately it boiled down to to freq control is manged by
    change in voltage, a description of PLL sections.

    A brief lineup of RU designs would be in order for RU TRXs, UW3DI,
    Ural84, Desna, Don-M and many others with some peculiar characters.

    Now on the topic there are another few page of these region that
    also need some looking into for hombrew projects:

    http://ra3ggi.qrz.ru/

    and yet another

    http://www.qsl.net/sp3abg/index.html

    Hope all enjoy.

    73

    Rahul VU3WJM


    Hans Summers <Hans.Summers@t...> wrote:

    BITX'ers

    Note that if you want to see an English translation, you could try
    the Altavista "babel fish" see
    http://babelfish.altavista.com/babelfish/tr. You can type in the web
    page, and view the translated web page. It's rather neat. The
    translation is obviously not perfect but it's quite easy to follow the
    ideas. If you look at the home page http://www.cqham.ru/index.phtml
    you'll find all kind of gems. Numerous transceiver projects etc. Also
    many downloaded QST articles, and more. There is an English flag on
    the home page which provides a translation, but it does not work as
    well as the Altavista page.

    73 Hans G0UPL
    http://www.HansSummers.com

    -----Original Message-----
    From: Rahul Srivastava [mailto:vu3wjm@y...]
    Sent: 01 October 2004 06:57
    To: BITX20@...
    Subject: Re: [BITX20] Extra capacitors in your BITX...?


    Dear Arv,

    From what I could make out of mechanical translations, the concept
    among RU friends was popularised with Ural 84 design. Desna was the
    more updated version probably it means dew.

    the RU page for Desna design is here:

    http://www.cqham.ru/desna.htm

    The main board ckt I am posting under files section for thers to
    have a look at another way of implimenting Bi-directional concept.

    73

    Rahul VU3WJM





    Arv Evans <arvevans@e...> wrote:
    Rahul-VU3WJM

    I did a search (using Google) for :Ural 84" and for "Desna" and did
    find some textual mention of these units, but I did not find any web
    sites that showed equipment or schematics. Do you have a URL that we
    might use to see schematics for this equipment?

    Thanks,
    Arv-K7HKL
    _._

    On Wed, 2004-09-29 at 22:17, Rahul Srivastava wrote: Hi!

    On mention of PSK mini I also suggest looking at RU designs Ural 84
    and Desna. Similar concepts are used there while using bipolar
    transistors.

    I am sure the coupling caps for filters can be removed. Had I been
    and audiophile I would like not to have even one of them in signal path.

    73

    Rahul VU3WJM



    Arvid Evans <arvevans@e...> wrote: Hello

    As I sit here looking at the BITX20 schematic it 0ccured to me that
    some of the capacitors may not be necessary:

    1) There is a 0.1 mf on the base of Q1, that connects to a 0.1 on
    the collector of Q13. These then connect via a 10 pf to the front-end
    bandpass filter. Would it not be acceptable to use only one 0.1 mf
    between the collector of Q13 and the Base of Q1, and connect the base
    of Q1 to the bandpass filter via the 10 pf cap?

    2) There is a 0.1 mf on the collector of Q2 that connects to the
    crystal filter, and another 0.1 that connects the base of Q12 to the
    same point on the crystal filter. Would it be sufficient to use just
    the 0.1 mf from the collector of Q2 to the crystal filter, and then
    connect the base of Q12 directly to the same point on that filter?
    Since crystals do not pass DC, the same amount of DC isolation would
    be maintained.

    3) There is a 0.1 mf between the end of the crystal filter and the
    base of Q3, and another 0.1 mf between that same point on the crystal
    filter and the collector of Q11. It seems that it would suffice to
    have the 0.1 mf between the collector of Q11 and the base of Q3, with
    the crystal filter simply connected to the base of Q3. Again, the
    crystal does not conduct DC, so there would still be the same level of
    DC isolation.

    OK, for all you purists out there, I know that it looks more
    symetrical with the "pairs of 0.1 mf capacitors", but are they really
    necessary?

    What spawned this evaluation is my comparison of RV3GM's PSK-20
    schematic with the BITX20 design by Farhan. I was wondering if Oleg's
    method of using one transister in bi-directional mode could also be
    applied to the BITX20 where we are using pairs of transisters to
    obtain bi-directionality.

    Arv-K7HKL
    _._



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    BITX20 Photos

    kaliediscope2004 <kaliediscope2004@...>
     

    Greetings fellow BITX20 Builders. I have just uploaded some photos
    of my BITX20 in the newly completed homebrew enclosure. Still need
    to add the sides and top but the hard part is mostly done.

    This is one FB radio and I have had many enjoyable QSO's with the
    little radio. Am looking forward to a possible 2X QSO with another
    BITX20.

    73's
    Pete W6JFR

    Re: Extra capacitors in your BITX...?

    Rahul Srivastava
     

    Dear Hans and Arv
     
    Hi!
     
    It is indeed pleasure to see some interest in ones post. I find this as a case of history repeating itself. Similar on the line of two different concept that evolved during development of a space suit one a 7 layered design and other in RU teritories almirah door type ones.
     
    Hams I see you did some serious work on the hammer/ screwdriver page ( This is what i comprehend from the icon). At times it appeared funny to see something translated like the administration is done by change it pressure. Ultimately it boiled down to to freq control is manged by change in voltage, a description of PLL sections.
     
    A brief lineup of RU designs would be in order for RU TRXs, UW3DI, Ural84, Desna, Don-M and many others with some peculiar characters.
     
    Now on the topic there are another few page of these region that also need some looking into for hombrew projects:
     
     
    and yet another
     
     
    Hope all enjoy.
     
    73
     
    Rahul VU3WJM
     

    Hans Summers wrote:
     
    BITX'ers
     
    Note that if you want to see an English translation, you could try the Altavista "babel fish" see http://babelfish.altavista.com/babelfish/tr. You can type in the web page, and view the translated web page. It's rather neat. The translation is obviously not perfect but it's quite easy to follow the ideas. If you look at the home page http://www.cqham.ru/index.phtml you'll find all kind of gems. Numerous transceiver projects etc. Also many downloaded QST articles, and more. There is an English flag on the home page which provides a translation, but it does not work as well as the Altavista page.
     
    73 Hans G0UPL
    http://www.HansSummers.com
    -----Original Message-----
    From: Rahul Srivastava [mailto:vu3wjm@...]
    Sent: 01 October 2004 06:57
    To: BITX20@...
    Subject: Re: [BITX20] Extra capacitors in your BITX...?

    Dear Arv,
     
    From what I could make out of mechanical translations, the concept among RU friends was popularised with Ural 84 design. Desna was the more updated version probably it means dew.
     
    the RU page for Desna design is here:
     
     
    The main board ckt I am posting under files section for thers to have a look at another way of implimenting Bi-directional concept. 
     
    73
     
    Rahul VU3WJM
     
     
     


    Arv Evans wrote:
    Rahul-VU3WJM

    I did a search (using Google) for :Ural 84" and for "Desna" and did find some textual mention of these units, but I did not find any web sites that showed equipment or schematics.  Do you have a URL that we might use to see schematics for this equipment?

    Thanks,
    Arv-K7HKL
    _._

    On Wed, 2004-09-29 at 22:17, Rahul Srivastava wrote:
    Hi!
     
    On mention of PSK mini I also suggest looking at RU designs Ural 84 and Desna. Similar concepts are used there while using bipolar transistors.
     
    I am sure the coupling caps for filters can be removed.  Had I been and audiophile  I would  like not to have even one of them in signal path.
     
    73
     
    Rahul VU3WJM
     
     

    Arvid Evans wrote:
    Hello

    As I sit here looking at the BITX20 schematic it 0ccured to me that
    some of the capacitors may not be necessary:

      1)  There is a 0.1 mf on the base of Q1, that connects to a 0.1 on
    the collector of Q13.  These then connect via a 10 pf to the front-end
    bandpass filter.  Would it not be acceptable to use only one 0.1 mf
    between the collector of Q13 and the Base of Q1, and connect the base
    of Q1 to the bandpass filter via the 10 pf cap?

      2)  There is a 0.1 mf on the collector of Q2 that connects to the
    crystal filter, and another 0.1 that connects the base of Q12 to the
    same point on the crystal filter.  Would it be sufficient to use just
    the 0.1 mf from the collector of Q2 to the crystal filter, and then
    connect the base of Q12 directly to the same point on that filter?
    Since crystals do not pass DC, the same amount of DC isolation would
    be maintained.

      3)  There is a 0.1 mf between the end of the crystal filter and the
    base of Q3, and another 0.1 mf between that same point on the crystal
    filter and the collector of Q11.  It seems that it would suffice to
    have the 0.1 mf between the collector of Q11 and the base of Q3, with
    the crystal filter simply connected to the base of Q3.  Again, the
    crystal does not conduct DC, so there would still be the same level of
    DC isolation.

    OK, for all you purists out there, I know that it looks more
    symetrical with the "pairs of 0.1 mf capacitors", but are they really
    necessary?

    What spawned this evaluation is my comparison of RV3GM's PSK-20
    schematic with the BITX20 design by Farhan.  I was wondering if Oleg's
    method of using one transister in bi-directional mode could also be
    applied to the BITX20 where we are using pairs of transisters to
    obtain bi-directionality. 

    Arv-K7HKL
    _._



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    Re: Extra capacitors in your BITX...?

    Arvid Evans <arvevans@...>
     

    Rahul & Hans

    Thanks for the info on the RU designed Desna Xcvr. It is interesting
    that they used a valve-type linear instead of solid state.

    In the Desna design, Vt2 and VT3 layouts do show one way of obtaining
    proper bias when using BJTs in a bi-directional layout.

    After looking at the Desna and the PSK-20 by RV3GM, I opened Eagle CAD
    and put together a quick conceptual drawing of a minimalist DSB Xcvr
    layout that uses this switched bidirectional amplifier idea. The
    result has been uploaded to <BITX20/FILES/K7HKL/DSB-Mite "Conceptual
    Drawing".gif> if anyone wants to look and comment.
    NOTE: THIS IS A CONCEPTUAL DRAWING ONLY...NOT TESTED...DO NOT BUILD
    FROM THIS DRAWING.

    73
    Arv-K7HKL

    --- In BITX20@..., Hans Summers <Hans.Summers@t...> wrote:

    BITX'ers

    Note that if you want to see an English translation, you could try the
    Altavista "babel fish" see http://babelfish.altavista.com/babelfish/tr
    <http://babelfish.altavista.com/babelfish/tr> . You can type in the web
    page, and view the translated web page. It's rather neat. The
    translation is
    obviously not perfect but it's quite easy to follow the ideas. If
    you look
    at the home page http://www.cqham.ru/index.phtml
    <http://www.cqham.ru/index.phtml> you'll find all kind of gems.
    Numerous
    transceiver projects etc. Also many downloaded QST articles, and
    more. There
    is an English flag on the home page which provides a translation, but it
    does not work as well as the Altavista page.

    73 Hans G0UPL
    http://www.HansSummers.com

    -----Original Message-----
    From: Rahul Srivastava [mailto:vu3wjm@y...]
    Sent: 01 October 2004 06:57
    To: BITX20@...
    Subject: Re: [BITX20] Extra capacitors in your BITX...?


    Dear Arv,

    From what I could make out of mechanical translations, the concept
    among RU
    friends was popularised with Ural 84 design. Desna was the more updated
    version probably it means dew.

    the RU page for Desna design is here:

    http://www.cqham.ru/desna.htm <http://www.cqham.ru/desna.htm>

    The main board ckt I am posting under files section for thers to
    have a look
    at another way of implimenting Bi-directional concept.

    73

    Rahul VU3WJM





    Arv Evans <arvevans@e...> wrote:

    Rahul-VU3WJM

    I did a search (using Google) for :Ural 84" and for "Desna" and did find
    some textual mention of these units, but I did not find any web
    sites that
    showed equipment or schematics. Do you have a URL that we might use
    to see
    schematics for this equipment?

    Thanks,
    Arv-K7HKL
    _._

    On Wed, 2004-09-29 at 22:17, Rahul Srivastava wrote:

    Hi!

    On mention of PSK mini I also suggest looking at RU designs Ural 84 and
    Desna. Similar concepts are used there while using bipolar transistors.

    I am sure the coupling caps for filters can be removed. Had I been and
    audiophile I would like not to have even one of them in signal path.

    73

    Rahul VU3WJM



    Arvid Evans <arvevans@e...> wrote:

    Hello

    As I sit here looking at the BITX20 schematic it 0ccured to me that
    some of the capacitors may not be necessary:

    1) There is a 0.1 mf on the base of Q1, that connects to a 0.1 on
    the collector of Q13. These then connect via a 10 pf to the front-end
    bandpass filter. Would it not be acceptable to use only one 0.1 mf
    between the collector of Q13 and the Base of Q1, and connect the base
    of Q1 to the bandpass filter via the 10 pf cap?

    2) There is a 0.1 mf on the collector of Q2 that connects to the
    crystal filter, and another 0.1 that connects the base of Q12 to the
    same point on the crystal filter. Would it be sufficient to use just
    the 0.1 mf from the collector of Q2 to the crystal filter, and then
    connect the base of Q12 directly to the same point on that filter?
    Since crystals do not pass DC, the same amount of DC isolation would
    be maintained.

    3) There is a 0.1 mf between the end of the crystal filter and the
    base of Q3, and another 0.1 mf between that same point on the crystal
    filter and the collector of Q11. It seems that it would suffice to
    have the 0.1 mf between the collector of Q11 and the base of Q3, with
    the crystal filter simply connected to the base of Q3. Again, the
    crystal does not conduct DC, so there would still be the same level of
    DC isolation.

    OK, for all you purists out there, I know that it looks more
    symetrical with the "pairs of 0.1 mf capacitors", but are they really
    necessary?

    What spawned this evaluation is my comparison of RV3GM's PSK-20
    schematic with the BITX20 design by Farhan. I was wondering if Oleg's
    method of using one transister in bi-directional mode could also be
    applied to the BITX20 where we are using pairs of transisters to
    obtain bi-directionality.

    Arv-K7HKL
    _._



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    Re: Extra capacitors in your BITX...?

    Hans Summers <Hans.Summers@...>
     

     
    BITX'ers
     
    Note that if you want to see an English translation, you could try the Altavista "babel fish" see http://babelfish.altavista.com/babelfish/tr. You can type in the web page, and view the translated web page. It's rather neat. The translation is obviously not perfect but it's quite easy to follow the ideas. If you look at the home page http://www.cqham.ru/index.phtml you'll find all kind of gems. Numerous transceiver projects etc. Also many downloaded QST articles, and more. There is an English flag on the home page which provides a translation, but it does not work as well as the Altavista page.
     
    73 Hans G0UPL
    http://www.HansSummers.com

    -----Original Message-----
    From: Rahul Srivastava [mailto:vu3wjm@...]
    Sent: 01 October 2004 06:57
    To: BITX20@...
    Subject: Re: [BITX20] Extra capacitors in your BITX...?

    Dear Arv,
     
    From what I could make out of mechanical translations, the concept among RU friends was popularised with Ural 84 design. Desna was the more updated version probably it means dew.
     
    the RU page for Desna design is here:
     
     
    The main board ckt I am posting under files section for thers to have a look at another way of implimenting Bi-directional concept. 
     
    73
     
    Rahul VU3WJM
     
     
     


    Arv Evans wrote:
    Rahul-VU3WJM

    I did a search (using Google) for :Ural 84" and for "Desna" and did find some textual mention of these units, but I did not find any web sites that showed equipment or schematics.  Do you have a URL that we might use to see schematics for this equipment?

    Thanks,
    Arv-K7HKL
    _._

    On Wed, 2004-09-29 at 22:17, Rahul Srivastava wrote:
    Hi!
     
    On mention of PSK mini I also suggest looking at RU designs Ural 84 and Desna. Similar concepts are used there while using bipolar transistors.
     
    I am sure the coupling caps for filters can be removed.  Had I been and audiophile  I would  like not to have even one of them in signal path.
     
    73
     
    Rahul VU3WJM
     
     

    Arvid Evans wrote:
    Hello

    As I sit here looking at the BITX20 schematic it 0ccured to me that
    some of the capacitors may not be necessary:

      1)  There is a 0.1 mf on the base of Q1, that connects to a 0.1 on
    the collector of Q13.  These then connect via a 10 pf to the front-end
    bandpass filter.  Would it not be acceptable to use only one 0.1 mf
    between the collector of Q13 and the Base of Q1, and connect the base
    of Q1 to the bandpass filter via the 10 pf cap?

      2)  There is a 0.1 mf on the collector of Q2 that connects to the
    crystal filter, and another 0.1 that connects the base of Q12 to the
    same point on the crystal filter.  Would it be sufficient to use just
    the 0.1 mf from the collector of Q2 to the crystal filter, and then
    connect the base of Q12 directly to the same point on that filter?
    Since crystals do not pass DC, the same amount of DC isolation would
    be maintained.

      3)  There is a 0.1 mf between the end of the crystal filter and the
    base of Q3, and another 0.1 mf between that same point on the crystal
    filter and the collector of Q11.  It seems that it would suffice to
    have the 0.1 mf between the collector of Q11 and the base of Q3, with
    the crystal filter simply connected to the base of Q3.  Again, the
    crystal does not conduct DC, so there would still be the same level of
    DC isolation.

    OK, for all you purists out there, I know that it looks more
    symetrical with the "pairs of 0.1 mf capacitors", but are they really
    necessary?

    What spawned this evaluation is my comparison of RV3GM's PSK-20
    schematic with the BITX20 design by Farhan.  I was wondering if Oleg's
    method of using one transister in bi-directional mode could also be
    applied to the BITX20 where we are using pairs of transisters to
    obtain bi-directionality. 

    Arv-K7HKL
    _._



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    New file uploaded to BITX20

    BITX20@...
     

    Hello,

    This email message is a notification to let you know that
    a file has been uploaded to the Files area of the BITX20
    group.

    File : /desna.gif
    Uploaded by : vu3wjm <vu3wjm@...>
    Description : Another way to impliment Bi-directional concept.

    You can access this file at the URL:
    http://groups.yahoo.com/group/BITX20/files/desna.gif

    To learn more about file sharing for your group, please visit:
    http://help.yahoo.com/help/us/groups/files

    Regards,

    vu3wjm <vu3wjm@...>

    Re: Extra capacitors in your BITX...?

    Rahul Srivastava
     

    Dear Arv,
     
    From what I could make out of mechanical translations, the concept among RU friends was popularised with Ural 84 design. Desna was the more updated version probably it means dew.
     
    the RU page for Desna design is here:
     
     
    The main board ckt I am posting under files section for thers to have a look at another way of implimenting Bi-directional concept. 
     
    73
     
    Rahul VU3WJM
     
     
     


    Arv Evans wrote:
    Rahul-VU3WJM

    I did a search (using Google) for :Ural 84" and for "Desna" and did find some textual mention of these units, but I did not find any web sites that showed equipment or schematics.  Do you have a URL that we might use to see schematics for this equipment?

    Thanks,
    Arv-K7HKL
    _._

    On Wed, 2004-09-29 at 22:17, Rahul Srivastava wrote:
    Hi!
     
    On mention of PSK mini I also suggest looking at RU designs Ural 84 and Desna. Similar concepts are used there while using bipolar transistors.
     
    I am sure the coupling caps for filters can be removed.  Had I been and audiophile  I would  like not to have even one of them in signal path.
     
    73
     
    Rahul VU3WJM
     
     

    Arvid Evans wrote:
    Hello

    As I sit here looking at the BITX20 schematic it 0ccured to me that
    some of the capacitors may not be necessary:

      1)  There is a 0.1 mf on the base of Q1, that connects to a 0.1 on
    the collector of Q13.  These then connect via a 10 pf to the front-end
    bandpass filter.  Would it not be acceptable to use only one 0.1 mf
    between the collector of Q13 and the Base of Q1, and connect the base
    of Q1 to the bandpass filter via the 10 pf cap?

      2)  There is a 0.1 mf on the collector of Q2 that connects to the
    crystal filter, and another 0.1 that connects the base of Q12 to the
    same point on the crystal filter.  Would it be sufficient to use just
    the 0.1 mf from the collector of Q2 to the crystal filter, and then
    connect the base of Q12 directly to the same point on that filter?
    Since crystals do not pass DC, the same amount of DC isolation would
    be maintained.

      3)  There is a 0.1 mf between the end of the crystal filter and the
    base of Q3, and another 0.1 mf between that same point on the crystal
    filter and the collector of Q11.  It seems that it would suffice to
    have the 0.1 mf between the collector of Q11 and the base of Q3, with
    the crystal filter simply connected to the base of Q3.  Again, the
    crystal does not conduct DC, so there would still be the same level of
    DC isolation.

    OK, for all you purists out there, I know that it looks more
    symetrical with the "pairs of 0.1 mf capacitors", but are they really
    necessary?

    What spawned this evaluation is my comparison of RV3GM's PSK-20
    schematic with the BITX20 design by Farhan.  I was wondering if Oleg's
    method of using one transister in bi-directional mode could also be
    applied to the BITX20 where we are using pairs of transisters to
    obtain bi-directionality. 

    Arv-K7HKL
    _._



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    Re: Extra capacitors in your BITX...?

    Arv Evans <arvevans@...>
     

    Rahul-VU3WJM

    I did a search (using Google) for :Ural 84" and for "Desna" and did find some textual mention of these units, but I did not find any web sites that showed equipment or schematics.  Do you have a URL that we might use to see schematics for this equipment?

    Thanks,
    Arv-K7HKL
    _._

    On Wed, 2004-09-29 at 22:17, Rahul Srivastava wrote:
    Hi!
     
    On mention of PSK mini I also suggest looking at RU designs Ural 84 and Desna. Similar concepts are used there while using bipolar transistors.
     
    I am sure the coupling caps for filters can be removed.  Had I been and audiophile  I would  like not to have even one of them in signal path.
     
    73
     
    Rahul VU3WJM
     
     

    Arvid Evans wrote:
    Hello

    As I sit here looking at the BITX20 schematic it 0ccured to me that
    some of the capacitors may not be necessary:

      1)  There is a 0.1 mf on the base of Q1, that connects to a 0.1 on
    the collector of Q13.  These then connect via a 10 pf to the front-end
    bandpass filter.  Would it not be acceptable to use only one 0.1 mf
    between the collector of Q13 and the Base of Q1, and connect the base
    of Q1 to the bandpass filter via the 10 pf cap?

      2)  There is a 0.1 mf on the collector of Q2 that connects to the
    crystal filter, and another 0.1 that connects the base of Q12 to the
    same point on the crystal filter.  Would it be sufficient to use just
    the 0.1 mf from the collector of Q2 to the crystal filter, and then
    connect the base of Q12 directly to the same point on that filter?
    Since crystals do not pass DC, the same amount of DC isolation would
    be maintained.

      3)  There is a 0.1 mf between the end of the crystal filter and the
    base of Q3, and another 0.1 mf between that same point on the crystal
    filter and the collector of Q11.  It seems that it would suffice to
    have the 0.1 mf between the collector of Q11 and the base of Q3, with
    the crystal filter simply connected to the base of Q3.  Again, the
    crystal does not conduct DC, so there would still be the same level of
    DC isolation.

    OK, for all you purists out there, I know that it looks more
    symetrical with the "pairs of 0.1 mf capacitors", but are they really
    necessary?

    What spawned this evaluation is my comparison of RV3GM's PSK-20
    schematic with the BITX20 design by Farhan.  I was wondering if Oleg's
    method of using one transister in bi-directional mode could also be
    applied to the BITX20 where we are using pairs of transisters to
    obtain bi-directionality. 

    Arv-K7HKL
    _._



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  • Re: Extra capacitors in your BITX...?

    Rahul Srivastava
     

    Hi!
     
    On mention of PSK mini I also suggest looking at RU designs Ural 84 and Desna. Similar concepts are used there while using bipolar transistors.
     
    I am sure the coupling caps for filters can be removed.  Had I been and audiophile  I would  like not to have even one of them in signal path.
     
    73
     
    Rahul VU3WJM
     
     


    Arvid Evans wrote:
    Hello

    As I sit here looking at the BITX20 schematic it 0ccured to me that
    some of the capacitors may not be necessary:

      1)  There is a 0.1 mf on the base of Q1, that connects to a 0.1 on
    the collector of Q13.  These then connect via a 10 pf to the front-end
    bandpass filter.  Would it not be acceptable to use only one 0.1 mf
    between the collector of Q13 and the Base of Q1, and connect the base
    of Q1 to the bandpass filter via the 10 pf cap?

      2)  There is a 0.1 mf on the collector of Q2 that connects to the
    crystal filter, and another 0.1 that connects the base of Q12 to the
    same point on the crystal filter.  Would it be sufficient to use just
    the 0.1 mf from the collector of Q2 to the crystal filter, and then
    connect the base of Q12 directly to the same point on that filter?
    Since crystals do not pass DC, the same amount of DC isolation would
    be maintained.

      3)  There is a 0.1 mf between the end of the crystal filter and the
    base of Q3, and another 0.1 mf between that same point on the crystal
    filter and the collector of Q11.  It seems that it would suffice to
    have the 0.1 mf between the collector of Q11 and the base of Q3, with
    the crystal filter simply connected to the base of Q3.  Again, the
    crystal does not conduct DC, so there would still be the same level of
    DC isolation.

    OK, for all you purists out there, I know that it looks more
    symetrical with the "pairs of 0.1 mf capacitors", but are they really
    necessary?

    What spawned this evaluation is my comparison of RV3GM's PSK-20
    schematic with the BITX20 design by Farhan.  I was wondering if Oleg's
    method of using one transister in bi-directional mode could also be
    applied to the BITX20 where we are using pairs of transisters to
    obtain bi-directionality. 

    Arv-K7HKL
    _._



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    Re: Progress with BITX

    Arv Evans <arvevans@...>
     

    John-G0UCP

    Congratulations on the birth of your new BITX20 transceiver!


    Arv-K7HKL
    _._
    On Wed, 2004-09-29 at 13:02, market10gardener wrote:
    Hi
    I'm pleased to say that my BITX20 is now complete and it performs
    exactly as described. With my 132' doublet it has received excellent
    reports incuding 59 from PJ4 in one direction and UN7 in the other.
    Like Chris I made a few contacts with the penultimate (2N2218) stage
    on its own and these included an island off the coast of ES which was
    satisfying with 100Mw.
    At first the PA was a little unstable so I put in a small (abt 45pf)
    trimmer capacitor from the gate to the drain of the IRF510, lowered
    the value of the 2.2K resistor between the base and collector of the
    2N2218 by putting a 1K resistor in parallel with it and substituted a
    300pf cap for the 0.1mf between the drain of the IRF510 and the low
    pass filter. I now get 4 watts with a 12 volt power supply and 5
    watts with about 13v from a 17 Ah storage battery.
    I heard VU2PEP wkg most of North America (with 200 watts) the other
    evening but the pile up was formidable. It would be nice to meet
    another BITX on the air. Is any one interested in taking one along to
    Rochdale on the 9th October?
    72, 73
    John  G0UCP


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  • Extra capacitors in your BITX...?

    Arvid Evans <arvevans@...>
     

    Hello

    As I sit here looking at the BITX20 schematic it 0ccured to me that
    some of the capacitors may not be necessary:

    1) There is a 0.1 mf on the base of Q1, that connects to a 0.1 on
    the collector of Q13. These then connect via a 10 pf to the front-end
    bandpass filter. Would it not be acceptable to use only one 0.1 mf
    between the collector of Q13 and the Base of Q1, and connect the base
    of Q1 to the bandpass filter via the 10 pf cap?

    2) There is a 0.1 mf on the collector of Q2 that connects to the
    crystal filter, and another 0.1 that connects the base of Q12 to the
    same point on the crystal filter. Would it be sufficient to use just
    the 0.1 mf from the collector of Q2 to the crystal filter, and then
    connect the base of Q12 directly to the same point on that filter?
    Since crystals do not pass DC, the same amount of DC isolation would
    be maintained.

    3) There is a 0.1 mf between the end of the crystal filter and the
    base of Q3, and another 0.1 mf between that same point on the crystal
    filter and the collector of Q11. It seems that it would suffice to
    have the 0.1 mf between the collector of Q11 and the base of Q3, with
    the crystal filter simply connected to the base of Q3. Again, the
    crystal does not conduct DC, so there would still be the same level of
    DC isolation.

    OK, for all you purists out there, I know that it looks more
    symetrical with the "pairs of 0.1 mf capacitors", but are they really
    necessary?

    What spawned this evaluation is my comparison of RV3GM's PSK-20
    schematic with the BITX20 design by Farhan. I was wondering if Oleg's
    method of using one transister in bi-directional mode could also be
    applied to the BITX20 where we are using pairs of transisters to
    obtain bi-directionality.

    Arv-K7HKL
    _._

    Progress with BITX

    market10gardener <market10gardener@...>
     

    Hi
    I'm pleased to say that my BITX20 is now complete and it performs
    exactly as described. With my 132' doublet it has received excellent
    reports incuding 59 from PJ4 in one direction and UN7 in the other.
    Like Chris I made a few contacts with the penultimate (2N2218) stage
    on its own and these included an island off the coast of ES which was
    satisfying with 100Mw.
    At first the PA was a little unstable so I put in a small (abt 45pf)
    trimmer capacitor from the gate to the drain of the IRF510, lowered
    the value of the 2.2K resistor between the base and collector of the
    2N2218 by putting a 1K resistor in parallel with it and substituted a
    300pf cap for the 0.1mf between the drain of the IRF510 and the low
    pass filter. I now get 4 watts with a 12 volt power supply and 5
    watts with about 13v from a 17 Ah storage battery.
    I heard VU2PEP wkg most of North America (with 200 watts) the other
    evening but the pile up was formidable. It would be nice to meet
    another BITX on the air. Is any one interested in taking one along to
    Rochdale on the 9th October?
    72, 73
    John G0UCP

    Re: Progress with BITX

    Charles Darley
     

    I wish I could make the event but I have a 21st birthday of my daughter to attend ...  Would have been nice to have met up with you ...
     
    Mine has still a long way to go as I have had so many other commitments with the BRATS ...
     
    Regards Charles  G4VSZ
     
     

    -----Original Message-----
    From: market10gardener [mailto:market10gardener@...]
    Sent: 29 September 2004 20:03
    To: BITX20@...
    Subject: [BITX20] Progress with BITX


    Hi
    I'm pleased to say that my BITX20 is now complete and it performs
    exactly as described. With my 132' doublet it has received excellent
    reports incuding 59 from PJ4 in one direction and UN7 in the other.
    Like Chris I made a few contacts with the penultimate (2N2218) stage
    on its own and these included an island off the coast of ES which was
    satisfying with 100Mw.
    At first the PA was a little unstable so I put in a small (abt 45pf)
    trimmer capacitor from the gate to the drain of the IRF510, lowered
    the value of the 2.2K resistor between the base and collector of the
    2N2218 by putting a 1K resistor in parallel with it and substituted a
    300pf cap for the 0.1mf between the drain of the IRF510 and the low
    pass filter. I now get 4 watts with a 12 volt power supply and 5
    watts with about 13v from a 17 Ah storage battery.
    I heard VU2PEP wkg most of North America (with 200 watts) the other
    evening but the pile up was formidable. It would be nice to meet
    another BITX on the air. Is any one interested in taking one along to
    Rochdale on the 9th October?
    72, 73
    John  G0UCP


    Re: Ideas on using BITX20 for PSK31

    Arv Evans <arvevans@...>
     

    Jay

    Check out the FILES section and you will find several suggested circuits for the features that you mentioned.  There are two different VOX circuits there (I use the all-transistor version).  There is a circuit in FILES for adding RIT, and a bookmark in the LINKS section showing more info on this circuit.  My circuit for transistorized PTT is also in the FILES section.

    Adding the interface for PSK-31 has been discussed on this forum in the past.  All that is necessary is to take off the high-side of your Volume control with a pair of resistors to get the audio level down to where it will match the microphone input on your PC sound card.  The PSK transmit is handled by adding another resistive attenuator to match sound card output levels to the microphone input level of your BITX transceiver.  In my BITX20 I put two RCA-jacks on the rear panel and connected these to the above-mentioned attenuators.  The VOX works fine to perform Rx-Tx switching for PSK.

    Good luck,

    Arv
    _._

    On Fri, 2004-09-24 at 02:03, null1969 wrote:
    Hello all,
       I have not seen any practical designs for using BITX20 for PSK31
    mode. I am still working on completing the assembly but would like to
    learn more about what mods can be incorporated as I am building. Some
    ideas that I have thought about are:
    1. Implementing VOX so that PSK31 can be used using VOX switching.
    2. Using a transistor switch for PTT switching (similar to design
    used in Small Wonder Labs design).
    3. Building in the USB & LSB mode in the BFO (similar to the one
    illustrated by Farhan in his 2 band rig).

    Any ideas of implementions that can be uploaded to the files section?

    Regards,
    Jay


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  • Ideas on using BITX20 for PSK31

    null1969
     

    Hello all,
    I have not seen any practical designs for using BITX20 for PSK31
    mode. I am still working on completing the assembly but would like to
    learn more about what mods can be incorporated as I am building. Some
    ideas that I have thought about are:
    1. Implementing VOX so that PSK31 can be used using VOX switching.
    2. Using a transistor switch for PTT switching (similar to design
    used in Small Wonder Labs design).
    3. Building in the USB & LSB mode in the BFO (similar to the one
    illustrated by Farhan in his 2 band rig).

    Any ideas of implementions that can be uploaded to the files section?

    Regards,
    Jay

    Another RIT Circuit...

    Arvid Evans <arvevans@...>
     

    Hi

    A new RIT circuit drawing has been added to
    <BITX20/Files/Modifications/K8IQY RIT Circuit.png>

    This one is a bit simpler than my earlier circuit, and in true
    BITX style this design uses an NPN transistor.

    This design came from K8IQY, but I found it on the web page
    of W1HUE.

    I added the voltage regulator sections, but these may not be
    necessary if your power source is stable.

    I also added a URL to the BITX20/Links/Modifications/ section
    that will take you to W1HUE's web site and a little different
    version of this RIT circuit.

    Arv - K7HKL
    _._