Topics

AGC and S-meter for the BITX20 (from Hendrickx-kits)

Marcel De Meyer <marceldemeyer@...>
 

Hallo homebrewers
I have built the BITX20. It work very good !!!
From Belgium I make a nice QSO with VP8DLG in the Falklands ( about
12000 km !!) with a 3-element 3-band beam .
It is a kit from Hendrickx and it will be fine if I could add a AGC
and a S-meter . Please kan somone help me to find a schematic with
description . That will be nice and I thanks the people that want to
help me.
Marcel ON5MDM

Martien <sproet01@...>
 

--- In BITX20@..., "Marcel De Meyer" <marceldemeyer@...>
wrote:

Hallo Marcel,

I uploaded a file for you in the file section. Its called "audio AGC".
Got it from the PI4RAZ website. I build it and it works really great. I
added an S meter on the control voltage (voltage over the 100uF elco).
I am sure you be amazed how much the audio AGC improves your receiver.

73

Martien PA4H

Larry Critchfield <ws3z711@...>
 

Hi Martien,
I am also interested in the AGC/SMeter.
Can you be more specific on where and how the S Meter connects in the
circuit.
I see the 100uf elec, does "over" mean parallel?
Thanks
Larry

On Wed, Feb 25, 2009 at 4:27 AM, Martien <sproet01@...> wrote:

--- In BITX20@... <BITX20%40yahoogroups.com>, "Marcel De
Meyer" <marceldemeyer@...>
wrote:

Hallo Marcel,

I uploaded a file for you in the file section. Its called "audio AGC".
Got it from the PI4RAZ website. I build it and it works really great. I
added an S meter on the control voltage (voltage over the 100uF elco).
I am sure you be amazed how much the audio AGC improves your receiver.

73

Martien PA4H


Martien <sproet01@...>
 

--- In BITX20@..., Larry Critchfield <ws3z711@...> wrote:

Hi Larry,
Yes, sorry...over means in parallel. This is the control voltage for
the AGC and thus a measure of signal strength. I used an opamp to
convert this voltage to current to adapt to a small meter. I will draw
the circuit and put it in the file section as "s-meter amp". My meter
happend to be 0,15mA but a different meter will also work, just allign
the pot meter.


73

Martien PA4H

Larry Critchfield <ws3z711@...>
 

Thanks Martien,
I really appreciate you sharing your expertise with me.
I am sure others are interested also
73's
Larry WS3Z

On Thu, Feb 26, 2009 at 2:55 AM, Martien <sproet01@...> wrote:

--- In BITX20@... <BITX20%40yahoogroups.com>, Larry
Critchfield <ws3z711@...> wrote:

Hi Larry,
Yes, sorry...over means in parallel. This is the control voltage for
the AGC and thus a measure of signal strength. I used an opamp to
convert this voltage to current to adapt to a small meter. I will draw
the circuit and put it in the file section as "s-meter amp". My meter
happend to be 0,15mA but a different meter will also work, just allign
the pot meter.

73

Martien PA4H


Robert Meadows <hamradio_wv4b@...>
 

i've looked for this file in the BITX Group site, but cannot find it.  Am I blind?
Bob  wv4b

--- On Wed, 2/25/09, Martien <sproet01@...> wrote:

From: Martien <sproet01@...>
Subject: [BITX20] Re: AGC and S-meter for the BITX20 (from Hendrickx-kits)
To: BITX20@...
Date: Wednesday, February 25, 2009, 4:27 AM






--- In BITX20@yahoogroups. com, "Marcel De Meyer" <marceldemeyer@ ...>
wrote:

Hallo Marcel,

I uploaded a file for you in the file section. Its called "audio AGC".
Got it from the PI4RAZ website. I build it and it works really great. I
added an S meter on the control voltage (voltage over the 100uF elco).
I am sure you be amazed how much the audio AGC improves your receiver.

73

Martien PA4H

ka9gpx
 

--- In BITX20@..., Robert Meadows <hamradio_wv4b@...> wrote:

i've looked for this file in the BITX Group site, but cannot find
it. Am I blind?
Bob wv4b
Hi Bob,

Think this is what your looking for.....

http://f1.grp.yahoofs.com/v1/8B6nSQfFY9lrHfUswFf6vgUGDSguaBIJr7KJzfFmonYqPgFYkXuU76LXGSPOqJNea3u4T08pCxS4T5p58PYg3v_n1R5n/audioagc.jpg

If this link doesn't work, go to the "Files" section of the
group,...start looking at the "files" (below the FOLDERS). About the
3rd "File" down you should see one called,... "AUDIOACG.jpg" If you
look it will have a Feb,25,2009 date.

Pretty sure thats the one you seek...

Hope this helps,
Carl
KA9GPX

Robert Meadows <hamradio_wv4b@...>
 

Hi Carl,
Thank you for the link. The only file I have relating to this subject is one dated 01-25-09and it is really buried down in the list (alphabetical) of files. Is there some way to organize these files by date? they are all alphabetically listed?
73's,
Bob  wv4b

--- On Thu, 2/26/09, ka9gpx <KA9GPX@...> wrote:

From: ka9gpx <KA9GPX@...>
Subject: [BITX20] Re: AGC and S-meter for the BITX20 (from Hendrickx-kits)
To: BITX20@...
Date: Thursday, February 26, 2009, 6:16 PM






--- In BITX20@yahoogroups. com, Robert Meadows <hamradio_wv4b@ ...> wrote:

i've looked for this file in the BITX Group site, but cannot find
it. Am I blind?
Bob wv4b
Hi Bob,

Think this is what your looking for.....

http://f1.grp. yahoofs.com/ v1/8B6nSQfFY9lrH fUswFf6vgUGDSgua BIJr7KJzfFmonYqP gFYkXuU76LXGSPOq JNea3u4T08pCxS4T 5p58PYg3v_ n1R5n/audioagc. jpg

If this link doesn't work, go to the "Files" section of the
group,...start looking at the "files" (below the FOLDERS). About the
3rd "File" down you should see one called,... "AUDIOACG.jpg" If you
look it will have a Feb,25,2009 date.

Pretty sure thats the one you seek...

Hope this helps,
Carl
KA9GPX

Frank Waarsenburg <waarsenburg@...>
 

The Audio AGC was part of a larger project from the PI4RAZ radio club.
The original schematic is here:
http://www.pi4raz.nl/images/stories/tech/bitx20/display/adagc2.jpg
There is a 6.2V zener across the 100u capacitor because we used it as
part of a Frequency counter / S-meter / SWR indication for the Bitx20.
You will find details in the PI4RAZ forum, or, for people not able to
read dutch, on my website http://pa3cno.qsl.nu/

Frank PA3CNO

--- In BITX20@..., Robert Meadows <hamradio_wv4b@...> wrote:

i've looked for this file in the BITX Group site, but cannot find
it.  Am I blind?
Bob  wv4b

Martien <sproet01@...>
 

--- In BITX20@..., "Frank Waarsenburg" <waarsenburg@...>
wrote:

Hi Frank,

Nice website!

As said: I copied the audio AGC circuit from the PI4RAZ website. Works
really great and a must-have addition to my BITX-20. I did not mount
the zener diode you mentioned and the AGC voltage goes up to 10V with
no signal, this is no problem for me. I did add an S-meter circuit. You
can find it in the files section if you are interested (s-meter amp)

73

Martien PA4H

ohwenzelph
 

likewise i do not find the feb.25, 2009 file
but i do find the feb 26009 s-meter file
jerry terres aa1of

Martien <sproet01@...>
 

--- In BITX20@..., "jerry" <ohwenzelph@...> wrote:
Hi Jerry,
Scroll down in the files section and than watch for the 5th file below
the yellow maps. Its called "audioagc.jpg" .

73's

Martien PA4H


likewise i do not find the feb.25, 2009 file
but i do find the feb 26009 s-meter file
jerry terres aa1of

k5xrf
 

Hi all,

I've just about completed building the audio AGC circuit (posted by Martien) and have been looking at where to insert it (electrically) into my BITX20A. I'm assuming somewhere around C81. I've checked postings to this group for how to connect it but didn't find anything.

For those that have used the audio AGC circuit with your BITX20A... how did you connect it to your BITX20A?
73,

Jon K5XRF

--- In BITX20@..., Larry Critchfield <ws3z711@...> wrote:

Hi Martien,
I am also interested in the AGC/SMeter.
Can you be more specific on where and how the S Meter connects in the
circuit.
I see the 100uf elec, does "over" mean parallel?
Thanks
Larry


On Wed, Feb 25, 2009 at 4:27 AM, Martien <sproet01@...> wrote:

--- In BITX20@... <BITX20%40yahoogroups.com>, "Marcel De
Meyer" <marceldemeyer@>
wrote:

Hallo Marcel,

I uploaded a file for you in the file section. Its called "audio AGC".
Got it from the PI4RAZ website. I build it and it works really great. I
added an S meter on the control voltage (voltage over the 100uF elco).
I am sure you be amazed how much the audio AGC improves your receiver.

73

Martien PA4H



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

Martien <sproet01@...>
 

--- In BITX20@..., "k5xrf" <k5xrf@...> wrote:

Hi Jon,
Between C81 and and the volume potmeter (I think its R80) would be a good spot.

73's

Martien PA4H

Joel Trenalone
 

Hello,
I have been reading this post over, and want to ensure that I have it correct.

I am building this AGC for the BITX20A.


Just to be clear (I am still new at home build), I would cut the wire between the volume pot R80 and C81 and insert the AGC. Looking at the schematic (audioagc.jpg by martien), the "From pre-amp" side would be at the C81 side, and the "To Speaker-amp" at the R80 volume control side.

Is this correct?

Thanks,
Joel

--- In BITX20@..., "Martien" <sproet01@...> wrote:

--- In BITX20@..., "k5xrf" <k5xrf@> wrote:

Hi Jon,
Between C81 and and the volume potmeter (I think its R80) would be a good spot.

73's

Martien PA4H

martienrijssemus <sproet01@...>
 

Hi Joel,

Yes, that is correct.

73's

Martien PA4H

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

Hello,
I have been reading this post over, and want to ensure that I have it correct.

I am building this AGC for the BITX20A.


Just to be clear (I am still new at home build), I would cut the wire between the volume pot R80 and C81 and insert the AGC. Looking at the schematic (audioagc.jpg by martien), the "From pre-amp" side would be at the C81 side, and the "To Speaker-amp" at the R80 volume control side.

Is this correct?

Thanks,
Joel

--- In BITX20@..., "Martien" <sproet01@> wrote:

--- In BITX20@..., "k5xrf" <k5xrf@> wrote:

Hi Jon,
Between C81 and and the volume potmeter (I think its R80) would be a good spot.

73's

Martien PA4H

Joel Trenalone
 

Thank You for the reply Martien,
One more quick questions.

The AGC schematic shows what looks like a pre-set resistor at the input and output (a flat line on the side of the resistor).

Does it have a preset or variable resistor at these points? If so, will a veriable resistor work? Or can this be a fixed value resistor?

Again, my inexperianced questions,
Thanks again,
Joel

--- In BITX20@..., "martienrijssemus" <sproet01@...> wrote:

Hi Joel,

Yes, that is correct.

73's

Martien PA4H

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

Hello,
I have been reading this post over, and want to ensure that I have it correct.

I am building this AGC for the BITX20A.


Just to be clear (I am still new at home build), I would cut the wire between the volume pot R80 and C81 and insert the AGC. Looking at the schematic (audioagc.jpg by martien), the "From pre-amp" side would be at the C81 side, and the "To Speaker-amp" at the R80 volume control side.

Is this correct?

Thanks,
Joel

--- In BITX20@..., "Martien" <sproet01@> wrote:

--- In BITX20@..., "k5xrf" <k5xrf@> wrote:

Hi Jon,
Between C81 and and the volume potmeter (I think its R80) would be a good spot.

73's

Martien PA4H

martienrijssemus <sproet01@...>
 

Hi Joel,

I guess you are referring to R1 and R14, those are both variable resistors (trimming pot's). R14 is set for comfortable audiolevel, R1 sets the AGC. Just start halfway and allign them both for comfortable listening. By the way: I also added the schematics for an S-meter to go with this AGC circuit. You can find it in the file section: S-meter amp.pdf

73's

Martien

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


Thank You for the reply Martien,
One more quick questions.

The AGC schematic shows what looks like a pre-set resistor at the input and output (a flat line on the side of the resistor).

Does it have a preset or variable resistor at these points? If so, will a veriable resistor work? Or can this be a fixed value resistor?

Again, my inexperianced questions,
Thanks again,
Joel

--- In BITX20@..., "martienrijssemus" <sproet01@> wrote:

Hi Joel,

Yes, that is correct.

73's

Martien PA4H

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

Hello,
I have been reading this post over, and want to ensure that I have it correct.

I am building this AGC for the BITX20A.


Just to be clear (I am still new at home build), I would cut the wire between the volume pot R80 and C81 and insert the AGC. Looking at the schematic (audioagc.jpg by martien), the "From pre-amp" side would be at the C81 side, and the "To Speaker-amp" at the R80 volume control side.

Is this correct?

Thanks,
Joel

--- In BITX20@..., "Martien" <sproet01@> wrote:

--- In BITX20@..., "k5xrf" <k5xrf@> wrote:

Hi Jon,
Between C81 and and the volume potmeter (I think its R80) would be a good spot.

73's

Martien PA4H

Joel Trenalone
 

Martien,
Thanks. I am looking at your schematic for the S-meter, and cannot read the resistor value comping off of the +13.8v. It looks like 3kg?
Thanks,
Joel

--- In BITX20@..., "martienrijssemus" <sproet01@...> wrote:

Hi Joel,

I guess you are referring to R1 and R14, those are both variable resistors (trimming pot's). R14 is set for comfortable audiolevel, R1 sets the AGC. Just start halfway and allign them both for comfortable listening. By the way: I also added the schematics for an S-meter to go with this AGC circuit. You can find it in the file section: S-meter amp.pdf

73's

Martien

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


Thank You for the reply Martien,
One more quick questions.

The AGC schematic shows what looks like a pre-set resistor at the input and output (a flat line on the side of the resistor).

Does it have a preset or variable resistor at these points? If so, will a veriable resistor work? Or can this be a fixed value resistor?

Again, my inexperianced questions,
Thanks again,
Joel

--- In BITX20@..., "martienrijssemus" <sproet01@> wrote:

Hi Joel,

Yes, that is correct.

73's

Martien PA4H

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

Hello,
I have been reading this post over, and want to ensure that I have it correct.

I am building this AGC for the BITX20A.


Just to be clear (I am still new at home build), I would cut the wire between the volume pot R80 and C81 and insert the AGC. Looking at the schematic (audioagc.jpg by martien), the "From pre-amp" side would be at the C81 side, and the "To Speaker-amp" at the R80 volume control side.

Is this correct?

Thanks,
Joel

--- In BITX20@..., "Martien" <sproet01@> wrote:

--- In BITX20@..., "k5xrf" <k5xrf@> wrote:

Hi Jon,
Between C81 and and the volume potmeter (I think its R80) would be a good spot.

73's

Martien PA4H

martienrijssemus <sproet01@...>
 

Hi Joel,

The value is 3k9 or 3900 Ohm. Sorry for my handwriting I admit it looks a bit like 3kg :-)

73's

Martien PA4H

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

Martien,
Thanks. I am looking at your schematic for the S-meter, and cannot read the resistor value comping off of the +13.8v. It looks like 3kg?
Thanks,
Joel

--- In BITX20@..., "martienrijssemus" <sproet01@> wrote:

Hi Joel,

I guess you are referring to R1 and R14, those are both variable resistors (trimming pot's). R14 is set for comfortable audiolevel, R1 sets the AGC. Just start halfway and allign them both for comfortable listening. By the way: I also added the schematics for an S-meter to go with this AGC circuit. You can find it in the file section: S-meter amp.pdf

73's

Martien

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


Thank You for the reply Martien,
One more quick questions.

The AGC schematic shows what looks like a pre-set resistor at the input and output (a flat line on the side of the resistor).

Does it have a preset or variable resistor at these points? If so, will a veriable resistor work? Or can this be a fixed value resistor?

Again, my inexperianced questions,
Thanks again,
Joel

--- In BITX20@..., "martienrijssemus" <sproet01@> wrote:

Hi Joel,

Yes, that is correct.

73's

Martien PA4H

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

Hello,
I have been reading this post over, and want to ensure that I have it correct.

I am building this AGC for the BITX20A.


Just to be clear (I am still new at home build), I would cut the wire between the volume pot R80 and C81 and insert the AGC. Looking at the schematic (audioagc.jpg by martien), the "From pre-amp" side would be at the C81 side, and the "To Speaker-amp" at the R80 volume control side.

Is this correct?

Thanks,
Joel

--- In BITX20@..., "Martien" <sproet01@> wrote:

--- In BITX20@..., "k5xrf" <k5xrf@> wrote:

Hi Jon,
Between C81 and and the volume potmeter (I think its R80) would be a good spot.

73's

Martien PA4H