Re: AGC circuit to try?

ajparent1/KB1GMX

Retired engineer,  about 45 years of commercial antenna design, RF, Digital, Audio

I have the mother of all junk boxes, from accumulating for that long.

Allison

Re: AGC circuit to try?

Gordon Gibby

​how many cubic feet, perchance?

Do you use fishing tackle boxes to sort?

I have a bunch of junk, but not nearly the range of stuff you seem to have and I need to figure out how to allocate space in the "bonus room"

Gordon

From: BITX20@groups.io <BITX20@groups.io> on behalf of ajparent1 <kb1gmx@...>
Sent: Saturday, April 7, 2018 5:50 PM
To: BITX20@groups.io
Subject: Re: [BITX20] AGC circuit to try?

Retired engineer,  about 45 years of commercial antenna design, RF, Digital, Audio

I have the mother of all junk boxes, from accumulating for that long.

Allison

Re: AGC circuit to try?

Lee

I also have a X1M with the AGC board installed. I attached the install manual from the X1M group for those interested.

Re: RadioKits.in Case #ubitx Encoder knob fit

K Buehler

Back of the hex on the front of the knob & it expands the internal collect & it falls on (it clamps on shaft when you tighten it

73
Ken VE3KCY

EMRFD Butler VXO for Intermod Testing

Nigel Maund

Hi,

I am building the Oscillator from EMRFD,page 7.19 Fig. 7.32.  I have reviewed the corrections from the W7ZOI EMRFD Errata site.
Designing for 7 MHz, I plan to adjust by using the formula Fold/Fnew and multiply (i.e. by 2) all the required LC components.  This works for the pi filter, fine enough.
My question: (1) how do I modify the Transformer that is in the Oscillator Collector circuit?  I see that for 14 MHz, the inductance is actually giving a 44 Ohm impedance; would I simply calculate the primary inductance of the transformer, to try and obtain the same impedance, but for 7 MHz?  I haven't found much info on Butler oscillator design,  and how its LC values are set, and cannot find a good site on the web to refer to.  Can I use the same 220 pF and 440 pF capacitors?  Butler VXOs seem to be often used for overtones of the crystal.   (2) why are there 2 x 0.1 microFarad bypass capacitors on the Base of the Final transistor?

Thanks,
Nigel
VA2NM

Re: EMRFD Butler VXO for Intermod Testing

emi constantino

Hi Nigel, I am working on  vfo butler osc but with series L C instead of a crystal.I dont have the EMRFD book so i cant give an opinion.If you can email me that particular page maybe i can give a cent of experience.
I am looking for a stable vfo since the original vfo of Bitx40 is now replaced with digital and i dont know how to program.

Best regards,

Emi Constantino,DW3 CBO

On Sun, Apr 8, 2018 at 6:15 AM, Nigel Maund
<maund.n@...> wrote:
Hi,

I am building the Oscillator from EMRFD,page 7.19 Fig. 7.32.  I have reviewed the corrections from the W7ZOI EMRFD Errata site.
Designing for 7 MHz, I plan to adjust by using the formula Fold/Fnew and multiply (i.e. by 2) all the required LC components.  This works for the pi filter, fine enough.
My question: (1) how do I modify the Transformer that is in the Oscillator Collector circuit?  I see that for 14 MHz, the inductance is actually giving a 44 Ohm impedance; would I simply calculate the primary inductance of the transformer, to try and obtain the same impedance, but for 7 MHz?  I haven't found much info on Butler oscillator design,  and how its LC values are set, and cannot find a good site on the web to refer to.  Can I use the same 220 pF and 440 pF capacitors?  Butler VXOs seem to be often used for overtones of the crystal.   (2) why are there 2 x 0.1 microFarad bypass capacitors on the Base of the Final transistor?

Thanks,
Nigel
VA2NM

Re: POP fix

Gary Anderson

From a visual inspection of Wayne’s original VA7AT “9-component” Pop Fix circuit (awesome document by Don ND6T on his website), I see the potential issue with why a loud noise to the microphone could ‘sneak’ into the uBITX audio output in RX mode. The Source and Drain of the n-FET Q1 (To C50, Audio receive) are swapped in the design.  There’s a body diode from source (pin 3) to drain (pin 2).  As drawn, there is still an attenuated signal path from the microphone to the receive audio amplifier though this body diode. Swapping the Source and Drain will eliminate this path, with no negative consequences that I can see.  I am curious if this would fix this “glitch”.

I am not at a point where I can try this out.  But since I spied a possible simple circuit enhancement, I thought it better to share my thoughts and be wrong, then to be correct and not share.  That wouldn’t be of any use.

Best Regards,
Gary
AG5TX

Re: AGC circuit to try?

ajparent1/KB1GMX

How many cubic feet?  Best guess something on the order of 250-400 cubic feet.
Mind you not all of that is junk in the classic sense.  Much of that is what I'd call
stockpiles.

I use 50 drawer bins and some with larger drawers that are only 18 drawers in the same
overall size.  There are 8 of those for just routine stuff like screws, resistors, caps, diodes,
connectors, LEDs, common transistors, and so on.  ITs part of the non-junk part.  Tackle boxes
are not space efficient.   However there are maybe 12 of the variable pocket size clear
polyethylene boxes of varying heights for things like batteries, electrolytic caps, crystals,
small relays and the like.

Junk aka random assemblies, chassis and boards, mechanical, cable and wire
are in large tubs maybe of the 30 gallon size.  FIgure 10 of those.  Plus another 15
printer paper boxes (10 ream size) many are marked as to content.

Its organized so the two car garage can hold two cars, and a workbench there
for messy activities, even after 35 years.

The running joke with friends is, I likely have unobtainium.

Regarding the X1M info I have that and its good but cannot be used directly
with BITX as it was designed based on the MC1350 IF chip.  That would be
tough to shoe horn into the BITX design.  The basic idea is worth understanding
and with some changes could be applied would be very useful.

Allison

Re: AGC circuit to try?

Jerry Gaffke

That was a general "you", addressed to the now thousands of uBitx owners.
I'm still concerned that a random 1n400* off an ebay site could do most anything at 45mhz
There are lots of different manufacturers using lots of different processes.

So if ordering parts for this, I'd get a BAP64 or similar.
The BAP64-03 is in a bigger package than the -02, still plenty small.
If what's on hand are some one amp power rectifiers mostly used at 60hz,
by all means give them a try first.

Very encouraging that Allison usually finds these 1n400*'s to work well at RF.

Jerry

On Sat, Apr 7, 2018 at 02:29 pm, ajparent1 wrote:
Rare is an order for just one part here.  Typical order for my lab are 4-20 parts and quantity.
Stock devices like 1n4007 a hundred in a order is common, same for 2n2222A, 2n3906, 2n3904
as they are cheaper when purchased in volume.  I do have the BAP64 in various packages and
several others as well. Even some exotic Avago PIN parts.  I maintain a stock that allows me
to build then optimize.  I get annoyed when I don't have something unless exotic like 10ghz
gain blocks.
On Sat, Apr 7, 2018 at 01:32 pm, Jerry Gaffke wrote:

If you are paying \$5 postage to ship in some 1n4007's, you might consider
also getting some BAP64-02's at \$0.43 each single unit pricing, Mouser 771-BAP64-02-T/R.
Down to \$0.10 or so if you buy a reel.
Fully spec'd for use as an RF PIN diode.

Re: Variation on Ian's KD8CEC uBitx software (based on his 1.04 release for now) and ATU sketch.

John <passionfruit88@...>

Hello Tim,

If I remember well it is only a one liner or so. I will add it as an option.

73, John  (VK2ETA)

Re: Variation on Ian's KD8CEC uBitx software (based on his 1.04 release for now) and ATU sketch.

W2CTX

You also need to know the I2C address

rOn

From: John <passionfruit88@...>
To: BITX20@groups.io
Sent: Saturday, April 7, 2018 8:42 PM
Subject: Re: [BITX20] Variation on Ian's KD8CEC uBitx software (based on his 1.04 release for now) and ATU sketch. #ubitx

Hello Tim,

If I remember well it is only a one liner or so. I will add it as an option.

73, John  (VK2ETA)

#bitx40 Help needed with compiler error

AGØH

I've downloaded v1.27.7 sketch to the Arduino IDE.  Installed the necessary driver (Ch340/341).  My OS is WIN10.  Installed the PinChangeInterrupt library  to the same directory that raduino_v1.27.7.ino is in.  Hooked up the raduino and then tried to compile the sketch.  I got the following:

I removed the word '-master' from the title as suggested by  the readme file but to no avail.  as you can see it stopped after starting the compile telling me that the compilation stopped because of an error.  When I scrolled up, you can see it's listing the #include <PinChangeInterrupt.h> as the error.  There are three other lines in that sketch but it looks like it stopped after not being able to find the first one.
A little background:   I did go by a set of instructions by Pat AA4PG (updated by VE3RRD). My main directory for the Arduino IDE is C:\\.  I created another directory in C:\\ for Bitx40Software where I placed the raduino_v1.27.7 sub directory.  I copied the unzipped raduino_v1.27.7.ino in that directory along with the PinChangeInterrupt directory. Clicking on the Sketch file automatically starts the IDE and the result you see in the above capture.
Thanks es 73 for any and all help,
Keith - AGØH

Re: AGC circuit to try?

Tim Gorman

Allison,

These amplifier circuits are very carefully designed to provide 50ohm
inputs and outputs so that proper terminations are provided to the
mixers in order to maximize rejection of unwanted carriers. The output
of the second amplifier is to provide the proper termination to the
crystal filter.

If you replace the emitter resistors with a diode then you have
effectively changed the input and output impedances of the amplifiers.
This would be especially bad for the termination into the crystal
filter.

Google "w7zoi" and "termination insensitive amplifiers" for a
discussion.

What you suggest would probably work but without testing it is
difficult to determine the actual result on the overall operation of

tim ab0wr

On Sat, 07 Apr 2018 12:15:15 -0700
"ajparent1" <kb1gmx@...> wrote:

It is incomplete..

You have the audio detection to get an AGC control voltage but you

What I find odd in general every one seems to be bent on leveling the
audio volume in the audio circuit. Why?  I understand protecting ones
ears and all but what an audio compressor?

The Bitx or uBitx has enough gain and handy places that RF gain
control based on audio detection works very well.  The easy way is
replace R13 (ubitx) with a diode such as 1n400x (x=1 to 7) and
controlling the current through the diode to make it behave as a
variable resistance at RF.

The current would be about 4-6ma at max gain and decrease to zero (0)
at minimum gain.  For that design the AGC range is about 26 to 32db
depening on band.  If you feel that is not enough agc range then add
the same mod at R35 then with both the agc range is near 60+ DB,
generally enough.  AGC in this form is less prone to overload
distortion as you are lowering gain.  The control could be a pot
between 8V (or RX-V) and ground and a series 1K resistor to the he
diode (x2 of your using both diodes).  That is a manual gain
control.   To make it automatic use a circuit like just published to
detect the voltage at the top of the audio gain pot and feed that
voltage to the gain control diodes.  The circuit should be arranged
to put 4-8V out at NO Audio and decrease to zero volts with
increasing audio.

Side note the 1n400x series with minor reservations makes a fine
substitute for a PIN diode, the prefered but more costly device for
this function.  Beside being widely available and cheap ( I buy them
in quantities of 100 for pennies each) makes it useful.  It also
makes a good 20pf varicap and a 1A rectifier to 1000V (1n4007).

This was tested on the first bitx20 I built over a decade ago to test
AGC and is used on several  older Tentec radios and more than few of
my own design.   That said its far from a new idea or design as its
documented in EMRFD and the older SSD (Solid State Design AARL press,
out of print).

Allison

Re: #bitx40 Help needed with compiler error

Mike Woods

Keith

You need to install the PinChangeInterrupt library first.  Then restart the Arduino IDE and all should be well.   Go to "Tools" and "Include library" in the menu system.

Mike ZL1AXG

On 8/04/18 1:17 PM, AGØH wrote:
I've downloaded v1.27.7 sketch to the Arduino IDE.  Installed the necessary driver (Ch340/341).  My OS is WIN10.  Installed the PinChangeInterrupt library  to the same directory that raduino_v1.27.7.ino is in.  Hooked up the raduino and then tried to compile the sketch.  I got the following:

I removed the word '-master' from the title as suggested by  the readme file but to no avail.  as you can see it stopped after starting the compile telling me that the compilation stopped because of an error.  When I scrolled up, you can see it's listing the #include <PinChangeInterrupt.h> as the error.  There are three other lines in that sketch but it looks like it stopped after not being able to find the first one.
A little background:   I did go by a set of instructions by Pat AA4PG (updated by VE3RRD). My main directory for the Arduino IDE is C:\\.  I created another directory in C:\\ for Bitx40Software where I placed the raduino_v1.27.7 sub directory.  I copied the unzipped raduino_v1.27.7.ino in that directory along with the PinChangeInterrupt directory. Clicking on the Sketch file automatically starts the IDE and the result you see in the above capture.
Thanks es 73 for any and all help,
Keith - AGØH

--
Mike Woods
mhwoods@...

Re: Variation on Ian's KD8CEC uBitx software (based on his 1.04 release for now) and ATU sketch.

Tim Gorman

I don't think it is going to be that easy to do. I'm afraid the I2C
libraries are large enough they will make the compile too big for the
nano.

tim ab0wr

On Sat, 7 Apr 2018 12:28:14 -0500
"K9HZ" <@Doc_Bill> wrote:

Ya know this is really easy to do with "#If defined" statements in
just a single sketch... if you uncomment a symbol like "#define
I2C_Display" and comment out the "#define Parallel_Display" (or vice
versa) it could automatically switch libraries... depending upon what
print libraries are used, the print/write calls are the same so those
don't have to change. Just the two variables.

Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ
PJ2/K9HZ

Owner - Operator
Big Signal Ranch – K9ZC
Staunton, Illinois

Owner – Operator
Villa Grand Piton – J68HZ
Soufriere, St. Lucia W.I.
Rent it: www.VillaGrandPiton.com

Moderator – North American QRO Yahoo Group.

email:  @Doc_Bill

Re: Variation on Ian's KD8CEC uBitx software (based on his 1.04 release for now) and ATU sketch.

Tim Gorman

If you can do it with a one-liner and keep the program size small
enough to fit into the nano then it will be an easy fix.

What I2C library are you going to use?

tim ab0wr

On Sat, 07 Apr 2018 17:42:21 -0700
"John" <passionfruit88@...> wrote:

Hello Tim,

If I remember well it is only a one liner or so. I will add it as an
option.

73, John  (VK2ETA)

Re: Variation on Ian's KD8CEC uBitx software (based on his 1.04 release for now) and ATU sketch.

Tim Gorman

You can figure out the address with an I2C scanner program uploaded
into the nano. You can then include the address before you compile

tim ab0wr

On Sun, 8 Apr 2018 00:44:53 +0000 (UTC)
"Ronald Pfeiffer via Groups.Io" <w2ctx=yahoo.com@groups.io> wrote:

You also need to know the I2C address
rOn

From: John <passionfruit88@...>
To: BITX20@groups.io
Sent: Saturday, April 7, 2018 8:42 PM
Subject: Re: [BITX20] Variation on Ian's KD8CEC uBitx software
(based on his 1.04 release for now) and ATU sketch. #ubitx
Hello Tim,

If I remember well it is only a one liner or so. I will add it as an
option.

73, John  (VK2ETA)

Re: AGC circuit to try?

Gordon Gibby

Thanks!!!  Gives me lots of good ideas.

On Apr 7, 2018, at 19:29, ajparent1 <kb1gmx@...> wrote:

How many cubic feet?  Best guess something on the order of 250-400 cubic feet.
Mind you not all of that is junk in the classic sense.  Much of that is what I'd call
stockpiles.

I use 50 drawer bins and some with larger drawers that are only 18 drawers in the same
overall size.  There are 8 of those for just routine stuff like screws, resistors, caps, diodes,
connectors, LEDs, common transistors, and so on.  ITs part of the non-junk part.  Tackle boxes
are not space efficient.   However there are maybe 12 of the variable pocket size clear
polyethylene boxes of varying heights for things like batteries, electrolytic caps, crystals,
small relays and the like.

Junk aka random assemblies, chassis and boards, mechanical, cable and wire
are in large tubs maybe of the 30 gallon size.  FIgure 10 of those.  Plus another 15
printer paper boxes (10 ream size) many are marked as to content.

Its organized so the two car garage can hold two cars, and a workbench there
for messy activities, even after 35 years.

The running joke with friends is, I likely have unobtainium.

Regarding the X1M info I have that and its good but cannot be used directly
with BITX as it was designed based on the MC1350 IF chip.  That would be
tough to shoe horn into the BITX design.  The basic idea is worth understanding
and with some changes could be applied would be very useful.

Allison

Re: AGC circuit to try?

pierre@...

Dear All,

For those of you who are still wondering how does this X1M AGC circuit manages to control the gain of the RX (without any control element).

If you look at the circuit of the X1M transceiver you will see that it uses an MC1350p IF amp chip in its receiver, however the AGC pin on the MC1350p is not used for AGC action being held at a constant voltage in the standard X1M circuit.

You install the little X1M AGC circuit board in your X1M and carefully lift the AGC pin on the MC1350p and attach it to the output of the AGC circuit board, the input of the AGC circuit goes to the top of the volume control and you then get audio AGC for the MC1350p and your X1M.

The Bitx as built does not have an MC1350p, so no simple way of controlling the gain of the Bitx receiver using this X1M AGC board however as suggested by others you can use your imagination and add a controlling element(s) to your Bitx.

You could replace the RX 2nd IF amp in the Bitx with an MC1350p as used in the G6LBQ multi band Bitx circuit. You can google this circuit to see what it looks like.

Regards,

Peter VK1XP

On 08-04-2018 09:30, Jerry Gaffke via Groups.Io wrote:
That was a general "you", addressed to the now thousands of uBitx
owners.
I'm still concerned that a random 1n400* off an ebay site could do
most anything at 45mhz
There are lots of different manufacturers using lots of different
processes.
So if ordering parts for this, I'd get a BAP64 or similar.
The BAP64-03 is in a bigger package than the -02, still plenty small.
If what's on hand are some one amp power rectifiers mostly used at
60hz,
by all means give them a try first.
Very encouraging that Allison usually finds these 1n400*'s to work
well at RF.
Jerry
On Sat, Apr 7, 2018 at 02:29 pm, ajparent1 wrote:

Rare is an order for just one part here. Typical order for my lab
are 4-20 parts and quantity.
Stock devices like 1n4007 a hundred in a order is common, same for
2n2222A, 2n3906, 2n3904
as they are cheaper when purchased in volume. I do have the BAP64
in various packages and
several others as well. Even some exotic Avago PIN parts. I
maintain a stock that allows me
to build then optimize. I get annoyed when I don't have something
unless exotic like 10ghz
gain blocks.
On Sat, Apr 7, 2018 at 01:32 pm, Jerry Gaffke wrote:

If you are paying \$5 postage to ship in some 1n4007's, you might
consider
also getting some BAP64-02's at \$0.43 each single unit pricing,
Mouser 771-BAP64-02-T/R.
Down to \$0.10 or so if you buy a reel.
Fully spec'd for use as an RF PIN diode.
------
[1] https://groups.io/g/BITX20/message/45998
[2] https://groups.io/mt/16905058/236039
[3] https://groups.io/g/BITX20/post
[4] https://groups.io/g/BITX20/editsub/236039
[5] https://groups.io/g/BITX20
[6] https://groups.io/static/tos
[7] https://groups.io/g/BITX20/leave/defanged

Re: Variation on Ian's KD8CEC uBitx software (based on his 1.04 release for now) and ATU sketch.

K9HZ <bill@...>

Nope. Done. Works. Remember the I2C libraries are already there for the Si5351 chip. My code actually gets smaller.

Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ

Owner - Operator
Big Signal Ranch – K9ZC
Staunton, Illinois

Owner – Operator
Villa Grand Piton – J68HZ
Soufriere, St. Lucia W.I.
Rent it: www.VillaGrandPiton.com

Moderator – North American QRO Yahoo Group.

email: @Doc_Bill

-----Original Message-----
From: BITX20@groups.io [mailto:BITX20@groups.io] On Behalf Of Tim Gorman
Sent: Saturday, April 7, 2018 8:35 PM
To: BITX20@groups.io
Subject: Re: [BITX20] Variation on Ian's KD8CEC uBitx software (based on his 1.04 release for now) and ATU sketch. #ubitx

I don't think it is going to be that easy to do. I'm afraid the I2C libraries are large enough they will make the compile too big for the nano.

tim ab0wr

On Sat, 7 Apr 2018 12:28:14 -0500
"K9HZ" <@Doc_Bill> wrote:

Ya know this is really easy to do with "#If defined" statements in
just a single sketch... if you uncomment a symbol like "#define
I2C_Display" and comment out the "#define Parallel_Display" (or vice
versa) it could automatically switch libraries... depending upon what
print libraries are used, the print/write calls are the same so those
don't have to change. Just the two variables.

Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ
PJ2/K9HZ

Owner - Operator
Big Signal Ranch – K9ZC
Staunton, Illinois

Owner – Operator
Villa Grand Piton – J68HZ
Soufriere, St. Lucia W.I.
Rent it: www.VillaGrandPiton.com

Moderator – North American QRO Yahoo Group.

email: @Doc_Bill

---
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