Topics

New VK4PLN Audio Daughter Board + BCI


Nick VK4PP
 

Hi Everyone.
I am working on a new board that will give a few extra features to stock uBitx.

Its an Audio board providing easy access to Audio I/O pins. (add in your own AGC board, External amplifier...)
A place for an SSM2167 Mic Pre-amp. (with filtering for feedback and shutdown on TX)
Simple 4 component PTT POP fix. (BS170)
Switchable 200hz CW filter. (LM324)
and a bonus Snap off section with a 3.5MHZ BCI filter for the RX chain.

Here is a pre-view, NOTE this is a WORK-IN-PROGRESS.


Suggestions and corrections welcome.

73 Nick VK4PLN


BillandAgnes Franzwa <franzwa1@...>
 

Nick

looks great, and a good way to add mods to the uBITX

would you consider a pair of LM4562s for the CW filter?...a little quieter, and would use the same R/C components

Bill
K6SIK


On Wednesday, May 30, 2018 6:05 PM, Nick VK4PLN <nickpullen@...> wrote:


Hi Everyone.
I am working on a new board that will give a few extra features to stock uBitx.

Its an Audio board providing easy access to Audio I/O pins. (add in your own AGC board, External amplifier...)
A place for an SSM2167 Mic Pre-amp. (with filtering for feedback and shutdown on TX)
Simple 4 component PTT POP fix. (BS170)
Switchable 200hz CW filter. (LM324)
and a bonus Snap off section with a 3.5MHZ BCI filter for the RX chain.

Here is a pre-view, NOTE this is a WORK-IN-PROGRESS.


Suggestions and corrections welcome.

73 Nick VK4PLN



Nick VK4PP
 

Hi
I could change it, but that would increase cost for end user,
The LM324 are 50c the LM4562 are $5 each...
Will there be a noticeable difference with a 700hz cw signal?
73


K9HZ <bill@...>
 

Holes in the corners for mounting… of course…

 

 

Dr. William J. Schmidt - K9HZ  

 

From: BITX20@groups.io [mailto:BITX20@groups.io] On Behalf Of Nick VK4PLN
Sent: Wednesday, May 30, 2018 8:05 PM
To: BITX20@groups.io
Subject: [BITX20] New VK4PLN Audio Daughter Board + BCI

 

Hi Everyone.
I am working on a new board that will give a few extra features to stock uBitx.

Its an Audio board providing easy access to Audio I/O pins. (add in your own AGC board, External amplifier...)
A place for an SSM2167 Mic Pre-amp. (with filtering for feedback and shutdown on TX)
Simple 4 component PTT POP fix. (BS170)
Switchable 200hz CW filter. (LM324)
and a bonus Snap off section with a 3.5MHZ BCI filter for the RX chain.

Here is a pre-view, NOTE this is a WORK-IN-PROGRESS.


Suggestions and corrections welcome.

73 Nick VK4PLN

 

Virus-free. www.avg.com


Nick VK4PP
 

Hi.

I'm thinking I'll make the board so it reaches all the way to the LPF relays.
One end is supported by the connector and then you can just glue a couple of 12mm stand offs on the first and last relay for the board to screw to.
Ill leaver the extra area blank for prototyping...

What would be best in the area? Me-Squares? or Through holes?
Thanks for the feedback.

73, Nick VK4PLN


Kelly Jack
 

Hi Nik,

You could put the audio amp on there like a 2n3904 replacement version per the new ubitx version. Or some AGC circuitry?

Or one of the more sophisticated pop suppression circuits (admittedly not a clean installation as what you have designed here given need to link to traces on the board).

Could the SMM2167 stand vertically to conserve space for other stuff?

73



Simon
VK3ELH


Paul Galburt - K2AYZ
 

I believe there are many pin-compatible replacements for the LM324 for those who want better audio noise performance. For example MC33179, MAX414 - although many through hole DIP parts are reaching end of life for manufactureres. No need to change to two dual parts.


K9HZ <bill@...>
 

Hey what about a preamp for 6-15 meters?  I have a nice design for one using a PGA-103+ … only 12 parts if you include the bypass relay…

 

 

From: BITX20@groups.io [mailto:BITX20@groups.io] On Behalf Of Nick VK4PLN
Sent: Wednesday, May 30, 2018 8:05 PM
To: BITX20@groups.io
Subject: [BITX20] New VK4PLN Audio Daughter Board + BCI

 

Hi Everyone.
I am working on a new board that will give a few extra features to stock uBitx.

Its an Audio board providing easy access to Audio I/O pins. (add in your own AGC board, External amplifier...)
A place for an SSM2167 Mic Pre-amp. (with filtering for feedback and shutdown on TX)
Simple 4 component PTT POP fix. (BS170)
Switchable 200hz CW filter. (LM324)
and a bonus Snap off section with a 3.5MHZ BCI filter for the RX chain.

Here is a pre-view, NOTE this is a WORK-IN-PROGRESS.


Suggestions and corrections welcome.

73 Nick VK4PLN


Virus-free. www.avg.com


K9HZ <bill@...>
 

Thru holes

 

 

Dr. William J. Schmidt - K9HZ

 

From: BITX20@groups.io [mailto:BITX20@groups.io] On Behalf Of Nick VK4PLN
Sent: Thursday, May 31, 2018 12:13 AM
To: BITX20@groups.io
Subject: Re: [BITX20] New VK4PLN Audio Daughter Board + BCI

 

Hi.

I'm thinking I'll make the board so it reaches all the way to the LPF relays.
One end is supported by the connector and then you can just glue a couple of 12mm stand offs on the first and last relay for the board to screw to.
Ill leaver the extra area blank for prototyping...

What would be best in the area? Me-Squares? or Through holes?
Thanks for the feedback.

73, Nick VK4PLN

 

Virus-free. www.avg.com


ajparent1/KB1GMX <kb1gmx@...>
 

The PGA-103 is nice utility amp but too much gain for uBitx.  It needs more like a grounded gate Jfet
(10db is enough).  A wideband high gain without band limiting(tuned) will cause all sorts of havoc.


Allison


K9HZ <bill@...>
 

Not sure I agree with this being the wrong part for a preamp in the uBITx.  First I always design in a front end high pass filter on my preamps…(that should be a fairly obvious requirement for any preamp or amplification stage…don’t amplify things you don’t want amplified).  in this case I use a 5 pole chebby with a 3dB corner of about 18 MHz which works nicely for 12-10-6 meters.  Three 100pf caps in series and a two 330uH inductors to ground on the input is a decent design.  Second, variable gain control can easily be added.  The part has less than 0.5dB injected NF and therefore perfect as a preamp here IF DESIGNED RIGHT.   

 

You do know Elecraft uses it for their K3 preamp.  Must be something to it?

Dr. William J. Schmidt - K9HZ

From: BITX20@groups.io [mailto:BITX20@groups.io] On Behalf Of ajparent1/KB1GMX
Sent: Friday, June 1, 2018 12:17 PM
To: BITX20@groups.io
Subject: Re: [BITX20] New VK4PLN Audio Daughter Board + BCI

 

The PGA-103 is nice utility amp but too much gain for uBitx.  It needs more like a grounded gate Jfet
(10db is enough).  A wideband high gain without band limiting(tuned) will cause all sorts of havoc.

Allison

 

Virus-free. www.avg.com