Topics

BITX 14MHz Build #bitx20

Aaron K5ATG
 

Hello everyone,
I'm going to start building the BITX 14MHz build. It's going to be my first homebrew transceiver project so I will be learning as I go. The instructions say to solder the transistors first but since this is my first go around, I'm not really sure where I should put them on the PCB. I'm going to use Manhattan construction using the QRPme Little MeSquares. So if anyone has any tips or pointers for a newbie, I will be greatly appreciated.  

Arv Evans
 

If you are not using a Bitx pcb, then your question is questionable.  Build instructions are for using a bitx pcb.  For one-off builds using manattan or ugly method you just need to decide your own layout and construction sequence.

Arv. K7HKL
_-_


On Tue, Apr 7, 2020, 6:58 AM Aaron Scott via groups.io <k5atg=yahoo.com@groups.io> wrote:
Hello everyone,
I'm going to start building the BITX 14MHz build. It's going to be my first homebrew transceiver project so I will be learning as I go. The instructions say to solder the transistors first but since this is my first go around, I'm not really sure where I should put them on the PCB. I'm going to use Manhattan construction using the QRPme Little MeSquares. So if anyone has any tips or pointers for a newbie, I will be greatly appreciated.  

Jason Pirok
 

W2AEW (Alan Wolke) has a great video on the layout of Manhattan style PCB building. 

This one illustrates the island method, but the techniques can be used for Manhattan.
https://www.youtube.com/watch?v=blalAktxFoI  

This one goes over several other construction techniques.
https://www.youtube.com/watch?v=kH110yjYZ2g  

--
Jason Pirok
W4UNX

 

Hi Aaron,

I not used MeSquares, but have done quite a bit of "dead bug" construction (which is just placing parts - upside down or not - over an unetched PCB).  Basically I just follow the schematic as it pretty much already organizes the parts in the place you want them on the board.  Start with the receiver antenna connector (or short piece of coax or twisted line) and just start building out.  The receive bandpass filter is first, then the RF amp, mixer, etc all follow.  The build will probably end up long an narrow, but that is good as it keeps the higher level signals away from the lower level ones.  Reading the description of Farhan's build you will see he did it this way too.  You might want to build the VFO, BFO, and AF amp on separate PCB's.  This will allow you to shield the RF one's and also allow you to keep the build from getting too long.  For sure I would put the PA on a separate board.

When soldering parts to the ground plane, remember that is one big piece of copper that you are heating up.  It will take higher heat and a longer heating time than the parts.  Clean then wet the tip of the iron with fresh solder, place the tip on the board where you want to solder, and wait until solder placed on the PCB near the tip will melt by itself.  Then you can place the part to be soldered to it onto the board.  This will keep the part from over heating.

You can place parts upside down or rightside up -- whatever is easiest and makes connections the simplest.

73,


Mark

PS:  Ferrite core toroids or old TV baluns will work much better than tap washers for transformers and inductors as the designer found out in the end.

PSS: If you can't find Toko type transformers for the bandpass filter, you can use fixed inductors and accomplish the filter adjustment by making the capacitors variable instead (trimmer caps). 

Aaron K5ATG
 

I’m starting fresh with a blank PCB board.

 

72

Aaron K5ATG

K5ATG Blog

 

From: Arv Evans
Sent: Tuesday, April 7, 2020 10:45 AM
To: BITX20@groups.io
Subject: Re: [BITX20] BITX 14MHz Build #bitx20

 

If you are not using a Bitx pcb, then your question is questionable.  Build instructions are for using a bitx pcb.  For one-off builds using manattan or ugly method you just need to decide your own layout and construction sequence.

 

Arv. K7HKL

_-_

 

 

On Tue, Apr 7, 2020, 6:58 AM Aaron Scott via groups.io <k5atg=yahoo.com@groups.io> wrote:

Hello everyone,
I'm going to start building the BITX 14MHz build. It's going to be my first homebrew transceiver project so I will be learning as I go. The instructions say to solder the transistors first but since this is my first go around, I'm not really sure where I should put them on the PCB. I'm going to use Manhattan construction using the QRPme Little MeSquares. So if anyone has any tips or pointers for a newbie, I will be greatly appreciated.  

 

Aaron K5ATG
 

Thanks Mark,

Like I said, I’m a newbie so I will start identifying the VFO, BFO and AF amp and PA.

 

 

72

Aaron K5ATG

K5ATG Blog

 

From: Mark - N7EKU
Sent: Tuesday, April 7, 2020 11:09 AM
To: BITX20@groups.io
Subject: Re: [BITX20] BITX 14MHz Build #bitx20

 

Hi Aaron,

I not used MeSquares, but have done quite a bit of "dead bug" construction (which is just placing parts - upside down or not - over an unetched PCB).  Basically I just follow the schematic as it pretty much already organizes the parts in the place you want them on the board.  Start with the receiver antenna connector (or short piece of coax or twisted line) and just start building out.  The receive bandpass filter is first, then the RF amp, mixer, etc all follow.  The build will probably end up long an narrow, but that is good as it keeps the higher level signals away from the lower level ones.  Reading the description of Farhan's build you will see he did it this way too.  You might want to build the VFO, BFO, and AF amp on separate PCB's.  This will allow you to shield the RF one's and also allow you to keep the build from getting too long.  For sure I would put the PA on a separate board.

When soldering parts to the ground plane, remember that is one big piece of copper that you are heating up.  It will take higher heat and a longer heating time than the parts.  Clean then wet the tip of the iron with fresh solder, place the tip on the board where you want to solder, and wait until solder placed on the PCB near the tip will melt by itself.  Then you can place the part to be soldered to it onto the board.  This will keep the part from over heating.

You can place parts upside down or rightside up -- whatever is easiest and makes connections the simplest.

73,


Mark

PS:  Ferrite core toroids or old TV baluns will work much better than tap washers for transformers and inductors as the designer found out in the end.

PSS: If you can't find Toko type transformers for the bandpass filter, you can use fixed inductors and accomplish the filter adjustment by making the capacitors variable instead (trimmer caps). 

 

Aaron K5ATG
 

Thanks Jason,

Yeah those are nice videos. I have not seen his Youtube page before.

 

72

Aaron K5ATG

K5ATG Blog

 

From: Jason Pirok
Sent: Tuesday, April 7, 2020 11:06 AM
To: BITX20@groups.io
Subject: Re: [BITX20] BITX 14MHz Build #bitx20

 

W2AEW (Alan Wolke) has a great video on the layout of Manhattan style PCB building. 

This one illustrates the island method, but the techniques can be used for Manhattan.
https://www.youtube.com/watch?v=blalAktxFoI  

 

This one goes over several other construction techniques.
https://www.youtube.com/watch?v=kH110yjYZ2g  

 

--

Jason Pirok

W4UNX