Date   
Re: Antenna connector continuity Ubitx

Arvo W0VRA
 

Hey, César, are you using the case as a heat sink for the PA?

Something has been blown

César EA3IAV
 

Yesterday I installed everything and it worked fine...
Today I put everything in the box and decided to use the case as heatsink. I put insulator and thermal silicone. Ok i turned it on and there has been a little explosion and smoke in the area of the transistors. I don’t see anything blown... 
maybe i blew the transitors? How can I check? I did tested that there was no continuity between the metal thing of the transistor and the screw! 
Hell i hate this!

now after removing the transistors from the case it turns on normally 

Re: Something has been blown

Vince Vielhaber
 

Make sure one or both of those insulators didn't crush on one side and let the screw touch the FET.

Vince.

On 01/25/2018 03:48 PM, César EA3IAV wrote:
Yesterday I installed everything and it worked fine...
Today I put everything in the box and decided to use the case as
heatsink. I put insulator and thermal silicone. Ok i turned it on and
there has been a little explosion and smoke in the area of the
transistors. I don’t see anything blown...
maybe i blew the transitors? How can I check? I did tested that there
was no continuity between the metal thing of the transistor and the screw!
Hell i hate this!

now after removing the transistors from the case it turns on normally

Re: Power Supply Option

Steve
 

I'm a bit confused over operating voltage for BTX40.  Understanding that the PA can be run up to higher voltages, and the main board is spec'd at "12V", is it proper and safe to run the main at 12.6V- typical battery voltage?  How about 13.8V if, say, plugged into a running automobile system?  Thanks, Aloha, Steve WH6ST

Re: Antenna connector continuity Ubitx

César EA3IAV
 

That is what i tried but i think i blew something :(

End whistling into the mic

David
 

Instead of whistling into the mic when using an antenna tuner on SSB, we could easily add a tone generator and switch to do that for us. Thoughts?

Re: End whistling into the mic

Joe
 

Good idea - use a cheap 555 ic to generate nearly any tone.


Joe
VE1BWV

On Thu, Jan 25, 2018 at 5:20 PM, David <dokrent@...> wrote:
Instead of whistling into the mic when using an antenna tuner on SSB, we could easily add a tone generator and switch to do that for us. Thoughts?


Re: End whistling into the mic

Jerry Gaffke
 

From post 22764 of last Feb:

I got tired of saying AHHHHHHH after about 30 seconds, so spent the following 30 seconds adding a line to the Arduino sketch (anywhere) in the setup() function:

    tone(A0, 750);   
The Raduino is then emitting a 5v square wave at 750hz on the A0 pin.  (I prefer listening to 750 hz all day over 1khz.)  That's the black wire on one end of the 8 pin connector, the other end of that same connector has 3 wires over to the tuning pot.  I ran the black wire to a 1k resistor and a 20 ohm resistor in series to ground.  From the top of the 20 ohm resistor to ground (the bottom of the 20 ohm resistor is ground) I now have a 100mv 750hz square wave, which I ran into the microphone input.  Gives me a consistent signal to measure and make comparisons.


On Thu, Jan 25, 2018 at 01:20 pm, David wrote:
Instead of whistling into the mic when using an antenna tuner on SSB, we could easily add a tone generator and switch to do that for us. Thoughts?

 

 

Re: End whistling into the mic

Jerry Gaffke
 

Of course, in most cases you can just switch to CW mode for testing.
But need a tone to check the mike amp and modulator


On Thu, Jan 25, 2018 at 01:26 pm, Jerry Gaffke wrote:
I got tired of saying AHHHHHHH after about 30 seconds, so spent the following 30 seconds adding a line to the Arduino sketch (anywhere) in the setup() function:

    tone(A0, 750);   

Re: End whistling into the mic

John P
 

Here's another option! It has lots of other uses as well.
--
John - WA2FZW

Re: End whistling into the mic

 

How about just transmitting a carrier using CW ?  My BITX40 has a TUNE button wired in parallel to the KEY jack for just this purpose.

Michael VE3WMB 

Re: Power Supply Option

Jerry Gaffke
 

Many here run it at 13v and more.

But at 12v R141 is already cooking, over its 1/4W rating.
Q13 is also running hot.
Going above 12v makes it worse.

Several reports of having R141 open up, if it does then replace it with a 1/2W 10 ohm resistor.
Q13 could be replaced with a leaded version of the 2n3904, which can dissipate more power than the mmbt3904 that is normally stuffed.

I'd recommend a low dropout 12v linear regulator, such as the LT2940CT-12,
power to the IRF510 kept separate. 


On Thu, Jan 25, 2018 at 01:14 pm, Steve Thatcher wrote:
I'm a bit confused over operating voltage for BTX40.  Understanding that the PA can be run up to higher voltages, and the main board is spec'd at "12V", is it proper and safe to run the main at 12.6V- typical battery voltage?  How about 13.8V if, say, plugged into a running automobile system?  Thanks, Aloha, Steve WH6ST

Re: SMD Group Build

Ken KM4NFQ <km4nfq@...>
 

Hello Jack, W8TEE,

The Revolving LED SMD Practice Kit was my introduction to soldering SMDs.
So it was also my introduction to a Solder Paste Syringe, and application needles.
I have a heavy thumb (ham-fisted, I am).
A gentle squeeze on the syringe produced an on-going stream of solder paste.
I thought it would never stop coming out!
Another thing is, the needle was a mess to clean up afterwards.
I used a Q-Tip and a wire to clean it up as best as I could.
So my first experience kind of soured me on using the needle applicator.
I wanted more control over how much solder paste came out of the syringe.
So what I did was to make a screw-controlled applicator.
I don't use the needles at all. The solder paste comes out very slowly.
As it comes out, I use a pointed dental tool to get a small gob on the point.
Then I apply it to a pad with the dental tool.
Every once in awhile I give the screw a slight twist.
This works great for ME. YMMV.






There is a cap that screws over the end of the syringe, which I replace when I finish applying solder paste.
The scrap-wood prototype worked so well, I never made a finished product.
I call this tool my Solder Paster Extruder.

I found my 'Reflow Oven' at the Goodwill Store (re-purposed Toaster Oven).


I calibrated it with an old kitchen oven thermometer which is accurate.
I made marks on the dial, then checked the temperature for each mark.
In actual use, I turn it to my 3rd mark and wait for the temperature to get to 200degF.
Then I turn it to my 6th mark, and the temperature goes to 350degF.
I turn the oven off, open the door, and let the PCB cool down.

I got my SMD Tweezers, and Hot Air Gun, from eBay, as well as the SMD Practice Kit.
Since then, I have sourced 0805 SMD resistors, capacitors, and ICs from Mouser.
Most of the other tools I already had in my studio.

Regards,
Ken, KM4NFQ






On Thu, Jan 25, 2018 at 9:57 AM, Jack Purdum via Groups.Io <jjpurdum@...> wrote:
Mornin' Ken:

You're right, and I may have glossed over this idea too quickly. This might be a great way to get them to try at low expense and without insulting their fabrication abilities. I do have everything you suggested except the skillet. That might be the club's next project after the frequency counter.

Jack, W8TEE



From: Ken KM4NFQ <km4nfq@...>
To: BITX20@groups.io
Sent: Thursday, January 25, 2018 6:24 AM
Subject: Re: [BITX20] SMD Group Build

Hello Jack, W8TEE,

The SMD components are not the only thing that you might need.
Also look into:
Solder paste in a syringe with application needles (~ $20+ for 35gm)
Toaster Oven or Electric Skillet for melting the solder onto the PCB (find in a thrift store)
Tweezers (for manually placing the components)
Hot Air Gun (for removing parts)
Magnifying Loupe (for inspecting your work)
Desoldering wick (removing solder bridges from ICs)
Soldering Iron with fine tip (rework tombstoned parts)

The revolving LED kit is a challenge to build for beginners.
$3 - $4 per person in the group. All the components are in the kit.
The circuit itself is in the middle of the PCB.
But there are three columns of practice components on each side.
1206, 0805, 0805, 0603, 0603, and 0402 sizes are included, so you get an idea.
The practice columns are not connected to the revolving LED circuit.
The revolving LED circuit has a 555 and a CMOS 4017, as well as
transistors, diodes, and LEDs, so you get a variety of SMDs to work with.

In my recent and limited experience, making an SMD project consists of:
Identifying the components.
Applying solder paste evenly to the pads.
Placing the SMD components on the solder paste.
All the components are soldered at once.
Clean the flux from around the components (Isopropyl Alcohol & toothbrush)
Smoke test.
Only part of my circuit worked, but I got some SMD soldering practice for $3 - $4.

Regards,
Ken, KM4NFQ






On Wed, Jan 24, 2018 at 8:27 PM, Jack Purdum via Groups.Io <jjpurdum@...> wrote:
All:

We have a small group of local hams who enjoy building stuff, yet most are scared to death of SMD parts. Our last build had 29 do the build which is about half of our group. What I'd like to do is put together a small SMD project and have 30 or so boards made. (I have no idea what a good starter project would be.) If anyone has done this, are the board costs less than thru-holes boards? Also, are Mouser and Digikey the likely source for large (e.g., 1206) parts or do you know of a better source.

Thanks!

Jack, W8TEE




Re: Power Supply Option

Joe Puma
 

There should be some tolerance like 10% +/-  on the voltage applied that shouldn’t hurt or hinder it. My Yaesu takes 13.8v by t 12v on the line works just as well 


Joe
KD2NFC


Sent from my iPhone

On Jan 25, 2018, at 4:14 PM, Steve Thatcher <stevep2p@...> wrote:

I'm a bit confused over operating voltage for BTX40.  Understanding that the PA can be run up to higher voltages, and the main board is spec'd at "12V", is it proper and safe to run the main at 12.6V- typical battery voltage?  How about 13.8V if, say, plugged into a running automobile system?  Thanks, Aloha, Steve WH6ST

Re: Something has been blown

César EA3IAV
 

now, with finals away from the metal chasis I am testing if I have output. The power meter and needle doesn’t move at all. I do get about 1,3amp drain when ptt and i can hear myself on other radio though. 
I have tested with another watt metter with no joy either

maybe its too weak to be afected

Re: SMD Group Build

Ken KM4NFQ <km4nfq@...>
 

On Thu, Jan 25, 2018 at 12:03 AM, Ashhar Farhan <farhanbox@...> wrote:
I use double side, plain copper clad. Then, with a sharp knife (i use a glass cutter), i score off an island of 3x2 to 5x2 squares of about 0.25inch to a side. I use all around for the ground plane, and solder the 1206 betweeb the pads. The sot23 transistors are soldered at a corner of three squares. If the ground planing ia crucial, i drill a number of holes around the top ground plane and solder small pieces of wire to connect to the Bottom ground


Hello Ashhar, VU2ESE,

I really like the technique you have described for working with SMDs. It reminds me of Chuck Adam's (K7QO) MUPPET (Manhattan Ugly Professional Placement Experimental Technique) Style Construction. I have already used that style with PTH components. I can see how it will also work very well with 1206's. The soldered wire connecting the top and bottom of the board's ground planes is great. You must use a breakout board for SOICs.

Regards,
Ken, KM4NFQ

Re: Power Supply Option

Jerry Gaffke
 

Good to know your Yaesu is fine with 13.8v.
Unfortunately, R141 on a stock Bitx40v3 is not.


On Thu, Jan 25, 2018 at 01:44 pm, Joe Puma wrote:
There should be some tolerance like 10% +/-  on the voltage applied that shouldn’t hurt or hinder it. My Yaesu takes 13.8v by t 12v on the line works just as well 
 

Re: SMD Group Build

Dave Bottom <ars.kd6az@...>
 

I’m sure PCB manufacturing houses have improved a great deal, but in the Bay Area where you’d think no problem we found the best terrible. So many defective boards.

Parts were often difficult to obtain with some 52 week lead times - seriously this changes often.

We ended up going to Samsung’s prototype manufacturing facility where they take in small runs of boards to keep their facility humming along. Less than 500 boards max.

In the end they supplied us PCBs loaded with all glue logic (less our chip) and the landed cost was below blank PCBs. Every board worked! Absolutely an amazing facility.  Samsung buys glue logic in the millions so those parts were nearly free, installed.

BTW - They came back with a dozen questions about our Gerber files - all GOOD questions - before they produced anything. 

We used them for all prototype and high end low volume boards.

I really should check with them and see their availability as minimums. 

Dave WI6R


Sent from my iPhone

On Jan 24, 2018, at 8:54 PM, William R Maxwell <wrmaxwell@...> wrote:

0805 is a happy medium.

Bill, VK7MX


On 25/01/2018 3:20 PM, Jack Purdum via Groups.Io wrote:
I can barely see a 0603! I would prefer 1206 if I can find them and am not too worried about the cost differential.
Jack, W8TEE


From: Clark Martin <kk6isp@...>
To: BITX20@groups.io
Sent: Wednesday, January 24, 2018 9:15 PM
Subject: Re: [BITX20] SMD Group Build


Clark Martin
KK6ISP

On Jan 24, 2018, at 5:56 PM, Diver Martin <diver.martin@...> wrote:

Mouser & Digikey are my go-to for SMT parts.  They carry just about everything.  If you have other oddball SMT stuff, and either one are out, head to findchips.com.  There are alternate suppliers, but those two always have what I need, either in the exact specified part number, or an equivalent.  Other places will source 1206's and stuff, but might only sell by the full reel (which I have yet to need, except maybe 0.01uF caps or 0.1uF caps across multiple, multiple projects).

SMD resistors/caps (0603, 5% in my case) are usually cheap enough that I buy them in 1000-piece quantity, because $2 of parts for life or $0.5 for the parts I need for the project, and to always have them on hand, is easy.


I’ve only bought from Digikey a few times but I use Mouser all the time.  Also there are Newark and Allied for such supplies.

I bought a set of 0805 resistors (from 0 ohm through several Mohms) and a set of 0805 caps (10s of pF through 1µF).  They came on cards that fit a day planner binder.  There are between 1 and four strips of 25 each for each value (depending on expected usage levels).  I have little trouble working with 0805 parts and they  fit nicely on .1” grid perfboard (with plated through holes).  

When I use up a strip I buy a new strip of 25 at a local electronics shop (Silicon Valley still has a few).

I haven’t done any PCB fabricating yet but that is in the plans.

SMD diodes and transistors of most any size are easily soldered to perfboard.

I’ve also soldered up to 8 pin SOICss buy putting alternate pins on the perfboard pads and tack soldering leads to the other pins.

It definitely makes for smaller boards.



Re: Antenna connector continuity Ubitx

chris gress <Chrisg0wfh@...>
 

The tab of the pa transistors is live you need to insulate them from the chassis look for burnt copper tracks chris

On 25 Jan 2018 21:15, "César EA3IAV" <Cesarleon@...> wrote:
That is what i tried but i think i blew something :(

Re: Power Supply Option

Joe Puma
 

Well that definitely is the power requirement for the Yaesu but I was running my bitX40 On a computer power supply that I tweaked to 13.8 V And it was running fine, no issues. I even was doing digital modes with it, FT8 specifically. I’ll make sure I use the proper power requirement for my micro bitx but as a real world example the bitx40 did run on 13.8v and finals really didn’t feel hot at all. Maybe I was lucky. 

Joe,
KD2NFC 


Sent from my iPhone

On Jan 25, 2018, at 4:51 PM, Jerry Gaffke via Groups.Io <jgaffke@...> wrote:

Good to know your Yaesu is fine with 13.8v.
Unfortunately, R141 on a stock Bitx40v3 is not.

On Thu, Jan 25, 2018 at 01:44 pm, Joe Puma wrote:
There should be some tolerance like 10% +/-  on the voltage applied that shouldn’t hurt or hinder it. My Yaesu takes 13.8v by t 12v on the line works just as well