Date   
Re: Rugged Case Options? #ubitx

John AE5X <ae5x@...>
 

Just received my aluminum housing from a Thai eBay vendor:
https://ae5x.blogspot.com/2018/01/case-for-ubitx-arrives-from-thailand.html
--
John AE5X

 

Re: End whistling into the mic

Guy N7BIR <sgbridge@...>
 

How about from your android or iPhone?

Re: End whistling into the mic

Doug W
 

On Thu, Jan 25, 2018 at 02:24 pm, Guy N7BIR wrote:
How about from your android or iPhone?

John linked to this a few posts back.  https://play.google.com/store/apps/details?id=com.keuwl.functiongenerator
I use the same app.  It works great

Re: Rugged Case Options? #ubitx

Randy
 



Measures 8.7 by 17 by 2.8- inches

https://www.ebay.com/itm/Kikkerland-CU211RD-Radio-Tin-Lunch-Box-Red/282821302901?hash=item41d9769a75:g:HCQAAOSw38BaaL1c

Re: Antenna connector continuity Ubitx

KD8CGH
 

I learned from an accidental grounding on my Bitx40 that pcb traces make hard to replace fuses.
    Bob   KD8CGH

Re: SMD Group Build

Arv Evans
 

Farhan, and others...

The old stripline PCB technique also works well.  Just scribe through the copper on 0.1 inch
centers to make horizontal copper lines.  Then break these lines with a scriber as needed
to solder SMD across the breaks.  This method also allows surface mounting of transistors
and even 0.1 inch pin-spaced ICs.  You can even mix-and-match SMD and leaded parts.

This works well: 
This SMT stuff is not all that complex or difficult.  Tombstoning or standing SMD resistors
and caps on end allows them to be used as tie-points or for connecting them in series.
Soldering multiple SMD resistors or capacitors on-edge allows you to connect them in
parallel to make up special values. 

Use aluminium or wooden tweezers to hold them in place as you solder them.  The old
spring-type wooden clothespins can be ground to a point to make wooden tweezers. 
Tweezers can also be made with bare PCB substrate.  just pull off the copper to avoid
your SMDs sticking.

Many will try to convince you that this SMD stuff is very complex.  That may be true if
you are building to mil-spec requirements but with a bit of ham radio ingenuity you can
still work with these components much as we have done for years using Manhattan or

Arv  K7HKL
_._


On Thu, Jan 25, 2018 at 2:49 PM, Ken KM4NFQ <km4nfq@...> wrote:
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: #ubitx and 6 meters #ubitx

Ryan Flowers
 

Hmmmm, if the IF is at 45mhz, won't operating above that invert the sidebands? Easy enough to compensate for in the raduino I suppose. Just a thought. 

--
Ryan Flowers - W7RLF
MiscDotGeek.com
Multi Band BITX40
The BITX40 FAQ

Re: Antenna connector continuity Ubitx

César EA3IAV
 

So, you think the finals are fine? The radio turns on and receives... but I see no output on the external power meter... though i hear myself on a nearby radio 

Re: Antenna connector continuity Ubitx

César EA3IAV
 

I did insulate them... no continuity between tab and screw. I check both... i din’t know what happened but as soon as i separated the fers from the box chasis it was fine

Re: SMD Group Build

Tom Clifton
 

I am not sure if it has been stated or not, but the SMD trainer with the LED's is available on eBay, starting under $2.00 (depending how fast you want it). Comes with all SMD parts, you provide the solder, flux and appropriate heat source.  Just search for " smd rotating led kit "

Re: BitX40 voltage booster implementation

John T P
 

Dear OM,

when we increase the voltage, proportionally current has to be increased,  so as to maintain output impedence. Hence at 24v,  current should be 2A. such voltage and current will produce lot of heat on final IRF510. 

Hence I would recommend keeping 18v,  1.5A in the final.

Regards 

John T.P., 
VU2JON 
Tharayil House
Sree Ayyappa Road
Kuriachira PO
Thrissur 680 006
Mob : 8807007933
India 

On Jan 26, 2018 2:06 AM, "Arvo KD9HLC via Groups.Io" <arvopl=yahoo.com@groups.io> wrote:
On the power side, I'm thinking about a 19V laptop supply and building a small card with 19, 12, and 5V busses.   19V to the PA section, 12 V for the rig in general, and 5 to the SSM2167 card, and maybe to the Raduino.

Re: End whistling into the mic

Clark Martin
 

One advantage of a tone on SSB is that you can reduce  the signal level into the mic input and therefore the transmitter output.  This will help protect the transmitter until you have got the load “tuned up”.

Clark Martin
KK6ISP

On Jan 25, 2018, at 1:33 PM, Michael Babineau <mbabineau.ve3wmb@...> wrote:

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.

Re: Power Supply Option

Joe
 

I have 3 bitx 40 v3 and all run at 13.8 v
I run them almost all the time with ft8 or jt65
I have oversize heat sinks on each.
Output around 8watts
Powersupply is well filtered plus extra filters inside the rig

Joe
VE1BWV


On Thu, Jan 25, 2018, 6:09 PM Joe Puma <kd2nfc@...> wrote:
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 
 

Re: End whistling into the mic

Allard PE1NWL
 

You could use this simple CW mod to generate a carrier for tuning:

https://github.com/amunters/bitx40/blob/master/CW-CARRIER%20wiring.png
If you use a 100K potentiometer instead of the fixed 4.7K resistor you can control the power of the carrier too.

73 Allard PE1NWL

Re: BitX40 voltage booster implementation

Gordon Gibby <ggibby@...>
 

"when we increase the voltage, proportionally current has to be increased,  so as to maintain output impedence. Hence at 24v,  current should be 2A. such voltage and current will produce lot of heat on final IRF510. "


This  raises a question to me.   Is it guaranteed that the impedance remains the  same?   Or it is the TRANSONDUCTANCE of the IRF510 that remains unchanged?   

Has this been checked experimentally in this transmitter?






From: BITX20@groups.io <BITX20@groups.io> on behalf of John T P <tpjohn@...>
Sent: Thursday, January 25, 2018 6:26 PM
To: BITX20@groups.io
Subject: Re: [BITX20] BitX40 voltage booster implementation
 
Dear OM,

when we increase the voltage, proportionally current has to be increased,  so as to maintain output impedence. Hence at 24v,  current should be 2A. such voltage and current will produce lot of heat on final IRF510. 

Hence I would recommend keeping 18v,  1.5A in the final.

Regards 

John T.P., 
VU2JON 
Tharayil House
Sree Ayyappa Road
Kuriachira PO
Thrissur 680 006
Mob : 8807007933
India 

On Jan 26, 2018 2:06 AM, "Arvo KD9HLC via Groups.Io" <arvopl=yahoo.com@groups.io> wrote:
On the power side, I'm thinking about a 19V laptop supply and building a small card with 19, 12, and 5V busses.   19V to the PA section, 12 V for the rig in general, and 5 to the SSM2167 card, and maybe to the Raduino.

Re: BITX QSO Afternoon/Night, Sunday, January 28, 3PM/7PM Local Time, 7277 kHz in North America, 7177 kHz elsewhere

ekelley
 

Look for us in the mid-west to be on 7278 the other frequency is too close to the 7275
traffic that is on every Sunday.

On 1/25/2018 1:34 PM, John P wrote:
BITX QSO Afternoon/Evening, Sunday, January 28, 3PM & 7PM Local Time, 7277 kHz in North America, 7177 kHz elsewhere.

While not the greatest band conditions, the afternoon session last week was better than the evening session! So hopefully, we can try both times again this week.

Join us as we make contacts from BITX40 to BITX40 on 7.277 MHz in 40 meters!

This is a worldwide event for BITX40 stations starting at 7pm in each time zone. To participate, call CQ BITX on Sunday, starting at 3PM and/or 7PM your local time. The BITX QSO Night continues through the evening and conditions usually improve after sunset, so it is worthwhile to participate later in the evening.

Suggested Best Operating Practices:

Work at QRP power levels unless conditions require more power.
Call and listen for CQ BITX on the hour and every quarter hour.
It is helpful if you call CQ BITX with your callsign, name and location. 
Repeat your callsign a number of times during your CQ BITX and during QSO's.
Start a QSO by confirming the callsign, location, name and signal report of the other operator.
Say the callsign, name and location of the other operator so others can hear.
If the frequency is busy, avoid long conversations.
After your initial QSO is complete, ask if there are any other stations who would like to contact.

Report your QSO's, discuss propagation, noise, signal reports, audio reports, antenna type, etc. in this thread.

This is an undirected, scheduled event.  The BITX QSO Night relies on you to call CQ BITX to initiate contacts with other stations, so warm up that final and transmit a few calls on Sunday evening.  Talk to you then!
--
John - WA2FZW


Re: Something has been blown

KC9SGV <kc9sgv@...>
 

Cesar,
Those Mosfets are really cheap on eBay...
Get a handful....
I did.

Bernie,
KC9SGV
Chicago

Sent from my iPad

On Jan 25, 2018, at 2:48 PM, César EA3IAV <Cesarleon@...> wrote:

<A713F7E8_C6D7_471C_A728_141FF07B8525.jpeg><16F70DE6_396F_47AA_9F38_CC4CC3B8E7A8.jpeg><9B9D5551_AC32_441C_B1E6_A5C862D29063.jpeg><70C5A1C8_DB48_4535_B786_60FE4E8A568F.jpeg>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: SMD Group Build

Jack, W8TEE
 

Great idea on the tool. Might have to make one of those!

Jack, W8TEE



From: Ken KM4NFQ <km4nfq@...>
To: BITX20@groups.io
Sent: Thursday, January 25, 2018 4:39 PM
Subject: Re: [BITX20] SMD Group Build

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: Something has been blown

Arv Evans
 

César EA3IA

Since there is no short with the IRF-510 devices in place but not connected to the chassis, it is 
possible that the antenna was disconnected, shorted, or some other anomaly.  Unfortunately
MOSFETs used as RF power amplifiers tend to self-destruct if the load is not of proper
impedance.  Too low an impedance and they will overheat, and too high an impedance and
they will go into oscillation and destroy themselves with high current. 

As Bernie KC9SGV has suggested replacement devices are relatively inexpensive from Ebay
vendors.  Some will probably raise the issue of Ebay sourced parts being less than perfect
but I have been using Ebay sourced IRF-510's for over 10 years with no problems. 

Safest way to bring a new BITX on-line is to use a known good dummy load.  Once you have
verified it is working properly you can connect it to your antenna via an ATU and apply only a
little amount of audio to generate a low output power while you tune the ATU for as close as
you can get to a 50 ohm match.  Once you have a good match between BITX and antenna
you can then apply normal audio or full CW power. 

It would be nice if there were a way to make the IRF-510 devices immune to impedance
mis-match problems, but to-date that does not seem to be available. 

Arv  K7HKL
_._

Re: Analog keyer revisited #ubitx

Mike Woods
 

John

I like this solution and I hope to give it a try out this weekend.

Mike ZL1AXG

On 26/01/18 9:38 AM, John Pieper wrote:
I incorporated the keyer code from W0EB and W2CTX into my personal software build, but being determined to save the last analog input for S/power metering, kept the single input that detects three levels (four originally, but I don't care much about straight keying so I left that out for now). Some of the errors I've experienced and others have reported with the single line seemed to me consistent with the ADC deciding the state was "both" instead of "dit", for example an 'I' becoming an 'N' while the dit paddle is held closed. Looking at the nominal voltage levels with the provided resistors, I saw that there was only around 0.22 volts between the "dit" and "both" levels (1.60 vs 1.38 V). On the other hand, there is 1.8 volts between "dit" and "dah". Errors due to fluctuations would be much more likely between "dit" and "both".

Hoping to improve the situation, I did a little numerical study of the divider circuit. It turned out that there is really no area in the 2D "space" of possible resistor values that gives an ideal result (large equal intervals between both pairs of levels), but it is possible at least to increase the dit-both spacing significantly, at the expense of the dit-dah spacing. In the end I replaced the 2.2k resistor with a 5.1k one. Now the nominal levels are 3.4 V for "dah", 2.6 V for "dit", and 2.1 V for "both". I made an educated estimate of what the boundary ADC values should be and put them into my customized paddle-latch function.

The results so far are favorable. I have sent a fair amount of practice code (I also added a "practice" mode that only plays the sidetone) at speeds up to 25 wpm, and have detected no errors that were not caused by my fist. The iambic action seems flawless and smooth. I might actually get good at sending iambic style someday...

73, John AD0RW


--
Mike Woods
mhwoods@...