Date   

Re: SB2 Q6 failure

Steven Weber
 

 

I hope that doesn’t become a problem. Using the 2N7002 as a diode isn’t exactly what it’s designed to do, but it saved from having to kit one diode just for that function. If they do start popping left and right, I guess tacking in a 1N4148 won’t be too hard to do.

 

Nice looking cabinet 😊

 

Steve KD1JV

 

 

 

 

The Slop Bucket II s/n 144 has been working flawlessly until this morning in mid-QSO I noticed that the modulation indicator wasn't flashing in tandem with the on-the-air lamp. I glanced at the antenna current and it was normal. I opened it to find that Q6, the RF sense detector diode had developed an open source-to-drain diode. Quickly replaced it with a 2N7002 that I had in the drawer and it is back on the air in less than an hour. One advantage of constructing your own equipment: You become familiar with the circuitry and with the maintenance techniques. A cheap and useful education!

 


SB2 Q6 failure

Don, ND6T
 

The Slop Bucket II s/n 144 has been working flawlessly until this morning in mid-QSO I noticed that the modulation indicator wasn't flashing in tandem with the on-the-air lamp. I glanced at the antenna current and it was normal. I opened it to find that Q6, the RF sense detector diode had developed an open source-to-drain diode. Quickly replaced it with a 2N7002 that I had in the drawer and it is back on the air in less than an hour. One advantage of constructing your own equipment: You become familiar with the circuitry and with the maintenance techniques. A cheap and useful education!


Re: SB II build project

John VA7JBE
 

Nice build, Jim, very clean!

cheers,
John VA7JBE 


Re: SB II build project

John AE5X
 

Looks absolutely professional. I applied power to mine for the first time today and now the troubleshooting begins ;-(


Re: SB II build project

Roy Appleton
 

Looks really nice!

Roy
WA0YMH

On Wed, Mar 6, 2019, 8:42 AM Jim Reagan <jimreagans@...> wrote:
#127 is finished and fully functional!  6 1/2 watts and receives well.  Housed in a cut down Hammond 1455P160 case. I'm a happy camper!
Your mileage may vary,
Jim W0CHL


Re: SB II build project

 

#127 is finished and fully functional!  6 1/2 watts and receives well.  Housed in a cut down Hammond 1455P160 case. I'm a happy camper!
Your mileage may vary,
Jim W0CHL


Re: Adafruit booster cables and 5V powerbanks as ATS/MTR power sources

Joe Street
 

I put my contraption in a hammond die cast box with common mode chokes on the in and out wires.  I don't hear it in the RX but while I was testing it open on the bench I certainly did, but that was educational.  I know some designs run a fixed switching frequency but what I discovered with mine was that if a birdie came on the shoulder of my filter I could make it fly off by simply tweaking the pot for the output voltage of the switcher because in doing so the switching frequency would change.  This gave me the confidence to keep going and put it in a box.  The nice thing about it is the USB battery pack can stay in an inner pocket and stay warm and I can tune up at low voltage to save the finals and the change in DC supply voltage which sits outside or in my outer pocket at least, it also allows me to vary my output power by a full S unit. This makes it easy to see if they can still hear you when you QRPp.

On Mon, Mar 4, 2019 at 4:11 PM ajparent1/kb1gmx <kb1gmx@...> wrote:
Paul,

The trick for switching converters is building them into a box with filter inputs and outputs.
Your not trying to keep the TX clean I'd be surprized if the other guy heard it.
However not have the converter whistling in your ears (your RX) or adding a large
chunk of wide band noise to try and hear over is critical.

My solution is if the radio runs on 9-12.6V well enough I use 3x 2800mAh Lipo 18650 cells
(4.2V full charge and 3.7 nominal discharge per cell) as it is small light and compact.  If
its fussy radio or wants more voltage its 4x LiFePO cells (3.65V max charge and 3.2V
nominal discharge cells).  They work well for me for my SB-1, 1W, QCX, KNQ7A, 
and ft817 ( for that I have a 4Px3S 11ah pack at 2.3 pounds and runs it for over
8 hours average use).

Less hardware and plastic and wires.  Less loss to conversion and no risk of converter
noise ( I test on 80M as it seem to be the band most impacted).

Allison


Re: Adafruit booster cables and 5V powerbanks as ATS/MTR power sources

ajparent1/kb1gmx
 

Paul,

The trick for switching converters is building them into a box with filter inputs and outputs.
Your not trying to keep the TX clean I'd be surprized if the other guy heard it.
However not have the converter whistling in your ears (your RX) or adding a large
chunk of wide band noise to try and hear over is critical.

My solution is if the radio runs on 9-12.6V well enough I use 3x 2800mAh Lipo 18650 cells
(4.2V full charge and 3.7 nominal discharge per cell) as it is small light and compact.  If
its fussy radio or wants more voltage its 4x LiFePO cells (3.65V max charge and 3.2V
nominal discharge cells).  They work well for me for my SB-1, 1W, QCX, KNQ7A, 
and ft817 ( for that I have a 4Px3S 11ah pack at 2.3 pounds and runs it for over
8 hours average use).

Less hardware and plastic and wires.  Less loss to conversion and no risk of converter
noise ( I test on 80M as it seem to be the band most impacted).

Allison


QRP Brazilian - off-topic

Carlos Tomazelli
 

Sorry for the off-topic
Someone in the group has unused a PCB Board The Mountain Topper
Tri-bander to sell?
That you are not interested in mounting more, or you have unused PCBs.
I know that it is an equipment that is not in line and it is a great equipment.
 
Looking forward to a direct email return.
 
Carlos PY2CSU.
I love QRPs montage.


Re: Adafruit booster cables and 5V powerbanks as ATS/MTR power sources

Joe Street
 

One thing I didn't like with these boost converters is the efficiency really drops as the difference between Vin and Vout gets larger than a few volts.  They are always sold with a quoted efficiency which is tested in a best case scenario.  On the SOTA page you linked Ji1kbf commented that he used a boost converter based on the XL6009 chip which was what I also used but to get around the efficiency issue I mentioned previously, I put two of these cheap and widely available boost converters in series.  I removed the onboard multiturn potentiometers from each board and instead connected the two boards to a single dual stage pot with some external limiting resistors so that each of the boost converters only has to do half the job and efficiency stays high. 

On Mon, Mar 4, 2019 at 11:17 AM Paul Schreier <aa1mi@...> wrote:
Given the abundance of inexpensive powerbanks for mobile phones, I was looking for a way to use one of them as a power source for my ATS and MTR rigs. I ran across two very inexpensive booster cables from Adafruit that convert the powerbank 5V to 9V and 12V, respectively. I was warned there might be some spurious emissions from the dc/dc converter, but after examining the setup with a spectrum analyzer, everything looks great. And the power budget is within that specified for the Adafruit booster cables.

You can read a detailed report, including photos and spectrum analyzer screen shots, on the SOTA reflector at
http://reflector.sota.org.uk/t/cable-for-usb-power-banks-with-kd1jv-rigs-ats-mtr-models/19509

There are also links to the Adafruit Model 2777 and 2778 booster cables. Seems like quite a viable option! I've tried the cables in several SOTA activations, and got plenty of contacts and no complaints about the quality of my signal. Can't ask for more!

de Paul, HB9DST / AA1MI


Adafruit booster cables and 5V powerbanks as ATS/MTR power sources

Paul Schreier
 

Given the abundance of inexpensive powerbanks for mobile phones, I was looking for a way to use one of them as a power source for my ATS and MTR rigs. I ran across two very inexpensive booster cables from Adafruit that convert the powerbank 5V to 9V and 12V, respectively. I was warned there might be some spurious emissions from the dc/dc converter, but after examining the setup with a spectrum analyzer, everything looks great. And the power budget is within that specified for the Adafruit booster cables.

You can read a detailed report, including photos and spectrum analyzer screen shots, on the SOTA reflector at
http://reflector.sota.org.uk/t/cable-for-usb-power-banks-with-kd1jv-rigs-ats-mtr-models/19509

There are also links to the Adafruit Model 2777 and 2778 booster cables. Seems like quite a viable option! I've tried the cables in several SOTA activations, and got plenty of contacts and no complaints about the quality of my signal. Can't ask for more!

de Paul, HB9DST / AA1MI


Re: SB2 #118 Update

 

Got some time on the spectrum analyzer over the weekend.
I measured power in CW mode.

I think I bumped the MOD adjustment so I'll have to redo that sometime this week.




On 2/19/2019 7:09 AM, Steven Weber wrote:

I guess putting it on the wrong side of the board would make it not work so good, hi.

Surprised that didn’t hurt it.

Glad your on the right track now.

KD1JV

 

 

You know, a picture's worth 1000 words, or approximately one awshit.

I did have to replace the IRF510, but only to the other side of the PCB.
That's what I get for building past midnight...

I'll tweak it at the office and see what it looks like on the SA.
I did see the my power meter peaking up to around 4W just
playing around a bit.

Where's the best place to check the modulation with a scope?
At the gate of the IRF510 or the antenna?

Thanks for your patience!

John

On 2/18/2019 8:06 PM, Steven Weber wrote:

It’s kind of hard to cook those fets. If it’s not shorted, it’s probably good.

It would take a pretty good static spike to cook the gate.

 

Do you have 12V on the tab?

Your not seeing any current increase with the bias pot?

You sure the voltage is making it to the gate?

 

Take  a close look at T1 and T2 and make sure their installed correctly.

Transpose the ends of the windings and it doesn’t work anymore.

 

Just going down the check list. This is when having a ‘Scope saves a lot of time.

KD1JV

 

The diodes were good.  5.1V supply was good.

I think I cooked my IRF510 somewhere along the line.
No shorts. 
Power out with the modulation pot at it's highest is 5-10 mW.
Bias pot doesn't make any difference to the output despite raising
the gate voltage.  I did start fully CCW.

I think I'm getting a pretty good signal to the gate, but not much
is happening at the output.

I'll replace the IRF510 and try again.

John

On 2/17/2019 8:41 AM, ajparent1/kb1gmx wrote:

Check to be sure you didn't put the zener diode (d1) in backward.

FYI the crystal for the 5351 will age and move in frequency with time
so retest in a month or two. 

Allison

 

 

 

 



Re: SB II build project

John VA7JBE
 

Thank you Alison, John, and Joe!

 

I've been away working for the last few weeks and unfortunately won't get a chance to start building for a few more.  The upside is that I get to obsess over details in my free time!

Joe, good advice on layering the gloves/mitts.  I have a similar approach, though I tend to have dedicated gloves for getting sweaty going up and then getting colder skiing down.  Making the micro switch glove friendly is an excellent idea, I might have to try that once i get more comfortable with morse.  I'm new enough that I need a comfortable, low-pressure environment to send/receive comfortably and that means summer.  I have a QCX that I've been playing with just for that purpose.  I even modified it to draw 75 mA on receive!

 

John, thanks for the link!  I went with the 100x100x44mm box for the extra depth (not much, admittedly, but enough to provide a bit of wiggle room with the batteries.)  It's arrived from China already and it looks like it will be small and light enough to be worth bringing on multi-day trips, which I'm very excited about!  I really like this idea of designing boards to fit inside these enclosures and there seems to be enough variety that designers have don't feel too much pressure to conform to any one standard.

Alison, informative as ever!  Thanks so much for the information about the TCXO and also the 817, that had been bothering me for a while.  There's an old trick SOTA operators in the UK have been doing for years to keep their radios splash proof, and that's to use a clear disposable shower cap placed over top of the radio while operating.  I might start there.  This enclosure seems small enough to fit in my jacket pocket so I'll be able to add that to my list of ways to keep the batteries warm. 

Through some extensive, and somewhat random, browsing on wikipedia I discovered Lithium-Titanate batteries, which have a temperature operating range down to -30C in addition to higher charge/discharge rates, greater cycle life, and being much more environmentally friendly than other lithium chemistries.  The downside is that they have a lower energy density and inherent voltage (2.4v/cell) than lithium ion cells, though still better than nickle chemistries.   They are also more expensive at $13 for a 1300mAh 18650 cell from battery space (link: https://www.batteryspace.com/Lithium-Titanate-Battery.aspx ).  I may or may not explore this option at a later date.  For now it's just fun to think about. 

 

Thanks again to everyone, I'll keep posting developments as they happen!

Cheers,
John VA7JBE


Re: FS: MTR 5B

Randy
 

Sold.

73,
Randy, KS4L 

On Mar 1, 2019, at 12:53 PM, Randy via Groups.Io <wrmoore47@...> wrote:

I have an MTR 5B for sale. I built it from KD1JV's kit and it works great. Packaged in a clear plastic case with an added encoder for frequency changing. $225 plus $15 shipping to US. PayPal only. Email me for pix and any questions if you're interested.

73,
Randy, KS4L


Re: SB2 on 75/80m

Don, ND6T
 

Thanks to Steve the firmware issues are resolved. Installed it in the case and put it on the air. First contact was T31EU, the Kanton Island, Kiribati DXpedition. Nice for 80m! Love the smooth QSK. 73, Don


Re: SB2 on 75/80m

Don, ND6T
 

John,
Those that I made for the BITX series. I removed the dynamic elements from some old CB hand held microphones and replaced them with electret elements. I used rubber grommets, drilled out the proper size holes for the new elements and installed. The rubber makes a tight fit to the old element holding structure and provides a degree of acoustic isolation. I found that I had to crank the gain back on the SB2 considerably to prevent overdriving. I would think that it might have enough gain to accommodate a dynamic microphone if one removed R34.  You are going to have some serious fun! 73, Don


Re: SB2 on 75/80m

John AE5X
 

Good job, Don. I'm curious what microphone you're using?

Tnx/73,
John AE5X


Re: SB II manual corrections.

Steven Weber
 

Higher voltage, higher current carrying capacity then the chip caps.

 

The reason for C22 a+b is 33 pfd was needed there for 20M, I didn’t have any 33’s but I had a lot of 22’s and 15’s. Close enough.

 

Steve

 

 

Just curious, why is C10 a film cap?

 

On Fri, Mar 1, 2019 at 2:15 PM Steven Weber <steve.kd1jv@...> wrote:

These two caps are in parallel, hence a +b. So yea, pencil in a ‘b’ after C22.

Steve

 

The nomenclature for C22:

The list of parts to be installed has a C22a and C22b
The diagram lists C22 and C22a  - assuming the C22 refers to the C22b value?

Photo attached.

 

 


Re: SB II manual corrections.

Jer Tres
 

Just curious, why is C10 a film cap?

On Fri, Mar 1, 2019 at 2:15 PM Steven Weber <steve.kd1jv@...> wrote:

These two caps are in parallel, hence a +b. So yea, pencil in a ‘b’ after C22.

Steve

 

The nomenclature for C22:

The list of parts to be installed has a C22a and C22b
The diagram lists C22 and C22a  - assuming the C22 refers to the C22b value?

Photo attached.

 


Re: SB II manual corrections.

Steven Weber
 

These two caps are in parallel, hence a +b. So yea, pencil in a ‘b’ after C22.

Steve

 

The nomenclature for C22:

The list of parts to be installed has a C22a and C22b
The diagram lists C22 and C22a  - assuming the C22 refers to the C22b value?

Photo attached.