Date   
Re: VK4PP uBitx LPF BANK add-on Board

Gordon Gibby
 

....was  supposed to read  "a low pass filter above 20 METERS"  (not MHz)

cheers,  gotta go cut some grass before it pours again....


gordon




From: BITX20@groups.io <BITX20@groups.io> on behalf of Gordon Gibby <ggibby@...>
Sent: Friday, August 31, 2018 2:41 PM
To: BITX20@groups.io
Subject: Re: [BITX20] VK4PP uBitx LPF BANK add-on Board
 

Warren, you are right on, but you might not have seen all the posts where I did exactly what you are saying.   Both BEFORE the daughterboard and AFTER the daughterboard so i had proof of its effectiveness.   I also did some calibrations of the S-meter using BNC attenuators (which is all I have).   I then did the suggested measurements of today, measuring bleed-through (unmeasureable, whereas I was clearly able to measure the harmonics and able to measure their reduction by moving the input side of the relay chain OFF the board.)


Here, I'll see if I can find the posts (I'm not too used to that):


(1)Very first "before" measurements:   https://groups.io/g/BITX20/message/57840

(2)Complete baseline data:   https://groups.io/g/BITX20/message/57974

(3) Calibration of the S-meter and proof that the measurement setup itself didn't have bleed thru:  https://groups.io/g/BITX20/message/58070

  [This distinctly showed that 1 S unit in the range of 7-9 is 12 db onthat receiver on that frequency)

(4)Photos of the measurement setup:  https://groups.io/g/BITX20/message/58070

(5) DAta AFTER daughterboard:   https://groups.io/g/BITX20/message/58070



What I CANNOT prove is that the receiver maintains identifical response at all frequencies (hence, is "flat")  however it is reasonable that the differnces aren't mroe than a few dB based on specifications for rigs of this price range etc.   


Poor man's spectrum analyzer.   What is problematic is the 24MHz harmonic range --- here I achieved only 6 dB reduction so there is something else going on there...maybe a series resonance in a filter or somethign I haven't thought of.   Every other range was dramatically reduced by the daughterboard system.   So for my purposes --- a low pass filter above 20 MHz and I have every digital band I need for what I need out of the radio and I don't need to use the bands where the "spurs" are a thorn.   



Hope that makes more sense.   

Cheers,


gordon




From: BITX20@groups.io <BITX20@groups.io> on behalf of Warren Allgyer <allgyer@...>
Sent: Friday, August 31, 2018 2:24 PM
To: BITX20@groups.io
Subject: Re: [BITX20] VK4PP uBitx LPF BANK add-on Board
 
Gordon

Your reasoning makes perfect sense. But I think you can measure at the actual harmonic frequencies which is where the issue would be . Your IC-718 can tune the third, fifth and 7th harmonics of 80 meters. So you can know exactly (within the limits of the S meter calibration and linearity) what the residual level is at the harmonic frequencies themselves. You have checked your S-meter and you know what represents 45-50 dB below S9+30 (normally one S unit = 6 dB but in real life S meters rarely replicate that). So just tune the harmonics directly and measure them. Or am I missing something?

WA8TOD

Re: UBITX V3 TX GAIN VARIATIONS

Bo Barry
 

Enjoying all the mod ideas, just can't keep up with them.
I keep doing screen captures on my iPhone for later reference. I follow about 90% of the technical ideas, but working on these tiny parts dulles my excitement. 

I'm starting the easy way for now. Socket pins for the 6 3904s.  Just got a bunch of supposedly Motorola 2222A's to try. And some 3866A's.  Use WT15 code at www.  witonics.  Com and get 15% off for next 2 weeks. 😁

Question. Do the tiny parts have solder on them? I read about some that do and they can be mounted by using hair dryer. I assume you have to hold them down good. 🤔.  
Bo W4GHV 

Re: 4.2" Nextion Bezel? #3d_printing #ubitx-help

 

Chris:

 

I would be looking for flat black. The inner dimensions are 4 1/8 inches by 2 11/16. I would be looking for a simple rectangle that is 1/8 inch in thickness and 1/4 inch wide all around. What would this (or a spool) cost???

 

David A Posthuma, WD8PUO

1 (616) 283-7703

 

From: BITX20@groups.io <BITX20@groups.io> On Behalf Of Christopher Miller
Sent: Friday, August 31, 2018 11:49 AM
To: BITX20@groups.io
Subject: Re: [BITX20] 4.2" Nextion Bezel? #3d_printing #ubitx-help

 

I could probably help but I don't have any black pla to print with. Here in Tucson we have a maker space called xero craft. You may have one where you live. Xero for example has a couple of printers that can be used for a donation. Another option would be to use shapeway or some other site that will print and mail an object for a fee.

 

Feel free to contact me if you are willing to pay for a spool of filament and I will be happy to do it.

 

Chris

 

On Fri, Aug 31, 2018, 8:31 AM David Posthuma <davep@...> wrote:

I am using the 4.2" Nextion touch screen on my Ubitx. Does anyone know where I can get a small black bezel/frame for it? I only need about 1/4-inch on all sides. Unfortunately, I don't have access to a 3D printer. Thank you for any leads the group may provide.

Re: UBITX V3 TX GAIN VARIATIONS

Christopher Miller
 

Smd parts don't come with solder on them. You can use a hot air gun to rework a pcb. A decent iron with a fine tip is what I use with leaded solder. I also use tweezers designed for smd work to hold parts in place. It would be advisable to get a couple of practice boards before working on something important. 

Re: UBITX V3 TX GAIN VARIATIONS

Jerry Gaffke
 

Parts do not come with solder on the pins.

When manufacturing, the usual process is to lay a stainless steel mask over the board with holes cut into it for each pad,
then squeegie on some solder-paste, which is solder with the consistency of play-dough.
Then auto-insert all those dinky R's and C's and transistors with a pick-and-place machine.
Send the board through a heat process of some sort.
Surface tension of the melted solder tends to pull any slightly wayward arts into the center of their pads.

Some hobbyists do this by applying solderpaste from a syringe, laying down a straight bead across consecutive pads
on something like a QFP with 100 pins on 20 mil centers. Then run it through a toaster oven.
When the solder melts it will adhere to the pad and separate nicely to one little blob per pin/pad.
    http://store.curiousinventor.com/guides/Surface_Mount_Soldering/Solder_Paste_and_Toaster_Oven

For rework on a uBitx of course, you can't use a toaster oven.
I'd melt some ChipQuik low temp solder alloy in around the part to be removed using a soldering pencil,
then use something like an embossing gun (a hot air heat gun, maybe 250 watts?) to get the part 
hot enough to pluck it off the board with tweezers.  For R's and C's, it's easiest to take two soldering
pencils, one on each end simultaneously.  For 3 pin parts such as all those mmbt2n3904's, perhaps heat
up that single pin on one side with the soldeirng pencil and lift it up off the board using a knife, then 
free up the other two pins using two soldering pencils as if it was an R or C.

Jerry, KE7ER


On Fri, Aug 31, 2018 at 12:20 PM, Bo Barry wrote:
Question. Do the tiny parts have solder on them? I read about some that do and they can be mounted by using hair dryer. I assume you have to hold them down good.

Re: VK4PP uBitx LPF BANK add-on Board

Jerry Gaffke
 

Seems whatever I had in post 58293 is contagious.
Everyone should take precautions!

Wear a mask fitted with an appropriate low pass filter.   ;-)

Jerry, KE7ER



On Fri, Aug 31, 2018 at 12:12 PM, Gordon Gibby wrote:

....was  supposed to read  "a low pass filter above 20 METERS"  (not MHz)

cheers,  gotta go cut some grass before it pours again....

 

gordon

 

Re: 4.2" Nextion Bezel? #3d_printing #ubitx-help

Terence Taylor
 

I talked to David and am going to laser cut one for him out of acrylic.


On Friday, August 31, 2018 12:21 PM, David Posthuma <davep@...> wrote:


Chris:
 
I would be looking for flat black. The inner dimensions are 4 1/8 inches by 2 11/16. I would be looking for a simple rectangle that is 1/8 inch in thickness and 1/4 inch wide all around. What would this (or a spool) cost???
 
David A Posthuma, WD8PUO
1 (616) 283-7703
 
From: BITX20@groups.io <BITX20@groups.io> On Behalf Of Christopher Miller
Sent: Friday, August 31, 2018 11:49 AM
To: BITX20@groups.io
Subject: Re: [BITX20] 4.2" Nextion Bezel? #3d_printing #ubitx-help
 
I could probably help but I don't have any black pla to print with. Here in Tucson we have a maker space called xero craft. You may have one where you live. Xero for example has a couple of printers that can be used for a donation. Another option would be to use shapeway or some other site that will print and mail an object for a fee.
 
Feel free to contact me if you are willing to pay for a spool of filament and I will be happy to do it.
 
Chris
 
On Fri, Aug 31, 2018, 8:31 AM David Posthuma <davep@...> wrote:
I am using the 4.2" Nextion touch screen on my Ubitx. Does anyone know where I can get a small black bezel/frame for it? I only need about 1/4-inch on all sides. Unfortunately, I don't have access to a 3D printer. Thank you for any leads the group may provide.


Which xmit transistor is blown?

Sean W7SKD
 

I have had periodic issues with the ubitx that led me to believe that my finals (IRF510) were blown, and the radio seemed to work as expected after replacement, so perhaps they were.

I have a question though...is there a good way to tell what has gone out in the xmit power chain?  I recently replaced Q90 with an mmbt2222a (smt version of the 2n2222a), and then the next two stages with 2n2222a's (in TO-18 form).  No other changes to the radio.

It worked fine for a few days, though the 2n2222a's would get hot to the touch in digital mode transmit (which I think is to be expected).  Today I started to experience 'bouncing' power readings during transmit (as shown in the meter on my tuner) before the radio simply stopped putting out much power at all.  Nothing feels hot...and nothing looks burned or heat stressed to the naked eye.

So...before I start replacing things, I wanted to ask how to diagnose the problem.  Is it most likely that I cooked some transistors, and how do I best till which ones?

73

Sean

Re: UBITX V3 TX GAIN VARIATIONS

MadRadioModder
 

Current capabilities of capacitors in RF service.  The most forgotten issue.

 

 


Virus-free. www.avg.com

--

…_. _._

Re: 4.2" Nextion Bezel? #3d_printing #ubitx-help

 

Thanks all for responding and being so supportive!

 

David A Posthuma, WD8PUO

1 (616) 283-7703

 

From: BITX20@groups.io <BITX20@groups.io> On Behalf Of Terence Taylor
Sent: Friday, August 31, 2018 3:50 PM
To: BITX20@groups.io
Subject: Re: [BITX20] 4.2" Nextion Bezel? #3d_printing #ubitx-help

 

I talked to David and am going to laser cut one for him out of acrylic.

 

On Friday, August 31, 2018 12:21 PM, David Posthuma <davep@...> wrote:

 

Chris:

 

I would be looking for flat black. The inner dimensions are 4 1/8 inches by 2 11/16. I would be looking for a simple rectangle that is 1/8 inch in thickness and 1/4 inch wide all around. What would this (or a spool) cost???

 

David A Posthuma, WD8PUO

1 (616) 283-7703

 

From: BITX20@groups.io <BITX20@groups.io> On Behalf Of Christopher Miller
Sent: Friday, August 31, 2018 11:49 AM
To: BITX20@groups.io
Subject: Re: [BITX20] 4.2" Nextion Bezel? #3d_printing #ubitx-help

 

I could probably help but I don't have any black pla to print with. Here in Tucson we have a maker space called xero craft. You may have one where you live. Xero for example has a couple of printers that can be used for a donation. Another option would be to use shapeway or some other site that will print and mail an object for a fee.

 

Feel free to contact me if you are willing to pay for a spool of filament and I will be happy to do it.

 

Chris

 

On Fri, Aug 31, 2018, 8:31 AM David Posthuma <davep@...> wrote:

I am using the 4.2" Nextion touch screen on my Ubitx. Does anyone know where I can get a small black bezel/frame for it? I only need about 1/4-inch on all sides. Unfortunately, I don't have access to a 3D printer. Thank you for any leads the group may provide.

 

Re: UBITX V3 TX GAIN VARIATIONS

Kees T
 

MRM,

What is the attached ? I also think it's a good idea to have a small capacitor across the RF drains of those MOSFETs as I previously mentioned.....load them up a little.

Jerry,

I've found that adding a little liquid flux to the smt pad with a wooden toothpick from a local restaurant ....before placing and holding the part with tweezers, while bringing over a SMALL dab of solder on a soldering iron tip (the flux in that dab will be long gone due to heating) works very well.

For component removal a handheld vacuum pump solder sucker works well (only if you keep the tip clean) and if you are removing smt chip parts off the board just 2 soldering irons, one on each end. Beats moving back and forth and don't use a heat gun unless you just want to strip everything in an area off the board.  

Bo,

Good idea going to the 2N2222A parts, those things are excellent. I plan to use one 2N2222A to replace each of the three sets of dual 2N3904 parts and adjust the emitter resistor accordingly. Yes, the 2N3904 parts cost less.

Still waiting for my relay switched LPF daughter boards, the filter boards I have.....should have sprung for the extra $4 for DHL delivery.

73 Kees K5BCQ

Re: UBITX V3 TX GAIN VARIATIONS

ajparent1/KB1GMX
 

MRM,

Actually I’ve been doing a lot of experimentation on flattening/ linearizing the transmit chain.  The parts I’ve fallen on are the NE46134’s.  They have plenty of gain, Ft of 5 GHz, and with the proper inter stage transformer design… An almost flat (-0/+0.6 dB) frequency profile swept from 0.5-60 MHz is possible.  I suppose prototyped, it isn’t much of a uBITx though.

Good part one of many that will work.  The right device and the right transformer,
The other third of the story is layout.  

Allison

Re: VK4PP uBitx LPF BANK add-on Board

Glenn
 

Gordon, the Common terminals being 5 & 12 in the uBITX Sch numbering scheme, -32dB

Approx -40dB from Common one set (5)  to the NO contact on the other contact set (16)

Picture is between common terminals as above. Typical curve of standard relays.




On Sat, Sep 1, 2018 at 02:17 AM, Jerry Gaffke wrote:
I interpret this measurement from Glenn:
    "-32dB from one set of contacts to the other. (common terminal)"
as being from KT1 pin 14 to pin 16 as seen in the uBitx schematic.

Also, interpret his -39 and -41 dB numbers to be from one relay section to the other,
which I averaged as -40dB.    For example, KT1 pin 12 to pin 5.

I now suspect those assumptions are incorrect, but the analysis could easily be adjusted to for any change to those two numbers.

Jerry


On Fri, Aug 31, 2018 at 03:40 AM, Glenn wrote:
All good points Warren.   I did some checks of isolation using a typical DIP relay, type HK19F. DPDT

I made a small jig to hold the relays and measure isolation across contacts etc.
Typically it was -34dB across open contacts,
-32dB from one set of contacts to the other. (common terminal)
-41dB from open terminals on each side
-39dB from common of one pole to open on the other pole.
-48db from common to coil.
 At 30MHz.  Better as freq drops of course.
That's without effects of a PCB and various other traces.

glenn

Re: UBITX V3 TX GAIN VARIATIONS

ajparent1/KB1GMX
 

On Fri, Aug 31, 2018 at 12:41 PM, Jerry Gaffke wrote:
Parts do not come with solder on the pins.

When manufacturing, the usual process is to lay a stainless steel mask over the board with holes cut into it for each pad,
then squeegie on some solder-paste, which is solder with the consistency of play-dough.
Then auto-insert all those dinky R's and C's and transistors with a pick-and-place machine.
Send the board through a heat process of some sort.
Your right but most part have either tin or gold plating that takes solder like a fish to water.
It takes very little added material to stick them down.

Me I use really fine solder 0.020 and a moderate tip iron maybe .12"  unless then are
very close to each other its nothing.    I can lay down parts very fast.  Come with practice.

Having a "thumb" (check around the net for ideas) can be handy for some parts.

Allison

Re: ATU for mBITX

Guy N7BIR <sgbridge@...>
 

Just to add to what others had to say about the T1. I’ve built and used it with both an EFHW and a 40 meter Gap Antenna and it works great!

Guy WB7SZI

Re: VK4PP uBitx LPF BANK add-on Board

Jerry Gaffke
 

Losses in dB are additive.
So loss from pin 12 to pin 16 is 40-32 = 8 dB when pin 16 is open?
That would be killer, doesn't seem right.



On Fri, Aug 31, 2018 at 03:11 PM, Glenn wrote:
Gordon, the Common terminals being 5 & 12 in the uBITX Sch numbering scheme, -32dB

Approx -40dB from Common one set (5)  to the NO contact on the other contact set (16)

Re: VK4PP uBitx LPF BANK add-on Board

Glenn
 

perhaps my terminology wasn't clr.  Relay in resting state:

Loss from 12 to 16 (NO contact, uBITX pinout) is ~ -34dB at 30MHz

Loss from 12 to 1 (to NO contact of the opposite side) is ~-39dB

Loss from 12 to 5 is ~-33dB

Loss from 12 to coil ~-52dB

Re: UBITX V3 TX GAIN VARIATIONS

Jerry Gaffke
 

Hans let the cat out of the bag here:  
   https://groups.io/g/QRPLabs/message/26092
He's using a couple BS170's in push-pull to drive the IRF510's on the QSX.

They look ideal.
Ideal in that they approach $0.05 each in volume.

I've got a bunch of BS170's here, bought for spares in my ATSprint and MTR rigs from KD1JV.
He ran 3 in parallel, got a bulletproof 5 Watts out in class E for CW.

Apparently, a push-pull pair of BS170's can give over a Watt in linear service
as used in the Softrock Ensemble RXTX:
    http://www.qsl.net/in3otd/ham_radio/BS170_PA/BS170_PA.html
Note the curious circuit around Q4 and Q5 for setting the gate bias voltage.
Q5, Q7 and Q8 should be matched for similar Vgs.

Jerry, KE7ER





On Fri, Aug 31, 2018 at 03:06 PM, ajparent1/KB1GMX wrote:
MRM,

Actually I’ve been doing a lot of experimentation on flattening/ linearizing the transmit chain.  The parts I’ve fallen on are the NE46134’s.  They have plenty of gain, Ft of 5 GHz, and with the proper inter stage transformer design… An almost flat (-0/+0.6 dB) frequency profile swept from 0.5-60 MHz is possible.  I suppose prototyped, it isn’t much of a uBITx though.

Good part one of many that will work.  The right device and the right transformer,
The other third of the story is layout.  

Allison

 

 

Re: KARMA and BITX

Timothy Fidler
 

Karma for not building an AM-FM radio design  (as per your group designator ). ??

Karma that is coming for making Irrelevant and meaningless posts on a technical forum ? and perhaps doing a bit of self promotion in the the process. 

Karma for  trying to design and build a multiband radio outside of Japan/PRC .??

What does the comment mean ??

4.2” Nextion Bezel?

Gary Hanson
 

David,

Here is a two step process to get a black plastic bezel for your Nextion display.

First, go to the ITEAD website and down load the 3d bezel zip file for the size of your display and unzip to your desktop.

Go here: https://www.itead.cc/wiki/Nextion_HMI_Solution#3D_printing_bezel

Next, go to https://www.3dhubs.com and go through their order process that requires that you upload the file from step one above.  You will need to indicate the color and the material you want to print with. I went with the cheapest and looks great.  The 3dhub company has great customer service.

Mine cost $9 including postage and took about 10 days.  Hope this works for you.

Gary, KJ5VW