Re: Removing surface mounted resistor #ubitx

William Cullison

Where did you find that tip?

73 Bill WA8VIH/4

On Thu, Jun 7, 2018, 10:14 <n7nsd@...> wrote:

I found some tips for my Hakko iron that are wide with a square notch in the end that straddles the part and melts both sides at once.?

Re: ND6T AGC question

#51531

Mike,

These simple circuits are rife with subtleties. No real benefit in using higher voltage when there is an easy access to the 5 volts from the Raduino. I don't understand why a voltage trace needs to be cut. The most concern that I can voice is that I have not tried it and there are many things that could go wrong, not anything that I can think of that would be improved. A classic risk/benefit ratio situation. If you are feeling adventurous then go for it. Remember to use appropriate voltage ratings. Do not use the resultant control voltage for an S meter without a divider (so not to exceed the 5 volt limit on the analog pin) and, if you do, keep the resistances very high to avoid a short AGC hang time. Remember that the 12 volt bus may not be regulated. See what I mean?
Driving the MOSFETs with a higher bias voltage will not result in more attenuation. Try it. I found (for some unexplained reason) that it actually decreased attenuation. I tried it several times to be certain. I have no idea why it does that.
If you do try it then please let us all know how it worked and what you finally decided upon. It could save all of us a lot of work. 73, Don

Re: IFshift

#51530

?ajparent1/KB1GMX

10:34 am???#51528??

I swept mine, same deal.? About 1750hz wide which for SSB is a bit tight unless contesting.
I bumped the caps down to some 82PF 5% I had (happen to be ceramic ATC parts)
and it was about 2350 after that which I like so 82 for around 2300-2400 works.?

Since Ralph did this and got the same result it may be a fairly consistent thing.

After doing this you may have to move the BFO down a bit.

Allison

Re: uBitx first power on - issues

#51529

Thank you for the quick response Rick!? So, you really think that's it huh?? And what you're saying is the wire-up directions should be modified to include this caveat.

Thank you again!

--Jim <insert call sign I don't have memorized yet.. and I'm an extra w/out having ever made a contact>

?

Show quoted text

On Thu, Jun 7, 2018 at 11:50 AM Rick Price <rickprice48@...> wrote:

Make sure you have the 4.7K resistor installed in the keyer circuit per the wiring diagram attached

?

Rick KN4AIE

Re: RF power chain mods and improvements..

#51527

Here's an outline of how to get dangerous with LTSpice:

Download the free LTSpice from Linear Tech:
? ??
It primarily targets the various MSoftWindows operating systems.
They also have a version out now for Mac OS-X.
Will run under linux with Wine.

Also download this file:??/g/BITX20/files/KE7ER/ubitx_pa.asc

Kick off LTSpice.
Click File, then Open, browse for that ubitx_pa.asc file you just downloaded.
Should display a schematic of Q90 on out through the finals for the uBitx.

Click the RunningMan menu icon (5 over from the left edge) to run the simulation.
It should open a second window to show waveforms, but the window will be empty.
Click on nodes in the schematic to see the voltage waveform at that point.
Double clicking will erase all other waveforms and just show the last one selected.
Click where wires enter into part symbols to see currents there.

Edit part values by clicking on that value.
Edit wires by using the Scissors icon to cut away wires, then using the Pencil icon?
to add new wires.? (You first have to click somewhere in the schematic to select that window.)
You can add grounds, caps, coils, resistors and diodes by clicking on their icon in the menu bar.
Click the AND-GATE icon to explore the various other parts available to you.

Someday, click the Help menu item, browse the destructions.

LTSpice is an incredible gift from LinearTech to the electronics hobbyist and professional engineer.
It has a full catalog of the various LinearTech products and complete demo circuit simulation models for each.
Fortunately, it is also a first rate generic analog simulator with an easy to use interface.

Jerry, KE7ER

Show quoted text

On Thu, Jun 7, 2018 at 09:37 am, Jerry Gaffke wrote:

I'm not one that takes easily to new tools,?
but found LT-Spice easy to get started with.
Changes can be hacked in and checked faster than it takes for my soldering iron to heat up.
You can easily instrument voltage, current, power dissipaton, and much more.
It's worth a couple hours of fiddling with to get started.
I'm no expert, but let me know if you get hung up on those first steps.

Re: Current Firmware

Dennis Yancey

#51526

Also, once you have the files extracted , it should have created a sub directory. That sub directory name is the same as the main file. Another thing that ishelpful is. If you try to load any .ino file in that directory. IDE, at least in Linux, will load the main file. So, it is hard to not load the correct file.?

Re: uBitx first power on - issues

#51525

开云体育

Make sure you have the 4.7K resistor installed in the keyer circuit per the wiring diagram attached

?

Rick KN4AIE

ubitx_wiring.svg_-1-768x743.png

uBitx first power on - issues

#51524

Hi everyone,

I thought I'd posted this message already but it hasn't shown up.. so here goes again.

I'm assembling my uBitx and I'm having an issue when I power it on.? So far I've only wired up the antenna and power.? When I power on the uBitx (using my linear bench PS, set to 13.8v and 1.2a), the uBitx seems to power on just fine, after 103- seconds the power supply starts oscillating (voltage rapidly fluctuates all over the place) and I hear what sounds like a relay clicking. I've 2x, 3x, 4x checked that everything is correct... red/brown twisted together and soldered (as shown in the photo), black to neg side of power connector.? Diode, with strip toward pos side soldered.? To make sure it's not the diode I cut it off (sigh), no change.? To make sure it's not the power connector I unsoldered the wires and just connected red/brown to the PS with an alligator clips.? Again no change.

Is this expected?? Should I move forward with assembly?? What should I do?

Thanks everyone,
--Jim

Re: IFshift

#51523

If it sounds muffled the carrier could just too close to the filter. You might see to move it 500hz further

Show quoted text

Il 07/giu/2018 18:23, "Tim Gorman" <tgorman2@...> ha scritto:

Ralph,

I personally like the narrower bandwidth. I do get comments that the
audio is muffled but it seems to get through ok and the narrower
bandwidth is a good choice for receiving on a crowded band.

tim ab0wr

On Wed, 6 Jun 2018 23:36:25 -0400
"Ralph Mowery" <rmowery42@...> wrote:

> My ubitx was about 1600 to 1700 khz wide.? By changing the 5
> capacitors from the crystals in the filter to ground from 100 pf to
> 82 pf the bandwidth widened out to about 2400 hz for the same
> reduction in power/audio bandwidth.
>
>
> That may be slightly too wide, but was the next value down from 100
> pf that had.? I did try the next value down first, but it was way too
> wide.? I have been thinking of paralleling the 82 pf ones with about
> 5 pf but have not done it.
>
>
> On Wed, Jun 6, 2018 at 6:11 PM, Eardan <ke4htb@...> wrote:
>
> > Im currently using KD8CEC skecth and my audio is about 200-1800 and
> > im want to change it to 200-2400 range. i have no problem using the
> > IFS to get it into range but have had no luck changing it in the
> > sketch so that i dont need to use IFS any help to figure this out
> > would be nice thankyou
> > KE4HTB
> >
> >
> >?

Re: RF power chain mods and improvements..

#51522

Tim,

I'm not one that takes easily to new tools,?
but found LT-Spice easy to get started with.
Changes can be hacked in and checked faster than it takes for my soldering iron to heat up.
You can easily instrument voltage, current, power dissipaton, and much more.
It's worth a couple hours of fiddling with to get started.
I'm no expert, but let me know if you get hung up on those first steps.

My uBitx is easily flipped over, I don't mind working on the bottom.
The (mostly) solid ground plane (mostly) ensures my new stuff doesn't see the old stuff.
And vice-versa.

Jerry, KE7ER

Show quoted text

On Thu, Jun 7, 2018 at 09:13 am, Tim Gorman wrote:

Jerry,

One of the reasons I want to put it before Q90 is to make it easy to
access and test.

If you'll remember I was the first person on here to show spectrum
analyzer screen shots showing how the 3rd order IMD and carrier
suppression is marginal. I don't plan on doing anything less with this
amp in the chain. If Q90 distorts it should show up in 3rd order IMD
results.

I'm not much on LTSpice and that genre of software. I tried using it
once but just too many demands on my time to learn how to use it.
Easier to just measure actual results!

Re: ND6T AGC implementation for uBIT-X

#51521

The money has been deposited on Paypal for a kit of each (AGC and anticlick)

73 Kees

F1BFU Gilles

2018-06-07 0:28 GMT+02:00 Kees T <windy10605@...>:

Show quoted text

F1BFU, Gilles,

I don't see a PayPal from you, please check and send me a note directly at? K5BCQ"at"

73 Kees K5BCQ??

Re: RF power chain mods and improvements..

#51520

Lowered the gain and the spur got worse?
As I have said, some of this can be counter-intuitive.
There's a lot going on.

Also curious that you found need to swap out the voltage followers at Q21, Q22.
Though driving 50 ohms at 45mhz is asking a lot of a 2n3904.

The BFR106's look good, $0.10 on Mouser if you buy a bunch.
A reasonable choice for volume production.

The 2n2222a's are $1 at quantity, $2 for singles.
An extra $6 in parts for an all band HF rig that performs flat is not a bad deal.
Though I'll bet Farhan will spend weeks of sleepless nights before doing that upgrade.
An IRF510 costs $0.50, plus another $0.15 for the bias pot, hmm...

Jerry

Show quoted text

On Wed, Jun 6, 2018 at 03:42 pm, ajparent1/KB1GMX wrote:

One of the factors not reported was the consistency of the gain vs spur. Simple put
the gain and the spur interacted even when I held the level to the mixer constant.
I'd lower the gain and the spur would get worse as an example.???It varied?
greatly with supply voltage as well.

Reason sluggish 3904s (low FT, Maybe Low? HFE).? Remember we are using a
300mhz device and that is a typical value and can be as low as 250 (batch and
vendor) or much higher.? I changed them out for BFR106 (Q20, Q21, Q22), Seems
the 3904s were not up to the task of keeping the amp load independent.?

The net result was what others had reported as lower spur production, in mine it
dropped the 10M spur nearly 12db.? So it was either distortion in the? 45Mhz amp
or its ability to be a low output impedance which should be with emitter follower
with the 47ohm making it look near 50 ohms.? I didn't? try 2n2963A as I didn't
have any left in SMT but I suspect they would have been better.

For now I'm taking a break on output power and addressing other things.? The
power thing stands at 10W at 80m, 7W at 10M with the spur 46db down.??

I'll list all the changes as my unit stands while I do pop/click and mod then agc.

For now mods I have in place, I'm not 100% happy but that is what
us experimenters enjoy.? Likely others to come. ;)
?
Replace and reset bias OF Q90 with 2n2369A or better (BFR106),
Set bias for 18ma (r86 2.2K).? Make C81 470pf, and r83 8.2ohms.

Change C82 to 470pf (peaking for 10M).??

T9 is now 9 turns #28 bifilar (one winding was never used).

All the 2n3904s in the predriver and driver replaced with 2n2222A or better.
Hint I mounted them on the underside with very short leads as it makes
the top less crowded.??

Driver amp has 2.7uh SMT choke in series with R86 and that is now 1.6Kohms
R87, r88 Both have a 270PF cap in parallel with them.

R911,r96, R941, R942 emitter resistors for driver reduced to 11ohms (add parallel 22ohm).
R92, R95 replaced with 1.5K ohm in series with 2.7uh choke.? (resets bias and adds peaking.)

T10 has one less turn.
T11 reduced by 1 turn.

45mhz IF replace (Q20, Q21, Q22) with BFR106.? Change R23 to 18ohms.? Change R27 to 39 ohms.
!2mhz IF amp change R43 to 18 ohma and put a .1uf in series with 680 ohms across R41.

Replaced Q10 with BFR106 for better receive gain at 20mhz and up.? (I may change out the two 3409s).

Add LM7806 regulator in handy location to limit voltage to ta2822 to 6V on pin 2.
Add 1K resistor from negative side of C77 to ground (prevents pop when pluging in
headphone or speaker)

Add 16K resistor from base o ground of Q70 for better overload performance.

The one change that really helped the transmitter was going to the 2n2222A (TO18) part.
Before that it was 13W on 80 and barely 7 on 40 and less on 20.? After that change alone
40 was near 10W and 20 was about 8.5W.? This has been tried on another unit that
was weak on 40M and it really helped with no other tricks.

Enough for now.? I plan to spend a few days re-rolling the software off the V4.3 release
for my user interface which will not include CAT, CW or a rotary encoder.? Without CW
mode the sidetone CW-Tone and CW-KEY pins are usable for general IO by removing
R256 and R105.

Allison

Re: Noob tx problem #ubitx-help

#51519

开云体育

No problem.

On 6/7/2018 7:20 AM, davedt1e@... wrote:

Show quoted text

I reversed the orange and purple leads and all is well.? Guess I had the mic wired opposite everyone else.

Thanks Howard and Bo!

Re: IFshift

#51518

Ralph,

I personally like the narrower bandwidth. I do get comments that the
audio is muffled but it seems to get through ok and the narrower
bandwidth is a good choice for receiving on a crowded band.

tim ab0wr

On Wed, 6 Jun 2018 23:36:25 -0400
"Ralph Mowery" <rmowery42@...> wrote:

My ubitx was about 1600 to 1700 khz wide.  By changing the 5
capacitors from the crystals in the filter to ground from 100 pf to
82 pf the bandwidth widened out to about 2400 hz for the same
reduction in power/audio bandwidth.


That may be slightly too wide, but was the next value down from 100
pf that had.  I did try the next value down first, but it was way too
wide.  I have been thinking of paralleling the 82 pf ones with about
5 pf but have not done it.


On Wed, Jun 6, 2018 at 6:11 PM, Eardan <ke4htb@...> wrote:

Im currently using KD8CEC skecth and my audio is about 200-1800 and
im want to change it to 200-2400 range. i have no problem using the
IFS to get it into range but have had no luck changing it in the
sketch so that i dont need to use IFS any help to figure this out
would be nice thankyou
KE4HTB

Re: RF power chain mods and improvements..

#51517

Jerry,

One of the reasons I want to put it before Q90 is to make it easy to
access and test. 

If you'll remember I was the first person on here to show spectrum
analyzer screen shots showing how the 3rd order IMD and carrier
suppression is marginal. I don't plan on doing anything less with this
amp in the chain. If Q90 distorts it should show up in 3rd order IMD
results.

I'm not much on LTSpice and that genre of software. I tried using it
once but just too many demands on my time to learn how to use it.
Easier to just measure actual results!

tim ab0wr

On Wed, 06 Jun 2018 21:14:50 -0700
"Jerry Gaffke via Groups.Io" <jgaffke@...> wrote:

Tim,

The reason to add a stage of amplification like that is so we can
reduce the amplification of pretty much all the other stages.
With reduced gain, they have a much better chance of giving the same
gain at 30mhz as they do at 3.5mhz.

You could try patching this amp in when operating at 30mhz.
Turn RV1 down all the way, then slowly bring it up to get the power
you want. But you had best be ready to measure distortion in your
signal before getting on the air with it.

It could well be that Q90 will not work properly with the 10dB
increased input signal and will distort.? Having the amp after Q90
allows you to adjust RV1 down until any stage after the new amp does
not have too strong a signal, strong enough to distort.

I don't think you want this new amp in there at all when operating on
the lower frequencies with an otherwise stock rig.? Too much gain.?

I'm just kibitzing here, have not analyzed the Q90 stage.
You could take the LT-Spice model for the uBitx power amp from the
KE7ER directory in the files section, see what the simulation does
when Q90 is driven harder.

Jerry

On Wed, Jun 6, 2018 at 07:36 pm, Tim Gorman wrote:


Allison,
Jerry,

I have my little mmic board built. Would it be ok to add it before
Q90 by removing C80 and inserting the input and output on those
pads. Doing that would allow me to stick the board on top of the
relay that is right beside Q90. It would facilitate testing,
experimentation, and parts changeout if needed. It would also be
right beside my 7812 voltage regulator so I would have short power
leads.

Will another 10-12db of gain into Q90 be a problem?

tim ab0wr

Re: RF power chain mods and improvements..

#51516

Allison is shooting for a clean and even 10 Watts out.
I would be happy with a variety of 5 to 10 Watts if that reduced the mod count significantly.

Some in the group have reported nearly 20 Watts out, perhaps by increasing PA-PWR
or by increasing mike gain.? Those that do should look hard at the output LPF toroids
and output transformer.? ?And understand that they are off in terra incognita
with regard to spurs and other forms of distortion.

Jerry

Show quoted text

On Thu, Jun 7, 2018 at 08:27 am, Dennis wrote:

Hi atouk,
I had the same thought. Make the UBITX as clean as possible with fairly even power across the bands say at 10 watts. Create an amplifier supplying about 50+ watts and small as possible. Would be great for portable use.

73, Dennis
W7DRW

Re: RF power chain mods and improvements..

#51515

The modularity is the happiness of the one who wants to do the QRP, the one who wants to do the digital to the one who wants a great power for a better comfort of traffic.

I bought QRplabs kits and the modularity of its kits made that one is afraid of the will and the will to evolve towards a station according to his desires and these financial means. It also allows beginners to progress to a more than serious editing.

I am currently assembling my uBitx without any modifications to begin. I still ordered the AGC and anticlick kits to incorporate them later.

It's only my opinion.

73 QRO

Gilles from F1BFU

2018-06-07 17:27 GMT+02:00 Dennis <dennis@...>:

Show quoted text

On Thu, Jun 7, 2018 at 06:59 am, atouk wrote:

With the amount of rework and component changes on the board to get higher power, wouldn't a better strategy be to get the cleanest output possible, and spend the time designing an external PA that compliments the uBitx?
Hi atouk,
I had the same thought. Make the UBITX as clean as possible with fairly even power across the bands say at 10 watts. Create an amplifier supplying about 50+ watts and small as possible. Would be great for portable use.

73, Dennis
W7DRW

Re: RF power chain mods and improvements..

#51514

Atouk,

I'm of a mind to agree.? Though 10w is not increasing the power, only trying to get more than 2W
at 10M maybe.? However general cleanliness of the output spectra is important if only to meet
PSTN/FCC or applicable agency as a first order thing.? It is also trying to advance the art and
get a "clean signal" over all.? However power out and transmitter performance run hand and
hand with insuring no additional signals are added.

Dennis:
Actually I considered flattening it down to 2-4W and driving a external linear.? Most all do?
40-50W and really if five or ten watts is not enough that is the next logical step for a S-unit
increase at the far end.

For more power I have amps.? I'd rather have a radio that is 10W or less and battery friendly
so it isn't a prisoner of my radio desk and the really large battery next to it.?

It is tough to do even 10W on a board 6x6 inches for the price of uBITX.? That someone did it
and it works is something worthy of great praise.? To get that kind of power out of commodity
transistors is a great job done.??

Allison

Re: Current Firmware

Jack Purdum

#51513

Dennis:

For the Win 7 machine, unpack the ZIP file into a temporary directory. With the Arduino IDE (or a text editor), open each INO file until you find the one that holds both the setup() and loop() functions. This file is the "primary" ino file. Let's assume it is named ubitx_20.ino.?

I would suggest creating a root directory for the software named uBITXCode, probably on the C drive. So you would have:

???? C:/uBITXCode

The Arduino compiler DEMANDS that the directory that holds the project code have the exact same name as the primary file name. Therefore, create a subdirectory with that name:

???? C:/uBITXCode/ubitx_20

Now, copy ALL of the project files into that new directory:

??? C:/uBITXCode/ubitx_20/ubitx_20.ino

??????????????????????????????????????????? ubitx_cat.ino

??????????????????????????????????????????? ubitx_menu.ino

??????????????????????????????????????????? // ...and so on

Now, start the IDE and click the Open menu option and navigate to the directory and double-click on unbitx_20.ino. The IDE will open the project and automatically create tabs for every file in the project, with the primary file being located in the first tab on the left side of the screen. Then just connect your USB cable to the Arduino and your PC, select the proper board (Tools --> Boards) and port (Tools --> port) and you should be ready to compile and upload the project.

Jack, W8TEE

On Thursday, June 7, 2018, 11:13:17 AM EDT, Dennis <dennis@...> wrote:

Hi Armin,

1. The file I used from Gary was an ino file. (he also sent along a hex file, but I couldn't get ArduinoBuilder to work)
2. I originally used the zip file from Github - this file contained several ino files - I didn't (don't) know how to compile them altogether to create one compiled file to upload to the Arduino.
3. I am using Arduino IDE on three different machines.
issue with the mac - I would get a "failed to upload" message. This seems to be a port assignment issue.
issue with the win10 machine - I would get a "failed to upload" message. Again this seems to be a port assignment issue, but I didn't spend the time to try and resolve the issue.
Win 7 machine ran without issue after I properly assigned the port.
I couldn't get Arduino Builder to work on the Mac again I suspect a port assignment issue as within the port pull down menu there were no ports to assign.

My most pressing questions are: 1. how to assign the port on the Mac and 2. how do I compile the several files included in the zip file from GitHub into one combined file for upload.

Thanks for you help,

73, Dennis
W7DRW

Re: RF power chain mods and improvements..

#51512

On Thu, Jun 7, 2018 at 06:59 am, atouk wrote:

With the amount of rework and component changes on the board to get higher power, wouldn't a better strategy be to get the cleanest output possible, and spend the time designing an external PA that compliments the uBitx?

Hi atouk,
I had the same thought. Make the UBITX as clean as possible with fairly even power across the bands say at 10 watts. Create an amplifier supplying about 50+ watts and small as possible. Would be great for portable use.

73, Dennis
W7DRW