Re: RF power chain mods and improvements..
Dear Allison,? Thank you. Just a few clarifications please:
¡° I didn't? try 2n2963A as I didn't have any left in SMT but I suspect they would have been better.¡± I assume that¡¯s a 2N2369A, and what is a surface mount version called, if I wanted to find one?
?
Are the cores for T9 T10 & T11 the same toroids that it came with?? If one wanted to run more than ten watts would a different core be needed?
?
Is there any change in the chokes that feeds the finals? You didn¡¯t change to a bifilar wound choke?
?
¡°the 2n3904s in the predriver and driver replaced with 2n2222A¡± Instead of the TO-18 part, could I use these SOT-223s from Mouser: 512-PZT2222A? How about if I soldered a copper penny (pre 1982) to the large tab for a heat sink?
?
¡°Replaced Q10 with BFR106 for better receive gain at 20mhz and up.? (I may change out the two 3409s).¡± ?Are ¡®the two 3409s¡¯ Q11 & Q12?
?
¡°Add 1K resistor from negative side of C77 to ground¡± Is it C74?
Again, thank you for the experimentation and the information, I look forward to trying your mods.
jerry aa1of
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Re: Building homebrew ubitx: Need pre-v3 schematic PDF. Also, source for 45M15 (45 MHz IF) filter?
This appears to be a narrower 45MHz filter but impedance unknown
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Kj6etl, did you solve your tuning issue? I remember it as seeming similar to the issue I had. In my case it was what I first expected, ie a bum encoder and the new encoder made the issue disappear.?
Mike
On Jun 7, 2018 2:46 AM, "kj6etl" < pa1zz@...> wrote: Actually it was the fist time for me doing this with rather modest tools.
I clamped the board in a small vise and used a spring loaded solder sucker to remove the solder from all the pins on both sides.
Ended up using plyes to carefully pull the Arduino from the board. Then pulled the remaining pinns from the board one by one.
I think the the most challenging part is to solder the new Arduino back in place and avoid "bridges" between the solder joints. A magnifying desklamp is your biggest friend.
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I¡¯m trying to help you make it run on your Mac and for this have some questions, if you don¡¯t mind.
So you got a hex file or a ino file from Gary and you had to use Windows for uploading or compiling and uploading?
Did you use the Arduino IDE on Windows for this or used the ArduinoBuilder?
It¡¯s ?somewhat confusing.
i don¡¯t think it¡¯s a problem with your Mac if compilation fails. A lot of people, including me use Macs for Arduino development without problems.?
First you need to have a proper C ( ino) file, which according to the errors you posted is not the case. You are trying to compile a file with ?html content, so as already mentioned before obviously something went wrong with your download. The same file compiled under Windows would als have thrown errors.
Did you use the downloaded ?zip file from GitHub or used another method to fetch the files?
73 Armin, DJ2AG
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Actually it was the fist time for me doing this with rather modest tools.
I clamped the board in a small vise and used a spring loaded solder sucker to remove the solder from all the pins on both sides.
Ended up using plyes to carefully pull the Arduino from the board. Then pulled the remaining pinns from the board one by one.
I think the the most challenging part is to solder the new Arduino back in place and avoid "bridges" between the solder joints. A magnifying desklamp is your biggest friend.
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Re: Removing surface mounted resistor
#ubitx
Btw,? you don't have to remove anything to make the 'pop cure' mod. You can leave that resistor in and add another in series with it on an outboard circuit.?
- f
On Thu, Jun 7, 2018 at 3:25 AM, Jerry Gaffke via Groups.Io <jgaffke@...> wrote: Could work.
But it's real easy to rip the pads off the board with any mechanical movement or pressure.
I use two soldering irons, one on each end.
Yes those surface mount parts are cheap.
And those those metal end pieces can separate away electrically when removing the part.
I avoid re-using them.
Jerry
On Wed, Jun 6, 2018 at 01:52 pm, K9HZ wrote:
I use a sharp awl to break them in the center easily.? Then remove each end.? Those parts are extremely cheap.
?
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Easy enough I suppose, but I do see a lifted pad there, 4 up from the bottom left. The biggest problem with most rework is damage to the board, though that one looks easy to deal with. How did you go about removing it?? My guess is a full blown rework station with vacuum solder sucker. If you clipped the pins first and pulled them out one by one,? I'm curious how you went about clipping them. A socketed Nano is nice, but then it mechanically interferes with the LCD display. I've socketed my Nano on the opposite side of the raduino as per this post ? ?? /g/BITX20/message/50027Quite happy with the result.
On Wed, Jun 6, 2018 at 09:08 pm, kj6etl wrote:
Its not that hard to replace the Arduino.I have done it on my uBitx and will do it soon on a Bitx40.
You can buy a
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Interesting. Did the
proposal go anywhere? Are you continuing development to
enhance the proposal or has the project now become a hobby in
itself, Mike?
Might have all sorts
of applications including home brew of the liquid variety.
Bill, VK7MX
On 7/06/2018 10:18 AM, Michael Hagen
wrote:
toggle quoted message
Show quoted text
Well, it is a Heater
Control.? Done with a Pic and Assembly done code.? Lots of
nice features.
I have not had a
paycheck in 3 yrs now, so this design was part of a
proposal.
This is the nth
change, I keeps going on and on?
A shot in the dark!
Mike, WA6ISP
On 6/6/2018 4:54 PM, William R
Maxwell wrote:
But now you
really should tell us what is, Mike.You have us all
curious.
Bill VK7MX
On 7/06/2018 9:30 AM, Michael Hagen
wrote:
A mistake,
sorry.? Went to group when I meant to send it to myself.
Mike, WA6ISP
On 6/6/2018 3:18 PM, Allen
Merrell via Groups.Io wrote:
I am lost
here, what is this.
--
Allen ?Merrell
--
Mike Hagen, WA6ISP
10917 Bryant Street
Yucaipa, Ca. 92399
(909) 918-0058
PayPal ID "MotDog@..."
Mike@...
--
Mike Hagen, WA6ISP
10917 Bryant Street
Yucaipa, Ca. 92399
(909) 918-0058
PayPal ID "MotDog@..."
Mike@...
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Re: RF power chain mods and improvements..
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
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Show quoted text
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
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uBitx Encoder information needed.
I have 2 items I need info on.
first, does anyone have the specs for the stock encoder for the uBitx?
second, have any of you had to make software changes to get a KY-040 encoder to work properly?
Thanks for your help.
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Its not that hard to replace the Arduino.I have done it on my uBitx and will do it soon on a Bitx40. You can buy a  
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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
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Re: Removing surface mounted resistor
#ubitx
Another option is to use Chip Quik solder remover. This product is heated with your iron over existing solder joints forming a low temp melting point alloy whi ch stays liquid long enough to lift the part off with tweezers. Then remove the low temp stuff with removal braid.
--
Kevin B. G. Luxford
kbgluxford@...
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Re: RF power chain mods and improvements..
Nice treat,? Allison.
?It takes time and patience with workmanship to implement the mods on the original pcb.
Thanks and regards
sarma /? vu3zmv
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You either have miss wired the
connector, or a bad connector.
On 6/6/2018 10:06 PM, davedt1e@... wrote:
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Show quoted text
Just checked the
mic at the plug.? It shows no continuity until I push the the
button...then about 1.6k when I push the button. Have I wired the
mic correctly?
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I'm not sure you can do anything to expand the audio range. That is determined by the 12Mhz filter which has a pretty narrow bandwidth. You could move the bfo to get a 600-2400hz audio but I'm not sure that is what you want. You'll be knocking out a lot of the low-freq audio. tim ab0wr On Wed, 06 Jun 2018 15:11:06 -0700 "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..
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 On Wed, 06 Jun 2018 15:42:13 -0700 "ajparent1/KB1GMX" <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
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Re: RF power chain mods and improvements..
Allison you referred to T9 being reduced to 9 turns of #28 bifilar did you mistake it with T8 which is bifilar with one winding not used?
toggle quoted message
Show quoted text
On Jun 6, 2018, at 18:42, ajparent1/KB1GMX < 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
|
Just checked the mic at the plug.? It shows no continuity until I push the the button...then about 1.6k when I push the button. Have I wired the mic correctly?
|
Thanks for your help.? So I just checked with mic plugged in.? It seems to be shorting the ptt (orange wire) to ground without pushing the button.? Indicating a problem with the mic itself?
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kj6etl
Skip Davis