Date   
Re: RF power chain mods and improvements..

Tim Gorman
 

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

Re: RF power chain mods and improvements..

Skip Davis
 

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?


Skip Davis, NC9O 

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

Re: Noob tx problem #ubitx-help

davedt1e@...
 

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?

Re: Noob tx problem #ubitx-help

davedt1e@...
 

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?

Re: RF power chain mods and improvements..

K9HZ <bill@...>
 

I guess i don't understand where you are going with the software... but wouldn't it be easier to convert your display work from the I2C buss?  Then you have a whole host of pins to work with... freed up from the parallel data lines of the ex-display?

 

Dr. William J. Schmidt - K9HZ


On Jun 6, 2018, at 11:42 PM, 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

Re: Noob tx problem #ubitx-help

Howard Fidel
 

Did you check with an ohmeter with the unit off at the connector with the mic plugged in that the PTT switch is working and wired to the right pin, i.e. high impedance when not pushed, and short to ground when PTT is pushed?

On 6/6/2018 9:05 PM, davedt1e@... wrote:
Still no joy.  I've checked all the wiring and confirmed connections to jacks with meter.  I wired up the mic and ptt button as a simple open/close circuit.  Is this correct?  Pretty frustrated.  Goes straight to tx when mic is plugged in.  Also verified that ptt button is working and soldering to the mic element looks good.

Would appreciate any help.  Thanks


ubitx & case #ubitx

Bo Barry <bobarr@...>
 

My friend gave up despite all the help I gave so here's his equipment.



I have an unopened uBitx kit (I think version 3) and one of Sunil's cases (grey) plus parts also unopened.  Too many hardware and software changes for me to deal with.  $187.00 plus shipping, PayPal preferred but cleared check accepted.  
 
Tim k5oi
Las Cruces, NM

Re: Noob tx problem #ubitx-help

davedt1e@...
 

Still no joy.  I've checked all the wiring and confirmed connections to jacks with meter.  I wired up the mic and ptt button as a simple open/close circuit.  Is this correct?  Pretty frustrated.  Goes straight to tx when mic is plugged in.  Also verified that ptt button is working and soldering to the mic element looks good.

Would appreciate any help.  Thanks

Re: #bitx40 - CW Side Tone Wiring #bitx40

 

Allard : 

You raise a good point. 

By using R111 as the injection point for the constant +12V supply to the LM386, I avoid messing with the switching of the power to Q16. So Q16 is off during TX.

The one thing that I did forget is that I actually have an "anti-thump mod" in place that grounds the input to the LM386 via a 2N7000 on PTT closure (see MSG # 25870).
So this combination would explain why I don't hear audio from the mic in the headphones.

 It would be interesting for someone to try this mod on a BITX40 without an anti-thump mod in place to see if their is any appreciable mic audio getting through. 
 The danger when using a speaker on SSB  is that you might get some audio feedback, which would be bad. 

Cheers

Michael VE3WMB 

Re: HarleyHeat1ASCH

Michael Hagen
 

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@...

Re: Mods and improvements..

Tom Cooper
 

If you are like me, Kent, nothing ever works right the first time.  So, the answer to the last question is probably "no." 

I suggest building the radio into a temporary housing like a cardboard box and trying it out.  You can always transfer it to a better cabinet and make a better informed set of mods easier in the process.

Should you build it?  Only you will ever know.  I'm certainly happy with my results and what I learned in the process.

73,

Tom  W1EAT

 

Re: Current Firmware

Dennis
 

Just an update - I was able to load 4.3 onto the Arduino Nano by using the file Gary sent me. I used a Windows 7 machine to accomplish this. I don't think the Mac is well suited for uploading to the Arduino - at least in my shack.

73, Dennis
W7DRW

Re: HarleyHeat1ASCH

William R Maxwell
 

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@...

Re: Mods and improvements..

Doug W
 

On Wed, Jun 6, 2018 at 04:15 pm, Doug W wrote:
I am running a totally stock rig
I need to correct that.  I am running a totally stock board.  I have changed the audio pot to fit a knob I wanted to use and have added a fan to cool the irf510's even though Ashhar, the µBIT's designer, doesn't think it is necessary as well as changing the LCD for a white on black one and using a non stock mic/ptt jack.  If anything my haste in responding and the other responses pilling up show you how many of us are very happy with this radio.  Build it, you will like it.
 
--
www.bitxmap.com

Re: HarleyHeat1ASCH

Michael Hagen
 

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@...

Re: Mods and improvements..

Daniel Conklin <danconklin2@...>
 

This little radio is many, many times better than what I used as a novice. I'm having a blast with it. Put it together and be amazed 
Dan, W2DLC 

Re: Mods and improvements..

Arv Evans
 

Kent    KQ4KK


The mods and changes will never stop.  That is part of the BITX phenomena.  The
transceivers are designed to be tinkered with, but basic units also work fine for those
who do not want to tinker with the design or add modifications to make it fit their
particular interests and desires. 

Arv  K7HKL
_._


On Wed, Jun 6, 2018 at 4:54 PM KENT HUFFORD <khufford@...> wrote:

I just received v4 ubix board to build my first one.

 

With all the mods, improvements, shortfalls showing up on this reflector… should I even build it?

 

Will it work when I finish it as documented?

 

Thanks,

Kent

KQ4KK

Re: Mods and improvements..

Doug W
 

Seems to me the time to decide if you should shoot it before you pull the trigger.

IMNSHO for a little over $100 it is a steal.  I am running a totally stock rig.  It is the first µBITX version sold.  Lately I have been operating mostly digital.  In just over a month I have hundreds of QSO's, I have worked all continents except for Antarctica, I am one state short of WAS and have many 1000 mile plus per watt contacts.  So will it work?  I tend to think so.  Don't let all the mods and improvements scare you off.  This is a very active community with many interests.  Build it stock to start and I bet you are happy.


--
www.bitxmap.com

Re: uBitx on its way!

Doug W
 

On Wed, Jun 6, 2018 at 06:37 am, Gwen Patton wrote:
 
I ordered that EF01 enclosure from Banggood, so someday that'll arrive, as well as the 3d printed front and back plates on eBay. (Yeah, pricey, but so what? Saves me the time and effort to drill stuff.)
I haven't put much effort into marketing but there is an option other than the guy on ebay for panels https://groups.io/g/BITX20/message/50308 .  I went with a much more minimalist design approach.  Of course if you are like most of us you are going to want to make changes after your first build and will end up cutting, drilling and melting anyway.  Also while shielding the case is certainly a best practice many have gotten away without doing it.  I am not recommending (or admitting to) one way or another.
 
--
www.bitxmap.com

Mods and improvements..

KENT HUFFORD <khufford@...>
 

I just received v4 ubix board to build my first one.

 

With all the mods, improvements, shortfalls showing up on this reflector… should I even build it?

 

Will it work when I finish it as documented?

 

Thanks,

Kent

KQ4KK