Date   
uBITX v3 - Wiring in a 6 pin Mini-Din for Data

Andy Wragg
 

Hi folks, Whilst I wait for my InKits enclosure to arrive courtesy of IndiaPost, I thought I'd double check my thoughts on a mod for my ubitx.
I want to use this radio for data (WSJT-X FT-8) and already have cables for my FT-450. My data cable is 6 pin Mini-DIN at the radio end. Is it simply a case of connecting a Mini-DIN socket as follows;

Mini Din                       uBITX
1  (DATA IN)              Vol High (Yellow Wire)
2  (GND)                        GND (Blue wire)
3  (DATA PTT)                PTT (Orange wire)
4  (FSK IN)                     
5  (DATA OUT)               MIC (Violet wire)
6  (SQL OUT)                

These are the same pin outs as the FT-817/8. I'm using a RadioArena UD04YA interface at home and with the laptop, but will also be getting a WolphiLink for use with my tablet/phone.

Cheers

Andy

Re: Raduino_v1.27 will not compile

Tom, wb6b
 

Hi,

It looks like you are trying to compile the HTML code from a GitHub web page, not the Arduino Sketch code you are intending to compile. 

It is interesting as this is the second time someone has done this in recent time. As it looks like you are interested in the uBITX40 his might be a link to what you really want: https://github.com/afarhan/bitx40/archive/master.zip 

The Raduino_v1.27.ino file looks like it was contributed by a user. It may have been incorporate into the main body of code. 

Here is a link to a similar issue where someone downloaded HTML code and tried to compile it, rather than the computer code they intended to compile.

https://groups.io/g/BITX20/message/51424

Tom, wb6b


On Sun, Jun 10, 2018 at 03:33 am, <davidzdeb@...> wrote:
Raduino_v1.27.ino

Re: Raduino_v1.27 will not compile

Gary Anderson
 

Looks like you are trying to compile web page source not C Code.
Pretty sure you didn't properly download the code from GitHub.
To download the sketch source use the green "Clone or Download"  button on the web page  (not a save as button on your web browser)
and select the Download Zip option.


Re: Raduino_v1.27 will not compile

Gary Anderson
 

Hi Tom,
Sorry I had a reply going then had to attend to other morning activities before finishing and hitting the send, so I didn't see what you had written until after I sent.
Not meant to duplicate what you said, but then again maybe 2 people saying the same thing in short order is helpful. :)
BTW, I think this person is trying to get Allard's code. 

Regards,
Gary
AG5TX

Re: uBitx daughter board

Howard Fidel
 

My plan is the same size as the uBitx

On 6/10/2018 4:55 AM, Ashhar Farhan wrote:
Wow! What is the size of this board? 

On Sun, 10 Jun 2018, 09:35 Howard Fidel, <sonic1@...> wrote:
I posted a file, copy attached that is a collection of additions for the uBitx board. I posted this, but it never showed, so I am restating it here.

I am working on the board which I will describe below. Please comment if you see anything to improve or other features to add, and if you are interested in a PCB or a kit which I might offer it there is interest.

Page 1
U4 is an audio amp to replace the problematic TDA2822. U3A and Q1 etc. form the AGC circuit, not original. U3B is a log amp the drives an analog S meter (the digital one is better) that is in my enclosure. U1 is a switch to put the CW filter in or out of the circuit. (Note there is a drawing error +VM shouldn't connect to U3.)
Page 2
The Cheybchev 750 Hz LPF 0.1 db ripple
Page 3
I/O JP2 and JP3 plug into connectors soldered on the underside of the uBitx. The odd pins connect to the Raduino and audio connectors. The even pins are hardwired to the uBitx.
Page 4
Chebychev Low pass filters, 0.5 dB ripple for the external linear amp I posted previously.
Page 5
Relays for the above filters. Copied from and driven by the uBitx
Page 6
New driver for IRF510s. connects between VR1 and the output of T10 which is removed.

Howard



n 6/9/2018 9:01 PM, BITX20@groups.io Notification wrote:

Hello,

This email message is a notification to let you know that a file has been uploaded to the Files area of the BITX20@groups.io group.

File: ubitxassessories.pdf

Uploaded By: Howard Fidel

Description:
A collection of accessories and improvements for the uBitx. See post for description

You can access this file at the URL:
https://groups.io/g/BITX20/files/ubitxassessories.pdf

Cheers,
The Groups.io Team



Re: External Amp

Nick
 

This is good information. I also picked up the same amplifier and the IRF530s were quick to self distruct.

When testing into a 50ohm dummy load I was initially only getting about 10 watts. The resistors that came with the unit were 100 ohm instead of what I found in the online schematic of 150ohm . 

I made a low pass filter for it but I think the toroids are a bit small as they got really warm. I also made an attenuator pad at the input as I read that the pa does not seem to like more then about 2.5watts in.  The pad was a 220, 22, 220 with about 4db calculated loss. 

I found that with my o'scope the output waveform from the bitx was very distorted into the amp which could explain the low power and heating in my filter. In an attempt to figure out what was going on, I modeled the amplifier in ltspice .It did not work well as per the schematic I found. I had to increase the bias voltage and put a 10 ohm resistor across the two mosfet gates to get a nice input swr and a somewhat nice 70ish watt waveform out of it. This was simulated at 7.2Mhz with the ltspice model of the irf530 and all other components were ideal.

Since it looked good in simulation I attached the resistor and started increasing the bias voltage. I was not using a very small current limited power supply and while doing this there was a small puff of smoke and my supply voltage dropped to nothing. Oops...

I suspect not paying attention to the drain current may have been a problem. I think maybe they turned on and "shorted" at dc. Not sure if I trust the components that came with the kit though as they were in standard bubble wrap with no esd protection for the MOSFETs. They could also be fake MOSFETs.  

I don't currently have replacements available but I might try your suggestion of using the 520s in parallel.

I appreciate your post,
Nick

Re: External Amp

Howard Fidel
 

Nick:
You reminded me I left out an important piece. I added 10 ohm resistors in series with each of the gates. The circuit was oscillating at 120 MHz, which is probably why the IRF530s blew. I revised schematic is attached. For the 20 meter band, I made 2 air core coils I wound on a 1" D  piece of schedule 40 pipe using 9 turns 14 AWG wire. The pipe is just a winding form, not used in the circuit
That is about .9 nH each. The caps were 240 pF at the input at output and 360 in the middle.
I posted another schematic yesterday with the LPF designs for all the bands.
I adjusted VR1 in the Ubitx to get the correct drive level. Of course the uBitx's output is not uniform across the bands, so you need to set it properly for each band. I had to drive the amp at 28 VRMS to get the full output. I'm not sure what the input impedance is, so I can't measure the drive level in watts. However, at the same setting the uBitx was putting out 24.4 volts RMS into 50 ohms, or 12 watts.
Howard

On 6/10/2018 10:08 AM, Nick wrote:
This is good information. I also picked up the same amplifier and the IRF530s were quick to self distruct.

When testing into a 50ohm dummy load I was initially only getting about 10 watts. The resistors that came with the unit were 100 ohm instead of what I found in the online schematic of 150ohm . 

I made a low pass filter for it but I think the toroids are a bit small as they got really warm. I also made an attenuator pad at the input as I read that the pa does not seem to like more then about 2.5watts in.  The pad was a 220, 22, 220 with about 4db calculated loss. 

I found that with my o'scope the output waveform from the bitx was very distorted into the amp which could explain the low power and heating in my filter. In an attempt to figure out what was going on, I modeled the amplifier in ltspice .It did not work well as per the schematic I found. I had to increase the bias voltage and put a 10 ohm resistor across the two mosfet gates to get a nice input swr and a somewhat nice 70ish watt waveform out of it. This was simulated at 7.2Mhz with the ltspice model of the irf530 and all other components were ideal.

Since it looked good in simulation I attached the resistor and started increasing the bias voltage. I was not using a very small current limited power supply and while doing this there was a small puff of smoke and my supply voltage dropped to nothing. Oops...

I suspect not paying attention to the drain current may have been a problem. I think maybe they turned on and "shorted" at dc. Not sure if I trust the components that came with the kit though as they were in standard bubble wrap with no esd protection for the MOSFETs. They could also be fake MOSFETs.  

I don't currently have replacements available but I might try your suggestion of using the 520s in parallel.

I appreciate your post,
Nick


Re: RF power chain mods and improvements..

ajparent1/KB1GMX
 

Tim,

It could have maybe.  But even it if were saturated the down stream can't follow so....
no significant power.

The other and likely is the MMIC took off at UHF  and the poor transistor following that
stage was simply driven off the rails bias and inability to produce gain there wise.

Each stage has to do three things. 
Produce enough power without compression.
Operate at the selected frequency with the defined gain. 
Any failure of one of the three results in a loss of output power or distortion.

Between Q90 and the predriver is better as with the pot out and 
some landscape there you have room. 

Gain and power line up (some wishful...):

Mixer output at full tilt about -10 dbm.

Q90 no mods at 80m about 16db at 10M about 10-11db  and not more than 3mW power.

Pre-driver  take that 1mw and boost it to about 40mw, We hope.
What I saw was about 45mW at 80m and barely 8mW. 
note gain at 80m is about 16db and at 10m maybe 9db..

Driver  take that 40mw and make about .4W at 80 and sinks to barely .08W at 10M
Gain for that stage is supposed to be about 16db and likely is at 80mbut at 10M
I measured for different 3904s 8 to 11db. 

Finals IRF510 at 80M approaches 15-20W with a gain over 17db,  at 10M
its about 13db and but the drive is so low that yields maybe 2W.

Maybe its me but there is a pattern and its 3904s.  Some maybe "hotter"
and some just really fall short.  Solution, make sure each stage retains
enough gain at 10M to produce at least 13db of gain and will produce
the required power.


Allison



Allison

Re: Raduino_v1.27 will not compile

Allard PE1NWL
 

Here's how to download and compile the sketch:

1. On the github page, press the green button "clone or download"
2. Open the downloaded file "bitX40-master.zip" and extract all files to a location of your choice
3. Go to the extracted folder "bitX40-master" and open it
4. Inside this folder there are several files. Find the file named "raduino_v1.27.7.ino" and double click it
5. The Arduino IDE will start
6. A message box will pop-up: The file "raduino_v1.27.7.ino" needs to be in a sketch folder named "raduino_v1.27.7". Create this folder, move the file, and continue?. Click YES.
7. The downloaded sketch will now be opened and shown in your IDE.
8. In the IDE, go to Sketch => Verify/Compile (or press ctrl-R), then the sketch should be compiled without errors.

73 Allard PE1NWL

Re: Raduino_v1.27 will not compile

davidzdeb@...
 

ah, thank you everyone.  I have never used github before.  This rig has made me learn so much.

Re: RF power chain mods and improvements..

ajparent1/KB1GMX
 

On Sun, Jun 10, 2018 at 09:23 am, ajparent1/KB1GMX wrote:

Gain and power line up with a few possible solutions listed:

*Mixer output at full tilt about -10 dbm.
Go higher and the spur gets bigger so lower output here is better.

==========================================================================
*Q90 no mods at 80m about 16db at 10M about 10-11db  and not more than 3mW power.
Replace it with a really hot transistor.  BFR106 has a FT of 5ghz and can do over 100mW.
This should keep the stage gain at about 16-18db from 80 through 10M and deliver the 3mw!
It is the easiest stage to make flat and high gain as this get more difficult at higher power out.

==========================================================================
*Pre-driver takes that 1mw and boost it to about 40mw, We hope.  What I saw was about 45mW
 at 80m and barely 8mW. note gain at 80m is about 16db and at 10m maybe 9db.

We need the gain again to be more stable and higher as well.  Transistors tried that worked better
included the TO18 2n2222A, 2n3866, and 2n5109.  The 5109 was best even though I used only 1.
Second best was tie between a single 3866 and two 2n2222.  MPSH10 was disappointing.
*** I plan to try an oddball 2n6661A, [at 14$ each most will choke] a VMOS fet has potential
and requires many circuit changes[Bipolar bias to MOSFET].  They worked really well in
another project at VHF.

==========================================================================
*Driver take that 40mw and make about .4W at 80 and sinks to barely .08W at 10M Gain for that stage
is supposed to be about 16db and likely is at 80mbut at 10M measured for different 3904s 8 to 11db.

This is where the 2n3904 really fails. Its bandwidth at high currents actually does down.  The 2n2222A
has the reverse, the gain and bandwidth increased with increasing current.  While not an ideal part
it does work better.  The ideal part dow be two devices push pull [not 4] and higher FT.   I havent
tried 5109 here but its a solid bet.  I wish 2n3553s, 2SC2166, 2SC799, 2sc1306 and others were
still around [real ones].

*** I plan to try an oddball 2n6661A here too as its good for up to 6W.
==========================================================================
*Finals IRF510 at 80M approaches 15-20W with a gain over 17db, at 10M its about 13db and but
the drive is so low that yields maybe 2W.

If there is enough power at the gate it does the job we ask.   RD16HHF does not offer more gain or
bandwidth as MOSFETS do not have the equivilent of FT.  IT does offer a handy groundable tab.
==========================================================================

To go from -10 dbm[.0001W] to +40 dbm[10W] we need 50 db of gain over all.  That includes
losses to transformers and other circuit features.  So we need more gain than that by maybe
6 to 10DB to allow some latitude on the gain adjustment pot.

So with four stages and the last being limited to the IRF510s.  We set a few rules.

*One we never run a transistor wide open as one may exceed and another fall short.
For 2n3904s that happens and the lowest common denominator for them is around
10db. Use better transistors and lots of feedback.  More likely to work for everyone
than a bet on Monte Carlo.  

*Two we only have four stages!  The board is layed out that way.  Reality sucks.

*Three:   IRF510 or RD16HHF you get about 13-16db of gain, period.  More
is wishful thinking or running wide open and risking stability.  Hint IRF510s blown
about 2$, RD16HHFs blown 10$.    Going to IRF520 and 530 not better [for 10W]
as the internal capacitances are significantly higher and it doesn't make the drivers
job easier.

*Four Based on total gain needed and what the finals can be reasonably expected to do...
 The three prior stages must deliver 45 to 47 db of gain.  Its also a lot so attention to
 stability is everything.

*Five  the result must be stable.  Oscillation will kill the finals.

Item four is the killer as its basically asking for 16db from all three stages.
You need good parts for that.  Also the interstage coupling must be up to the job
while not introducing uncontrolled losses.  Tall order.  So far I have only partial
answers.

==========================================================================
Dump the 3904s and use 2n22222(to18),  for those interested in 80-17M it works remarkably
well and give a boost up high too.  If you go to 2n5109s you may need 1 is predriver and 2 in driver
besides they are big and the space small.  Whatever is use SHORTEST leads possible.

Replace or parallel R941,R911, R96,R942 to get 11 ohms each (I paralleled 22ohms across them).
Lower emitter resistance helps gain and power out to finals.

Replace Q90 with BFR106,  note R81 has to be increased to between
2K and 2.7K for this part.    (for those making suggestions I tried 2n2369 in
SMT, it was better but not great).  Besides mouse has the BFR106 for a
whooping 38 cents each.

Change C81 to 470 pf,  This flattens the 80 and 40M runaway power and helps the higher bands.

There are many changes to transformers possible but for the moment the above are best bang for the buck.
Aslo changing the transformers might be a handful for some.

Warning every time I tried the 2;4 turn transformer with any ferrite the finals were heating a lot and the
stage efficiency was well under 40% [terrible with IRF or RD16].  The 2:3 was better at high power
but below 50%.  This is still in the grinder...

==========================================================================

Allison

Re: External Amp

ajparent1/KB1GMX
 

Nick,

That amp with IRF530s was created back in 1999 and known as the "hints and kinks"
amp.  When Wa2EBY tried to copy it he got your result blown transistors.  Its unstable into
reactive loads (mismatches) and the transformers were poor.  It also presents a rather
reactive load to the driver (QRP rig) and is known for making that final oscillate as well.

IF the low pass filter is heating either the design Q is too high or the harmonic content is.
assuming the cores ar T37 size.  IF T50 something is wrong as I've run 60W though those.

FYI I also tried that amp (two IRF530s), it tried to blow!  I used a current regulated power supply
so it could never exceed the blowup current.  The only things that helped was a better output
transformer and a 3DB pad at the input to keep the input tame.  I abandoned it.

The 100/150 ohm resistor are negative feedback in an attempt to stabilize the amp. 

For the 'EBY amp 2W is max power as at that point that amp is cranking serious power.
That and more power will likely fry the gates.

Look at the WA2EBY amp (it is the two files [HF use fet] in files under my call).  With 2W I see
at  80 and 40M about 55W at 28V using 2 IRF510 and about 37W at 10M.  I got a board
for it from FARCircuits.  I use it with a 4db input pad as most of the HB rigs I have do
about 4W.    Do copy the mechanical layout as its critical to cooling and stability.
FYI I bilt mine back around 2006 and its still running despite various "operator errors".

One note.  one must use very good care with parallel MOSFETs regarding layout.
They are known to become unstable and fry.  Adding  a 1-4 ohm SMT (1206) resistor
right at the gate before it goes into the part can calm them.  FYI SHORT leads, the
board and the heatsink should nearly be one unit and the MOSFET leads short as possible.


Allison

Re: RF power chain mods and improvements..

Jerry Gaffke
 

That looks very promising!
Looking forward to seeing where this comes out.

A few obvious observations:

The BFR106@1000 is $0.10, the 2n5109 @ 1000 in a to-39 from Central Semi is $1.50.
Those seem excellent choices if they work.
Looking like these fixes to the uBitx might get done for around $5-$10 more in parts cost, no board changes.

That 2n5109  is cheaper than two of the 2n2222a's in a to-18.
Though the DXT2222A-13  in a SOT-89-3  can be had for $0.10 @ 1000
Central Semi has a 2n5109ub in surface mount, they claim it dissipates a Watt, can't find a price. 

I'm fine if it comes to a fourth stage on a small daughterboard placed between T8-5 and RV1.
if that makes upgrading old boards easier.  (I know, broken record.)

Weird that my search of post  https://groups.io/g/BITX20/message/51550  didn't find any of these higher Ft NPN's.
Either the Mouser parameterized search tool is not very reliable, or me.

Jerry, KE7ER


On Sun, Jun 10, 2018 at 10:54 am, ajparent1/KB1GMX wrote:
Gain and power line up with a few possible solutions listed:

Re: RF power chain mods and improvements..

ajparent1/KB1GMX
 

Jerry,

The DXT2222A-13 is a possible choice for pre-driver as the power is fairly low.  For the driver
the board layout to get the tab on enough copper is nasty space wise.  I've used that part
and its otherwise a good SOT89 2N2222A maybe a tiny bit better (lead inductance is smaller).
It would be hard to apply to the current V3 and V4 board. 

The SMT 5109 is not useful for the same reasons [board layout] for the driver. it
would work a bit better for the pre-driver. 

NOTE on SOT89 the pinout is BCE and the boards are EBC so attaching them to existing
boards would be very messy with lots of cutting and jumpers even for test reasons. They
would also need a flag to radiate the heat (copper .020 thick by .25 side and .4 tall.).
Someone else can do that for a test.

The BFR106 works for Q90 and also in the 45mhz IF amp section very well.  Its not a choice
for other parts of the radio. As more power capability is needed or 3904 is fine.

One possible layout I looked at was strip the power amp completely Q90 though IRF510s
and have a board above the main board carry the input filters, improved amp, then 
using the output  filters on the lower main board. Two pieces of coax and a few control
lines. That and other added features as there would be space.  That would make an
upgrade far easier as its a whole board and wires. 

Allison

Re: External Amp

ajparent1/KB1GMX
 

A note: the commercial version of the 'EBY amp is the K5OOR HF packer.
the power supply is unique as it runs only on TX and does a 12 to 24V boost
to power the IRF510s to high power.  

Allison

Re: External Amp

Nick
 

Allison,

Thanks for the reply! I will read the articles regarding WA2EBY.

For the low pass filter I am using T50 the actual Fair-Rite part number is: 5961000301 which is mix 61, lower permeability and should be lower loss at HF. It could be that the whole system like you said is not stable as I have seen the distorted waveform at the input of the amp.

I will likely order some new MOSFETs and give it another go. The gate resistors might be a good addition.

I have attached what I put together in LTspice for anyone that wants to play with it. I did not put in an accurate representation for the transformers but I think the ratio is correct. What I have could be completely wrong.

--
Nick

Re: RF power chain mods and improvements..

Nick VK4PP
 

Good Morning Allison, et al.

Just thought I'd throw a few cents in the hat.

I have managed to get my uBitx to output 16w at 80m to 14w at 10m. (CW key down)
In a nutshell, Q90 changed to MMBTH10 (20 for a few $ on ebay...) 220/300  pf cap across emitter resistors of all 3904 drivers, 2:4 wind BN43-202, 330pf mica on input. and RD16 with std feed back in place. Drive RV1 at 3/4. (maybe 20w at full?)

I have yet to check IMD and such but output seems stable.

I need to do more learning/testing...

My second ubitx will get the same mods except all the driver 3904 will be changed to MPSH10... and a common power feed(L8/L9) to the RD16 via a FT50-43 Bifilar. I have worked out a neat way to implement this on the STD board... Pics to come...

73 Nick VK4PLN 

Re: RF power chain mods and improvements..

Jerry Gaffke
 

Allison,

Yes, surface mount parts into current boards would be tough.
The to-39 and to18 parts are fine for current rev boards, no point in saving 
a couple bucks and then spending hours trying to whack them into place and heatsink them.

But nice to think about what hfsignals might do in the future.
If the smt 2n5109 is cheap or an smt 2n2222a works in the driver stage,
the additional cost in parts might be held to a dollar or so.

Could be that the IRF510's and others will behave better at 30mhz if laid out differently.
And not having so much RF on the main board might even help those mixers out?
If so, a Q30-to-IRF510 daughterboard makes good sense.
And as you say, many here will prefer that to swapping out a half dozen transistors and rewinding torroids. 
Especially since with the daughterboard it could be easily reversible, back to a stock uBitx.
 
Jerry


On Sun, Jun 10, 2018 at 01:24 pm, ajparent1/KB1GMX wrote:
Jerry,

The DXT2222A-13 is a possible choice for pre-driver as the power is fairly low.  For the driver
the board layout to get the tab on enough copper is nasty space wise.  I've used that part
and its otherwise a good SOT89 2N2222A maybe a tiny bit better (lead inductance is smaller).
It would be hard to apply to the current V3 and V4 board. 

The SMT 5109 is not useful for the same reasons [board layout] for the driver. it
would work a bit better for the pre-driver. 

NOTE on SOT89 the pinout is BCE and the boards are EBC so attaching them to existing
boards would be very messy with lots of cutting and jumpers even for test reasons. They
would also need a flag to radiate the heat (copper .020 thick by .25 side and .4 tall.).
Someone else can do that for a test.

The BFR106 works for Q90 and also in the 45mhz IF amp section very well.  Its not a choice
for other parts of the radio. As more power capability is needed or 3904 is fine.

One possible layout I looked at was strip the power amp completely Q90 though IRF510s
and have a board above the main board carry the input filters, improved amp, then 
using the output  filters on the lower main board. Two pieces of coax and a few control
lines. That and other added features as there would be space.  That would make an
upgrade far easier as its a whole board and wires. 

Allison

Re: External Amp

ajparent1/KB1GMX
 

For low pass filter either T50-2 bekow 10 mhz and T50-6 above as that is the most
commonly used.    The 61 mix has too high mu and is prone to overloading and
heating as anything but transformers at HF.

Wire, I'd use #26 if it fits or #28 as fallback.

Allison

Re: RF power chain mods and improvements..

ajparent1/KB1GMX
 

For futures [HFsignals] the SMT parts are a good choice as machine stuffed
lowers cost too.


Look at the EBY and HF Packer amps, also the K5BCQ for examples
of how to lay out just the IRF510 (or RD16) for performance and stability.

Allison