Date   
Re: uBitx first power on - issues

Russ KG0BK
 

The unit is switching from receive to xmit and back.
The 4.7 k resistor MUST be wired in to keep that from happening.
Even if you're not planning on using a key . . .the resistor must be in place.

Re: uBitx first power on - issues

Russ KG0BK
 

To make it simple . . . 
The resistor is wired to the green and blue wires.
That again is a MUST.

Re: No Power

G8HAV
 

Thanks Allison and Lee.

There are no changes on the LCD screen. just TX and the frequency in use VFO A. CW is set to ST.

The CW-KCLK#2 R100, and it is not a clean waveform; Scope indicates about 100 mV average.

Hope this helps

Re: ubitx first power up

StephenT
 

I had a similar problem - I couldn't understand anything on SSB.  I experimented with varying the IF and +3800 on LSB did the trick!  It's in the menu after uploading version 1.061 of the KB8CEC software.  Varying the BFO didn't really have any effect.

The Memory Manager software allows you to keep the IF change from taking affect when operating CW.

I think this whole BITX project and all the community help, programming, etc. is just wonderful.  Reminds me of what a great hobby/obsession we have and of the quality of the people that are willing to give of their time and talents to mentor and to help fellow hams.

73, Steve

Re: CB amplifiers RM-Italy KL203P

iz oos
 

I have checked the schematic and both the kl-203P and the CTE seem similar. Is the cap necessary or just a jumper would suffice to lower the frequency of operation? Would a mod at the input to keep the SWR acceptable be necessary? How much power you would use? Maybe a 6db attenuator at the input would be a solution, as the Ubitx provides over 10w at the lower frequencies and you might overdrive that amp in the lower bands.


Il 11/giu/2018 18:51, "Valentin Braescu" <valentin_braescu@...> ha scritto:
I use the CTE Booster 747 amplifier modified like this : www.radioamatoripeligni.it/i6ibe/pdf/cte747.pdf

It works well , up to 80w on 40meters . I only need some ebay hf lpf's .


On Mon, Jun 11, 2018 at 19:47, iz oos

The MS1307 seem similar to the IRF520 btw


Il 11/giu/2018 18:39, "iz oos" <and2oosiz2@...> ha scritto:

On their website you can download the schematic. They are a bit obscure on the mosfets, it seems they are four MS1307. As said they lack of any lowpass filters so as such they do not comply to the FCC rules.


Il 11/giu/2018 15:48, "Richie Chambless" <rchambless7@...> ha scritto:
I’ve thought about these amplifiers, also. Despite the negativity around them, I think the only thing that’s missing is the low pass filters (the ones biased for linear operation). I’m thinking they all use RF transistors, but I could be wrong.

Re: External Amp

allen west
 

I bought and built the 100 watt version but have not tried it out yet.  I also bought a multi band LPF but have not integrated it yet with the amp.  Does anyone have experience with the 100 watt Chinese kit?

Al
KB4RA


On Jun 11, 2018, at 1:43 PM, W0PWE <j.b.hall@...> wrote:

I bought one of these out of curiosity more than anything but if it worked I was going to use it as a 40M only amp while operating mobile with my scratch built Bitx40. To my surprise it worked pretty well. Output on 40 was about 50 watts with 1 watt drive and 70 watts with 5 watts drive. I built a 3dB attenuator for the input and a 40M LPF using T50-6 cores. I also built a signal operated PTT driver based on the WA2EBY design. My heat sink was salvaged from the motor control board that died in our Bosch washing machine. It is about 50mm x 100mm and the fins are about 50mm tall. After a long winded transmission the heatsink was just a little warm and the MOSFETs were likewise.

Then one day I was speaking a little too loud into the mic and the MOSFETs shorted. New MOSFETs should be in the mailbox when I get home today so I will try again. I think if I work on keeping the drive level down it will serve it's intended application just fine. I have certainly had more than $18 worth of fun with it so far. 73.
Jerry - W0PWE

Re: KD8CEC Firmware S-Meter usage

Mark M
 

Thanks for the inputs, guys. I'll probably build Don's AGC circuit and use it. It's just frustrating that I can't get such a simple circuit to work. I'm probably not seeing something obvious. 

If it was easy, it wouldn't be as much fun, tho, would it?   ;)

73...   Mark    AA7TA

Re: External Amp

Richie Chambless
 

I have the same amp on my Bitx. I’ve gone through several IRF530s. I did find a suggestion to fix this issue. I found an article that said to put a 22 ohm one-watt resistor across output of the first transformer (gates of the finals). This is said to help with instability. I am also going to install a 50 ohm pad as suggested by Allison. My goal is to get to a stable 35-40 Watts out.

Re: KD8CEC Firmware S-Meter usage

Don, ND6T
 

Before you give up on Ian's circuit entirely, let's take a look at a few voltages Mark. With the '386 wired up as shown, and with the meter measuring from common ground, pin #6 should measure pretty close to +5 volts. Pins #2, #3, and #4 should all be at 0 volts. Pin #5 should be around +2.5 volts. Is this what you measure? Did you connect a capacitor between 7 and 8?. -Don

Re: 2.5 MHz low pass fiilter uses no toroids, SMDs #ubitx

Peter Parker
 

A further update. Couldn't resist joining the early morning 160m SSB net on 1860 kHz.  I can confirm that my values give satisfactory sensitivity on 160m.  Loaded the G5RV against the kitchen plumbing. 

Heard by VKs 3CAF, 3AX, 5IS.

Some distortion / RF feedback due to the non-use of balanced antenna, shielded coax and plastic case for tx. 

You would need to add an LPF for routine operation on 160m. 

Re: Transmitter Mods

Art Olson
 

Ralph

Bought one of these and it works great


Art N2AJO 


On Jun 11, 2018, at 9:50 AM, Ralph Mowery <rmowery42@...> wrote:


As mentioned you do need a good stereo microscope.  I use one of the better low end ones by Amscope se4000z for just under $ 200.  It comes with 10 and 20 power lenses.  I most often use the 10 power.  That and a very fine soldering iron and some .015 or so solder. You can get one of the hot air rework stations from ebay for about $ 60 that has a fine tipped iron and hot air wand.  Doubt they would hold up under heavy usage,but for a hobby they are fine.  At 68 I am lucky not to have shaking hands either..  My problem is picking up the parts with the tweezers and then taking off my glasses to look through the microscope.

Ralph KU4PT


On Mon, Jun 11, 2018 at 12:35 AM, Tom Christian <tmchristian@...> wrote:
Hahaha!  I'm amazed that anyone can work with 0201! Some day maybe in my dreams.....:). Thanks again!
Tom
AB7WT

Re: Transmitter Mods

Arv Evans
 

Art N2AJO

Okay, what did you do to make it work?  I have had one of the exact same tool
for several years and cannot make it reliably hold onto small SMD parts long
enough to place them on the PCB.  Seems that the tip does not make an air-tight
seal that will hold parts on it for more than a couple of seconds, if that.

Arv
_._


On Mon, Jun 11, 2018 at 3:28 PM Art Olson via Groups.Io <olsonaj6927=yahoo.com@groups.io> wrote:
Ralph

Bought one of these and it works great


Art N2AJO 


On Jun 11, 2018, at 9:50 AM, Ralph Mowery <rmowery42@...> wrote:


As mentioned you do need a good stereo microscope.  I use one of the better low end ones by Amscope se4000z for just under $ 200.  It comes with 10 and 20 power lenses.  I most often use the 10 power.  That and a very fine soldering iron and some .015 or so solder. You can get one of the hot air rework stations from ebay for about $ 60 that has a fine tipped iron and hot air wand.  Doubt they would hold up under heavy usage,but for a hobby they are fine.  At 68 I am lucky not to have shaking hands either..  My problem is picking up the parts with the tweezers and then taking off my glasses to look through the microscope.

Ralph KU4PT


On Mon, Jun 11, 2018 at 12:35 AM, Tom Christian <tmchristian@...> wrote:
Hahaha!  I'm amazed that anyone can work with 0201! Some day maybe in my dreams.....:). Thanks again!
Tom
AB7WT

Re: RF power chain mods and improvements..

Nick VK4PP
 

Dr. William, Same mods as me?
73 Nick VK4PLN

Re: RF power chain mods and improvements..

Nick VK4PP
 

Here is my implementation, yet to be tested:

Re: RF power chain mods and improvements..

ajparent1/KB1GMX <kb1gmx@...>
 

Nick,

From what I can see it looks like a bifilar DC feed to the drains and
a 1:1 transformer to the load (filters).

Schematic fragment and details please.

Looks nicely done.


Allison

Latest Build, Mods and results.

Mharpen@...
 

Hello, I enjoyed by first build so much I built another one. Avoiding all of the mistakes of the first one. Attached are the photos, below are the mods and results.
TX: 1. Choke in series with R86.
       2. All emitter resistors in buffer, predriver and driver bypassed.
       3. Feedback resistor in PA increased to 600 Ohms.
       4. Output Xformer replace with 2:4 on BN43-202.
       5. Adafruit audio compressor in mic line with chokes to eliminate RF feedback.
       6. PA powered by buck boost at 13.8V the rest of the board by 12V battery.
RESULTS: 30W on 80 and 40, 20W on 20. RV1 adjusted to reduce output to 15W.
RX: 1. ND6T AGC installed (underneath main board) at K3 powered by 5V regulator chip.
       2. Additional stage of audio gain installed between Q70 and U1 to make up for loss due to AGC.
RESULTS: Plenty of audio!! and good AGC action.
       3. VE1BWV audio pop mod (similar to the one standard on the new ubitx) installed underneath the main board.
       4. To further enhance the pop suppression PIN 1 at K3 is grounded.
RESULTS: Sounds fine to me.
Trivial Mods: a red/green LED TX/RX LED is installed on front. A TX/RX relay to key an external PA is installed on the back.
Ya'll have a nice day. Mike N6CMY. 

Re: Transmitter Mods

ajparent1/KB1GMX <kb1gmx@...>
 

0201 is insane.  I've done 0402, bad enough.

Personally the 233ball (BGA package) Blackfin cpu was a real pita.

After those 0603 feels huge.


Allison

Re: Transmitter Mods

Art Olson
 

Arv 

Nothing special. Mine just worked for 1206 smd parts

Art


On Jun 11, 2018, at 5:36 PM, Arv Evans <arvid.evans@...> wrote:

Art N2AJO

Okay, what did you do to make it work?  I have had one of the exact same tool
for several years and cannot make it reliably hold onto small SMD parts long
enough to place them on the PCB.  Seems that the tip does not make an air-tight
seal that will hold parts on it for more than a couple of seconds, if that.

Arv
_._


On Mon, Jun 11, 2018 at 3:28 PM Art Olson via Groups.Io <olsonaj6927=yahoo.com@groups.io> wrote:
Ralph

Bought one of these and it works great


Art N2AJO 


On Jun 11, 2018, at 9:50 AM, Ralph Mowery <rmowery42@...> wrote:


As mentioned you do need a good stereo microscope.  I use one of the better low end ones by Amscope se4000z for just under $ 200.  It comes with 10 and 20 power lenses.  I most often use the 10 power.  That and a very fine soldering iron and some .015 or so solder. You can get one of the hot air rework stations from ebay for about $ 60 that has a fine tipped iron and hot air wand.  Doubt they would hold up under heavy usage,but for a hobby they are fine.  At 68 I am lucky not to have shaking hands either..  My problem is picking up the parts with the tweezers and then taking off my glasses to look through the microscope.

Ralph KU4PT


On Mon, Jun 11, 2018 at 12:35 AM, Tom Christian <tmchristian@...> wrote:
Hahaha!  I'm amazed that anyone can work with 0201! Some day maybe in my dreams.....:). Thanks again!
Tom
AB7WT

Re: CB amplifiers RM-Italy KL203P

Dennis
 

I have been using a RM Italy HLA-305v for a year or so. Passes the US requirements and was favorably reviewed by ARRL. I hooked up the uBitx to it and had no issues.

73, Dennis
W7DRW

Re: KD8CEC Firmware S-Meter usage

Ian Lee
 

Mike

Yes, You can use any signal meter circuit.
It is a way to specify the level for the signal meter, so any signal meter circuit is supported.

My circuit may appear to be unchanged when measuring with a multimeter. So I thought your S-Meter sensor might be in normal operation.
When your S-meter sensor is connected to the uBITX, the ADC will periodically measure the ADC and each time the capacitor is expected to change state as it discharges.

Ian KD8CEC

2018-06-12 5:05 GMT+09:00 Mark M <junquemaile@...>:

Thanks for the inputs, guys. I'll probably build Don's AGC circuit and use it. It's just frustrating that I can't get such a simple circuit to work. I'm probably not seeing something obvious. 

If it was easy, it wouldn't be as much fun, tho, would it?   ;)

73...   Mark    AA7TA



--
Best 73
KD8CEC / Ph.D ian lee
kd8cec@...
www.hamskey.com (my blog)