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Hello Walter,

I have been doing some work around this same subject. You can take the low-level audio signal to an external amplifier by connecting the signal in to Vol-H (R170). This is the yellow wire coming off of the audio connector (diagram on HF Signals is incorrect). You can also reduce the headphone volume by inserting two small value resistors (under 100 ohm) in series with the output of the audio amp. Do this by connecting the output of the amp to pins 4&5 of the headphone jack. Now put the resistors across pins 1&2. I hope that makes sense! Google the Realistic DX-160 schematic to see what I鈥檓 talking about.

My name is Qonita, and I am a student i my last semester. I'd like to learn about BITX40 because it is very suitable for my last project.听

I design a case for my uBITX. see the attached PDF File.听 I print them on my 3D Printer and have had very good feedback from the ones I have sold.听 Take a look.

On Wed, Feb 28, 2018 at 05:33 am, Kerr Smith wrote:

Hi Walter,

There is a clear schematic at the following location (found on the hfsignals site):



This is for version 3 of the UBITX.

As for getting a selection of SMD resistors I would suggest getting a mixed pack from somewhere like Banggood:



I have bought several of these small kits in the past and they are a great way to instantly (after shipping of course) get a wide range of resistor values.

I hope this helps,

Kerr

Outstanding Schematic and SMD source.听 What value SMD's do you think these are? I see 0603,0805, 1206.听 What is the standard size using for electronic projects like these?

Thanks for your help
听
--
73, W9KJO
Walter

On Wed, Feb 28, 2018 at 05:15 am, Thomas Smith wrote:

Hi Walter,

What are you using to power your UBITX?听 If you are using a power supply plugged into your wall, this may be coupling 60 (50?) Hz noise into your rig.听 If you are powering it from the wall, can you use a battery (even just temporarily) to see if that is the source?

Tom

On Wed, Feb 28, 2018 at 1:23 PM, Walter <W9KJO@...> wrote:

I notice while using headphones with my new UBITX that there is a low level hum in my headphones.听 I only seem to notice this with the headphones at low volume.

Is there a fix for this?

Thanks

--
73, W9KJO
Walter

听

听

It is powered off the batteries from my solar system, 12vdc system used only for my ham radio station, no inverter (yet).听 Four large deep cycle batteries charged by an MPPT Controller.听 I check it for noise often.听 I have a power supply on the batteries to make up for low charge at night but it was off at the time as that charger is disconnected by my Internet relays during the daytime.听 I'm pretty sure there wasn't any noise introduced from my power supply,BTW

BTW, I am so impressed by the Solar System, now 2 years old, That I am going to build a second system to power much of my house in the near future.听 These panels even provide charge under cloud cover, it drops from 15 amps to 3 or 4 amps but that is enough to keep the batteries at charge even when operating my station at 27 amp current draw with the batteries making up the difference.听 The duty cycle is low enough, even while in digitial modes, that it keeps up on only a few amps.听 I even use my 12vdc HF Amp while on solar power.听 It's been amazing and reliable.

I do have a DC Boost Regulator installed in my UBITX to raise the PA Voltage to a stable 24vdc.听 I thought this might be the noise so I disconnected it and used only the 13.8vdc from my batteries but the noise was still present.听 So the boost regular it not causing the noise.

--
73, W9KJO
Walter

Hi Walter,

There is a clear schematic at the following location (found on the hfsignals site):



This is for version 3 of the UBITX.

As for getting a selection of SMD resistors I would suggest getting a mixed pack from somewhere like Banggood:



I have bought several of these small kits in the past and they are a great way to instantly (after shipping of course) get a wide range of resistor values.

I hope this helps,

Kerr

I totally agree with you Michael.听 I think some realized it after they got things together.听 I've seen them put the large 4 or 8 pin mic jacks next to the tuning knob.听 That would drive me nuts.听听 Yours looks clean and smooth.听听 Ne mess cables in the front.听 Even the side would be a better option than the front in my opinion.听

73, Michael
KM4OLT

I ordered mine on the 29th of December 2017, and I haven't gotten notice of shipping yet.
Dan W2DLC

Carl,

Bad connection on the power jack, see if you can find another jack from a discarded walwart the fits snugly.
Some have a slightly small hole and can be drilled to enlarge to fit.

Raj

Well, I just got a paypal notice that the tracking of my uBitx as been issued. I ordered my uBitx on Jan 2 and today is Feb 28. So soon I'll have the uBitx in hand, not sure when I'll get a chance to build it up but hopefully it will be soon.

-Obe (KC4VZT)
Middleburg, FL

Have you already aligned the PA BIAS and PA DRIVE according to the instructions on hfsignals.com?

1. Attach a dummy load to the antenna
2. Insert a ammeter (you may use your VOM meter in high amps range) into the PA power supply鈥檚 positive line
3. Keep the PA BIAS preset (RV1) to fully clockwise position. Now when you press the PTT button, the ammeter should read about zero.
4. Increase PA BIAS without speaking into the mic until the PA current shows 100 ma
5. Give a loud and long HAAAALLLOOWW into the mic and the current should jump to slightly over 1 amp
6. Adjust the RV136 to increase the PA drive if the current doesn鈥檛 jump all the way to 1A
7. Keep monitoring your signal on a nearby receiver.

73 Allard PE1NWL

I notice while using headphones with my new UBITX that there is a low level hum in my headphones.听 I only seem to notice this with the headphones at low volume.

Is there a fix for this?

Thanks

--
73, W9KJO
Walter

If I use the Speaker jack with headphones, then I naturally have to turn the audio down very low.听 However, if doing digital modes then the audio is too low for the signal link.听

What would I need to do to install a second jack for headphones and lower the audio for headphones while leaving the speaker volume up higher?听

Would a simple resistor work or is more required for such a modification?

Is there a place to tap into a constant audio level that is not affected by the volume control?听 Kind of like a line level output?

Thanks for your help.
--
73, W9KJO
Walter

Hi everyone.
I recently received the ubitx and have wired it up but am not getting any audio signal.
When I initially wired it up I accidentally had the PTT shorted to ground causing it to go into TX immediately. I disconnected the power, rewired the jack and continued.
Powers up fine
All functions appear to work (except audio)
Rotary encoder tunes up and down the bands and goes through the menus a like a hot knife through butter.
Screen says that it Goes into TX when PTT is engaged or when Keying begins.
During receive everything appears fine but no audio
Speaker and headphones are tested and work.
Audio Jack is correctly wired and works.
Potentiometer is wired correctly, tested and works.
Antenna works and brings in a signal just fine on other radios.
Antenna jack is wired correctly and connected to the board.
I am tuned to a frequency where I know my antenna is receiving signals heard on other radios.

Audio is completely nonexistent. No sidetone heard from CW, no static, hissing, popping, nothing.
I am pretty sure the issue is something simple and located on the board somehow but even with the schematic of the received audio path I just do not know how to diagnose and am not sure where on the board to take readings. Any help would be much appreciated.

-Brett Deschene

On Wed, Feb 28, 2018 at 04:08 am, DrZ wrote:

Last night while trying various speakers, smoke started rolling out of my uBitx. 听The audio IC U1 was fried. 听I'm assuming the audio line shorted while inserting plugs. 听They are cheap (5 for $6) and I'll install a socket for easy replacement. 听But a word of warning.....
Howard K4LXY

i Noticed the volume switch has an on/off switch built into it.听 perhaps I will connect this in line with the speaker jack and turn it off before plugging and unpluggings speakers and stuff.
听
--
73, W9KJO
Walter

Last night while trying various speakers, smoke started rolling out of my uBitx. 听The audio IC U1 was fried. 听I'm assuming the audio line shorted while inserting plugs. 听They are cheap (5 for $6) and I'll install a socket for easy replacement. 听But a word of warning.....
Howard K4LXY

Where can I download a better Schematic of the UBITX?听 I cannot read the one off the website the resolution is low.

I need the resistor values for R63 and R60.听 I did the dynamic mic mod and may have to replace these resistors if I cannot get my dynamic mic to work with the UBITX.听 I need these values to order some SMD's

Does anyone know where to buy a package of SMD resistors with many different values?

Thanks for your help
--
73, W9KJO
Walter