Gerard,

Here's a few more old posts on how this works:
/g/BITX20/message/44515
/g/BITX20/message/44278
/g/BITX20/message/35235

Jerry, KE7ER

Received my kit here in W3 land. Yeahhhhh

73
Goody
K3NG

Makes sense!.? Thanks for the feedback.?

Right now I've built the SMD1206 pcb Daylight allanalog circuit ( less the power RF) 80x70mm, but I can do better, of course, this is just a test.
Some more? questions:
1) What the exact frequency of BFO?
2) BFO output is not sinusoidal: is this a problem? It seem heavely polarized, without Xtal, collector is at 1.5Vcc, it goes at 5Vcc with a resistor in the range of MegaHoms.
3) The 100 ohm R18 resistor on balanced modulator seems too low, it destroys my zener , I used a 1Kohm as the other circuit with SA602 ( I use SA612)
3) Again on Q11, Q12 an Q13: is Q12 base really connected with the emitter of Q11?
Can we save some transistor ( they are seven on TX section!) using a large band little? transformer on Q11 and delete Q12 & Q13?
4) On PTO again: without a 3d printer, and no one selling it, is someone interested in an alternative PTO, built with part of PCB with nuts solderet on it, something
as output RF transformers for high power push-pull power fet RF amplifiers?
That's all for now, soon I will add a pic of my PCB
Paolo

Hi All I am receiving the SBITX this week per DHL.? Any cautions that I should be aware of?? I have been reading up on the 5V LDO supply and replacements with a buck converter.?
Just wondering if there are any.. don't do this.. or that types of comments.?
It looks like the 5V is for the Pi and display so wondering what the new Rx current looks like with the higher efficiency buck converters.??
Just anticipation :-)
73 Brad N8YG

Hi Scttmtclf and Mark,

I used the same regulator and yes, you can test the radio with just the regulator and you are correct, don’t transmit. ?Testing the PA transistors is easy but I would not trust them. ?Digi-Key has the IRFZ24NPBF version for $0.82 each. ?I ordered 10.

The regulator board is very touchy to adjust. ?Be very careful and adjust it for about 5.3VDC. ?I added a low pass filter on the input side and a filter cap on the output of the regulator. ?I replaced one of the main PCB mounting screws with a standoff so I could mount the new board. ?You likely do not need the filter(s) but it was stuff I had in the drawer so what the heck.



Good luck, Scott


. ?

Ah the joys of trying to relearn AP courses in order to teach them at a private high school....

For some lighter reading, I perused Jack & Albert's text on their radio -- wonderful illustrations and information -- then dug into Chapter 8 (Receiver) -- what a wonderful resource they have taken the time to compile!? ?Loads and loads of knowledge being poured out here.? ?Writing such a book is a labor of love (been there, done that to some similar degree) -- and Jack even sent me a copy for free!!? ?It will be slowly devoured and greatly appreciated, to be kept forever beside my college days' text on Digital Signal Processing.? ?I suspect this will be a great help to me in understanding the code of the sBitx.....

My 8th graders bombed their last test, and trying to get young minds to dig into TECHNOLOGY -- the discoveries that mapped out the atomic structure -- is so so much work....likewise teaching AP Physics and AP Calc....but this is part of what hams do -- TEACH others to preserve our culture, our social structures.? ?Jack and Albert have put forth a great text that will teach many.? ?None of us has time to do EVERYTHING, so I'm grateful for all the work put forward by Ashhar, Jack and so many others here.? ?They are bringing digital processing right down to our levels with all that they do.

73,
Gordon KX4Z

Jack,

I am at home and downloaded the newest file in the groups.io file section, extracted it, and compiled it.? I did not get any errors.? Here is the tools dropdown in the Arduino IDE:



73
Evan
AC9TU

Should R51 be connected to TX or 12V? On the schematic it's not connected to anything.

In the PTO the text talks about a 7809 but the schematic shows 7805.

On a happy note, the PTO 3D print worked perfectly for me. It's getting harder to find real brass bolts here but eventually I tracked some down. The nuts fit the holes snugly.

Thanks Ashhar. Perhaps I should have thought of volunteering to distribute for Australian purchasers earlier but hopefully the postage costs for HF Sigs weren't too high. .?
73 Bill. VK7MX

You are correct. I should have read the email better. I will blame it on grandkids distraction.?

I have not run into the issue you describe. ?I would verify that you have the correct card selected and that you are using the old boot loader.?

Sorry for any confusion I created.?

73
Evan
AC9TU

开云体育

You may need to use the LTS version of the Nextion editor. Look for it on the Nextion web page. I am away from my qth right now. ?If you can not find it I will post the link when I get home.?

73
Evan
AC9TU

Need help troubleshooting. #sketch-too-big
For those who have successfully installed the latest drop of N8ME_2_VU3GAO_Mods, what Arduino ISP version are you using?

-What are the parameters in the ISP you are using for a "stock" uBITX V6 complete kit? I have noodled with several:?
-Board: Arduino Mini
-Processor: ATmega328P
-Programmer ArdunoISP (and a couple of similar appearing entries)

I am getting the infamous "Sketch too big" error even after playing with several versions of the ISP and following Ashhar's description of compiling and loading the sketch.
part of error message reads: text section exceeds available space in board Sketch used 29214 bytes(101%) of available space. Maximum is 288672 bytes.
I don't mess with Arduino enough to have a clue what to comment out or otherwise eliminate that would allow a good compile. Have read something about eliminating the boot loader from compile, but isn't boot loader required to init the firmware?

Currently have ISP 1.8.12 installed.
Pretty obvious some parameter or other is not right and I am unable to prevent the bloat on compile.
A search of the messages found a lot addressing the issue for other firmware, but little useful for the N8ME/VU3GAO version.

Thanks in advance for any clear text, non jargon laden explanations offered.

73 -
Jack KD4IZ

开云体育

I have some updates available for testing here:

Dave

Actually there’s already literature on it. I’m going to dig again

ex:?Re: #uBITX Firmware KD8CEC - IF-Shift etc. (groups.io)
[email protected] | Need some explanation on v4 sketch

cdt
....

This is the one I have been using for a while.?

I also need to swap my IRFZ24 FETs but that was due to a high SWR scenario, the buck converter is still working fine.?

Anyone know if it is safe to run the sbitx as a receiver with the IRFZ24s removed (assuming you don't transmit)?