As a homebrewer I wanted to try out how good a uBITX is , as compared to a mono bander which I was used to , I started to collect all the information on it. I could not afford to buy the commercial version of the build and wanted to experiment with it on my own , with help from my well wishers.
Before I could even dream of trying to homebrew one I wanted to know the approximate BOM cost and look into my stock of the available components required for the build.
I realised that the BOM cost was not as much justified for what it was been sold for and I felt I could afford to try it , even if it had to fail. The only costliest parts in the list were the Toroids and for that I had some in stock with which some things got easier.
Having made up my mind to Homebrew it , the next step was to draft a PCB. I got over it and drafted my ver 1 PCB and got it fabricated on a paper phenolic Single Side board. Here my objective wsa to only test the exciter part of the project and hence keeping it simple, I only got the Basic part of the entire project PCB made.
I got hold of a 45Mhhz Filter from some well wisher and assembled the board. There were obviously some goof up with the relay circuit to switch VDD between Tx/RX but that was easy to handle.
With some help from a local ham (VU2IIA) , I got it tuned and tested. He also built one of the earlier protype and used it for a while.
After the intial success and a proof , that the design worked, it wss time for a more better build / design on a Glass Epoxy , Double Sided, PTH board.
This success story was further shared with M0RVI (Ravi Miranda)who got interested in the project and came forward with a PCB draft on a properly design board. I(VU2UPX) and M0RVI had lots of discussion on this design objectives and got the design ready.
Our design was purly based on “A Termination Insensitive Amplifier for Bidirectional Transceivers ” by Wes Hayward, w7zoi, and Bob Kopski, k3nhi and adaption of Ashhar Farhan’s design.
We did modify a few things in our circut , that was , the LM386 based Audio Amplifier and a LM324 based AGC system which we borrowed from the BIXEN design.
Just as M0RVI was to get his work fabricated, Ashhar Farhan, released his v5 board in which he had modified a few set of transistors. It didn’t take Ravi to incorporate the changes in his design and get the job processed from China (JLCPCB)
After duly getting the boards , it was promptly assembled and tested. Once again , VU2IIA (Mahesh) help me test and tune the project and it was a success.
A few extra boards that we had were duly shared with like minded people , of which only a few were able to realize it.
The signla Source was a Raduino which was cloned using a Arduino Promini and the Si5351 board. That was a project which was appropriated from some other project for this testing. Later on a Nextion 2.8″ Board was also built for this purpose.
What is shared , here below is what was successfully realised.
Some videos of its performance would be shared in due course.
Futher to this , there are a few add-ons also which are being planned and realised in this series. Those would also be shared soon.
de VU2UPX (Charudatt)
microkits 