Friday, December 30, 2016

Bitx40 Project ~ So you want to build a Bitx40?

Building the Bitx40 ~ The how to for the newcomer!

12/31/2016 ~ Life is Too Short for QRP!

So Ok guy's here is how to boost your signal (using an external linear amp)  so you can be heard and duck those dreaded repeats of your name and QTH.

 It is pretty simple to implement. All you need is three diodes if you include the 1N4148 snubber diode across the reed relay coil, a RCA phone jack and a terminal strip. One side of the relay contact is simply grounded by soldering to the PC board that holds the reed relay (yep super glued upside down to a scrap piece of PC Board). The other lead goes to the rear panel mounted RCA jack. The two 1N4007 isolate the circuits from each other. With this arrangement I am able to drive my SB200 to 100 watts output. Pretty cool.

Pete N6QW


Pete N6QW

About a month ago I agreed to give a Skype presentation to a local ham club known as the Ventura County Amateur Radio Club (VCARC) on the subject of homebrewing. Hey I am really good at soldering my fingers together so I guess I sort of qualify as a homebrew radio enthusiast. In the course of discussing the presentation with the club president Joe, K6NE, I suggested that the club might want to engage in a group project using the Bitx40 board available from India for the amazing price of $45 shipped to your door. Bitx40 is the link to the website where the radio can be purchased.
[The club presentation will take place two weeks from today and so I have been under the gun to get everything completed.]
For your $45 you get a complete built radio transceiver board with all of the controls, connectors, wire harnesses and even a microphone element and PTT. As shipped the radio is on 40M and is capable of over 5 watts output. The means of frequency control is a voltage tuned oscillator using a panel mounted pot to change the frequency. It works but a better alternative is to purchase the Digital VFO kit and LCD which adds another $14 --so less than $60 and you have quite an impressive radio. I purchased my board in late November 2016 and the Digital kit was not offered so I rolled my own Arduino/AD9850. The add on kit uses the Si5351 PLL.
Thus the builder (in this case the club members) provide the value added by integrating the parts and pieces into an enclosure and along the way learn about the nuts and bolts of the radio. VU2ESE developed this kit specifically to learn about what makes up a transceiver and to experiment to your hearts content and indeed he has met that goal.
To aid the club with this project I volunteered to create a series of webpages hosted on my website so that in addition to the excellent information on the website that I would provide detail on how to execute the actual build. My webpages have many links to where you can purchase enclosures or special tools and even a grounded soldering iron.
In the early days most ham stations were entirely home built and thus many of the fundamental hand tools and parts were in the junk box. But today it is "flash the plastic" and in two days UPS has a black box radio sitting in your shack. So to actually build something takes a lot more effort. My webpages make it an easier task. Hey are you looking for a QRP SWR bridge (there is a link to the DX Engineering MFJ Model 813). Well in my case I built my own but not everyone wants to do that. 
So here is the link There are sub links that explain how to metal bash, detail on the wiring (including a link on where to buy the wire) and the check out process. Again my pages are to supplement what is on the website.
I have made four contacts with this radio and this has been a fun project but now I need to move on and this will be the last posting on the Bitx40.
Pete N6QW