Posts Tagged With: homebrew

BITX PROJECT

IMAG1637

Most hams who know me, know that I love to tinker and work on projects.  Sometimes they even work out in the end.  So begins this one.  I’m an avid follower of the Soldersmoke podcast and website.  Bill Meara N2CQR and Pete Juliano N6QW host a monthly podcast all about QRP and radio homebrew.  Their inspiration has given me the courage to begin and successfully complete several projects.  The Michigan Mighty Mite is a good example.  One of their homebrew heroes is Ashhar Farhan VU2ESE who invented the BITX transceiver 14 years ago.  Last year they reported that he’s selling the board fully constructed and tested.  All you need to do is find a suitable enclosure and attach the peripherals.  At the $45 price point it’s hard to beat as a development platform.  The basic radio can be upgraded to stabilize the analog VFO or even improved by adding a DDS or PLL VFO quite easily.  Low pass output filters can be added to take it from a 40m monobander to all band operation.  I couldn’t resist!

IMAG1638With the circuit fully complete, this amounted to a one day project to get the basic assembly done.  I found a suitable Christmas tin for a cabinet.  The majority of my time was spent laying out and marking holes for the board standoffs and all the jacks and pots to be connected.  It’s not exceedingly elegant but I IMAG1639was able to accomplish it all with a hand drill, pliars, and a couple wrenches.  I chose the metal enclosure because I thought It might provide good shielding.  Eventually I’ll probably add a small fan and punch some holes for ventilation.  There should also be enough room to add an Arduino, DDS or PLL board, and cool LCD display.  I think it would make a perfect radio for portable operation with a battery and 40m dipole at the park.

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I wanted to include a couple shots of the innards.  Everything came included with the kit, including the wiring pigtails to attach to the board headers.  Pretty straight forward assembly.  The HF Signals webpage has all the technical info, assembly

IMAG1641instructions, reference materials, and purchase info.  The product is sourced and shipped out of India and constructed by a local women’s collective that helps provide skills and jobs.  They typically arrive in less than a month.  Not bad turn around time.  Easy ordering with Paypal.

So here it is with a couple knobs out of the junk drawer.  I trialed it on the bench and it plays great, minus the drift.  Even that settles down after about 15 minutes.  Crisp, clear analog audio…but you have to ride the AF gain what for having no AGC.  I bet you could probably hack that into the circuit pretty easy, too.  I could generally hear just about anything I could copy on the Flex-5000, so that says something about the sensitivity.  This was a fun and functional one day project with only minimal soldering required.  Looking forward to doing some more hacking on this one!  Will try to produce a companion post with a little video production for everyone playing along at home.  73 all.

IMAG1642

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BOOK REVIEW

minqrpcover

The cold winter months are good for spending time in the radio shack, and also in a comfy chair doing a bit of reading.  I just finished reading this book and thought I’d write up a little review to share with my blog followers.

 

Minimum QRP is written by Peter Parker VK3YE.  Many followers of Soldersmoke and youtube will recognize Peter from his many videos on low power operation, pedestrian mobile, and homebrew electronics.  In his book, Peter covers all aspects of low power operation from radio, to antenna, to operating location, and even strategies for successful operation and maximizing the chances of making contacts.  He covers HF/VHF/UHF, both terrestrial and satellite.  It’s impossible to cover everything QRP in great deal, but this book offers a lot of great info on the subject.

 

I don’t really consider myself a QRP aficionado but I found the book quite enjoyable.  It’s easy to read and not overly technical in any way.   If nothing else, it offers a great deal of encouragement and support to people interested in pursuing low power operation.  At $5 via Amazon Kindle it’s hard to argue with the price.  I’ve certainly wasted more money on useless items!

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THE MICHIGAN (INDY) MIGHTY MITE

 

Most of my ham friends know I’ve been a devoted listener of the SolderSmoke podcast for some time.  Bill Meara N2CQR and Pete Juliano N6QW make a great team discussing the building and operating of all manner of homebrew, boatanchor, and QRP gear.  Their enthusiasm is obvious and they really give the listener a sense of confidence that it just might be possible to really build something yourself in this modern age.

Building components and constructing circuits is to me the essence of ham radio.  I’ve built small kits like the N0XAS Pico Keyer from Ham Gadgets and similar odds and ends, but never any “real” ham gear.  I’m kinda like the average Joe that watches the home remodeling show on TV and thinks it’s cool to restore the 100 year old house, but lives in a newer house with little maintenance.  It all sounds glorious, but you have no idea where to start.

Enter the Michigan Mighty Mite.  This simple transmitter requires only seven components and produces around 500 mW RF output.  To up the ante Bill sent out the necessary 3.579 MHz colorburst crystal for free to anyone who emailed him a request and promised to use it.  Pete built the circuit and added some pro tips of his own on MMM construction on the blog.  Now this seemed to be a project I could handle!  I fired off an email in short order.

My crystal got torqued by the USPS!

My crystal got torqued by the USPS!

What arrived was something of a disappointment.  Evidently USPS sorts mail with a steam roller.  My precious crystal looked like momma worked it over with a rolling pin!  This depressed me enough that I delayed building the transmitter for some time.  I panicked and purchased a whole bag of crystals, just to be safe.  Eventually I turned up some magnet wire, a pill bottle and the necessary capacitor and resistors.  The remaining air variable cap was ordered from Amazon.  Turns out they have all manor of useful materials, who knew?

First winding with tap.

First winding with tap.

The hardest part was winding the coil.  That wasn’t too bad, though.  I held it together with tape.  Everything was assembled on a bread board for trial.  I must admit to being overjoyed when I saw the visual waveform on the PowerSDR panafall display of my Flex-5000A main shack radio.  So much so, that I ran through the house calling for my YL, KC9TAH.  She was in the shower

Second winding over the first goes to antenna and ground.

Second winding over the first goes to antenna and ground.

and thought I’d cut off a finger or something while in the mad scientist lair.  Much to her dismay, it was only a nasty CW signal emanating from the Flex speaker.  She did humor me by going out to see the marvelous project before asking me what I was going to fix for lunch.

So where do I go from here?  I have a small piece of perfboard on the bench.  I guess I should assemble it on that in a proper arrangement.  My friend Brian KB9BVN has requested a QSO but I’ll need to build a low pass filter to knock down the harmonics.  No sense of incurring the wrath of the FCC and homebrewers everywhere.  My next project is a small regen receiver and the Ugly Weekender and Ugly Weekender II combo.  Both of these come from old issue of QST.  I have the circuit boards from Far Circuits and plan to build them with the boys.  Might as well infect the next generation with a case of “the knack” if at all possible.

Join the revolution!

Join the revolution!

Categories: Activities, Amateur Radio, Projects | Tags: , , , , | 2 Comments

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