The 147.120 Tech Net Blog

Hellraiser Transmitter Project - Photo by Hans Summers

Hello again. I would like to share another resource that will inspire, inform, and astound. Hans Summers, G0UPL, is an Electronic Wizard of the Twelfth Degree (see the International Brotherhood of Electronic Wizards Handbook for further information). He has built a website that abounds with inspiration. His projects are visual and functional. He likes to use tubes and will spurn convention to create a visually appealing project. This is art. The amount of information is sure to keep you busy and should be bookmarked for reference.  I am interested in his extensive information on Huff and Puff Oscillator stabilizers and identifying crystal parameters. He builds his own test equipment and documents so that we can follow in his path. Several QRSS projects are detailed. I have added QRSS to my list of future projects. Thank you Hans, for sharing a lifetime of experience at HansSummers.com. 73

Robin

Resources abound on the Internet. The G-QRP Club located in England is one that I enjoy. If you “click” on their logo above it will take you to the site. They have data sheets with excellent  information for the beginner to the advanced builder. The Club magazine, SPRAT, is published quarterly and is full of inspiration. I just received the fall edition and found an article on Weak Signal Propagation Reporting, WSPR for short. There are plans for The SixBox, a very simple 6m AM transceiver. The G-QRP Club is devoted to low power communication. Membership is $15 a year and you will receive four issues of SPRAT.  73

Robin

As Radio Amateurs who like to build, anything that we come across could be inspiration for a project or upgrade. I was Elmered into the hobby by  Dave Carter, KA1HDG, during a one week class at Great Lakes Adventist Academy. GLAA is an ARRL “The Big Project” School. With part of their funding they set up a satellite station… the inspiration.

Satellite Station at K4LKL Field Day 2009

This is the top of my satellite station. I made a 100 point field day contact with AO51 at 10 degrees over the horizon. My first soldered component of my first kit was inspired by that satellite station at GLAA. Needing computer control of the AZ/EL rotors I purchased the PIC16F688 Satellite Tracker Interface: ST1 from FOX DELTA. I wanted USB control so that required soldering a small FT232R chip.

My first soldered IC chip

This chip was the first thing I put on a board. I figured that if it didn’t work, why solder the rest.

If I can solder a chip anyone can. Heat up the iron and follow your inspiration. 73

Robin

NORCAL S9

When I started planning the Hendricks BitX20a Project there were several pieces of test equipment that I found would help. One of the needed items was a signal generator. NorCal QRP Club makes a fine kit with easy to follow directions for those such as I, i.e. directionally handicapped. It has four crystal controlled frequencies. I needed 11Mhz so a quick trip to Sky Craft (that was a joke) supplied a crystal that was exchanged for the supplied 10Mhz crystal.  The S9 kit is a mix of surface mount and through-hole construction. It also has an attenuator that drops the signal to an S1 level. I am guessing  this could be helpful when adjusting the receive end filters. Upon completion I found the signal to be very weak and when I switched in the attenuator the signal disappeared. I took it to my Elmer, K4DF, and he described the circuit to me as we hooked it into his HF rig. When he finished showing me the oscillator and attenuation circuits he suggested I check the solder joints in the oscillator section. A magnifying glass and some quick soldersmoking solved the problem. This kit will fit in a Altoids tin, but I do like looking at it. These kits are great fun and provide practice with an iron. Soldersmoking rules. 73

Robin

KC4ZVW, Dave, commented on my last post and ask some basic questions that started me thinking. Does it work? It leads me to why I am building the BitX20. I have a strong desire to learn electronics. This project allows immediate feedback on each section that is completed.

When I completed the audio amp, I needed to find an input source to check it out. Travis, my son, and I built a crystal radio with an audio amplifier circuit. This Fox Delta design is made to learn with and has the ability to separate the audio amp from the crystal radio. I fed the signal into my BitX and it worked. I have already received the local AM station through my Bitx. DAVE, it works.

Then I built the Mic Amplifier. By jumping a signal and powering the audio amp section I was able to hear my own voice through my small amplifier setup. Yes it does squeal when you get the mic near the speaker just like the real audio setups, and yes I played with all the feedback noise I could create. That worked too.

I have completed all soldering on the radio. A radio is an oscillator that allows us to throw electromagnetic waves through the air and catch them at a different location. This radio has two oscillators. One is a carrier oscillator that is a 11.00001 Mhz, and the other is a variable oscillator, VFO, that is close to 3.0 Mhz. When combined, the frequency that adds up is near 14. Mhz, the 20m Band! Well , there’s a problem Dave. First, I have both signals oscillating and measurable although the VFO is only variable by 3.5 Khz. Not enough to qualify as a VFO. On this radio I will need a couple of hundred Khz to cover a portion of 20m phone band. I soldered in a different variable resistor and air variable capacitor and the oscillations stopped. I will go back on that change. Second, I am unable to find the 14. Mhz signal. I have unbalanced the modulator to let the carrier signal through to the mixer near the VFO and where I feel it should be, it ain’t.  There I is. Stuck again.

Dave, does it work? Wonderfully! I am learning radio theory, trouble shooting, soldersmoking, and burning my fingers. LIFE IS GOOD. Oh… the radio, well I’m sure it will work when I am done. 73

Robin

Bitx20A Alignment in Progess

Hello, I have been graciously allowed to post some thoughts about my ongoing relationship with a Bitx20A.

Where to begin… my name is Robin and I am a homebrewer. It all began when I found out you could build your own and learn about how a radio really works. No more black boxes with multiple-multifunction knobs and buttons for me. I was completely innocent, without a clue of the power this would have over me. Before I knew it I was a frequent-flyer at SkyCraft. Late night sessions at the dining room table with smoke wafting about as I ponder the perplexities of mixed oscillator signals filtered through polycrystalline mineral wafers. I still remember the joy of hearing the audible oscillations of my first Colpitts, but I digress. Consider the consequences, it is not for the faint of heart. If this is the path you choose, know what lies ahead. Capacitors that disintegrate before your eyes, signals that disappear after just a small tweak, and the frustration of “dang, I followed the directions and it don’t work”. I warned you!

That said, I will post a few photos and discuss my Bitx20 from time to time. I want to thank Tracy for his inspiration on the Tech Net and David for his Web expertise that allows me to be here. 73

Robin