The KØNR Weblog

I was trying to provide some semblance of order in our basement, which is the storage area for my extensive collection of great radio and computer treasures (sometimes referred to as “junk”). I ended up wading through piles of stuff that I didn’t even know I had. It was like Christmas all over again!

I came across this little gem built into a RadioShack enclosure:

I guessed that it was a Code Practice Oscillator and that I must have built it some time ago. I had a vague recollection of the project. It certainly looked like something I might have built. There was a straight key in the same box that plugged right into the key jack.

I opened the inside and found this circuit board populated with through-hole parts. Replacing the 9V battery with a fresh one, the circuit came to life. A little action on the key and the sound of Morse Code filled the room.

I was curious about the design. There is one integrated circuit on the board but it was labeled only with a proprietary part number. What would I have used to built a code practice oscillator? Probably a good old 555 timer, so I pulled up an online datasheet for that part and got its pin out.

Then I started to do a some lite reverse engineering of the circuit and this partial schematic diagram appeared:

The circuit is not complete — I just sketched out enough to confirm that the design was based on the 555 timer.  There is a lowpass RC filter on the 555 output to round out the square wave before it is fed to the speaker. It’s interesting that the key connects to the reset pin on the IC. I think this was to ensure a clean start up of the oscillator, to eliminate any frequency chirp.

So that’s a little diversion I had this weekend. Now back to cleaning out the basement.

73, Bob K0NR

Well, that’s what the FCC says: the Amateur Radio Service is not an emergency radio service. K1ZZ’s QST editorial quotes the FCC and points out that the mission of the Amateur Radio Service is indeed broader than emergency communications. (The FCC does recognize the role that amateur plays in emergencies — see this web page.)

Lately, I’ve noticed a number of blog postings and other statements from hams that define amateur radio way too narrowly. The common thread is taking the part of ham radio that is most important to them and arguing that Real Ham Radio is focused on that segment of the hobby/radio service.

For some folks, amateur radio is emergency communications (only). Others argue that only technical pursuits are true ham radio and those appliance operators are just holding us back. For others, ham radio is defined by getting on the air and operating (might be QRP, might be contesting, might be something else).

I think K1ZZ got it right….the purpose is broader than that. Just go read Part 97.1 of the FCC rules:

The rules and regulations in this Part are designed to provide an amateur radio service having a fundamental purpose as expressed in the following principles:

(a) Recognition and enhancement of the value of the amateur service to the public as a voluntary noncommercial communication service, particularly with respect to providing emergency communications.

(b) Continuation and extension of the amateur’s proven ability to contribute to the advancement of the radio art.

(c) Encouragement and improvement of the amateur service through rules which provide for advancing skills in both the communications and technical phases of the art.

(d) Expansion of the existing reservoir within the amateur radio service of trained operators, technicians, and electronics experts.

(e) Continuation and extension of the amateur’s unique ability to enhance international goodwill.

Let’s reject the narrow view and think a bit broader.

73, Bob K0NR

Ham Radio Two-Day License Class

Monument, Colorado

Saturday Jan 30 and Saturday Feb 6 (8 AM to 5 PM)

Tri-Lakes Monument Fire Station 1

Sponsored by the Tri-Lakes Monument Fire Radio Association

The Technician license is your gateway to the world-wide excitement of Amateur Radio …

• Earn your ham radio Technician class radio privileges
• Pass your FCC amateur radio license exam right in class on the second day
• Multiple-choice exam, No Morse Code Required
• Live equipment demonstrations
• Learn to operate on the ham bands, 10 Meters and higher
• Learn to use the many VHF/UHF FM repeaters in Colorado
• Find out how to participate in emergency communications

There is no cost for the class

However, students must have the required study guide:
Gordon West Technician Class guide $18.95
And pay the FCC Exam Fee: $15.00

Advance registration is required (no later than Jan 25^th).

To register for the class, contact: Bob Witte KØNR   techclass@k0nr.com

For more information on amateur (ham) radio visit www.arrl.org
or www.wedothat-radio.org

Update: As of Jan 6th, the class is full. We have had a surprising number of people interested in this class. We are keeping a waiting list and we are likely to offer another class later in the year.

Here is a funny comic that I came across recently (thanks Kelly AB9RF):

“Spinal Tap” is a reference back to the classic Rob Reiner film This is Spinal Tap, where Nigel explains the value of an amplifier gain control that goes all the way to eleven.

For more fine, sophisticated Spinal Tap culture, see the fan web site or the official Spinal Tap site.

73, Bob

We’ve been looking at optimizing the performance of the D-STAR repeater here in Monument (W0TLM, 446.8875 MHz), so I’ve been searching the web for information on what other groups have uncovered. Not surprisingly, there has been some creative reverse-engineering and re-engineering of the ICOM D-STAR repeaters.

Here’s a summary of some Good Stuff that I found:

1. NU5D paper on DSTAR Repeater Modifications & Interference Testing

2. A good overview of the ICOM D-STAR repeater block diagram and a few modifications to the ICOM repeaters on the dstar.ca web site

3. The N5EBW LED Board – a drop in board to add transmit/receive LEDs to the ICOM D-STAR repeaters

4. The Utah VHF Society D-STAR page — some of the best technical information and practical evaluation of D-STAR technology

5. A Look Inside D-STAR Modulation – an article I wrote for CQ VHF magazine that explains the vocoder and modulation scheme in D-STAR.

If you come across other D-STAR resources, please let me know.

73, Bob K0NR