Electronics

Rescue the Easter Bunny – Ham Radio Fox Hunting for Beginners

4th April

2013

written by Todd Harrison

This video covers beginner’s tips and tricks on ham radio fox hunting and includes details to build a DIY yagi antenna.

In the last 3 minutes of the video 4 young kids go out to rescue the poor lost Easter Bunny and his basket of candy. The Easter bunny is wearing a radio transmitter so this fox hunt becomes an Easter Sunday bunny rescue. The boys did great and had no problem learning to use a ham radio and directional antenna to locate the lost bunny.

Our fox, aka bunny, was the Byonics micro-Fox 15 which is a 15mw transmitter in the 2 meter ham band. This fox is sold by a company local to my area on www.Byonics.com I will do a review and tutorial of the micro-Fox 15 in a follow up video.

Where to buy the fox: Byonics http://www.byonics.com/mf

How to build this yagi antenna: Dupage Amateur Radio Club http://www.w9dup.org/club_projects_pdfs/fox_hunt_antenna_2010_apr.pdf

Link to tape measure yagi: http://theleggios.net/wb2hol/projects/rdf/tape_bm.htm

Material for yagi antenna that I build in the video:
6 feet schedule 40 PVC
1 schedule 40 PVC Tee
2 tie wires
6 feet RG58 coax cable
2 21 inch long brash rods 3/16 diameter rod
1 35 inch long aluminum 3/16 diameter rod
1 40 inch long aluminum 3/16 diameter rod

Photo Gallery

CLICK PHOTO for gallery view and click a SECOND time for hi-resolution image. Click thumbnails on lower right and lower left of gallery to navigate gallery photos.

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Electronics, Ham Radio

Arduino Frequency Display for Kenwood TS-520S HF ham radio PART 1

7th February

2013

written by Todd Harrison

This is (PART 1). Links to all parts: (PART 1), (PART 2), (PART 3), (PART 4), (PART 5)

A friend has a Kenwood TS-520S HF (high frequency) ham radio. He does not have the optional DG-5 frequency display and calibrating the dials between bands is not much fun. He gave me some information about the DG-5 and through some review I believe I can make a substitute for the DG-5 using an Arduino, LCD Shield and hand full of chips.

He could buy a DG-5 but that would cost more than he paid for the whole rig and it really is not necessary to use the radio, just more convenient.

This is part one so watch this video which covers my idea and some pre-testing. All looks good so far and I’m already working on part two.

I got the Arduino frequency library from this site:

http://interface.khm.de/index.php/lab/experiments/arduino-frequency-counter-library/

In the video I just use the library example scketch so I have no code to share in part 1.

I also followed some circuit examples shared at these two sites which both built HF frequency counts and were great sources of information to help me on my way to building an Arduino derivative HF frequency counter. My counter is for a single custom application and so doesn’t incorporate all the features these other builds include.

http://aade.com/DFD2inst/DFD2inst.htm

http://www.avr-asm-tutorial.net/avr_en/fcount/fcount_m8.html

Arduino website to get development software and sample code:

http://arduino.cc

http://playground.arduino.cc/

I got my Arduino and LCD shield from Adafruit.com

http://www.adafruit.com/products/50

http://www.adafruit.com/products/714

Some chips and data sheets I have used in part one:

CD74HCT93

Used in 3 bit binary ripple counter mode for divide by 8 with input at CP1 and output at Q3

http://www.ti.com/lit/ds/symlink/cd74hc93.pdf

CD74HC153

Dual 4 to 1 Line Selector/Multiplexer

http://www.ti.com/lit/ds/symlink/cd74hc153.pdf

Here are some photos of what I covered in part one. CLICK ON PHOTO for hi-resolution image.

My Arduino I will be using to count freq and do some line select inputs and math.

RGB back light despaly by Adafruit.com for my freq display

RGB back light dispaly by Adafruit.com for my freq display

This are the freq I measured coming out of the three RCA jacks on the back of the TS-520S ham radio. I need to count these freq and do some math to know the freq the radio is using.

These are the freq I measured coming out of the three RCA jacks on the back of the TS-520S ham radio. I need to count these freq and do some math to know the freq the radio is using.

I can measure the VFO and BFO with the Arduino directly but not the HFO. I will need to use a prescaler to divide the HFO by 8 before it gets to the Arduino.

The library I’m using is coded to use just the one input so my plan is to use a line select chip to multiplex the three signals to this single Arduino input.

For a test of the Arduino measuring the BFO freq level directly I just created a nice clean 0-5v square wave at 3.395MHz on my freq generator and put it into the input pin the Arduino is coded to use per the library. As you can see it can count this just fine.

I use my leader to valdiate the Arduino is correct.

I use my leader to validate the Arduino is correct.

I then double check the Leader and Arduino with my HP counter. All instruments agree to within a 1Hz. WOW. Nice.

I then double check the Leader and Arduino with my HP counter. All instruments agree to within 1Hz. WOW. Nice.

For the HFO I have to use a MFJ-259 SWR analyzer to generate the higher 10 to 40 MHz signal for testing the Arduino.

For the HFO I have to use a MFJ-259 SWR antenna analyzer to generate the higher 10 to 40 MHz signal for testing the Arduino.

However this instrument only outputs a 1 to 1.5V peak wave which is too low of a voltage level for the Arduino to count.

However this instrument only outputs a 1 to 1.1V peak wave which is too low of a voltage level for the Arduino to count.

Even at the 5MHz level the Arduino only outputs 0 back to the serial monitor on the PC. It could measure the 5MHz but not at the low voltage levels. I will need to build an amplifier before the Arduino can use the SWR antenna analyzer output for testing.

On to testing the divide by 8 prescaler. I output a 4MHz square wave 0-5 v from my function generator.

I then pipe this 4MHz into the 4 bit binary ripple counter in 3 bit mode. It should output a clean divide by 8 signal at 500KHz

My Leader records the 4MHz in and the HP records the 500KHz out of the chip so we can compare to the Arduino freq count output.

The Arduino reads spot on with the HP at 499,997Hz

This just to show that the Arduino can then do some math to multiply what it counted back to 4MHz with (frq*8) code.

This just shows that the Arduino can then do some math to multiply what it counted back to 4MHz with (frq*8) code.

Close up showing the Leader which is counting the source at 4Mhz agrees with the Arduino's math down to 1Hz. NICE!

This shows the Leader which is counting the source at 4Mhz agrees with the Arduino’s math to within +/-4Hz. NICE! I only need to be within 100Hz in the end for this to work as a ham radio freq display

That is it for part one. Part two will start with signal amplification then multiplexing and more. I'm not sure how may parts this will end up being but it is fun to share and I hope fun to follow along.

That is it for part one. Part two will start with signal amplification then multiplexing and more. I’m not sure how many parts this will end up being but it is fun to share and I hope fun to follow along.

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Electronics, Ham Radio

My Mad Mad Hobby Life or Shave and a haircut, two bits

27th January

2013

written by Todd Harrison

This is part one of my crazy list of hobby projects that I don’t ever get enough time to work on. I need a 2nd life just to do all the projects I find interesting.

This is part two (It is not that entertaining)

I hope you enjoy the video and photo gallery below. CLICK ON PHOTO for hi-resolution image.

Unshaven

A little trim around the edges.

Funny shave 1

Funny shave 2

Funny shave 3

Funny shave 4

Funny shave 5

Kind of a short Fu Manchu

I call this a cop moustache but might be called a major.

The toothbrush moustache (also called Hitler moustache, Charlie Chaplin moustache, 1/3 moustache, philtrum moustache, the postage stamp, or soul (mou)stache)