Monday, April 25, 2016

On the air!

As described in  this post  the antenna (G5RV Jr) was mounted yesterday. Today, we finished the connections (see photo), and hooked up the Ten Tec Jupiter.
Ladder line connected to coax via a juntion box, to the balun and off to the rig
I was able to hear a lot on 20 meters and some on 40.  It's tough to break in at times, and it's not always clear whether I'm not getting through or some one else is transmitting over me. Very often, you only hear one side of a conversation.  For example, I could hear someone in the Czech Republic clearly. At one point he was talking to someone in Connecticut, probably 200-300 miles from hear, but I could not here the Connecticut station.  Propagation is funny like that.

I did check into a marine net just to be sure I was getting out, and a relay station in Georgia confirmed the check-in. Later I spoke with someone in Portugal and someone else in Nicaragua.  This is cool. Tommorow morning I'll try ECARS (East Coast Amateur Radio Service) to see how I do on 40 meters.

Sunday, April 24, 2016

G5RV Jr mounted--almost all set

On the house (middle)--J-Pole for 2 meters on the left
G5RV Jr on the mast with balun and juntion box
I wanted to get my new antenna mounted and installed yesterday (23 April) so I could get on the air for Marconi Day.  Unfortunately, it rained and we decided to be safe.

Today, we go the antenna mounted on the house and ran the horizontal wires out to trees, The job went smoothly almost without issue.  The only problem was that the ladder line extended down farther than I expected. We measured, and it was 19+ft.  I went back and checked the specs, which say 16ft. I went to my 2 meter rig and raised a local ham with the same antenna, and he verified the 16ft. 

So, we took the antenna down, cut the ladder line down, desoldered the existing connection from ladder line to the SO-239, and soldered the shorter piece. Then we re-mounted the antenna and ran the horizontals out to trees in the back yard. We used ropes connected to the insulators to secure the antenna to the trees, and inserted 24" rubber bungees for strain relief.

By that time we were ready to call it a day.  For tomorrow:

  1. mount the choke balun on then house
  2. mount a waterproof juntion box next to the balun
  3. connect the balun to the ladder line inside the junction box
  4. connect coax to the balun, with a lightning arrestor  between them
  5. ground the lightning arrestor to the ground rod
  6. run the coax through the wall to the shack and connect to the HF rig
  7. figure out what I need to do for station ground
  8. get on the air!

Saturday, April 9, 2016

@MAKE: Electronics Experiment 34 started

As I mentioned in this post, I became discouraged by the need for a $20 cable to program a $3 microcontroller, particularly since Charles did not mention it it the parts list or supplies.  Also, Charles dismissed the less expensive option of using a computer's serial port.  I submitted an erratum to the publishers on this--since the book's subtitle is "Learning by Discovery" and it's a +Make: book, I though it would be more in the spirit of the book to lead the reader to discover and make. I love the book and it has provided me with great deal of learning and satisfaction, but I found this irritating.  I got over it, and now I'm on to the project.

Also, I have not found any posts or videos of these experiments, so I might as well do it.

But first, I needed a serial port. Most late-model computers do not have the old-fashioned 9-pin RS232 ports for what is normally called a DB9 connector but really is DE9. Fortunately, I hoard old computers and have a 14-year old Windows XP computer with serial ports on the motherboard.  If there had been on a PCI card rather than the motherboard, I could have swapped that out  into my regular desktop.  That left me with 2 choices:  fire up the XP machine and use that to program the PICAXE, or buy a PCI card for my desktop. Since I doing this because I'm cheap, I chose the former. PCI cards cost US$7 and up from Amazon, Newegg, and the like, and as low as $4 on eBay. If I decide to use the PICAXE for more than this project, that's an option.

The XP machine started up fine, and I was able to download and install the PICAXE software according to the book instructions (or see the PICAXE web site).  I still needed a cable.  Here again, I had two options:
1. find a serial to something cable, cut it, figure out which wires go to which pin, and connect the 3 wires I need to the PICAXE
2. make my own
Again, this is a makers' book, so I decided to make one.  A quick Google yielded this set of instructions. I bought a DB9F (as in female) connector from Amazon. Following the aforementioned instructions, I soldered 24" solid core wires to the pins I needed:
red wire to pin 2       (Rx--receive--computer in)
green wire to pin 3   (Tx--transmit--computer out) I didn't have white solid core wire
black wire to pin 5   (Ground)
I heatshrinked the connections for insulation.
I then cut a servo wire in half and kept the half with the end that I could connect to a 3-pin header on the breadboard and:

  1. slid small heatshrink on each lead
  2. slid larger heatshrink over the 3 wires to the DB9
  3. spliced the servo wires to the connector wires with solder, matching the wires by color (red/red/ black/ black, white/green) 
  4. heatshrinked the splices
  5. heatshrinked the cable
  6. snapped the cover on the serial connector end
Viola, I had a cable.  Here are some photos of the process.
Tools and supplies ready 
to make the PICAXE cable
DB9F ready to solder

soldered wires ready for heatshrink
finished cable

Next step:  configure the breadboard:
  1. add a 2.1mm barrel jack to bring unregulated 9V to the breadboard via wall wart or 9V battery
  2. add a voltage regulator circuit to deliver clean 5V to the power rails on each side of the breadboard
    .  the circuit consists of 2 100uf capacitors, 2 .1uf capacitors, and an LM7805 voltage regulator
    .  Charles' instructions are good, see schematic
  3. add the PICAXE to the breadboard and connect it to power and to the computer serial output
    .  I have a PICAXE 08M2, pin 2 is serial in and pin 7 is serial out, so the red wire (computer out) goes to pin 2 (see next bullet), and the white wire (computer in) goes to pin 7 (i,e, computer in to PICAXE out, computer our to PICAXE in)
    .  actually the red wire goes to a breadboard hole in a row between a 10K resistor that goes to a breadboard ground rail and a 22K resistor that goes to PICAXE pin 2--keeping pin 2 pulled to GND when it's not receiving
    .  PICAXE pin 1 goes to a breadboard 5V rail, and pin 8 goes to a breadboard ground rail
  4. Add an LED for testing--connected to PICAXE pin 6 and on to GND through a 330Ohm resistor
Fritzing diagram of circuit--the business on the left is the voltage regulator circuit

I had a heck of a time with the voltage circuit.  I kept getting ~9V out. I tried multiple units, and checked ny wiring.  Finally I set up a circuit like the L7805 datasheet, and it worked--exactly 5V out. I was going to submit another erratum on the book, but as I wrote ti it didn't make sense that I would get 9V out, so I rewired it in a different spot on the breadboard: 4.98V out.  I moved it back to the original location: 9V out.  I'm doing something stupid, but I'm ready to move on to the PICAXE and test my cable, so I'll put it back where it works and declare victory.

breadboarded circuit with messy wires

Now, we're ready to test the cable and circuit.

Oops.  I cannot get the XP machine to recognize the PICAXE./  I have a problem with my cable (although I don't think so, but I'll check), the circuit, my computer, or something else. It could be the breadboard--I suspect that's the problem with the voltage regulator circuit--see above.  I've done some preliminary checking, but I'm not there yet.  The book is absolutely no help on this since Charles went the non-Maker route, I'll do another post if/when I get something working.

Monday, April 4, 2016

I passed my General tonight!

Step 2 on my Ham Radio journey. Now I need to buy an HF rig and build a multi-band dipole.

Sunday, April 3, 2016

Adjustable Power Supply Problem Solved - DUH!

I have this very useful Compact Switching Power Supply - Selectable Output 3-12VDC from +Adafruit Industries.

I noticed a while back that the polarity was not what I thought--center-pin negative instead of center-pin positive.  It didn't matter a whole lot, because I used it a lot for my 5V Regulated Power Supply, and since I used my meter to check which was + and which was -, I got away with it.  Later, I found that the adapter did not work in certain applications.

I put that away for a while, but it just started to bug me again, so I Google'd the problem and was taken to the Adafruit product page (see above).  Reading the not so fine print, I saw that the device can switch from center pin positive to negative. Next question: how?

I did not find an answer, so I went to look at the device.  It comes with tips to accommodate various size receptacles.  I turns out that the wire to the adapter has + and - on each side, and the tips have CEN with an arrow. So, if you want center pin positive, mate the side marked CEN to the side marked +, and vice versa. I never noticed that before. Live and learn. Anyway, my problem is solved. I must be some kind of genius!