Preparations are under way for the 2015 Charleston Hamfest. As usual, it's scheduled for the first Saturday in February and will be at the same location as last year in North Charleston. Door prizes, forums, VE exams, and all the normal fun things you expect at a hamfest. It's not a large hamfest, but I've enjoyed going to the last few and being able to meet other hams. I've also managed to score a few decent deals too. Looking forward to this next one.
My first attempt at building a circuit using the ugly construction technique. It's supposed to be a simple oscillator circuit using a J310 transistor.
One of the advantages of ugly construction is that if you're working from a schematic or circuit drawing, building is pretty easy. I found that soldering components to the copper clad required a bit of patience, because it's essentially a very large heat sink. Put the soldering iron on the copper clad, add solder until you get a good sized pool, leave the soldering iron in place and place the component.
For this particular circuit, Vcc is applied to the big resistor with the free lead and output is off the capacitor with the free lead. I soldered on a piece of wire to make the ground connection easier. Haven't applied power to test it out yet. Will see if it works later on.
After getting a bit of advice from some locals about soldering, I thought I'd get in a little more practice with the SA602s and the breakout boards. It was also a good excuse to see how my new glasses are for working at the bench.
To get a little more room to work, I switched to a conical tip on the soldering iron and soldered the board onto the header pins first. This makes for a pretty stable platform to work on.
Add a little bit of flux paste, tin one of the pads and then tack on the SA602 to the tinned pad.
Then flip it around and solder a pin on the other side.
Then solder the rest of the pins, making sure not to leave the soldering iron on the board too long, and waiting a few seconds between soldering each leg to let things cool down a bit. A method that I found worked pretty well was to place the soldering iron tip on the pad, apply a touch of solder to the tip, push it towards the pin, and then draw the tip back along the pad.
I soldered a total of 4 SA602s onto the breakout boards. Here's the result of about an hour's worth of practicing.
Using the same method, I soldered one of the SA604 chips onto the SOIC-16 breakout board. Although the SA604 is about the same width as the SA602, just longer, the SOIC-16 board is quite a bit larger than the SOIC-8 board. Having the header pins on the same side as the pads gives you a little less room to work with as well. Still, soldering the SA604 was pretty easy.
My attempts at cleaning off some of the residual flux left some cotton fibers behind from the swab I was using. I don't think it will affect how these work, but I'll spend some time trying to clean them off.
I think I'm getting the hang of this now. Next, learn how to use these.
The package from Dave arrived earlier this week, and the breakout boards arrived in the mail today.
The breakout boards came bubble-shrink wrapped which was a little unexpected. I thought they'd just come loose in a ziplock bag or something.
The boards are double sided, with SOIC-8/16 spacing on one side and TSSOP-8/16 spacing on the other side.
Interestingly enough, the SOIC-8 boards are half the thickness of the SOIC-16 boards, which are a regular thickness circuit board. Both have sets of holes (standard 0.1" spacing) to solder header pins to, making them convenient to use in breadboard projects. Or you could just solder wires to them if that's what the project calls for.
Off to the workbench to do some soldering. For SMD parts, these are actually pretty large, and soldering is relatively easy. First, tin one of the pads and then with tweezers, line up the IC and then heat up the tinned pad. Use the soldering iron to push the solder towards the IC pin and you're done.
I used a toothpick to apply a little bit of flux paste to the rest of the pads, and then soldered the rest of the pins. That part goes pretty easily with flux.
Pro tip #1: Don't do this with the board clamped in a vise, or if you do, don't leave the soldering iron on the board for too long. These SOIC-8 breakout boards are pretty thin and too much heat will make them melty. Oops.
Once you're done, it's time to add some header pins. This part is easy. Stick the header pins into a breadboard, put the breakout board on the header pins and solder.
Pro tip #2: In your enthusiasm to solder, don't forget to pay attention to where Pin 1 of the IC is supposed to go (ignore that bad solder job on Pin 2...easy to fix). That stripe on the SA602 should be where the 1 is printed on the board. Oops.
Got the log check results from CQ WPX 2014 in my email today. Out of my 77 QSOs, 4 of them got busted (1 incorrect call, 3 incorrect exchanges) leaving me with 73 QSOs and a score of 13510. On the other side, 3 stations copied my exchange incorrectly. Not as good compared to last year's CQ WPX. I'll just have to keep at it to get better, right?
************************** Summary *************************** 77 Claimed QSO before checking (does not include duplicates) 73 Final QSO after checking reductions 202 Claimed QSO points 193 Final QSO points 73 Claimed mults 70 Final mults 14746 Claimed score 13510 Final score -8.4% Score reduction 5.2% Error Rate based on claimed and final qso counts 0 (0.0%) duplicates (without penalty) 1 (1.3%) calls copied incorrectly 3 (3.9%) exchanges copied incorrectly 0 (0.0%) not in log 0 (0.0%) calls unique to this log only (not removed) ********************** Results By Band *********************** Band QSO QPts Mult Claimed 160M 0 0 Final 160M 0 0 Claimed 80M 0 0 Final 80M 0 0 Claimed 40M 4 4 Final 40M 4 4 Claimed 20M 2 6 Final 20M 2 6 Claimed 15M 5 11 Final 15M 3 7 Claimed 10M 66 181 Final 10M 64 176 Claimed All 77 202 73 Score 14746 Final All 73 193 70 Score 13510 *********************** Incorrect call *********************** 28625 PH 2014-03-30 1826 AB4UG 18 NY6Y 1623 correct NY6N *************** Incorrect Exchange Information *************** 21447 PH 2014-03-29 1748 AB4UG 1 NE5D 0034 correct 934 28581 PH 2014-03-30 1920 AB4UG 48 9A73P 5718 correct 5708 21235 PH 2014-03-30 2118 AB4UG 70 US5D 3354 correct 2354 ********************** Lost Multipliers ********************** 21447 PH 2014-03-29 1748 AB4UG 1 NE5D 0034 correct 934 28625 PH 2014-03-30 1826 AB4UG 18 NY6Y 1623 correct NY6N 28581 PH 2014-03-30 1920 AB4UG 48 9A73P 5718 correct 5708 ************************ Multipliers ************************* 5E5 8P5 9A5 AD5 CT1 D4 DA2 DQ8 E7 E77 EA3 EC1 ED1 ED5 EI7 EI9 F5 G5 HA1 HA6 HG1 HG7 HK1 I0 IB9 II2 II4 II9 IK2 IT9 IY1 IZ5 J42 KB3 KP4 LO5 LT7 LZ9 N9 NP2 OA4 OL4 OT5 PJ2 PW5 S50 S51 S52 S54 S55 S57 SN2 SN8 US5 VA5 VC6 VK4 VP2 WB2 WG3 WP2 WP4 WX3 XE1 XE2 YP0 YS1 YT0 YT5 YV4 ********* Stations Copying Your Exchange Incorrectly********** 28647 PH 2014-03-29 1810 EC1DBO 1452 AB4UG 0009 should be 5 28000 PH 2014-03-30 1844 US5D 2168 AB4UG 123 should be 23 28340 PH 2014-03-30 2019 YS1YS 987 AB4UG 0051 should be 61
For the circuit platform, copper clad PCB needs to be cut to an appropriate size. A circuit that only takes up 25 cm2 doesn't need to be built on a 100 cm2 board unless you're planning for future expansion.
In addition, for Manhattan style, I need some pads. A hole punch or nibbling tool is commonly used to create circular pads out of copper clad PCB. I haven't acquired any of the MeSquares that Dave/AA7EE prefers yet, nor have I added a hole punch or nibbling tool to the tools on the bench yet. I have a tin snip and a Dremel with some cutting wheels, so off I went to the workbench to experiment with what I had on hand.
I took one of the smaller pieces of copper clad PCB from the box I ordered earlier in the year and clamped it to the workbench. Using one of my utility knives, I made 3-4 cuts using a fair bit of pressure on the blade. Then I clamped it in the vise and with a bit of force, was able to break off the piece I had scored. I only scored one side, but it seemed to work pretty well. There were some sharp copper edges on the unscored side, so scoring both sides seems to be the way to go. Cutting through the copper was pretty hard on the blades, and I can see how you could go through a bunch of blades if doing it this way. Blades are pretty inexpensive though. For cutting larger pieces of PCB, this is probably the way to go.
Next were the tin snips, basically big beefy scissors. They cut through the PCB with a little bit of effort, but it's hard to make longer cuts with them because the tin snips are kind of stubby. For any cuts longer than 3-4 cm, the PCB ended up getting bent out of shape from the snips. I was able to take a strip of PCB (cut using the scoring technique) and use the snips to cut off some island-sized pieces of PCB. For small cuts, the snips worked pretty well. For large cuts, not so much.
Finally it was the Dremel's turn. With the PCB clamped to the table, the cutting wheel easily scored the PCB, but without a guide cutting a straight line takes a bit of practice. The cutting wheel cut through the PCB material pretty easily too, although the wheel got eaten up pretty quickly in the process. A good bit of dust was created too, so wearing some kind of mask would definitely be in order. I think for cutting or scoring PCBs, I'll skip the Dremel. Cutting wheels are significantly more expensive than utility knife blades, and copper and fiberglass dust probably isn't something I want floating around the workshop anyway.
For now, I'll work on practicing and refining my skills using the scoring method and the tin snips for cutting pads while I save a few dollars to get a decent hole punch. I suspect I'll end up doing a combination of hole punched and MeSquares for Manhattan islands in the future.
The panel mount potentiometer I used in the CPO was missing the nut needed to secure it into place. After determining that I needed a 1/4"-32 thread hex nut, I went scouring my Radio Shack and hardware store bins looking for some.
At Radio Shack, I found a bag of assorted hex nuts in their parts bins, with the right thread number, but none of them were smaller than 5/16". Next stop was a big box hardware store. There I found 1/4" nuts, but the finest thread they had was 28. The hex nuts they did have with a 32 thread were all #10 or smaller.
Then I went to a couple of the smaller box hardware stores. Much larger selection of nuts and bolts, but still the same problem as with the big box hardware store. Nothing with a finer thread than 1/4"-28, and nothing larger than a #10-32.
So much for instant gratification.
Thanks to a suggestion in the Google+ Ham Radio Homebrew community, I found some (Bourns H-38-1) at Mouser Electronics. Ordered 20 of them so I'd have extras in case I needed some for later. They arrived a few days ago and now my NT7S code practice oscillator is complete!
The mini-breadboard version of the NT7S code practice oscillator along with 9V battery fits perfectly into an Altoids tin (the preferred enclosure of tinkerers everywhere). This evening I spent some time wiring up the board to the jacks and power switch.
When I plugged in the headphones and my straight key, I was greeted with a continuous tone, and nothing happened when I tapped the key. Crap, I must have a short somewhere. After a bit of looking around on the board, I went back into the house to grab the schematic, and then realized I had plugged things into the wrong jacks. Swapped the headphones and key and got nice sounding tones when I tapped the key, just as expected. Works great and everything sits in the tin nice and securely. The battery slides around a tiny bit, but that's not a big deal.
Now I can bundle up my straight key and some headphones and practice wherever I want.
Spent about 4 hours playing in the North America QSO Party yesterday. Was just doing some casual tuning around, working a few stations and listening to some of the pileups. Spent most of my time tuning around 20m and 40m. Wasn't hearing much of anything up on 10m or 15m by the time I got on the radio.
While I was tuning around I also managed to find and work W1AW/5 (OK) on 20m and W100AW/4 in AL on 40m. That was the first W100AW station I had found.
My stats from last night, according to N1MM. Not a whole lot of contacts, but managed a a couple of good ones into OR and CA on 20m.
Band QSOs Pts Sec Mt2 7 15 15 11 0 14 9 9 7 0 Total 24 24 18 0 Score: 432
My 30 contacts and 360 points were good enough to get me 3rd place in the single-op low power category. Woohoo!
The 2014 SC QSO party happens during the weekend I'm back in Edmonton, so I'll be missing it this year. Next time though.