Wednesday, February 26, 2014

PFR3: Build Complete


I finally finished building the rig about 10 days ago. What an adventure! I last left off having completed Group 2 and started on a group 3. Finishing group 3 was actually pretty straightforward: wind and install a bunch of torroids, and solder in a few more components to complete the transmitter and BLT tuner. The only really tough aspect was winding the monster torroid in the transmitter. Wow--3 interleaving windings, with heavy gauge wire. More on that later...

Recycling an old photo of the board, let me assure you of one thing: random lead clippings that short pins on the programable chip can be quite annoying. I must have re soldered 10 different components before I saw the lead clipping laying there. Assemble, disassemble, reassemble, disassemble... That cost a good 20 minutes. But finally I have the main board complete!


Next, it was time to kit the box. The instructions recommend not kitting until the rig has been fully tested. In retrospect, that makes sense... sigh. Here's how it looks now that it's kitted, though!

The circuit board mounts into the top of the case, with 4 screws which seem to provide ground. That will become important shortly... Kitting everything was pretty straightforward, although I was surprised that the power tap didn't fit. I had to ream out the hole just a bit (nothing a really sharp tempered steel knife couldn't handle). Remember the comment about the external power? Well, if you look really close you'll see I connected the center pin on the external power jack to the ground (white lead), and the outside of the jack to the board's power. Yes, I'm sure you did the math and arrived at the conclusion I overlooked: this causes a short and can really heat up a battery quickly. I'm actually lucky I tested with 8 AA's at 12v rather than a larger 12v SLA battery that could have delivered a bigger punch!


The internal battery pack has sticky tape on it. It needs to be soldered to a wire. This is one of two complaints I have about the entire kit: the plastic battery case melts before the contacts are warm enough for the solder to flow. (My other complaint is about the documentation on T1 and on the monster torroid.) You can barely see it my workaround, but I ended up soldering to the spring inside the battery pack (topmost row, on the far right).


This is the rig, no decals yet. That yellow color is pretty bright--selected to help you find or avoid stepping on the rig while operating in the field.


Connection points. From left to right: power, BNC antenna, switch from BNC to balanced line, and balanced line contacts.

Well at this point I'm pretty happy. My buddy WB6YOK and wrapped up around 10:30 Saturday--another quite long evening and I know my wife will be happy when I'm done disappearing for half a day at a time. I know I will be!


Evidence: it runs on external power. It runs on internal power. It runs!

My preliminary testing was indeterminate--lower power reading on the SWR/power meter, but the antenna was poorly tuned. My Elecraft T1 tuner showed 5+ watts on 40 and 30 (the tuner has LEDs to indicate 1, 5 and 10 watts, so if the rig puts out 4.5 watts it's still not possible to know anything other than the righ puts out more than 1 watt). More testing yet to be done.

Next steps:
1. More output testing: I'd like to buy a few $0.50 50 Ohm resistors, build a dummy load, and test on a matched "line".
2. Install decals
3. Clear coat
4. I'm toying with spraying some reflective clear paint I have on various spots around the rig, to aid discoverability during nighttime
5. I would love to find some small rubber "covers" to put over the 4 switches. The rest of the through holes are actually sealed, but these 4 aren't. We swapped out cable boxes recently, but kept the old remote and it has a few rubber covers which just might work.
6. Build a balanced line and test the BLT
7. QSO! 

I broke this out a couple days ago and tuned around the bands. I was swapping back and forth between my 817 and the PFR. I got a report later from a ham in Oregon that he'd heard me call CQ on 40 but he couldn't get his rig set up in time to answer me (I QSY'ed a bit too quickly). I don't know which radio I was on at the time). 

Between the dummy load and figuring out the "recipe" for my Buddistick, I think I'll have this dialed in shortly.






Saturday, February 1, 2014

PFR3 Continues

Just an update: successfully finished group 2, all tests passed (although due to some unplanned massive remodeling at my buddy's, we couldn't get the oscilloscope out). Happy happy! So of course, I soldiered on and started group 3, which begins with a few soldered components and then a pretext. It was on the protest that I completely fell apart. The mistakes?

1. There are two "U8" markings on the board. Pins 1 and 13 are supposed to be at zero volts with the power on and the rig in straight key mode, then 1.2 volts with the key closed. Odd, I was seeing 4 volts on pin 1. Oops... Wrong U8. On the correct U8, I see 0 volts with the key opened and 2 with it closed. The group weighed and said 2 volts is fine--less important the voltage vs. the fact that the circuit is open or closed.

2. Wrong resistors. As I posted to the reflector:

* Manual R6 & R7 should be YEL/VOL/YEL
* Errata: ORG/ORG/YEL
* Installed: YEL/VOL/YEL

Which is right? The errata and the manual agree on 470k, which is YEL/VOL/YEL. Press onward.

3. While troubleshooting the voltage issues, I literally went back to the beginning and checked every single component. Oops, I installed the wrong captor C24. Desoldering, replace, resolder in C56. Oh, whoopsies... Omitted R35 (I remember now I couldn't find it on the board when I was doing stage 2, and apparently I forgot to look again).

Needless to say, I have now checked every component, looked at every solder joint, and made sure everything works. Finally, time to press forward wih L7 to finish the transmitter, so I can start the BLT.

Lessons? Go slow. Mark your questions. Pay very close attention to markings, esp on your caps. If you're tired, stop--rushing won't get it done sooner.

I cannot wait till this is done, if only to put my quirky tom-foolery behind me!


The blue cap on the right side, next to the LCD? Yah, it goes about 5 o'clock from the Dove treat (my wife is the best!). You can see the big trace, right next to the little yellow 104 cap.

See the LCD display? See the conspicuously large resistor spot traced out in white marking, much like a victim's profile at a murder scene? Yah, I don't know how I missed it either!

See the vertical chip just next to the Dove treat? That's U8. Oh, but wait--see the other U8, just below the LCD. Hello, I'm Daryl. This is my brother, Daryl and this is my other brother Daryl. No offense to the boys at Hendricks. I'm sure this is my careless reading of the manual and/or errata. I've made enough dumb mistakes to prove them the experts! And hey, every problem is an opportunity to learn!