Hendricks PFR3 - Early Build Phases

If you've read my other blog posts here, you know I'm really interested in light-weight portable operations. That's what led me to buy the Yaesu FT-817, but eventually I realized that was good for park bench or quick day-trip summit work, but it just wouldn't work for a long (3+ days) backcountry hike. 

I reviewed a ton of radios annd came to the conclusion that I needed to learn CW and move to a dedicated QRP rig. After a lot of research, I was about ready to buy an Elecraft KX-1 (http://www.elecraft.com/KX1/KX1.htm). It's highly rated, well-crafted, and quite popular. Then someone turned me onto the Hendricks PFR3 (http://www.qrpkits.com/pfr3.html). The owner of the company was at a QRP meeting listening to someone discuss backcountry QRP operation. An audience member asked what the best rig for backcountry is, and the presenter said it didn't exist yet. He proceeded to list out the features of the dream rig, and Hendricks wrote it all down. He and Steve Weber design, prototyped, and started selling the rig. Not only is it better designed for the backcountry, but it's also much cheaper (the PFR3 currently sells for $240).

About 3 years ago, in 2011, I ordered my kit. I think I sorted the kit the first day I received it, but that's about it. Life got very busy for me, I went through some ups and downs, and now three years later I'm finally building it. In researching the kit, I found there's very little available on the Internet on how to build this rig. If you can't figure it out in the manual, there aren't many resources other than the group. I decided to document the build process so others might benefit.

I am about 4 hours into the build, done with the first two stages.

Basically stage 1 is the LED and power switch. The receiver, stage 2, is most of the right half of the circuit board. The build is very straightforward, except for one item: there's a torrid with a 5-turn primary winding and a 40-turn secondary winding:

I discovered in the course of winding that there is only room for a 40-turn winding, but the manual calls for 40 turns followed by 5 turns. It was all very confusing, until I emailed the PFR3 Yahoo group. A group member clarified: the 5 turns go over the 40 turns. This is probably the least clear portion of the manual.

Another point of conversation: some people have had issues with torroid wires breaking due to the jostling of backcountry travel (shaking in the pack). After discussion with list members, I decided to drop some wax under each torroid. That's what you can see in the shot above. The torroid a are installed on what will be the bottom of the board.

It's difficult to tell, but the radio is powered up and showing 30.0 on the right three digits.

My kit arrived with every component, but unfortunately I lost one of the RF chokes. A list member sent me a replacement. In the lower left of the photo you can see the stock choke--it looks like a fat resistor, just below C42. In the middle of the photo, between the blue and green caps, is the replacement choke. I love the way amateurs help each other out all the time!

Just another random shot of the main board. The kit is very well laid out and goes together quickly--most people estimate 6-8 hours to build. I'm probably 4 hours in, but a lot more considering the head scratching I went through over that torroid!

The manual lists a modification to stage two which address noise in the receiver. It requires two caps to be added--one in a through-hole, and on jumping a couple pins on another component. I was in Seattle on business so I grabbed the components at Frys and installed them with Group 2.

Next step is to dial in the receiver, then build out stage 3 (transceiver). Finally, prep the case and finalize the install.