So as promised, here is a more comprehensive review of how I built and used the PFR-3 for the first time.
I saw the first news about the PFR-3 earlier this year but had to wait until mid May before I could order one… which I duly did the day the on-line order form opened on www.qrpkits.com. I had to wait a while and my kit arrived in mid June.
The reason I chose it is because of its “all in one” design. I have an ATS-3B kit that I was about to build but this seemed to be better for what I wanted i.e. A radio to take on SOTA activations and one that could travel with me pretty much wherever I want.
The “interesting” specifications for me are as follows:
5W output on 40, 30 and 20m
Built in tuner (coax and balanced inputs)
Built in absorptive SWR bridge (don’t blow your finals when tuning)
300 Hz narrow filter
Built in battery supply if needed.
This is not an exhaustive list of the features but they were the ones that I particularly liked.
All this for $220 including delivery to the UK. This worked out at £117 (€150) delivered!
Note that kits are exempt from import duty to the EU but you MAY get charged VAT… sometimes you get charged… sometimes not. It depends on how vigilant the post office is being.
I started building it a couple of weeks ago to be ready for my SM trip next week. I had to wait because the firmware was updated due to some minor bugs and my kit had the initial firmware on the chip. The vendors assured everyone their chips could be reprogrammed free of charge if they were sent back to the designer. I contacted him - Steve Weber, KD1JV and asked if he could rush the new one back when he had received the old one. He did better than that; he sent me a new one, trusting that I would put the old one in the post… great service!
Note that I’m not a natural builder and the times given below are genuine for me working at a careful, steady pace. I’m sure others could go quicker.
The build started well. Group 1 is related to the microprocessor and display. Note that the SMD’s were already mounted on the board… no need to worry about them. Testing this group is basically looking for a working display. Then you listen for the processor radiating somewhere near 2.115Mhz on a receiver.
I spent about 3 hours on preparation and group 1 build.
Group 2, the receiver, was also straightforward to assemble although there are couple of toroids to wind with 40 turns each. I had never wound any before and was a little nervous but it went fine. Actually I quite enjoyed it!
The smoke test for group 2 is all about reference frequency alignment and filter and BFO adjustment. I don’t have a frequency counter or an oscilloscope. But you probably have a receiver for 10MHz (WWV) and a PC where you can install spectrogram, then you will find it’s dead easy to get it aligned very well. I think I ended up within about 20Hz of where I should have been on 40m with filter centred and BFO aligned.
I spent about 3 hours on build and alignment for group 2.
Group 3, transmitter, was also easy with just 1 small toroid to wind. An easy test and then I moved on to Group 4, low pass filters, which required winding 6 toroids. Again it was easy and quite therapeutic listening to the radio.
These 2 groups took me about 4 hours altogether.
Group 5, the SWR bridge and tuner, is the last board construction step. This went fine although I wound L3, the large tuner toroid, the wrong way round. I had to unwind it and start again,. I had become rather lax and didn’t read the instructions properly. By the time I had rewound it, loads of time had passed and it was getting rather late so I rushed mounting it. I knew that I hadn’t prepared the leads well and I could see a “dry joint” or two.
So the following day I unsoldered L3, rewound it and adjusted the number of turns with the latest recommendations. This time it soldered in just fine and I fired the board up for a first power check. I was pleased to see about 5.5W on 40m and 30m and about 4.5W on 20m. I adjusted the power up to 5W on 20m by spacing the coils on a couple of toroids.
I spent about 4 hours on this group although I wasted a lot of time. It should have taken 2 hours or less.
The final step was boxing it all up. The hardware supplied with the kit is fine and, although some might think the yellow box is odd, I love it!
Boxing it and tidying it up took me about 2 hours
So today I finally started trying things out to see what it’s capable of. Now one thing to note is the fact that the tuner will not match everything. It really has been optimised for the 44ft Norcal doublet. I tried it on my G5RV at home and it would tune on 30 and 20m but not 40m.
When out this afternoon I was using my “double Norcal doublet” 88ft long and that tuned up just fine on all bands. I would imagine that a 44ft one would be fine as well. You can also use the tuner to tune coax fed antennas and long wire plus counterpoise as well.
Tuning is easy. You put the switch in the tune position, send a few dashs and try to dim the LED by moving the tune and load knobs. The LED is actually VERY bright… it was no problem in the sun and I think it would ruin your night vision! The tuning is quite sharp but it will go out completely when there is a perfect match. (I checked it with a dummy load beforehand so I could see how dim it got)
Tuning frequency with the buttons takes some getting used to. It moves 50Hz with each click and faster when you hold them down. You shouldn’t tune too fast as the filter bandwidth is only 300Hz so you could easily miss someone.
Changing bands requires that you move 2 switches. This might seem like a pain but it’s not and I can’t believe anyone would forget this. You also have to peak the receiver but this is also quick.
When I used the PFR-3 this afternoon for activation on G/CE-005, I just used the internal 8 x AA batteries (which were not fresh) so I would imagine I was probably radiating about 4W or so. I might carry a small SLAB and just use the internal batteries for emergency back up.
Stations calling were easy to copy although it took me a while to get used to the lack of AGC and remember that I could turn up the volume if a weak station was quiet.
I didn’t set up the memory keyer and it took me a few QSO’s to get used to the way the built-in Iambic keyer behaved (did you notice!). It “feels” different to the one on the 706. I was using Iambic mode A but you have the choice of mode B as well. I was running it at 20wpm (indicated on the display).
I’m very pleased with the rig on the first activation and, by the way, the all up weight of the rig with batteries loaded is 725g. Just take along a key, headphones and a light antenna and you are in business!
You will find all the build photos in my Flickr photostream here:
I will definitely take this rig to SM for the IOTA contest (QRP section) from EU-037 as SM7ZAU and, hopefully, the activation of Kullaberg SM/SE-001 on Friday (weather and travel schedule permitting) as SM7ZAU/P.
If anyone has any specific questions or comments on the build or this afternoon’s performance, I would be very happy to hear from you.
73 Marc G0AZS