I’ve made no secret of my enthusiasm for Index Labs’ little QRP+ transceiver. As a fairly new ham back when they were released I couldn’t afford one. I wasn’t much more than a kid then, with mostly empty pockets.
But today, my new-to-me QRP+ shares shack space right along with my K3, while most other rigs – the FT840 and many QRP rigs – are relegated to the closet, packed away in boxes. I truly believe the QRP+ is destined for “classic status” of ham radio transceivers.
I was quite surprised when I recently learned that Index Labs is once again producing a piece of equipment for us hams. In fact, they have been for the past 5 years, but being CW-centric, it was news to me, and perhaps to you too.
Today, Index Labs’ produces a Class D AM transmitter for 80 and 160 meters. AM remains a fairly common mode on 80/160 and the “Super Senior” operates there with a potent output, no tuning required and is designed to be rack mounted. The transmitter is described here at the new Index Labs website.
With a few exchanges of emails, Bruce K7DYY (the designer of the QRP+) has me up to date on the current doin’s at Index Labs. Rather than paraphrase his summary, here with his permission, is Bruce’s description of Index Labs today and a bit of the road along the way:
The class D A M transmitters have been available for about five years now. I originally became interested in the high efficiency switchmode R F amplifier technology because it seemed elegant but relatively unused outside the commercial broadcast industry.
I was first licensed in the 1950′s when AM was still the dominant voice mode and never much cared for the sound of SSB. Until about 1990 I was CW only. Then I heard some local A M on 3870KHz and got back on “fone” with some vintage gear. I think most of the AMer’s have a similar story.
Lately I’ve been mostly on ten meters both CW and AM. Its a treat to work old friends unheard for almost a decade.
I am using a home brew SDR receiver here, built into a Super Senior transmitter. The SDR field is moving very fast and there are much sharper folks than me working on new designs. I am, however, interested in the design of EER versions of the Class D amplifier which would make possible an all mode software defined transmitter with the high efficiency.
I’m basically retired and don’t want to set up the organization that would be required for a larger scale operation. The AM transmitters seem to be a good fit at the moment. We also sell a small AM transmitter intended for use in remote villages by missionaries. This transmitter has also been purchased by the US Army for NVIS shortwave broadcast in rugged areas of Afghanistan. Finally, I make RF generators for use in Medical high power ultrasound research.
When we ended production of the QRP+, I transferred the inventory to Stan Yarema who had worked for Index Labs as a technician. He did the final test on almost all of the QRP+ transceivers. He provided service for a number of years and even built and sold a few units on a one off basis. Unfortunately, Stan has passed and the old inventory is lost. I am happy to work on the QRP+ but am limited because I don’t have spares or programming tools for the product.
After the QRP+, I contracted with SGC to develop the SG-2020 transceiver. The high efficiency transmitters followed that.
Thanks for all the info, Bruce – very interesting indeed.